RU2490233C2 - Raw material for masonry mortar and method of its production - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to composition of raw material mixture for masonry mortar and method of its production, namely to production of porous building materials, based on cement binding agents, obtained by addition of porous substances. raw material mixture for masonry mortar contains wt %: Portland cement 18.76-20.70, quartz sand with the coarseness grains 2.5 and module of coarseness 2.37 56.29-62.10, wastes of foam-polystyrene, crushed to granules with size 2-7 mm, bulk density 38-40 kg/m³, modified 0.25-0.56, liquid sodium glass with density 1250 kg/m³ 0.415 - 0.9296, fly ash from brown coal burning 4.14-9.38, water - the remaining part. Method of producing masonry mortar from said raw material mixture includes crushing of foam-polystyrene waste to granules of said size and density, supply of obtained granules into mortar mixer, addition of said liquid glass with water in ratio by weight 1:1, mixing for 1-2 minutes, introduction of said fly ash and mixing for 1-3 minutes, introduction of Portland cement, said sand and remaining water into mortar mixer with modified said foam-polystyrene waste and mixing for 3-5 minutes.

EFFECT: obtaining masonry mortar with lower density and heat-conductivity of brands M25 - M100.

2 cl, 1 ex, 5 tbl

Description

The invention relates to the composition of the raw mix for masonry mortar and method for its manufacture, namely to the production of porous mortars based on cement binders obtained by the addition of porous substances. The effectiveness of this solution is manifested during masonry in building envelopes using piece materials (brick, cellular, aerated concrete, foam concrete blocks, etc.) with low thermal conductivity and density, to reduce heat loss through masonry joints.

A known method of reducing thermal conductivity and density by introducing into the concrete lightweight aggregates, including polystyrene granules. Styrofoam concrete is prepared by mixing cement, water, foam and polystyrene beads. A mixture of cement and water is prepared, polystyrene granules are fed into it in an amount of 0.2-0.4 m ³ per 1 m ^{3 of} concrete and mixed for 0.5-5 minutes, after which foam is fed in an amount of 0.4-0 , 8 m ³ per 1 m ^{3 of} concrete and mixed for 0.5-5 minutes, then again polystyrene granules in an amount of 0.2-0.4 m ³ per 1 m ^{3 of} concrete and mixed for 0.5-5 minutes [Patent RU 2198151, IPC C04B 38/08, C04B 38/10, 2001].

Significant disadvantages of this method of preparation and composition of expanded polystyrene concrete:

- pop up and unevenly distributed components in the mixture when using polystyrene foam granules;

- such compositions cannot be used in masonry mortars. the size of the granules does not allow evenly distributing the masonry mortar with a thin bonded layer on the surface, the polystyrene granules are exposed, the strength of this composition in a thin layer is low;

- low adhesion of the binder and other mineral components of the mixture to the filler - expanded polystyrene, the reason is the heterogeneous surfaces of the expanded polystyrene and the mineral component of the solution;

- during the preparation of the mixture polystyrene granules are electrified, stick together.

A known method of removing electrostatic voltage from the surface of a lightweight aggregate. By moistening the granules with solutions of salts of lignosulfonate acid with a sugar content, especially hexose and / or pentose, followed by the application of a binder (primarily cement, gypsum, anhydrite or lime, finely ground stone flour, quartz, limestone can be added to the binder as an additive and others) [Patent of Germany Cl. 80 No. 1281338, B 21/01, C04B 31/00, 08/24/72]. The main disadvantage of this method of removing electrostatic stress is that the salts of lignosulfonate acid and sugar reduce the setting and hardening of cement binders.

Building cement-sand mortars using expanded, natural crushed porous rocks (expanded clay, perlite, agloporite, pumice, vermiculite, etc.) are known [Gorchakov G.I., Bazhenov Yu.M. / Building materials: Textbook for universities. - M .: Stroyizdat, 1986. - 688 p., Ill .; GOST 28013-98 Building solutions. General specifications]. The disadvantages of these mortars: the high cost of natural material and the energy intensity of additional funds spent on its extraction and processing (drying, firing, crushing, etc.), as well as the open pore structure of the aggregate, which increases permeability and negatively affects water absorption, frost resistance and other operational properties of masonry mortars.

The closest in technical essence cement-sand mortar composition Portland cement: Sand: Water [Gorchakov G.I., Bazhenov Yu.M. / Building materials: Textbook for universities. - M .: Stroyizdat, 1986. - 688 p., Ill .; GOST 28013-98 Building solutions. General specifications]. It is often used in construction work for the laying of various stones and blocks. The disadvantages of this cement-sand mortar: increased, in comparison with building blocks, density ρ = 2100-2200 kg / m ³ , thermal conductivity λ = 0.6-0.7 W / m * ° C.

The closest in technical essence and the achieved result method, which consists in preparing a solution by sequentially mixing cement, aggregate and water and then laying the solution on a surface previously moistened with water [P.N. Klochanov, A.E. Surzhanenko, I.Sh. Eidinov. Prescription and technological reference for finishing work. - M .: Stroyizdat, 1973, p.100]. This method of preparation, when cement is first mixed with aggregate, and then sealed with water, does not make it possible to obtain a cohesive workable masonry mortar with a modified lightweight polystyrene foam aggregate.

The technical objectives of the invention are:

1. Development of the composition of the raw mix for masonry mortar with reduced density and thermal conductivity to improve the thermal characteristics of the wall structure by incorporating fine crushed polystyrene granules into the composition of the fine lightweight aggregate, preventing heat loss through masonry joints (“cold bridges”);

2. Development of the simplest method for the manufacture of masonry mortar satisfying technological and technical and economic requirements, the essential features of which are the special order of introduction of the components and mixing modes.

EFFECT: obtaining a masonry mortar with a reduced density and thermal conductivity of the M25-M100 grades, for laying bricks, building stones, cellular blocks, etc.

The technical result, according to the invention, is achieved by the fact that:

1. The raw material mixture for masonry mortar containing Portland cement, quartz sand, water, characterized in that the composition of the mixture is introduced modified polystyrene waste, crushed to granules of 2-7 mm in size, bulk density 38-40 kg / m ³ , liquid sodium glass with a density of 1250 kg / m ³ and fly ash from burning brown coal, the mixture contains these components in the following ratio, wt.%:

Polystyrene waste, crushed to granules size 2-7 mm, bulk density 38-40 kg / m ³ 0.25-0.56 Liquid sodium glass with a density of 1250 kg / m ³ 0.415-0.9296 Fly ash from burning brown coal 4.14-9.38 Portland cement 18.76-20.70 Sand quartz with the largest grain size 2.5 and fineness modulus 2.37 56.29-62.10 Water rest

2. A method of manufacturing a masonry mortar according to claim 1, which consists in pre-mixing polystyrene wastes, crushed to granules of 2-7 mm in size, bulk density 38-40 kg / m ³ , which are fed into the mortar mixer, add liquid sodium glass with a density of 1250 kg / m ³ , with water in a ratio by weight of 1: 1, mix for 1-2 minutes, introduce fly ash from burning brown coal and mix for 1-3 minutes until a uniform distribution of fly ash in the granules is achieved, then into a mixer with modified polystyrene foam gran administered s Portland cement, quartz sand with a maximum grain size of 2.5, fineness modulus 2.37, and the remaining water, mix for 3-5 minutes.

The masonry mortar contains the following components:

- Portland cement - GOST 10178 of the PTs500 DO brand (properties see table 1.1);

Table 1.1 Properties of Angarsk Portland cement PC 500-D0 The name of indicators GOST requirements 10178-85 Actual Values one 2 3 Mass fraction of additives,% absent absent Mass fraction of sulfur oxide,% 1.0-3.5 2.5-3.5 Compressive strength after steaming, MPa 28.0-32.0 28.0-32.0 Compressive strength after 28 days, MPa, not less 49.0 49.0-53.0 Bending strength after 28 days, MPa, not less 5.9 5.9-6.8 Setting time, min: Start not earlier than 45 210.0-260.0 end no later than 600 240.0-360.0 Mass fraction of alkaline oxides in terms of Na ₂ O,% Not standardized 0.5-1.0 Mass fraction of Cl no more,% 0.1 0.01-0.05 Mineralogical composition of clinker,% Calcium Silicate Not standardized 58.0-64.0 Dicalcium silicate Not standardized 12.0-16.0 Tricalcium Aluminate Not standardized 6.0-8.0 Four Calcium Aluminopherite Not standardized 11.0-14.0 Mass fraction of magnesium oxide, not more than,% 6.0 4.0-5.0 Specific efficiency of natural radionuclides, Bq / kg, no more 370.0 70-150

- quartz sand GOST 8736 with the largest grain size of 2.5 and a particle size modulus of 2.37 (properties, see table 1.2);

Table 1.2 The main physical properties of quartz sand Zuevsky quarry Fineness modulus Bulk density, kg / m ³ The density is true, kg / m ³ Total residues,% by weight, on sieves 2,5 1.25 0.63 0.315 0.14 <0.14 2,37 1640 2670 20.62 27.02 33.61 61.54 94.56 100.00

- granules of crushed polystyrene foam obtained by grinding polystyrene foam waste with a size of 2-7 mm, bulk Density ρ _us = 38-40 kg / m ³ GOST 15588, have a thin closed pore structure;

- liquid sodium glass ρ = 1250 kg / m ³ GOST 13078 - removes static electricity, serves as a connecting component in the formation of a shell of fly ash on polystyrene foam granules;

- fly ash (properties see table 1.3, 1.4), helps to remove static electricity on the surface of polystyrene granules, improves adhesion and affinity of polystyrene foam aggregate with mortar components, allows you to evenly distribute components in the mixture, improves adhesion of lightweight aggregate to mineral components, promotes reduction of salt formation, compaction of the cement stone of the solution, increasing the final strength of the hardened composition at a lower density;

Table 1.4 Physical properties of fly ash from burning brown coal Waste producer CHPP-6 of JSC Irkutskenergo Bulk density, kg / m ³ 1500-1600 Humidity,% Not> 1 Specific surface, ^cm2 / g Not <1500 Sieve residue No. 008,% by weight Not> 15 P.p.p.,% No more than 5 The value of the specific activity efficiency of natural radionuclides (allowable value of 370 Bq / kg) 138.4 Environmental hazard class V (safe) Radiation safety class according to GOST 30108-94 and NRB-99 I (A _eff <370 Bq / kg)

- water for concrete and mortar GOST 23732.

The study suggests that the required strength is guaranteed.

An example of the preparation of a masonry mortar (expanded polystyrene mortar M100): prepared by mixing all the components according to the invention, in the following sequence: waste from expanded polystyrene was crushed to granules of 2-7 mm in size, 0.25% by mass of the solution was fed into the granules obtained (CDM ) and liquid glass 0.41% CDM with water 0.41% CDM, mixed for 1-2 minutes, then fly ash was introduced in the amount of 4.14% CDM, mixed for 1-3 minutes until a uniform distribution of fly ash on the surface ty polystyrene granules. Then, Portland cement 20.70% CDM, sand 62.10 wt.%, The rest water 11.99% CDM were added to the mixer to the obtained modified polystyrene granules and mixed for 3-5 minutes. Mark of the obtained masonry mortar for mobility P ₂ .

Standard samples according to GOST 5802 were made from mortar, which were kept under natural hardening conditions for 28 days. They were compared with control masonry mortars and the range of the optimal number of crushed polystyrene foam granules was selected within the range of 0.25-0.56% of the mass parts of the solution. Thermal conductivity was determined on an electronic thermal conductivity meter ITP-MG4 "100" in accordance with the instruction manual. The average density, average compressive strength, bending, frost resistance was determined according to GOST 5802. The results obtained are presented in table 1.5.

Masonry mortar according to this formula is obtained cohesive, with evenly distributed components of the mixture, is easily applied with a thin layer; polystyrene foam granules do not expose, do not float, static electricity is removed, the strength of the hardened mortar corresponds to the grades M100-M25, the thermal conductivity of the masonry mortar is reduced by 1.5-3.27 times. The planned technical result is achieved.

When deviating from the formula for the composition of the masonry mortar, it is impossible to obtain a composition of a fused structure with a uniform distribution of polystyrene granules in the mixture; apply a thin layer of solution. Either the thermal conductivity changes insignificantly and the expediency of complicating the technology by adding modified polystyrene foam granules disappears.

Claims (2)

1. The raw material mixture for masonry mortar containing Portland cement, quartz sand, water, characterized in that the mixture is modified with polystyrene waste, crushed to granules of 2-7 mm in size, bulk density 38-40 kg / m ³ , liquid sodium glass with a density of 1250 kg / m ³ and fly ash from burning brown coal, the mixture contains these components in the following ratio, wt.%:
polystyrene waste, crushed to granules size 2-7 mm, bulk density 38-40 kg / m ³ 0.25-0.56 liquid sodium glass with a density of 1250 kg / m ³ 0.415-0.9296 fly ash from burning brown coal 4.14-9.38 Portland cement 18.76-20.70 quartz sand with the largest grain size 2.5 and fineness modulus 2.37 56.29-62.10 water rest 2. A method of manufacturing a masonry mortar according to claim 1, which consists in pre-mixing polystyrene wastes, crushed to granules of 2-7 mm in size, bulk density 38-40 kg / m ³ , which are fed into the mortar mixer, add liquid sodium glass with a density of 1250 kg / m ³ with water in a ratio by weight of 1: 1, mix for 1-2 minutes, introduce fly ash from burning brown coal and mix for 1-3 minutes until a uniform distribution of fly ash in the granules is achieved, then into a mixer with modified polystyrene granules vvo ny Portland cement, quartz sand with a maximum grain size of 2.5, fineness modulus 2.37, and the remaining water, mix for 3-5 minutes.