General information about building materials.
In the process of construction, operation and repair of buildings and structures, building products and structures from which they are erected are subjected to various physical, mechanical, physical and technological influences. A hydraulic engineer is required to competently choose the right material, product or structure that has sufficient resistance, reliability and durability for specific conditions.
LECTURE #1
General information about building materials and their basic properties.
Building materials and products used in the construction, reconstruction and repair of various buildings and structures are divided into natural and artificial, which in turn are divided into two main categories: the first category includes: brick, concrete, cement, timber, etc. They are used during construction various elements buildings (walls, ceilings, coverings, floors). To the second category - special purpose: waterproofing, heat-insulating, acoustic, etc. The main types of building materials and products are: natural stone building materials from them; binders, inorganic and organic; forest materials and products from them; hardware. Depending on the purpose, conditions of construction and operation of buildings and structures, appropriate building materials are selected that have certain qualities and protective properties from exposure to various external environments. Given these features, any building material must have certain construction and technical properties. For example, the material for the outer walls of buildings should have the lowest thermal conductivity with sufficient strength to protect the room from the outside cold; the material of the construction for irrigation and drainage purposes - water tightness and resistance to alternate moistening and drying; expensive coating material (asphalt, concrete) must have sufficient strength and low abrasion to withstand traffic loads. When classifying materials and products, it must be remembered that they must have good properties and qualities.Property- the characteristic of the material, which manifests itself in the process of its processing, application or operation. Quality- a set of material properties that determine its ability to meet certain requirements in accordance with its purpose. The properties of building materials and products are classified into three main groups: physical, mechanical, chemical, technological and etc . To chemical include the ability of materials to resist the action of a chemically aggressive environment, causing exchange reactions in them leading to the destruction of materials, a change in their original properties: solubility, corrosion resistance, resistance to decay, hardening. Physical Properties: average, bulk, true and relative density; porosity, humidity, moisture loss, thermal conductivity. Mechanical properties : ultimate strength in compression, tension, bending, shear, elasticity, plasticity, rigidity, hardness. Technological properties: workability, heat resistance, melting, hardening and drying speed.
Physical and chemical properties of materials.
Average densityρ 0 mass m unit volume V 1 absolutely dry material in its natural state; it is expressed in g/cm 3 , kg/l, kg/m 3 . Bulk density of bulk materialsρ n mass m unit volume V n dried loose material; it is expressed in g/cm 3 , kg/l, kg/m 3 . True Densityρ mass m unit volume V material in an absolutely dense state; it is expressed in g/cm 3 , kg/l, kg/m 3 . Relative densityρ(%) is the degree of filling of the volume of the material with a solid substance; it is characterized by the ratio of the total volume of the solid V in the material to the entire volume of the material V 1 or the ratio of the average density of the material ρ 0 to its true density ρ: , or
. PorosityP
- the degree of filling of the volume of the material with pores, voids, gas-air inclusions: for solid materials: 
, for bulk: 
Hygroscopicity- the ability of the material to absorb moisture from environment and thicken it in the mass of material. HumidityW
(%)
- the ratio of the mass of water in the material m in =
m 1
-
m
to its mass in a completely dry state m: 
Water absorptionAT
- characterizes the ability of the material in contact with water to absorb and retain it in its mass. Distinguish mass AT m and volumetric AT about water absorption. Mass water absorption(%)
- the ratio of the mass of water absorbed by the material m in to the mass of the material in a completely dry state m: 
Volumetric water absorption(%)
- the ratio of the volume of water absorbed by the material m in /
ρ
in
to its volume in the water-saturated state V 2
: 
Moisture return- the ability of the material to give off moisture. Mechanical properties of materials.
Compressive strengthR – breaking load ratio P(N) to the cross-sectional area of the sample F(see 2). It depends on the size of the sample, the rate of application of the load, the shape of the sample, and humidity. Tensile StrengthR R - breaking load ratio R to the original cross-sectional area of the sample F. Flexural strengthR and - determined on specially made beams. Rigidity- the property of a material to give small elastic deformations. Hardness- the ability of a material (metal, concrete, wood) to resist penetration into it under a constant load of a steel ball.natural stone materials.
Classification and main types rocks.
As natural stone materials in construction, rocks are used that have the necessary building properties. According to the geological classification, rocks are divided into three types: 1) igneous (primary), 2) sedimentary (secondary) and 3) metamorphic (modified). 1) Igneous (primary) rocks formed when molten magma that rose from the depths of the earth cooled. The structures and properties of igneous rocks largely depend on the cooling conditions of the magma, and therefore these rocks are divided into deep and poured out. Deep rocks formed during the slow cooling of magma in the depths of the earth's crust during high pressures overlying layers of the earth, which contributed to the formation of rocks with a dense granular-crystalline structure, high and medium density, high compressive strength. These rocks have low water absorption and high frost resistance. These rocks include granite, syenite, diorite, gabbro, etc. outflowing rocks were formed during the release of magma to the earth's surface during relatively rapid and uneven cooling. The most common outflowing rocks are porphyry, diabase, basalt, and loose volcanic rocks. 2) Sedimentary (secondary) rocks formed from primary (igneous) rocks under the influence of temperature changes, solar radiation, the action of water, atmospheric gases etc. In this regard, sedimentary rocks are divided into clastic (loose), chemical and organogenic. to clastic loose rocks include gravel, crushed stone, sand, clay. Chemical sedimentary rocks: limestone, dolomite, gypsum. Organogenic rocks: shell limestone, diatomite, chalk. 3) Metamorphic (modified) rocks formed from igneous and sedimentary rocks under the influence of high temperatures and pressures in the process of raising and lowering the earth's crust. These include shale, marble, quartzite.
Hydration (inorganic) binders.
Hydraulic lime is a slow setting and slow hardening substance. It is used for the preparation of mortars, low-grade concretes, lightweight concretes, in the production of mixed concretes. Portland cement- hydraulic binder, obtained by joint, fine grinding of clinker and two-water gypsum. clinker- the product of firing before sintering (at t> 1480 ° C) of a homogeneous, natural or raw mixture of limestone or gypsum of a certain composition. The raw mass is fired in rotary kilns. Portland cement is used as a binder in the preparation of cement mortars and concretes. Slag Portland cement- in its composition it has a hydraulic additive in the form of granulated, blast-furnace or electrothermophosphorus slag, cooled according to a special regime. It is obtained by joint grinding of Portland cement clinker (up to 3.5%), slag (20 ... 80%), and gypsum stone (up to 3.5%). Portland slag cement has a slow increase in strength in the initial stages of hardening, however, in the future, the rate of increase in strength increases. It is sensitive to ambient temperature, resistant to soft sulfate waters, and has reduced frost resistance. carbonate portland cement obtained by joint grinding of cement clinker with 30% limestone. It has reduced heat release during hardening, increased resistance.
Building solutions.
General information.
Mortars are carefully dosed fine-grained mixtures consisting of an inorganic binder (cement, lime, gypsum, clay), fine aggregate (sand, crushed slag), water and, if necessary, additives (inorganic or organic). In a freshly prepared state, they can be laid on the base in a thin layer, filling all its irregularities. They do not exfoliate, seize, harden and gain strength, turning into a stone-like material. Mortars are used in masonry, finishing, repair and other works. They are classified according to medium density: heavy with medium ρ \u003d 1500 kg / m 3, light with medium ρ <1500кг/м 3 . По назначению: гидроизоляционные, талтопогенные, инъекционные, кладочные, отделочные и др. Растворы приготовленные на одном виде вяжущего вещества, называют простыми, из нескольких вяжущих веществ смешанными (цементно-известковый). Строительные растворы приготовленные на воздушных вяжущих, называют воздушными (глиняные, известковые, гипсовые). Состав растворов выражают двумя (простые 1:4) или тремя (смешанные 1:0,5:4) числами, показывающие объёмное соотношение количества вяжущего и мелкого заполнителя. В смешанных растворах первое число выражает объёмную часть основного вяжущего вещества, второе – объёмную часть дополнительного вяжущего вещества по отношению к основному. В зависимости от количества вяжущего вещества и мелкого заполнителя растворные смеси подразделяют на fatty- containing a large amount of astringent. Normal- with the usual content of astringent. Skinny- containing a relatively small amount of binder (low-plasticity). For the preparation of mortars, it is better to use sand with grains that have a rough surface. Sand protects the solution from cracking during hardening, reduces its cost. Waterproofing solutions (waterproof)- cement mortars with a composition of 1: 1 - 1: 3.5 (usually fatty), to which ceresite, sodium amominate, calcium nitrate, ferric chloride, bituminous emulsion are added. ceresite- represents a mass of white or yellow color, obtained from anilic acid, lime, ammonia. Ceresite fills small pores, increases the density of the solution, making it waterproof. For the manufacture of waterproofing solutions, Portland cement, sulfate-resistant Portland cement, is used. Sand is used as a fine aggregate in waterproofing solutions. Masonry mortars- used when laying stone walls, underground structures. They are cement-lime, cement-clay, lime and cement. Finishing (plaster) solutions- subdivided by purpose into external and internal, by location in the plaster into preparatory and finishing. Acoustic solutions- light mortars with good sound insulation. These solutions are prepared from Portland cement, Portland slag cement, lime, gypsum, and other binders using light porous materials (pumice, perlite, expanded clay, slag) as fillers.Ordinary concrete on hydration binders.
In addition to partial residues, complete residues are found. BUT, which are defined as the sum of all private residues in % on the overlying sieves + private residue on this sieve:
Based on the results of sand sifting, its fineness modulus is determined:
where BUT– total residues on sieves, %. According to the fineness modulus, coarse sand is distinguished ( M to >2,5
), average ( M to =2,5…2,0
), small ( M to =2,0…1,5
), very small ( M to =1,5…1,0
) . By plotting the sand sifting curve on the graph of the permissible grain composition, the suitability of sand for the manufacture of concrete mixture is determined. 1 - laboratory screening curve for sand and coarse aggregate, respectively. Of great importance in the selection of sand for concrete mix is its intergranular voidness. V P (%)
, which is determined by the formula: ρ
n.p.- bulk density of sand, g / cm 3; ρ
– true sand density, g/cm 3 ; In good sands, the intergranular voidness is 30...38%, in uneven-grained sands it is 40...42%. coarse aggregate. Natural or artificial crushed stone or gravel with a grain size of 5 to 70 mm is used as a large aggregate of concrete mix. To ensure the optimal grain composition, coarse aggregate is divided into fractions depending on the largest grain size. D max.; At D naib=20mm coarse aggregate has two fractions: from 5 to 10 mm and from 10 to 20 mm; At D naib=40mm - three fractions: from 5 to 10 mm; from 10 to 20 mm and from 20 to 40 mm; At D naib=70mm - four fractions: from 5 to 10 mm; from 10 to 20 mm; from 20 to 40 mm; from 40 to 70 mm. The index of intergranular voidness of coarse aggregate has a great influence on the consumption of cement in the preparation of a concrete mixture. V p.kr (%),
which is determined with an accuracy of 0.01% by the formula: ρ
n.cr is the average bulk density of coarse aggregate. ρ
k.kus is the average density of coarse aggregate in a piece. The index of intergranular voidness should be minimal. Its smaller value can be obtained by selecting the optimal grain composition of coarse aggregate. The grain composition of the coarse aggregate is determined by sifting the dried coarse aggregate with a set of sieves with holes of size 70; 40; twenty; ten; 5 mm, taking into account its maximum D naib and minimum D hire fineness. rubble- usually artificial loose material with unrounded rough grains, obtained by crushing rocks, large natural gravel or artificial stones. To determine the suitability of crushed stone, it is necessary to know: the true density of the rock, the average density of the crushed stone, the average bulk density of the crushed stone, the relative intergranular voidness and the moisture content of the crushed stone Gravel- loose natural material with rounded, smooth grains, formed in the process of physical weathering of rocks. The same requirements apply to gravel as to crushed stone. Additives. The introduction of additives into cement, mortar or concrete mixture is simple and convenient way improving the quality of cement, mortar and concrete. Allowing to significantly improve not only their properties but also technical and operational indicators. Additives are used in the production of binders, the preparation of mortars and concrete mixes. They allow you to change the quality of the concrete mixture and the concrete itself; affecting workability, mechanical strength, frost resistance, crack resistance, water resistance, water resistance, thermal conductivity, environmental resistance. The main properties of the concrete mix include cohesion (the ability to maintain its uniformity without delamination during transportation, unloading), homogeneity, water-holding capacity (plays a significant role in the formation of the concrete structure, acquiring strength, water resistance and frost resistance), workability (its ability to quickly with a minimum energy consumption to acquire the required configuration and density, ensuring the production of high-density concrete). The freshly prepared concrete mixture must be well mixed (homogeneous), suitable for transportation to the place of laying, taking into account weather conditions, while resisting water separation and separation. The task of designing and selecting the composition of the concrete mix includes the selection of the necessary materials (binder and other components) and the establishment of their optimal quantitative ratio. On the basis of this, a concrete mix with specified technological properties is obtained, as well as the most economical and durable concrete that meets design and operational requirements with the lowest possible consumption of cement. Consequently, the concrete mixture of the designed composition must have non-separation, the necessary workability, cohesion, and the concrete made from this mixture must have the required properties: density, strength, frost resistance, water resistance. The simplest way to design the composition of a concrete mixture is the calculation by absolute volumes, which is based on the fact that the prepared, laid and compacted concrete mixture should not have voids. The design of the composition is carried out using the current recommendations and normative documents in this order: And the concrete yield:
Concrete output ratio β should be within 0.55 ... 0.75. The designed composition of the concrete mix is specified on test batches. They also check the mobility of the concrete mixture. If the mobility of the concrete mixture is greater than required, then water and cement are added in small portions to the mixture, while maintaining a constant ratio V/C until the mobility of the concrete mix becomes equal to the specified one. If the mobility is greater than the specified one, then sand and coarse aggregate are added to it (in portions of 5% of the original amount), while maintaining the selected ratio V/C. Based on the results of trial batches, adjustments are made to the designed composition of the concrete mixture, given that under production conditions the sand and coarse aggregate used are in a wet state, and coarse aggregate has some water absorption, consumption ( l Document
Important measures for the further improvement of water management construction are the improvement of the quality of work, the maximum reduction in construction time and cost reduction, which is closely related to the rational use of
The bowels of the Sakhalin region contain significant reserves of various types of building materials. Explored reserves and predicted resources of igneous, metamorphic and sedimentary rocks suitable for use as
The basis for the industrialization of the construction of agricultural facilities is the expansion of the use of prefabricated elements of buildings and structures, the comprehensive mechanization of all construction and installation processes and the use of a flow organization of work.
General information about building materials.
In the process of construction, operation and repair of buildings and structures, building products and structures from which they are erected are subjected to various physical, mechanical, physical and technological influences. A hydraulic engineer is required to competently choose the right material, product or structure that has sufficient resistance, reliability and durability for specific conditions.
LECTURE #1
General information about building materials and their basic properties.
Building materials and products used in the construction, reconstruction and repair of various buildings and structures are divided into natural and artificial, which in turn are divided into two main categories: the first category includes: brick, concrete, cement, timber, etc. They are used during the construction of various elements of buildings (walls, ceilings, coatings, floors). To the second category - special purpose: waterproofing, heat-insulating, acoustic, etc.
The main types of building materials and products are: natural stone building materials from them; binders, inorganic and organic; forest materials and products from them; hardware. Depending on the purpose, conditions of construction and operation of buildings and structures, appropriate building materials are selected that have certain qualities and protective properties from exposure to various external environments. Given these features, any building material must have certain construction and technical properties. For example, the material for the outer walls of buildings should have the lowest thermal conductivity with sufficient strength to protect the room from the outside cold; the material of the construction for irrigation and drainage purposes - water tightness and resistance to alternate moistening and drying; expensive pavement material (asphalt, concrete) must have sufficient strength and low abrasion to withstand traffic loads.
When classifying materials and products, it must be remembered that they must have good properties and qualities.
Property- the characteristic of the material, which manifests itself in the process of its processing, application or operation.
Quality- a set of material properties that determine its ability to meet certain requirements in accordance with its purpose.
The properties of building materials and products are classified into three main groups: physical, mechanical, chemical, technological and etc .
To chemical include the ability of materials to resist the action of a chemically aggressive environment, causing exchange reactions in them leading to the destruction of materials, a change in their original properties: solubility, corrosion resistance, resistance to decay, hardening.
Physical Properties: average, bulk, true and relative density; porosity, humidity, moisture loss, thermal conductivity.
Mechanical properties: ultimate strength in compression, tension, bending, shear, elasticity, plasticity, rigidity, hardness.
Technological properties: workability, heat resistance, melting, hardening and drying speed.
Physical and chemical properties of materials.
Average density ρ 0 mass m unit volume V 1 absolutely dry material in its natural state; it is expressed in g/cm 3 , kg/l, kg/m 3 .
Bulk density of bulk materials ρ n mass m unit volume V n dried loose material; it is expressed in g/cm 3 , kg/l, kg/m 3 .
True Density ρ mass m unit volume V material in an absolutely dense state; it is expressed in g/cm 3 , kg/l, kg/m 3 .
Relative density ρ(%) is the degree of filling of the volume of the material with a solid substance; it is characterized by the ratio of the total volume of the solid V in the material to the entire volume of the material V 1 or the ratio of the average density of the material ρ 0 to its true density ρ: , or.
Porosity P - the degree of filling of the volume of the material with pores, voids, gas-air inclusions:
for solid materials: , for loose materials:
Hygroscopicity- the ability of the material to absorb moisture from the environment and thicken it in the mass of the material.
HumidityW (%) - the ratio of the mass of water in the material min= m 1 - m to its mass in a completely dry state m:
Water absorption AT - characterizes the ability of the material in contact with water to absorb and retain it in its mass. Distinguish mass In m and volumetric In about water absorption.
Mass water absorption (%) - the ratio of the mass of water absorbed by the material min to the mass of the material in a completely dry state m:
Volumetric water absorption (%) - the ratio of the volume of water absorbed by the material min/ ρ in to its volume in the water-saturated state V 2 :
Moisture return- the ability of the material to give off moisture.
Mechanical properties of materials.
Compressive strengthR – breaking load ratio P(N) to the cross-sectional area of the sample F(see 2). It depends on the size of the sample, the rate of application of the load, the shape of the sample, and humidity.
Tensile StrengthR R - breaking load ratio R to the original cross-sectional area of the sample F.
Flexural strengthR and - determined on specially made beams.
Rigidity- the property of a material to give small elastic deformations.
Hardness- the ability of a material (metal, concrete, wood) to resist penetration into it under a constant load of a steel ball.
natural stone materials.
Classification and main types of rocks.
As natural stone materials in construction, rocks are used that have the necessary building properties.
According to the geological classification, rocks are divided into three types:
1) igneous (primary), 2) sedimentary (secondary) and 3) metamorphic (modified).
1) Igneous (primary) rocks formed when molten magma that rose from the depths of the earth cooled. The structures and properties of igneous rocks largely depend on the cooling conditions of the magma, and therefore these rocks are divided into deep and poured out.
Deep rocks were formed during the slow cooling of magma in the depths of the earth's crust at high pressures of the overlying layers of the earth, which contributed to the formation of rocks with a dense granular-crystalline structure, high and medium density, and high compressive strength. These rocks have low water absorption and high frost resistance. These rocks include granite, syenite, diorite, gabbro, etc.
outflowing rocks were formed during the release of magma to the earth's surface during relatively rapid and uneven cooling. The most common outflowing rocks are porphyry, diabase, basalt, and loose volcanic rocks.
2) Sedimentary (secondary) rocks formed from primary (igneous) rocks under the influence of temperature changes, solar radiation, the action of water, atmospheric gases, etc. In this regard, sedimentary rocks are divided into clastic (loose), chemical and organogenic.
to clastic loose rocks include gravel, crushed stone, sand, clay.
Chemical sedimentary rocks: limestone, dolomite, gypsum.
Organogenic rocks: shell limestone, diatomite, chalk.
3) Metamorphic (modified) rocks formed from igneous and sedimentary rocks under the influence of high temperatures and pressures in the process of raising and lowering the earth's crust. These include shale, marble, quartzite.
Natural stone materials and products are obtained by processing rocks.
By way of getting stone materials are subdivided into fragmented stone (but) - they are mined in an explosive way; coarsely chopped stone - obtained by splitting without processing; crushed - obtained by crushing (crushed stone, artificial sand); sorted stone (cobblestone, gravel).
Stone materials in form are divided into irregularly shaped stones (crushed stone, gravel) and piece products that have the correct shape (slabs, blocks).
rubble- acute-angled pieces of rocks ranging in size from 5 to 70 mm, obtained by mechanical or natural crushing of buta (ragged stone) or natural stones. It is used as a coarse aggregate for the preparation of concrete mixes, foundations.
Gravel- rounded pieces of rocks ranging in size from 5 to 120 mm, also used for the preparation of artificial gravel-crushed stone mixtures.
- a loose mixture of rock grains ranging in size from 0.14 to 5 mm. It is usually formed as a result of weathering of rocks, but can also be obtained artificially - by crushing gravel, crushed stone, and pieces of rocks.
Hydration (inorganic) binders.
1. Air binders.
2. Hydraulic binders.
Hydration (inorganic) binders called finely divided materials (powders), which, when mixed with water, form a plastic dough, capable of hardening in the process of chemical interaction with it, gaining strength, while binding the aggregates introduced into it into a single monolith, usually stone materials (sand, gravel, crushed stone) , thereby forming an artificial stone such as sandstone, conglomerate.
Hydrostatic binders are divided into air(hardening and gaining strength only in air) and hydraulic(hardening in a humid, airy environment and under water).
Building air limeCaO - a product of moderate firing at 900-1300 ° C of natural carbonate rocks CaCO3 containing up to 8% clay impurities (limestone, dolomite, chalk, etc.). Roasting is carried out in shafts and rotary kilns. The most widely used shaft furnaces. During the firing of limestone in a shaft kiln, the material moving in the shaft from top to bottom passes through three zones in succession: a heating zone (drying of raw materials and release of volatile substances), a firing zone (decomposition of substances) and a cooling zone. In the heating zone limestone is heated up to 900°C due to the heat coming from the firing zone from the gaseous products of combustion. In the firing zone burning of fuel and decomposition of limestone CaCO3 on lime CaO and carbon dioxide CO2 at 1000-1200°C. In the cooling zone burnt limestone is cooled to 80-100°C by cold air moving upwards.
As a result of roasting, carbon dioxide is completely lost and lumpy, quicklime is obtained in the form of pieces of white or gray color. Lump quicklime is a product from which different types of building air lime are obtained: ground powdered quicklime, lime dough.
Building air lime of various types is used in the preparation of masonry and plaster mortars, low-grade concrete (working in air-dry conditions), the manufacture of dense silicate products (bricks, large blocks, panels), and the production of mixed cements.
Hydrotechnical and hydro-reclamation structures and structures operate under conditions of constant exposure to water. These difficult operating conditions of structures and structures require the use of binders that have not only the necessary strength properties, but also water resistance, frost resistance and corrosion resistance. Such properties are possessed by hydraulic binders.
hydraulic lime obtained by moderate firing of natural marls and marl limestones at 900-1100°C. Marl and marl limestone used for the production of hydraulic lime contain from 6 to 25% clay and sand impurities. Its hydraulic properties are characterized by the hydraulic (or main) module ( m), representing the ratio in percentage of the content of calcium oxides to the content of the sum of oxides of silicon, aluminum and iron:
Hydraulic lime is a slow setting and slow hardening substance. It is used for the preparation of mortars, low-grade concretes, lightweight concretes, in the production of mixed concretes.
Portland cement- hydraulic binder, obtained by joint, fine grinding of clinker and two-water gypsum. clinker- the product of firing before sintering (at t> 1480 ° C) of a homogeneous, natural or raw mixture of limestone or gypsum of a certain composition. The raw mass is fired in rotary kilns.
Portland cement is used as a binder in the preparation of cement mortars and concretes.
Slag Portland cement- in its composition it has a hydraulic additive in the form of granulated, blast-furnace or electrothermophosphorus slag, cooled according to a special regime. It is obtained by joint grinding of Portland cement clinker (up to 3.5%), slag (20 ... 80%), and gypsum stone (up to 3.5%). Portland slag cement has a slow increase in strength in the initial stages of hardening, however, in the future, the rate of increase in strength increases. It is sensitive to ambient temperature, resistant to soft sulfate waters, and has reduced frost resistance.
carbonate portland cement obtained by joint grinding of cement clinker with 30% limestone. It has reduced heat release during hardening, increased resistance.
Building solutions.
General information.
Mortars are carefully dosed fine-grained mixtures consisting of an inorganic binder (cement, lime, gypsum, clay), fine aggregate (sand, crushed slag), water and, if necessary, additives (inorganic or organic). In a freshly prepared state, they can be laid on the base in a thin layer, filling all its irregularities. They do not exfoliate, seize, harden and gain strength, turning into a stone-like material. Mortars are used in masonry, finishing, repair and other works. They are classified according to medium density: heavy with medium ρ \u003d 1500 kg / m 3, light with medium ρ <1500кг/м 3 . По назначению: гидроизоляционные, талтопогенные, инъекционные, кладочные, отделочные и др.
Solutions prepared on one type of binder are called simple, mixed from several binders (cement-lime). Mortars prepared with air binders are called air mortars (clay, lime, gypsum). The composition of the solutions is expressed in two (simple 1:4) or three (mixed 1:0.5:4) numbers, showing the volume ratio of the amount of binder and fine aggregate. In mixed solutions, the first number expresses the volumetric part of the main binder, the second - the volumetric part of the additional binder in relation to the main one. Depending on the amount of binder and fine aggregate, mortar mixtures are divided into fatty- containing a large amount of astringent. Normal- with the usual content of astringent. Skinny- containing a relatively small amount of binder (low-plasticity).
For the preparation of mortars, it is better to use sand with grains that have a rough surface. Sand protects the solution from cracking during hardening, reduces its cost.
Waterproofing solutions (waterproof)- cement mortars with a composition of 1: 1 - 1: 3.5 (usually fatty), to which ceresite, sodium amominate, calcium nitrate, ferric chloride, bituminous emulsion are added.
ceresite- represents a mass of white or yellow color, obtained from anilic acid, lime, ammonia. Ceresite fills small pores, increases the density of the solution, making it waterproof.
For the manufacture of waterproofing solutions, Portland cement, sulfate-resistant Portland cement, is used. Sand is used as a fine aggregate in waterproofing solutions.
Masonry mortars- used when laying stone walls, underground structures. They are cement-lime, cement-clay, lime and cement.
Finishing (plaster) solutions- subdivided by purpose into external and internal, by location in the plaster into preparatory and finishing.
Acoustic solutions- light mortars with good sound insulation. These solutions are prepared from Portland cement, Portland slag cement, lime, gypsum, and other binders using light porous materials (pumice, perlite, expanded clay, slag) as fillers.
Ordinary concrete on hydration binders.
1. Materials for ordinary (warm) concrete.
2. Designing the composition of the concrete mix.
Concrete- an artificial stone material obtained as a result of the hardening of a concrete mixture, consisting of hydrated binders (cementing), small (sand) and large (crushed stone, gravel) aggregates, water and, if necessary, additives dosed in a certain ratio.
Cement. When preparing a concrete mix, the type of cement used and its brand depend on the working conditions of the future concrete structure or structure, their purpose, and methods of work.
Water. To prepare the concrete mixture, ordinary drinking water is used, which does not contain harmful impurities that prevent the hardening of the cement stone. It is forbidden to use waste, industrial or household water, swamp water for the preparation of concrete mix.
fine aggregate. As a fine aggregate, natural or artificial sand is used. Grain size from 0.14 to 5 mm true density over ρ >1800kg/m 3 . Artificial sand is obtained by crushing dense, heavy rocks. When assessing the quality of sand, its true density, average bulk density, intergranular voidness, moisture content, grain composition and size modulus are determined. In addition, additional qualitative indicators of sand should be investigated - the shape of the grains (acute angle, roundness ...), roughness, etc. Grain or the granulometric composition of the sand must meet the requirements of GOST 8736-77. It is determined by sifting dried sand through a set of sieves with holes of size 5.0; 2.5; 1.25; 0.63; 0.315 and 0.14 mm. As a result of sifting a sample of sand through this set of sieves, a residue is left on each of them, called privatea i. It is found as the ratio of the mass of the residue on a given sieve m i to the mass of the entire sample of sand m:
In addition to partial residues, complete residues are found. BUT, which are defined as the sum of all private residues in % on the overlying sieves + private residue on this sieve:
Based on the results of sand sifting, its fineness modulus is determined:
where BUT– total residues on sieves, %.
According to the fineness modulus, coarse sand is distinguished ( M to >2.5), average ( M k \u003d 2.5 ... 2.0), small ( M k \u003d 2.0 ... 1.5), very small ( M k \u003d 1.5 ... 1.0) .
By plotting the sand sifting curve on the graph of the permissible grain composition, the suitability of sand for the manufacture of concrete mixture is determined.
1 - laboratory screening curve for sand and coarse aggregate, respectively.
Of great importance in the selection of sand for concrete mix is its intergranular voidness. VP(%) , which is determined by the formula:
ρ n.s.- bulk density of sand, g / cm 3;
ρ – true sand density, g/cm 3 ;
In good sands, the intergranular voidness is 30...38%, in uneven-grained sands it is 40...42%.
coarse aggregate. Natural or artificial crushed stone or gravel with a grain size of 5 to 70 mm is used as a large aggregate of concrete mix.
To ensure the optimal grain composition, coarse aggregate is divided into fractions depending on the largest grain size. D max.; At D naib=20mm coarse aggregate has two fractions: from 5 to 10 mm and from 10 to 20 mm;
At D naib=40mm - three fractions: from 5 to 10 mm; from 10 to 20 mm and from 20 to 40 mm;
At D naib=70mm - four fractions: from 5 to 10 mm; from 10 to 20 mm; from 20 to 40 mm; from 40 to 70 mm. The index of intergranular voidness of coarse aggregate has a great influence on the consumption of cement in the preparation of a concrete mixture. Vp.kr(%), which is determined with an accuracy of 0.01% by the formula:
ρ n.cr is the average bulk density of coarse aggregate.
ρ c.cus is the average density of coarse aggregate in a piece.
The index of intergranular voidness should be minimal. Its smaller value can be obtained by selecting the optimal grain composition of coarse aggregate.
The grain composition of the coarse aggregate is determined by sifting the dried coarse aggregate with a set of sieves with holes of size 70; 40; twenty; ten; 5 mm, taking into account its maximum D naib and minimum D hiring fineness.
rubble- usually artificial loose material with unrounded rough grains, obtained by crushing rocks, large natural gravel or artificial stones. To determine the suitability of crushed stone, it is necessary to know: the true density of the rock, the average density of the crushed stone, the average bulk density of the crushed stone, the relative intergranular voidness and the moisture content of the crushed stone
Gravel- loose natural material with rounded, smooth grains, formed in the process of physical weathering of rocks. The same requirements apply to gravel as to crushed stone.
Additives. The introduction of additives into cement, mortar or concrete mixture is a simple and convenient way to improve the quality of cement, mortar and concrete. Allowing to significantly improve not only their properties but also technical and operational indicators. Additives are used in the production of binders, the preparation of mortars and concrete mixes. They allow you to change the quality of the concrete mixture and the concrete itself; affecting workability, mechanical strength, frost resistance, crack resistance, water resistance, water tightness, thermal conductivity, environmental resistance.
The main properties of the concrete mix include cohesion (the ability to maintain its uniformity without delamination during transportation, unloading), homogeneity, water-holding capacity (plays a significant role in the formation of the concrete structure, acquiring strength, water resistance and frost resistance), workability (its ability to quickly with a minimum energy consumption to acquire the required configuration and density, ensuring the production of high-density concrete).
The freshly prepared concrete mixture must be well mixed (homogeneous), suitable for transportation to the place of laying, taking into account weather conditions, while resisting water separation and separation.
The task of designing and selecting the composition of the concrete mix includes the selection of the necessary materials (binder and other components) and the establishment of their optimal quantitative ratio. On the basis of this, a concrete mix with specified technological properties is obtained, as well as the most economical and durable concrete that meets design and operational requirements with the lowest possible consumption of cement. Consequently, the concrete mixture of the designed composition must have non-separation, the necessary workability, cohesion, and the concrete made from this mixture must have the required properties: density, strength, frost resistance, water resistance.
The simplest way to design the composition of a concrete mixture is the calculation by absolute volumes, which is based on the fact that the prepared, laid and compacted concrete mixture should not have voids.
The design of the composition is carried out using the current recommendations and regulatory documents in the following sequence:
1. Assign for a given brand of concrete Rb rational brand of cement Rc.
2. Determine the water-cement ratio V/C, for conventional concrete With V/C ≥0,4: W/C=ARc/(Rb+0.5ARc) ; where Rc - brand of cement; Rb- brand of concrete; BUT- coefficient taking into account the quality of the components used.
3. Assign an approximate water consumption per 1 m 3 of concrete mix. The water consumption required to obtain a concrete mixture of a given mobility depends not only on the type and largest size of the aggregate, but also on the shape and roughness of the grains.
4. Calculate the consumption of cement (kg per 1 m 3 of concrete) according to the ratio found V/C and accepted estimated water consumption: ;
5. The consumption of aggregates is calculated based on the condition that the sum of the absolute volumes of all the constituent materials of concrete is equal to 1 m 3 of the laid and compacted concrete mixture:
C, V, P, Kr- the cost of cement, water, sand, coarse aggregate per 1 m 3 of the mixture, kg.
ρ c, ρ c, ρ p, ρ kr- the density of these materials, kg / m 3;
- their absolute volumes, m 3.
Formulas for determining the consumption of aggregates (kg per 1m 3 of concrete):
coarse aggregate:
r- coefficient. separation of coarse aggregate grains, taken approximately (table data)
P cr– voidness of large filler.
Ρ n.cr- bulk density of coarse aggregate.
fine aggregate (sand):
6. Calculate the calculated average density of the concrete mixture:
and concrete output coefficient:
Concrete output ratio β should be within 0.55 ... 0.75.
The designed composition of the concrete mix is specified on test batches. They also check the mobility of the concrete mixture. If the mobility of the concrete mixture is greater than required, then water and cement are added in small portions to the mixture, while maintaining a constant ratio V/C until the mobility of the concrete mix becomes equal to the specified one. If the mobility is greater than the specified one, then sand and coarse aggregate are added to it (in portions of 5% of the original amount), while maintaining the selected ratio V/C. Based on the results of trial batches, adjustments are made to the designed composition of the concrete mixture, given that under production conditions the sand and coarse aggregate used are in a wet state, and coarse aggregate has some water absorption, consumption ( l) the required water for the preparation of 1m 3 concrete mix is specified by the formula:
AT- consumption of found (calculated) water, l / m 3
P, Cr- consumption of sand and coarse aggregate, kg / m 3
WP, Wkr – moisture content of sand and coarse aggregate, %.
In kr– water absorption of coarse filler, %.
1. Preparation, transportation and laying of concrete mix. Freshly laid concrete care and quality control.
2. Hydrotechnical concrete.
3. Concrete of special types.
Concrete mixtures are prepared on stationary concrete plants or in mobile concrete mixing plants. The quality of the concrete mixture (homogeneity) is affected by the quality of its mixing during the preparation process. The mixing time is several minutes. Re-mixing of the concrete mixture is allowed within 3 ... 5 hours from the moment of its preparation. The most important condition preparation of concrete mix - careful dosing of constituent materials. Deviation in dosage is allowed no more than ±1% by weight for cement and water, and no more than ±2% for aggregates. The prepared concrete mix is delivered to the place of laying by special vehicles. The duration of transportation of the finished concrete mix to the place of laying should not exceed 1 hour. Currently, the concrete mix is laid mechanized with the help of concrete pavers, concrete distributors. Compaction of the concrete mixture during laying ensures high-quality filling of all gaps with the mixture. Vibration is the most common method of compacting a concrete mix. When the concrete mixture vibrates, the friction between its components decreases, the fluidity increases, the mixture passes into the state of a heavy viscous liquid and is compacted under the action of its own weight. During the compaction process, air is removed from the concrete mixture and the concrete acquires a good density. To improve the structure-forming concrete, to increase its strength, frost resistance, water resistance, re-vibration of the concrete mixture is used after 1.5-2 hours. from the moment of the first vibration.
Appropriate care of freshly laid concrete is essential to obtain high-quality concrete. Lack of care for freshly laid concrete can result in poor quality concrete. The main concrete care measures are covering with well-moistened burlap, sand, sawdust, coating with a film-forming composition. Cover should be no later than 30 minutes after compaction of the concrete mixture.
In winter, there are the following ways of care: unheated and with artificial heating. Non-heated methods include thermos methods with anti-frost additives. Artificial heating of concrete is carried out by electric heating, steam heating, air heating.
Concrete used in the construction of hydrotechnical and irrigation facilities, constantly or periodically washed by water, is called hydraulic engineering. Hydraulic concrete must have not only strength, frost resistance, but also water resistance and water resistance, which will ensure its long service life in the aquatic environment.
Depending on the location in relation to the water level, hydraulic concrete in structures or structures is divided into underwater- constantly in the water; variable level zones- subjected to periodic washing with water; surface- located above the variable level zone. According to the surface area of structures, hydraulic concrete is divided into massive and non-massive, and according to the location in the structure - external and internal zones.
The main construction and technical properties of hydraulic concrete- water resistance, frost resistance, water absorption, strength, resistance to the aggressive effects of water, heat generation, durability, mobility and stiffness of the concrete mix.
Portland cement is used as a binder for hydraulic concrete. To improve the quality of hydrotechnical concrete, it is recommended to introduce additives into it, which can reduce volumetric expansion, shrinkage, and water demand. Sand for hydrotechnical concrete is used coarse, medium-sized and fine natural or artificial, from hard and dense rocks. As a large aggregate for hydraulic concrete, gravel, crushed stone from rocks are used.
Extra heavy concrete- used for special protective structures (for protection against radioactive effects). It has an average density of over 2500 kg/m 3 . Magnetite, limonite, hydrogenite, hematite, barite are used as a filler, which determines the name of concrete - magnetite, limonite, barite, ... The binders in this concrete are Portland cement, Portland slag cement and aluminous cement.
road concrete- used in the construction of roads, airfields, city streets. High-quality materials are used to prepare road concrete mix. Plasticized Portland cement is used as a binder.
dry concrete- this is a dry concrete mix, dosed at the factory from dry components (cement, sand, coarse aggregate ...). At the place of laying, the concrete mixture is mixed with water in concrete mixers or directly in mixer trucks.
LECTURE №7
Concrete and reinforced concrete products in irrigation and drainage construction.
General information.
Reinforced concrete- This is an artificial material representing concrete, inside of which steel reinforcement is located. Steel reinforcement well perceives not only compressive, but also tensile forces that occur in the structure during eccentric compression, tension, and bending. Reinforced concrete structures they can be monolithic, when concreting is carried out directly at the construction site, and prefabricated, when structures are made at factories.
Reinforced concrete structures, structures and products are made from ordinary concrete of a grade of at least 200, lightweight concrete of a grade of at least 50 and dense silicate concrete of a grade of at least 100. Grade 200 concrete is used for the manufacture of lightly loaded concrete and reinforced concrete products, working mainly in compression. Concrete grades 300, 400, 500, 600 are used in the manufacture of reinforced concrete products with high bearing capacity.
Concrete used for the preparation of concrete and reinforced concrete products, structures and structures for irrigation purposes should ensure their reliability and durability.
For the formation of ordinary (non-stressed) reinforced concrete monolithic structures, as well as prefabricated products and structures, welded meshes and frames, rolled meshes from hot-rolled steel reinforcement are used. In the manufacture of non-stressed structures and products, high-strength wire and reinforcing ropes are used. The reinforcement is pre-stretched (tensioned). The tension of the reinforcement is carried out before concreting with the help of various anchors and clamps. After laying, hardening of the concrete mixture and gaining strength by concrete, the ends of the reinforcement are released (cut off) and it, trying to return to its original state, strains (compresses) the concrete. During the installation of stressed structures, the reinforcement is placed in special channels, after which it is stretched in such a way that during the stretching process, these elements are compressed in the structure. After reaching the required compression of the structure and stretching of the reinforcement, its ends are anchored, and the channels in which the reinforcement passes are monolithic with high-strength cement mortar. When the solution acquires the necessary strength, the ends of the reinforcement are cut off, as a result of which the structure acquires tension, which allows increasing its bearing capacity.
Prefabricated concrete products.
Drainage pipes made of soil silicate concrete are made from a mixture of local soil (sand, sandy loam, loam), ground slag and an alkaline component. Pipe length 333 mm, inner diameter 50; 70; 100; 150 mm, wall thickness 10; fifteen; 20 mm. They have a high bearing capacity, frost resistance. They are used in the construction of closed drainage dehumidifiers.
Drainage pipes made of filter concrete produced by layer-by-layer pressing. Pipe length 500, 600, 900 mm, inner diameter 100, 150 and 200 mm, wall thickness 25, 30, 40 mm. They are intended for the device of the closed drainage.
foundation pillars, made of concrete grade 100, are used as columnar foundations for log, panel and frame wooden buildings.
Foundation blocks for trays have brands F-12-6, F15-9, F18-9, F21-12, where the first digit indicates the length L, the second is the width AT block. They are made of hydrotechnical concrete grades of at least 200.
trays parabolic section for irrigation systems have a socket on one side and a smooth end on the other. They are released in relaxed (LR) length L=6000 mm, and stressed (SSR) length L=8000 mm grades, respectively, LR-4; LR-6; LR-8; LR-10 and LRN-4; OSR-6; OSR-8; LRN-10, where the number indicates the depth of the trays H in dm. The trays are made of grade 300 hydrotechnical concrete.
Glass and glass products.
Glass- supercooled melt of complex composition from a mixture of silicates and other substances. Molded glass products are subjected to a special heat treatment - firing.
Window glass produced in sheets ranging in size from 250x250 to 1600x2000mm of two grades. By thickness, glass is divided into single (2 mm thick), one and a half (2.5 mm), double (3 mm) and thickened (4 ... 6 mm).
Showcase glass produced polished and unpolished in the form of flat or bent sheets with a thickness of 6..12 mm. It is used for glazing shop windows and openings.
Sheet glass highly reflective- this is an ordinary window glass, on the surface of which a thin translucent light-reflecting film made on the basis of titanium oxide is applied. Glass with a film reflects up to 40% of the incoming light, light transmission is 50 ... 50%. Glass reduces the view from the outside and reduces the penetration of solar radiation into the room.
Glass sheet radioprotective- this is an ordinary window glass, on the surface of which a thin transparent screening film is applied. The screening film is applied to the glass during its formation on machines. Light transmission not less than 70%
Reinforced glass- made on production lines by continuous rolling with simultaneous rolling inside the sheet metal mesh. This glass has a smooth, patterned surface and can be colorless or colored.
Heat-absorbing glass has the ability to absorb infrared rays of the solar spectrum. It is intended for glazing window openings in order to reduce the penetration of solar radiation into the premises. This glass transmits visible light rays by at least 65%, infrared rays by no more than 35%.
glass pipes are made of ordinary transparent glass by the method of vertical or horizontal stretching. Pipe length 1000…3000 mm, inner diameter 38-200mm. Pipes withstand hydraulic pressure up to 2 MPa.
Sitally obtained by introducing a special composition of crystallization catalysts into the molten glass mass. Products are formed from such a melt, then they are cooled, as a result of which the molten mass turns into glass. During the subsequent heat treatment of glass, its complete or partial crystallization occurs - a sitall is formed. They have high strength, low average density, high wear resistance. They are used in the cladding of external or internal walls, the manufacture of pipes, floor slabs.
stemalite represents sheet glass of various textures, coated on one side with deaf ceramic crystals of different colors. It is made of unpolished display or rolling glass with a thickness of 6 ... 12 mm. It is used for exterior and interior cladding of buildings, the manufacture of wall panels.
Non-firing artificial stone materials and products based on hydration binders.
Unfired artificial stone materials and products are made from a mixture of binders, water and aggregates through its formation and appropriate processing. By type of binder they are divided into silicate, lime-slag, gas silicate, aerated concrete, gypsum, gypsum concrete, asbestos-cement, etc.
According to hardening conditions- they are divided into products hardening during autoclave and heat treatment, and into products hardening in an air-humid environment.
Materials and products of autoclave hardening.
For the production of autoclaved products, local materials are widely used: lime, quartz sand, industrial waste.
Strong and waterproof autoclave materials and products are obtained as a result of chemical interaction of finely ground lime and silica components during their hydrothermal treatment in a steam environment at 175°C in autoclaves at a pressure of 0.8 ... 1.4 MPa. As a result of a chemical reaction, a durable and waterproof substance (calcium silicate) is formed, which cements the sand particles, forming an artificial stone. Autoclave materials and products can have both dense and cellular structures.
Autoclaved silicate concrete- a mixture of lime-silica binder, sand and water. Lime-pozzolanic, lime-slag and lime-ash cements are used as binders. Products made of silicate autoclaved concrete have sufficient frost resistance, water resistance and chemical resistance to some aggressive environments. Large, dense, silicate wall blocks are made from autoclaved silicate.
Autoclaved cellular concrete prepared from a homogeneous mixture of mineral binder, silica component, gypsum and water. The binder materials are Portland cement, ground boiled lime. During the exposure of the product before autoclaving, hydrogen is released from it, as a result of which tiny bubbles form in a homogeneous plastic-viscous binder medium. In the process of outgassing, these bubbles increase in size, creating spheroidal cells in the entire mass of the cellular concrete mix.
During autoclave treatment under a pressure of 0.8..1.2 MPa in a high-humidity air-steam environment at 175 ... 200 ° C, an intensive interaction of the binder with silica components occurs with the formation of calcium silicate and other cementing neoplasms, due to which the structure of cellular highly porous concrete acquires strength .
Single-row cut panels, wall and large blocks, single-layer and double-layer curtain wall panels, single-layer slabs of interfloor and attic floors are made from cellular concrete.
silicate brick molded on special presses from a carefully prepared homogeneous mixture of pure quartz sand (92 ... 95%), air lime (5 ... 8%) and water (7 ... 8%). After pressing, the brick is steamed in autoclaves in a vapor-saturated environment at 175°C and a pressure of 0.8 MPa. Making a brick single size 250x120x65mm and modular(one and a half) size 250x120x88mm; solid and hollow, front and ordinary. Brick brand: 75, 100, 125, 150, 200, 250.
Asbestos cement products.
For the manufacture of asbestos-cement products, an asbestos-cement mixture is used, consisting of fine-fiber asbestos (8 ... 10%), Portland cement for asbestos-cement products and water. After the mixture hardens, an artificial asbestos-cement stone material is formed, representing cement stone. For the production of asbestos-cement products, grade III-IV asbestos, Portland cement for asbestos-cement products grades 300, 400, 500 or sand cement, consisting of Portland cement and finely ground quartz sand and water with a temperature of 20 ... 25 ° C, not containing clay impurities, organic substances and mineral salts.
Pipes non-pressure and pressure water pipes, for laying telephone cables and gas pipes have a regular cylindrical shape. They are smooth and have no cracks. Non-pressure pipes used for laying non-pressure internal and external pipelines transporting butovye and atmospheric wastewater; in the construction of non-pressure tubular hydraulic structures and drainage collectors of drainage systems; at underground laying cables. pressure pipes widely used in the construction of underground water pipelines, modern automated irrigation systems, heating systems.
Plates are flat facing pressed produce unpainted, painted. They are used for wall cladding, partition panels. Their length is 600…1600mm, width 300…1200, thickness 4…10mm.
Gypsum and gypsum concrete products.
Products based on gypsum binders have a relatively low density, sufficient strength, are fireproof, have high sound and heat insulating properties, and are easy to process (sawing, drilling). To increase the moisture and water resistance of gypsum products in their manufacture, gypsum-cement-pozzolonic and gypsum-slag-cement puzzolam are used. binders, cover them with waterproof waterproof protective paints or pastes. Products based on gypsum binders are made from gypsum dough, gypsum mortar or gypsum concrete with mineral aggregates (sand, expanded clay gravel ...) and organic fillers (sawdust, shavings, reeds ...). Gypsum and gypsum concrete products are highly fragile, therefore, during their manufacture, reinforcing materials are introduced in the form of wooden slats, reeds, metal fittings (mesh, wire ...)
Gypsum lining sheets made of gypsum sheet, lined with cardboard on both sides. Gypsum sheet is prepared from a mixture of building gypsum with mineral or organic additives. They are used for interior cladding of walls, partitions, ceilings of buildings.
Gypsum boards for partitions are made from a mixture of building gypsum with mineral or organic fillers. Plates are produced solid and hollow with a thickness of 80 ... 100 mm. Gypsum and gypsum concrete partition slabs are used for building partitions inside the building.
Gypsum concrete panels for subfloors are made of gypsum concrete with a compressive strength of at least 7 MPa. They have a wooden rack frame. The dimensions of the panels are determined by the dimensions of the rooms. The panels are designed for linoleum floors, tiles in rooms with normal humidity.
Gypsum ventilation blocks are made from building gypsum with a compressive strength of 12 ... 13 MPa or from a mixture of gypsum-cement-pozzolanic binder with additives. Blocks are intended for the device of ventilating channels in residential, public and industrial buildings.
General information.
Artificial firing materials and products (ceramics) are obtained by firing at 900 ... 1300 ° C molded and dried clay mass. As a result of firing, the clay mass turns into an artificial stone, which has good strength, high density, water resistance, water resistance, frost resistance and durability. The raw material for producing ceramics is clay with lean additives introduced into it in some cases. These additives reduce the shrinkage of products during drying and firing, increase porosity, and reduce the average density and thermal conductivity of the material. Sand, crushed ceramics, slag, ash, coal, sawdust are used as additives. The firing temperature depends on the temperature at which the clay starts to melt. Ceramic building materials are divided into porous and dense. Porous materials have a relative density of up to 95% and water absorption of not more than 5%; their compressive strength does not exceed 35 MPa (brick, drainage pipes). Dense materials have a relative density of more than 95%, water absorption less than 5%, compressive strength up to 100Mpa; they are durable (floor tiles).
Ceramic materials and products from fusible clays.
1) Ordinary clay bricks of plastic pressing are made from clays with or without thinning additives. The brick is a parallelepiped. Brick grades: 300, 250, 200, 150, 125, 100, 75.
2) Brick (stone) ceramic hollow plastic pressing is produced for masonry bearing walls one-story and multi-story buildings, interiors, walls and partitions, brick wall cladding. Brick grade: 150, 125, 100 and 75.
3) Lightweight building bricks are made by molding and firing a mass of clays with burnable additives, as well as mixtures of sand and clays with burnable additives. Brick size: 250x120x88mm, grades 100, 75, 50, 35.
Common clay bricks are used for laying internal and external walls, pillars and other parts of buildings and structures. Hollow clay and ceramic bricks are used when laying the internal and external walls of buildings and structures above the waterproofing layer. Light brick is used for laying the exterior and interior walls of buildings with normal indoor humidity.
4) roof tiles are made from fatty clay by firing at 1000 ... 1100 ° C. High-quality tiles, when lightly hit with a hammer, produce a clear, non-rattling sound. It is strong, very durable and fire resistant. Disadvantages - high average density, which makes the supporting structure of the roof heavier, fragility, the need to arrange roofs with a large slope to ensure rapid water flow.
5) Drainage ceramic pipes made of clays with or without lean additives, inner diameter 25...250 mm, length 333, 500, 1000 mm and wall thickness 8...24 mm. They are made in brick or special factories. Drainage ceramic pipes are used in the construction of drainage and humidification and irrigation systems, collector-drainage conduits.
Ceramic materials and products from refractory clays.
1) Stone for underground collectors is made of a trapezoidal shape with side grooves. It is used when laying underground collectors with a diameter of 1.5 and 2 m, when constructing sewer and other structures.
2) Facade ceramic tiles are used for facing buildings and structures, panels, blocks.
3) Ceramic sewer pipes are made from refractory and refractory clays with lean additives. They have a cylindrical shape and a length of 800, 1000 and 1200 mm, an inner diameter of 150…600 m.
4) Floor tiles by type front surface subdivided into smooth, rough and embossed; by color - one-color and multi-color; in shape - square, rectangular, triangular, hexagonal, tetrahedral. Tile thickness 10 and 13mm. It is used for flooring in the premises of industrial, water management buildings with a wet regime.
LECTURE №10
Coagulation (organic) binders.
Mortars and concretes based on them.
Organic binders used in the construction of waterproofing, in the manufacture of waterproofing materials and products, as well as waterproofing and asphalt solutions, asphalt concrete, are divided into bitumen, tar, bitumen-tar. They dissolve well in organic solvents (gasoline, kerosene), are water resistant, are able to change from a solid state to a plastic state and then liquid when heated, have high adhesion and good adhesion to building materials (concrete, brick, wood).
bituminous materials.
Bitumens are divided into natural and artificial. In nature, pure bitumen is rare. Usually, bitumen is extracted from mountain sedimentary porous rocks impregnated with it as a result of raising oil from the underlying layers. Artificial bitumen is obtained during oil refining, as a result of distillation of gases (propane, ethylene), gasoline, kerosene, diesel fuel from its composition.
natural bitumen- a solid or viscous liquid consisting of a mixture of hydrocarbons.
asphalt rocks- rocks impregnated with bitumen (limestones, dolomites, sandstones, sands and clays). Bitumen is extracted from them by heating, or these rocks are used in ground form (asphalt powder).
asphaltites- rocks consisting of solid natural bitumen and other organic substances that are insoluble in carbon disulfide.
Tar materials.
Tar obtained by dry distillation (heating at high temperatures without air access) of hard or brown coal, peat, wood. Depending on the feedstock, tar is divided into coal, lignite, peat, and wood tar.
Coal tar- a viscous dark brown or black liquid consisting of hydrocarbons.
coal tar pitch- a black solid substance obtained after distillation of almost all oil fractions from tar.
Coal tar, pitch, when heated or dissolved, forms toxic fumes, so care must be taken when working with them.
asphalt solutions.
Asphalt solutions are used in the installation of waterproofing plasters and coatings, sidewalks, floors. They can be hot (cast) and cold. The composition of asphalt solutions is selected depending on the conditions of their operation in structures.
cold asphalt mortar are made from a mixture of petroleum bitumen (5 ... 10%) with the addition of a solvent (benzene), powdered mineral filler (limestone, dolomite) and clean dry sand, mixed in special mortar mixers heated to 110 ... 120 ° C. The hardening of cold asphalt mortar occurs as a result of the evaporation of the solvent.
hot asphalt mortar are made from a mixture of bitumen (or tar, pitch), powdered mineral filler and sand. The mixture of components of the hot asphalt solution is mixed in special mixers with heating up to 120...180°C. Asphalt solution is laid in layers in a hot state with rolling of each layer with rollers.
asphalt concrete.
Asphalt concretes are prepared at specialized asphalt plants or installations. Depending on the purpose, they are divided into road, for flooring; depending on the composition - into bituminous and tar; depending on the laying temperature - cold and hot.
Cold asphalt concrete Lay in layers on dry or slightly damp surfaces with light rolling. It is made from a mixture of liquid bitumen, solvents, powdered mineral filler (limestone, sand), pure crushed stone and sand by mixing and heating.
LECTURE №11
polymeric materials.
General information.
Polymeric materials are natural or synthetic high molecular weight organic compounds consisting of a huge number of atoms. The structure of polymer molecules can have linear or volumetric character. Polymers, whose molecules have linear structure, have thermoplasticity - softening when heated, they harden again when cooled. Softening and hardening can be carried out repeatedly. Repeated heating followed by cooling does not significantly change the properties of the material (polyethylene, polystyrene). polymers that have volumetric structure molecules are thermosetting - they cannot repeatedly melt and solidify reversibly. During the first heating, they become plastic and take a given shape, turning into an infusible and insoluble state (phenolic plastics).
According to elastic properties Polymers are divided into plastics (rigid) and elastics (elastic).
Polymeric materials contain three groups of substances: binders, plasticizers and fillers. Binders are synthetic resins. As plasticizers introducing glycerin, camphor and other substances that increase the elasticity and plasticity of polymers, facilitating their processing. Fillers(powder, fibrous) give polymer products high mechanical strength, prevent shrinkage. In addition, pigments, stabilizers, hardening accelerators, and other substances are added to the composition.
In the manufacture of polymer building materials, products and structures, polyethylene (films, pipes), polystyrene (plates, varnishes), polyvinyl chloride (linoleum), polymethyl methacrylate (organic glass) are most widely used.
Due to good mechanical properties, elasticity, electrical insulating properties, the ability to take any shape during processing, polymeric materials have found wide application in all areas of construction and in our Everyday life.
Initial polymeric materials.
Polymers, depending on the method of preparation, are divided into polymerization and polycondensation. Polymerization polymers are obtained by polymerization. These include polyethylene, polystyrene. Polycondensation polymers are produced by the polycondensation method. These include polyester, acrylic, organosilicon and other resins, polyesters, polyurethane rubbers.
Polyethylene obtained by polymerization of ethylene from associated and natural gas. It ages under the action of solar radiation, air, water. Its density is 0.945 g/cm 3 , frost resistance is -70°С, heat resistance is only 60...80°С. According to the method of production, high-pressure polyethylene (LDPE), low-pressure polyethylene (HDPE) and on a chromium oxide catalyst (P) are distinguished. When heated to 80 ° C, polyethylene dissolves in benzene, carbon tetrachloride. It is used for the manufacture of films of finishing materials.
Polyisobutylene- rubbery or liquid elastic material obtained by polymerization of isobutylene. It is lighter than polyethylene, less durable, has very low moisture and gas permeability, and almost does not age. It is used for the manufacture of waterproofing fabrics, protective coatings, films, as additives in asphalt concrete, a binder for adhesives, etc.
Polystyrene- thermoplastic resin, polymerization product of styrene (vinylbenzene). It is used for the manufacture of tiles, facing tiles, enamel varnishes, etc.
Polymethyl methacrylate (organic glass)- is formed during the polymerization of methyl ester as a result of its treatment with methacrylic acid. In the beginning, methyl methacrylate is formed as a colorless, transparent liquid, and then a glassy product is obtained in the form of sheets, tubes ... They are very resistant to water, acids and alkalis. They are used for glazing, making models.
polymer pipes.
Pipes from polymer materials widely used in the construction of pressure pipelines (underground and aboveground), irrigation systems, closed drainage, tubular hydraulic structures. As a material for making polymer pipes use polyethylene, vinyl plastic, polypropylene, fluoroplast.
Polyethylene pipes are made by continuous screw extrusion (continuous extrusion of polymer from a nozzle with a given profile). Polyethylene pipes are frost-resistant, which allows them to be operated at temperatures from -80°С to +60°С.
Polymer mastics and concretes.
Hydraulic structures operating in an aggressive environment, the action of high speeds and solid runoff, are protected with special coatings or linings. In order to protect structures from these effects, to increase their durability, polymer mastics, polymer concrete, polymer concrete, and polymer solutions are used.
Polymer mastics- designed to create protective coatings that protect structures and structures from mechanical stress, abrasion, temperature extremes, radiation, and aggressive environments.
Polymer concretes- cement concretes, during the preparation of which organosilicon or water-soluble polymers are added to the concrete mixture. Such concretes have increased frost resistance, water resistance.
Polymer concretes- these are concretes in which polymer resins serve as a binder, and inorganic mineral materials serve as a filler.
Polymer solutions differ from polymer concrete in that they do not contain crushed stone. They are used as waterproofing, anti-corrosion and wear-resistant coatings for hydraulic structures, floors, pipes.
LECTURE №12
Heat-insulating materials and products from them.
General information.
Thermal insulation materials are characterized by low thermal conductivity and low average density due to their porous structure. They are classified according to the nature of the structure: rigid (plates, bricks), flexible (bundles, semi-rigid plates), loose (fibrous and powdery); in mind the main raw materials: organic and inorganic.
Organic thermal insulation materials.
sawdust, shavings- used in dry form with impregnation in the structure with lime, gypsum, cement.
Construction felt made from coarse wool. It is produced in the form of antiseptic-impregnated panels with a length of 1000 ... 2000 mm, a width of 500 ... 2000 mm, and a thickness of 10 ... 12 mm.
reeds produced in the form of plates with a thickness of 30 ... 100 mm, obtained by wire fastening through 12-15 cm rows of pressed reeds.
Inorganic thermal insulation materials.
Mineral wool- tangled fiber (5 ... 12 microns in diameter), obtained from a molten mass of rocks or slags or in the process of spraying its thin jet with steam under pressure. mineral wool used as thermal insulation of surfaces with temperatures from -200°C to + 600°C.
glass wool- tangled fiber obtained from molten glass. It is used for the preparation of thermal insulation products (mats, plates) and thermal insulation of surfaces.
Foam glass- a porous light material obtained by sintering a mixture of glass powder with gas-forming agents (limestone, coal). It is made with open and closed pores. Foam glass plates are used for thermal insulation of walls, coatings, ceilings, floor insulation.
LECTURE №12а
Waterproofing and roofing materials based on bitumen and polymers.
General information.
One of the important issues in construction is the protection of buildings and structures from the effects of precipitation, the surrounding humid environment, pressure and non-pressure water. In all these cases, the main role is played by waterproofing and roofing materials, which predetermine the durability of buildings and structures. Waterproofing and roofing materials are divided into emulsions, passes, mastics. Depending on the waterproofing and roofing materials binders are divided into bitumen, polymer, polymer-bitumen.
waterproofing materials.
emulsions- dispersed systems consisting of two liquids that do not mix with each other, one of which is in the other in a finely divided state. To prepare the emulsion, weak aqueous solutions of surfactants or finely dispersed solid powders are used - emulsifiers, which lower the surface tension between bitumen and water, contributing to its finer fragmentation. As emulsifiers, oleic acid, concentrates of sulphite-alcohol stillage, asidol are used. Emulsions are used as primers and coatings, applied in a cold state on a dry or damp surface in layers.
Pastes prepared from a mixture of emulsified bitumen and finely ground mineral powders (quicklime or slaked lime, highly plastic or plastic clays). They are used as primers and coatings for inner layers waterproofing carpet.
Roofing materials.
glassine- a non-covering material obtained by impregnating roofing paper with soft petroleum bitumen. It is used as a lining material.
Tol- is obtained by impregnating roofing paper with coal or slate tar materials and then sprinkling one or two sides with mineral powder. It is used for roofing.
LECTURE №13
Wood building materials and products.
General information.
Due to its good building properties, wood has long been widely used in construction. It has a low average density of up to 180 kg/m 3 , sufficient strength, low thermal conductivity, great durability (with proper operation and storage), is easily processed by tools, and is chemically resistant. However, along with great advantages, wood also has disadvantages: heterogeneity of the structure; the ability to absorb and release moisture, while changing its size, shape and strength; It quickly collapses from decay, easily ignites.
By species, trees are divided into coniferous and deciduous. The quality of wood largely depends on the presence of defects in it, which include oblique, knotty, cracks, insect damage, rot. Coniferous - larch, pine, spruce, cedar, fir. Deciduous - oak, birch, linden, aspen.
The construction properties of wood vary widely, depending on its age, growth conditions, wood species, and humidity. In a freshly cut tree, moisture is 35 ... 60%, and its content depends on the time of felling and the type of tree. The lowest moisture content in the tree in winter, the highest - in the spring. The highest humidity is conifers(50-60%), the smallest - hard hardwood (35-40%). Drying from the wettest state to the saturation point of the fibers (up to a moisture content of 35%), the wood does not change its dimensions; with further drying, its linear dimensions decrease. On average, shrinkage along the fibers is 0.1%, and across - 3 ... 6%. As a result of volumetric shrinkage, gaps are formed at the junctions of wooden elements, the wood cracks. For wooden structures, wood of the moisture content at which it will work in the structure should be used.
Materials and products from wood.
roundwood: logs - long segments of a tree trunk, cleared of branches; round timber (podtovarnik) - logs 3 ... 9m long; ridges - short segments of a tree trunk (1.3 ... 2.6 m long); logs for piles of hydraulic structures and bridges - pieces of a tree trunk 6.5 ... 8.5 m long. The moisture content of roundwood used for load-bearing structures should be no more than 25%.
lumber obtained by sawing round wood. Plates are logs sawn longitudinally into two symmetrical parts; the bars have a thickness and width of not more than 100 mm (four-cut and two-edged); the slab represents the sawn off outer part of the log, in which one side is not processed.
Planed long products- these are platbands (window and door openings), plinths, floorboards or timber, handrails for railings, stairs, window sills are made from coniferous and hardwood.
Plywood they are made from veneer (thin shavings) of birch, pine, oak, linden and other species by gluing its sheets together. The veneer is obtained by continuous removal of chips along the entire length of a log steamed in boiling water (1.5 m long) on a special. machine.
Joinery are made at specialized factories or in workshops from coniferous and hardwood. These include windows and door blocks various shapes, door leafs, partitions and panels.
Glued structures in the form of beams, frames, racks, piles, fences, they are used in coatings, ceilings, and other elements of buildings. They are made by gluing waterproof adhesives boards, bars, plywood. (Waterproof adhesive FBA, FOK).
LECTURE #14
Decoration Materials.
General information.
Finishing materials are used to create surface coatings for building products, structures and structures in order to protect them from harmful external influences, give them aesthetic expressiveness, and improve hygienic conditions in the room. Finishing materials include ready-made paint compositions, auxiliary materials, binders, rolled Decoration Materials, pigments. Colorful compositions consist of a pigment that gives them color; a filler that saves pigment, improves mechanical properties and increases the durability of color; a binder that connects the pigment and filler particles to each other and to the surface to be painted. After drying, the paint compositions form a thin film. In addition to the main components, if necessary, thinners, thickeners and other additives are added to the paint compositions.
Pigments.
Pigments- These are finely ground colored powders that are insoluble in water and organic solvents, but are able to mix evenly with them, transferring their color to the colorful composition.
white pigments. These include chalk, air building lime. Chalk used in the form of a finely divided powder, from which various water-borne (water) paint compositions, primers, putties and pastes are prepared.
Building air lime used as a pigment and binder for the preparation of colorful compositions, putties and mastics.
Black pigments. These include gas channel soot, manganese dioxide, and black.
Soot gas channel It is formed during the combustion of various oils, oil, resins with limited air access. Use it for the preparation of non-aqueous colorful compositions.
manganese dioxide occurs in nature as a mineral and pyrolusite. Use it for the preparation of aqueous and non-aqueous colorful compositions.
Black obtained by calcination without access to air nutshell, wood, peat.
gray pigments. These include graphite and zinc dust.
Graphite- a natural material of a grayish-black color with a greasy metallic sheen. It is used for preparing colorful compositions and for rubbing the surface of iron objects exposed to heat, which makes it look polished.
zinc dust- mechanical mixture of zinc oxide with metallic zinc. It is used for the preparation of non-aqueous paint formulations.
Red pigments. These include dry iron minium, natural mummy and art.
Minium iron dry obtained from iron ore containing iron oxide. It is a very durable pigment with high anti-corrosion properties and light fastness. It is produced in the form of a finely ground brick-red powder and used for the preparation of adhesives, enamels and oil paints.
Mummy natural- finely ground clay, dyed brown-red with iron oxides various shades. Used for the preparation of aqueous and non-aqueous paint formulations.
Mummy artificial- finely ground powder of a ceramic product of bright red color.
yellow pigments. These include dry ocher, dry lead crown and natural sienna.
Dry ocher obtained from clay dyed with iron oxides. Used for the preparation of all types of paints used in painting wood and metal surfaces.
Siena natural obtained from clay containing a large amount of iron oxide (70%) and silica.
Green, blue, brown and other pigments.
Drying oils and emulsions.
Drying oil natural linen and hemp obtained respectively from linseed and hemp crude oil by boiling it at 200 ... 300 ° C and air treatment with the introduction of a drying accelerator (desiccant). It is used for the preparation of paint compositions, primers and as an independent material for painting works for external and internal painting of wooden and metal structures.
Emulsion VM consists of natural drying oil, benzene, animal tile adhesive, 50% lime paste and water. It is used to dilute thick paints.
Emulsion MB prepared from a mixture of a 10% solution of animal glue, alkali (soda, borax, potash) and natural drying oil. It is used for painting indoor plaster, wood.
Lacquer compositions.
Oil paints- various whites and colored paint compositions prepared on natural or combined drying oils with various additives, brought to a paint consistency.
LECTURE #15
Metals and metal products.
General information.
Various materials in the form of rolled metal products and metal products are widely used in water management construction. Rolled metal is used in construction pumping stations, industrial buildings, production of metal shutters of various types. Metals used in construction are divided into two groups: ferrous (iron and alloys) and non-ferrous. Depending on the carbon content, ferrous metals are divided into cast iron and steel.
Cast iron- iron-carbon alloy with carbon content from 2% to 6.67%. Depending on the nature of the metal base, it is divided into four groups: gray, white, high strength and malleable.
Gray cast iron- contains 2.4 ... 3.8% carbon. It lends itself well to processing, has increased fragility. It is used for casting products that are not subject to impact.
White cast iron- contains 2.8 ... 3.6% carbon, has high hardness, but it is brittle, cannot be processed, has limited use.
Ductile iron obtained by adding magnesium to liquid cast iron 0.03 ... 0.04%; it has the same chemical composition as gray cast iron. It has the highest strength properties. It is used for casting pump housings, valves.
malleable iron- obtained by prolonged heating at high temperatures of white cast iron castings. It contains 2.5...3.0% carbon. It is used for the manufacture of thin-walled parts (nuts, brackets ...). In water management construction, cast-iron plates are used - for lining the surfaces of hydraulic structures that are subject to abrasion by sediments, cast-iron water valves, pipes.
Become- obtained as a result of the processing of white cast iron in open-hearth furnaces. With an increase in the carbon content in steels, their hardness and brittleness increase, while at the same time, ductility and impact strength decrease.
The mechanical and physical properties of steels are significantly improved when alloying elements (nickel, chromium, tungsten) are added to them. Depending on the content of alloying components, steels are divided into four groups: carbon (no alloying elements), low-alloyed (up to 2.5% of alloying components), medium-alloyed (2.5 ... 10% of alloying components), high-alloyed (more than 10% of alloying components) .
Carbon steels, depending on the carbon content, are divided into low carbon (carbons up to 0.15%), medium carbon (0.25 ... 0.6%) and high carbon (0.6 ... 2.0%).
Non-ferrous metals and alloys include aluminum, copper and their alloys (with zinc, tin, lead, magnesium), zinc, lead.
In construction, light alloys are used - based on aluminum or magnesium, and heavy alloys - based on copper, tin, zinc, and lead.
Steel building materials and products.
Hot rolled steel produced in the form of an equal-shelf corner (with shelves 20 ... 250 mm wide); unequal corner; I-beam; I-beam wide-shelf; channel.
For the manufacture of metal building structures and structures, rolled steel profiles are used: equal-shelf and unequal-shelf corners, channel, I-beam, and Taurus. Rivets, bolts, nuts, screws and nails are used as fasteners made of steel. When performing construction and installation works, various methods of metal processing are used: mechanical, thermal, welding. The main methods of production of metal works include mechanical hot and cold working of metals.
At hot processed metals heated to certain temperatures, after which they are given the appropriate shapes and sizes during the rolling process, under the influence of hammer blows or press pressure.
Cold working of metals subdivided into locksmith and metal cutting. Locksmith and processing consists of the following technological operations: marking, cutting, cutting, casting, drilling, cutting.
Metal processing, cutting is carried out by removing metal shavings cutting tools (turning, planing, milling). It is produced on metal-cutting machines.
To improve the construction qualities of steel products, they are subjected to heat treatment - hardening, tempering, annealing, normalization and carburizing.
hardening consists in heating steel products to a temperature slightly higher than the critical one, holding them at this temperature for some time and then rapidly cooling them in water, oil, oil emulsion. The heating temperature during hardening depends on the carbon content in the steel. Hardening increases the strength and hardness of steel.
Vacation consists in heating hardened products to 150 ... In the process of tempering, the viscosity of steel increases, the internal stress in it and its brittleness decrease, and its machinability improves.
Annealing consists in heating steel products to a certain temperature (750 ... 960 ° C), holding them at this temperature and then slowly cooling them in a furnace. When annealing steel products, the hardness of steel decreases, and its machinability also improves.
Normalization- consists in heating steel products to a temperature slightly higher than the annealing temperature, holding them at this temperature and then cooling them in still air. After normalization, steel with higher hardness and fine grain structure is obtained.
Cementation- this is a process of surface carburization of steel in order to obtain high surface hardness, wear resistance and increased strength in products; while the inner part of the steel retains a significant toughness.
Non-ferrous metals and alloys.
These include: aluminum and its alloys- it is light, technological, corrosion resistant material. In its pure form, it is used for the manufacture of foil, casting parts. For the manufacture of aluminum products, aluminum alloys are used - aluminum-manganese, aluminum-magnesium ... Aluminum alloys used in construction with low density (2.7 ... 2.9 kg / cm 3) have strength characteristics that are close to the strength characteristics of building steels. Products made of aluminum alloys are characterized by simplicity of manufacturing technology, good appearance, fire and seismic resistance, antimagnetism, and durability. This combination of construction and technological properties of aluminum alloys allows them to compete with steel. The use of aluminum alloys in enclosing structures makes it possible to reduce the weight of walls and roofs by 10...80 times, and to reduce the complexity of installation.
Copper and its alloys. Copper is a heavy non-ferrous metal (density 8.9 g/cm3), soft and ductile with high thermal and electrical conductivity. In its pure form, copper is used in electrical wires. Copper is mainly used in various types of alloys. An alloy of copper with tin, aluminum, manganese or nickel is called bronze. Bronze is a corrosion-resistant metal with high mechanical properties. It is used for the manufacture of sanitary fittings. An alloy of copper and zinc (up to 40%) is called brass. It has high mechanical properties and corrosion resistance, lends itself well to hot and cold working. It is used in the form of products, sheets, wire, pipes.
Zinc is a corrosion-resistant metal used as an anti-corrosion coating when galvanizing steel products in the form of roofing steel, bolts.
Lead is a heavy, easily machined, corrosion-resistant metal used for caulking the seams of socket pipes, sealing expansion joints, and manufacturing special pipes.
Corrosion of metal and protection against it.
Impact on metal constructions and environmental structures leads to their destruction, which is called corrosion. Corrosion begins from the surface of the metal and spreads deep into it, while the metal loses its luster, its surface becomes uneven, corroded.
According to the nature of corrosion damage, continuous, selective and intergranular corrosion are distinguished.
continuous corrosion subdivided into equal and uneven. With uniform corrosion, the destruction of the metal proceeds at the same rate over the entire surface. With uneven corrosion, the destruction of the metal proceeds at an unequal rate in different parts of its surface.
Selective corrosion covers individual areas of the metal surface. It is subdivided into surface, point, through, and spot corrosion.
Intergranular corrosion manifests itself inside the metal, while the bonds along the boundaries of the crystals that make up the metal are destroyed.
According to the nature of the interaction of the metal with the environment, chemical and electrochemical corrosion are distinguished. Chemical corrosion occurs when metal is exposed to dry gases or non-electrolyte liquids (gasoline, oil, resins). Electrochemical corrosion is accompanied by the appearance of an electric current that occurs when liquid electrolytes (aqueous solutions of salts, acids, alkalis), moist gases and air (conductors of electricity) act on the metal.
To protect metals from corrosion, various methods of their protection are used: sealing metals from an aggressive environment, reducing environmental pollution, ensuring normal temperature and humidity conditions, and applying durable anti-corrosion coatings. Usually, in order to protect metals from corrosion, they are coated with paints and varnishes (primers, paints, enamels, varnishes), they are protected with corrosion-resistant thin metal coatings (galvanizing, aluminum coatings, etc.). In addition, the metal is protected from corrosion by alloying, i.e. by melting it with another metal (chromium, nickel, etc.) and non-metal.
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TOPIC: MATERIAL INFORMATION
1. General information
2. Physical properties
3. Mechanical properties
5. Technological tests of metals and alloys
6. Structure of metals, alloys and liquid melts
Bibliography
1. General information
The world is material in nature. Everything that surrounds us is called matter. Atom, living cell, organism, etc. - all this different kinds matter. The observed diversity of phenomena in nature represents various forms of moving matter. Matter has various forms of motion: life processes, chemical transformations, electric current, heating and cooling, etc. Matter does not disappear and is not created again, it only changes its forms. Some forms of motion of matter can pass into others. For example, mechanical motion can turn into thermal, thermal - into chemical, chemical - into electrical, electrical - into mechanical, etc.
Each separate type of matter, which has a certain composition and properties, is called a substance. The features by which different substances differ from one another are called properties. Substances differ in color, state of aggregation (solid, liquid or gaseous), density, melting and boiling points, etc. To characterize a substance, you need to know a certain number - a set of features - of the properties that it possesses. For example, a substance whose density is 1000 kg / m 3, a boiling point of 100 ° C and a melting point of 0 ° C, is water H 2 O. The properties of materials are determined mainly in laboratory conditions using special methods provided for by State standards and specifications.
Substances can be simple or complex. Simple substances (iron, copper, oxygen, carbon, etc.) consist of atoms or ions of one element. Compounds (water, carbon dioxide, sulphuric acid, steel, etc.) consist of molecules formed by atoms or ions of different elements.
Substances can be pure or in the form of mixtures. Pure substances (simple and complex) consist of homogeneous molecules, atoms and ions. Mixtures consist of various simple and complex substances. An example of a mixture is air, which consists of molecules of various gases (nitrogen, oxygen, carbon dioxide, etc.). Granite is a mixture of quartz, mica and feldspar.
Properties of materials used in industrial production, conditionally divided into physical, mechanical, chemical, technological, etc.
2. Physical properties
To the physical properties depending on internal structure materials include: density, porosity, thermal conductivity, heat capacity, electrical conductivity, thermal (thermal) expansion, frost resistance, fire resistance, melting point, etc.
Density is a value equal to the ratio of the mass of a substance to the volume it occupies. By density, metals and alloys are divided into two groups: light, whose density is less than 5000 kg/m 3 , and heavy, whose density is more than 5000 kg/m 3 . Light metals include aluminum, magnesium, titanium and alloys based on them, heavy metals include copper, nickel, zinc and alloys based on them. In the production of machines and mechanisms, in order to reduce their mass, metals and alloys of lower density are used.
Porosity - the degree of filling the volume of the material with pores.
Thermal conductivity, heat capacity, frost resistance, water absorption depend on the porosity of materials.
Thermal conductivity is the ability of a material to transfer heat flow through its thickness, which occurs due to the temperature difference on opposite surfaces. Thermal conductivity is characterized by the amount of heat passing for 1 hour through a layer of material 1 m thick, 1 m 2 in area, with a temperature difference on opposite plane-parallel surfaces of one degree. Thermal conductivity depends on the internal structure of the material.
The high thermal conductivity of metals and alloys in comparison with other materials is explained by the fact that thermal energy in metals is carried by free electrons that are in constant motion. Free electrons collide with vibrating ions and exchange energy with them. The vibrations of the ions, which increase upon heating, are transferred by electrons to neighboring ions, while the temperature quickly equalizes throughout the entire mass of the metal. How more thermal conductivity metal, the faster the heat when heated spreads throughout the volume. This property is taken into account in the manufacture of heating devices, engines that heat up during operation, in the gas cutting of metals and alloys, in the processing of metals with a cutting tool.
Thermal conductivity is of great importance when choosing materials for heat-enclosing structures, heat exchangers, and pipe insulation.
Electrical conductivity - the ability of metals and alloys to conduct electric current under the influence of an external electric field. Free electrons carry electric current, so the thermal and electrical conductivity of pure metals are proportional to one another. The electrical conductivity of metals decreases with increasing temperature. This is due to the fact that when heated, the vibrations of ions in the metal increase, and this interferes with the movement of electrons. At low temperatures, when the vibrations of the ions decrease, the electrical conductivity increases sharply.
Silver, aluminum, copper and alloys based on them have high electrical conductivity, while tungsten and chromium have low electrical conductivity. From metals that conduct electric current well, they make electrical wires, conductive parts of electrical machines, and from metals and alloys that conduct electricity poorly (having high electrical resistance), electric heaters and rheostats are made.
Heat capacity - PROPERTY of materials to absorb a certain amount of heat when heated. The heat capacity shown is the specific heat capacity, which is equal to the amount of heat (in joules) that is needed to heat 1 kg of material by one degree. Specific heat capacity is used when calculating the processes of heating or cooling materials.
Water absorption is the ability of a material to absorb and retain water in its pores. The water absorption of a material depends on its porosity; the greater the porosity, the greater the water absorption.
Saturation of materials with water changes their properties: thermal conductivity increases, frost resistance decreases.
The moisture content of a material is determined by the ratio of the moisture content of a sample to the dry weight of that sample.
Water permeability is the ability of a material to pass water under pressure through itself. Water permeability is characterized by the amount of water that has passed through a sample with an area of 1 m 2 for 1 hour at a constant pressure of 1 N and a certain thickness of the sample. Water permeability depends on the porosity, density of the material, shape and size of the pores.
Vapor, gas permeability - properties that are characterized by the amount of steam or gas (air) that has passed through a sample of certain sizes at a given pressure.
Frost resistance - the ability of a material in a state saturated with water to withstand a multiple number of cycles of alternate freezing and thawing without visible signs of destruction and without a significant decrease in strength. Dense materials, as well as materials with low water absorption, are usually frost-resistant. According to the number of withstand cycles of alternate freezing and thawing (degree of frost resistance).
Thermal (thermal) expansion - the ability of materials to change their dimensions during heating at constant pressure. This property is taken into account when laying pipelines, railroad tracks. Long pipelines and steam pipelines in a heated state significantly increase their size. Therefore, so that the pipelines can freely lengthen while remaining unharmed, special devices are made - compensators that perceive the elongation of pipelines during thermal expansion. Bridges are equipped with movable supports. In buildings and structures of great length, thermal seams are provided. Rails on crane and railway tracks are laid with small gaps for free thermal expansion.
Melting point - the constant temperature at which a solid material changes into a liquid melt under normal pressure. To read the temperature, two scales are used: thermodynamic, where the unit of temperature is the kelvin (indicated by K), and international practical, where the unit of measure is the degree Celsius (indicated by ° C).
The melting point of materials depends on the strength of the bond between molecules, ions and varies over a very wide range: for example, the melting point of mercury is -39°C, tungsten +3410°C. Pure metals melt at certain temperatures, while most materials melt within a range of temperatures.
The self-resetting trolleys worked flawlessly, and the fingers for gripping the frames were not bent. It is necessary to periodically coat drying trolleys with anti-corrosion compounds and repair them in a timely manner. BASIC INFORMATION ABOUT THE DRYING PROCESS Brick drying is carried out only by the convective method, that is, by the method in which moisture evaporates due to heat exchange between the product and ...
Permits for the manufacture of a steam boiler. In connection with the foregoing, it is necessary to be able to perform one of the most complex and critical sections of calculating the strength of the boiler - calculating the strength of strengthening a single hole in the drums, Moreover, the problem is more relevant due to the use of boiler designs with large holes in the drums. Exists...
At technology lessons, children learn to process not only fabric, paper and cardboard, but also various parts of plants, minerals, artificial materials and waste materials - waste of consumer goods, etc. Children collect them on excursions, bring them in the form of semi-finished products and blanks or ready-made industrial products.
Natural materials include plant branches, leaves, flowers, seeds, roots, bark, moss, fruits, river and sea stones, sand, clay, as well as parts of animals - fish bones, shells and shells of mollusks, dried insects, poultry egg shells, feathers. In the form of semi-finished products in the classroom they use different size boards.
From artificial materials for work, students often use plasticine, plastic, plywood, fiberboard, soft sheet metals, pieces of plastic, ceramics.
Finished industrial products include such waste materials as packaging, boxes, ribbons for decorating gifts and bouquets, jars, bottles, accessories for decorating clothes and premises.
Processing of the listed materials is impossible without special knowledge of materials science and technology of their processing. Children acquire such knowledge in the process of observations and experiments.
In the first grade, the following observations should be made: determining the shape and color of leaves, acorns, nutshells, comparing the properties of sand and clay, wood and metal, identifying artistic expressive features in a folk toy, etc.
In the second class, observations of the properties of cones, bark, branches are carried out. Features of processing soft and hard materials are revealed.
In the third grade, students observe the properties of dried plants, straw, identify the properties of ceramics, plastics, glass. Students learn to choose best ways processing of these materials.
In the fourth grade, work is underway to generalize and deepen existing knowledge. Students independently choose the best ways to process materials, develop the simplest technological maps for creative projects.
The teacher provides thorough instruction on the collection, storage and pre-processing of various materials. Particular attention is paid to hygiene requirements, as well as safety rules for the collection, transportation and storage of materials. In addition, the teacher is obliged to point out that in our country there is a law on environmental protection, which obliges us to take care of natural resources. It is not recommended to use ready-made products that have undergone special processing and are suitable for human consumption (cereals, pasta, flour, legumes). For work, use only products with an expired shelf life.
To work with different materials, special tools are selected.
Marking and measuring tools.
Pencils– for marking details on wood, hard pencils of grade 2 are required T and 3 T. The sharpening angle of the pencil should be sharp. When marking, the pencil must be held at a slight inclination in the direction of its movement and pressed firmly against the edge of the template or ruler;
Rulers- For measurement, they usually use a metal ruler or tape measure. For marking on wood, it is more convenient to use a thick wooden ruler or a carpenter's square. The marking of round parts is carried out with a joiner's compass. The marking of straight lines on metal is carried out using a scriber, on wood - with a thickness gauge.
Cutting tools.
Scissors- in the processing process, clerical and rarely locksmith scissors are used more often.
Knives- for work, well-sharpened knives with a short blade (90-100mm) are used. For splitting wood, it is more convenient to use a mower - a knife with a shorter and thicker blade. In the process of cutting, the knife is held obliquely, guiding its movement with the index finger. Natural materials are cut on stands and lining boards.
Hacksaws and jigsaws– designed for sawing wood and metals. For convenience, the processed materials are clamped in a vice or clamp.
wire cutters- used for biting off wire, thin twigs.
Stichel- a narrow cutter, having the shape of an acute angle or arc in cross section (angular and semicircular). The shtichel is used when finishing wood products (flat-embossed carving), linoleum (cliché for linocut).
Mounting tools.
A hammer- used to assemble products with nails. When working with a hammer, care must be taken that the student does not hit the fingers holding the nail.
Pliers and round nose pliers- used when working with wire. These tools are used to bend and twist the wire.
Awl- used for making holes in soft or easy-to-machine materials. Piercing is performed on stands or backing boards.
Gimlet– Designed for drilling holes in harder materials. Work with a gimlet is performed on stands or lining boards.
Glue brush- should be tough. The width of the brush is chosen according to the dimensions of the surface of the connecting part.
Connecting parts and materials.
Nails- Large nails are not used in labor lessons. More often they use Nos. 1, 2, 3, 4, which corresponds to the length of the nail in centimeters.
Pin- a rod for a fixed connection of parts. The pin is easy to make from a match, twig or strip of paper. A pin connects parts from acorns, cones, stucco materials.
Glue- to connect natural materials, PVA glue, casein or carpentry glue is used. It is better to glue floating models with casein glue, PVA glue, BF, Moment. Gluing parts requires great care. Glue is applied to a thin material or the glued part of the surface of a smaller part. Dry leaves are smeared with glue from the center of the sheet to the edges. Glue the smeared leaves carefully after they have absorbed some of the moisture. Glue is applied to narrow and deep surfaces using the tip of an awl dipped in glue.
The task of a technology teacher is not only to provide students with tools and all the necessary materials, but also to keep them in good condition. Knives and scissors must be properly sharpened, the tip of the awls and gimlets must not be broken, the jigsaw file must be well stretched and ring like a string when touched with a finger, the swivel joints of the scissors and the engraver must be in good condition, the impact part of the hammer must be well fixed on the handle. At each lesson, the teacher is obliged to instruct students about the rules for safe work with tools and some materials.
processed materials.
Wood- most often used in the work of high school students. In the primary classes, pine, spruce, birch, linden wood, as well as three-layer plywood made from them, are used. Wood is sawn in the transverse direction with a hacksaw and a jigsaw. The ends of sawn wood are cleaned with files, sandpaper. coloring wooden crafts oil paint.
In elementary grades, students make pointers, ecker, labels for the class plot. Design specifications are required for the manufacture of such products. For example, boards for labels must correspond to the specified dimensions, their edges must be sanded; the pegs must correspond to the given dimensions in length, thickness, their surface must be processed with a file and sandpaper.
Straw- dried stems of cereal plants, more often use straw of wheat, rye, oats. Straw must be processed before work - remove nodes, sort internodes by length and thickness. For the manufacture of a straw strip, blanks are poured hot water for a day, then each straw is cut lengthwise and ironed with a hot iron on a wooden lining board. Depending on the temperature of the iron, the straw acquires different color shades. Applications are made from straw, it is used for inlaying wood products. Store the straw in a dry ventilated place.
egg shell- an excellent material for the manufacture of bulk and flat products. It is well stained with food coloring, parts from the shell are fixed on glue, plasticine. For the manufacture of bulk products from eggs using a medical syringe, it is necessary to remove the contents. The egg is also filled with heated paraffin using a syringe. By decorating the egg with various decoration details, you can make figures of animals, birds, fish, etc. A mosaic panel can be made from a painted eggshell by first covering the surface to be filled with a layer of plasticine.
plant leaves- used in dried form. The leaves are harvested in autumn, sorted by size, color, shape. The leaves are dried under pressure, or thermally (ironed with an iron). store finished material in a dry place.
birch bark- a favorite material of folk craftsmen. Birch bark is harvested in spring or early summer, cleaned of adhering particles. For the convenience of processing, the birch bark is steamed in hot water, divided into layers, cut into the desired shapes. Dry the material in a cool dry place.
Metals and alloys- in the lessons they often use thin soft wire, soft tin, foil made of aluminum, copper, brass, zinc, tin, lead. Manual processing of metals in a cold state is called locksmith work. Such materials are easy to process with scissors, wire cutters, hammers, pliers and round nose pliers. The cut edges of the parts are processed with a file or sandpaper. The color of parts or products can be changed by holding it over the flame of an alcohol lamp or painting with paints and varnishes for metal.
Holes in thin tin are made with an awl, punches. On thin tin and foil, it is easy to make indentations with the help of chasings, a ballpoint pen and master the simplest chasing techniques. Thin sheet can be bent and twisted with a hammer, pliers, round nose pliers.
Wire can be shaped into rings, polygons, spirals, etc. Wire can be used to make flat contour shapes and three-dimensional products, as well as frames for soft toys. Thin wire can also be used as a connecting material.
Stucco materials- clay, plasticine, plastic, gypsum, salt dough. They are currently available in stores. Clay can be obtained and prepared to work with students.
Oily clay is suitable for modeling. Skinny clay contains a large amount of impurities and is suitable for work after a special treatment - elutriation. Clay is harvested in the summer, dried, crushed and sieved. The crushed clay is placed in a large vessel (tub, tank), filled with water and thoroughly mixed. Floating impurities are removed. Heavy impurities (pebbles, sand) settle to the bottom, and small clay particles remain in suspension. This liquid composition is poured into another container, leaving large impurities at the bottom. After a while, the clay settles to the bottom. Water is drained from the surface. This process is called elutriation.
Before starting work, the clay is poured with water, mixed. A well-cooked mass should not stick to your hands. A sausage 10 cm long and 1 cm thick is rolled up from the prepared clay and lifted at one end. If the sausage does not fall apart, then the clay is ready to go. To improve the quality of clay, you can add paper fiber and vegetable oil. They work with clay on a backing board. Cut clay with wire or fishing line. Products are molded by hand, finishing details are made with a stack or special stamps.
Details made of stucco materials are connected by lubrication, pressing or pins. Products from stucco materials are painted with gouache mixed with PVA glue (1x1, 2x1), watercolors (honey), varnished, or glazed (a glossy glassy alloy fixed by firing, coated on the surface of the product). Dry products in muffle furnaces, on radiators or on a well-ventilated surface.
plastics- chemical products. In primary classes, easily processed plastics are used - organic glass, foam rubber, foam plastic, linoleum, nylon, etc. Plastic blanks are processed by cutting, drilling, they can be painted, joined with glue, stitched. Toys and souvenirs are made from foam rubber and polystyrene foam. Foam rubber can be used for stuffing soft toys.
Linoleum used to make appliqués or clichés. Cliches for linocuts are made using engravers. Paint (gouache, printing ink) is applied to the finished surface of the cliche with a roller, a clean sheet of paper is placed and ironed with a smooth object. Get an impression called a print.
waste materials- packing boxes, corks, reels, tubes of cream, toothpaste, synthetic nets used for packing vegetables, bouquets, empty rods, tubes, etc. Making useful things from waste materials teaches students to be thrifty, develops their creativity, imagination , ingenuity.
Papier mache- most available technology production of bulk products in primary classes. For work you will need: newsprint, paste, gouache. As a form for the manufacture of volumetric products, dishes, toys, home-made forms that are made from plasticine are suitable. Paste for work is made from starch or flour. Products are dried in well-ventilated and warm places. Uneven places on the forms are leveled with sandpaper. Products are painted with gouache paints mixed with PVA glue in the ratio: 2 parts of paint and 1 part of glue.
Features of the processing of various materials, the methodology for studying their properties are described in numerous methodological manuals, books on arts and crafts, magazines on design and needlework, in the books of V.A. Baradulina, A.M. Gukasova, N.M. Konysheva, V.P. Kuznetsova and others.
Test questions.
1. What materials are called natural?
2. What is the peculiarity of storing various materials?
3. By what principle is the selection of various materials for work with primary school students carried out?
4. What connecting materials are used to assemble products from natural materials?
Assignments for independent work.
1. Find (in printed or electronic sources) and study material containing information about the properties of natural materials, methods of their preparation and storage, processing techniques.
2. Select literature that covers the technology of manufacturing products from various materials.
Tasks for laboratory work.
1. Analyze the content of the module: “Processing technology construction materials and machine science" in the program "Technology". Highlight the skills that the authors of the program recommend to form in primary school students in the process of processing various materials.
2. Develop a plan for conducting an experiment for students in grade 3 to observe the properties of one of the specific natural materials.
3. Develop a summary of the lesson aimed at learning how to process one of the artificial materials.
4. Make 1 sample of products from natural materials, artificial materials and waste materials to demonstrate them at technology lessons in primary grades.
5. Develop instruction cards to teach students how to assemble one of the products from various materials.
