RU2828958C1 - Composition for making foamed polystyrene concrete with uniform distribution of filler - Google Patents

Abstract

FIELD: construction materials.

SUBSTANCE: invention relates to production of porous construction materials, particularly light concrete, and can be used as a filling mixture when filling internal cavities of monolithic enclosing structures of external and internal walls, insulating layers of coatings and ceilings, and is also used in installation of monolithic seamless floors. Disclosed is a composition for making foamed polystyrene concrete, which contains cement, expanded polystyrene granules and water, wherein the foamed polystyrene granules are treated with a mixture of magnesium stearate, calcium carbonate, animal protein and water. Composition uses foamed polystyrene granules selected by diameter from 3 to 7 mm, which are pre-sorted by size so that more than 90% of the granules are granules of the same size within the deviation ±0.3 mm, and remaining 10% of the granules differ in size by not more than 1 mm.

EFFECT: wider range of polystyrene-cement mixtures, as well as more uniform distribution of polystyrene capsules in foamed polystyrene concrete, reduced volume of foamed polystyrene granules in the mixture, improved sound insulation properties of foamed polystyrene concrete while reducing the proportion of cement and sand in the mixture.

1 cl, 4 dwg, 2 tbl, 2 ex

Description

The invention relates to the production of porous building materials, in particular lightweight concrete, and can be used as a pouring mixture for filling internal cavities of monolithic enclosing structures of external and internal walls, insulating layers of coatings and ceilings, and is also used in the construction of monolithic seamless floors.

A concrete mixture is known that contains prestressing cement, polystyrene granules and water, into which various additives are introduced (see Russian patent 1724620, class C04B 16/08, 1992).

Also known is a polystyrene cement mixture containing Portland cement, polystyrene granules and water (see A.S. 1544748, cl. C04B 16/08, 1990). The specified compositions are intended for the construction of monolithic floors with reduced moisture absorption, which is ensured by a certain ratio of components and the choice of additives, but they are of little use as a filler in monolithic load-bearing building structures.

A polystyrene cement mixture is known, containing cement, polystyrene foam granules, water and a binding additive (liquid glass or PVA) (see Russian patent 2117646, class C04B 28/02, 1998).

The disadvantage of this building material, which has increased heat transfer resistance, is its high bulk density and water absorption.

A METHOD FOR MANUFACTURING HEAT-INSULATING PRODUCTS is known from the prior art [RU 2254310, publ. [20.06.2005], in which Portland cement of grade 400-500, expanded granulated polystyrene PVG grade with a bulk density of 10-20 kg/ ^m3 are used, microsilica and superplasticizer C-3 are additionally introduced into the molding mixture, whereby the said Portland cement is first mixed with microsilica and the said foamed PVG for 2-3 minutes, then water containing superplasticizer C-3 is added, mixed for 3-5 minutes, the mixture is loaded into molding boxes, molding is carried out by vibration compaction and pressing, followed by removing the products from the molding boxes before heat treatment, which is carried out in the following mode: 2 hours at a temperature of 15-25 ° C, then 8 hours at 40-60 ° C and 1 hour at 15-30 ° C, with the following ratio of components, wt. %: the said Portland cement 60.0-65.6, microsilica 6.6-12.0, specified PVG 2.2-4.4, superplasticizer C-3 0.6-0.66, water - the rest. The technical result is the production of thermal insulation products characterized by reduced cement consumption, improved workability, moldability, increased strength and productivity.

The disadvantage of the analogue is the low content of polystyrene granules, as well as the absence of an air-entraining additive, such as saponified wood resin, which leads to an increase in the density of the material and does not allow achieving high strength indicators.

The prior art discloses a REINFORCED POLYSTYRENE CONCRETE MIXTURE, a METHOD FOR PREPARING THE MIXTURE, a METHOD FOR MANUFACTURING HEAT-INSULATING PRODUCTS, a PANEL AND a BLOCK (VARIANTS) [RU 2309134, publ. [27.10.2007], the mixture consists of (kg/ ^m3 ): Portland cement - 160-170, foamed granulated polystyrene - 15-17, basalt fiber - 0.50-0.70, saponified wood resin - 0.35-0.50, plasticizing additive - C-3 - 1.50-2.50, water-repellent additive - 0.4-0.5, polyacrylamide - 0.40-0.60, lignopan B-2 - 0.35-0.50, water - 50-55. The method for preparing reinforced polystyrene concrete mixture includes mixing the components of the composition to obtain it. In this case, expanded polystyrene, basalt fiber and additives introduced together with part of the mixing water are pre-mixed. Then, while mixing, add Portland cement, continue mixing for 5-15 seconds, then add water and mix for 25-40 seconds. The production of products from polystyrene concrete mixture is carried out by volumetric vibration pressing at a compaction value of 8-15 kg/ ^cm2 . The technical result consists in simplifying the method of preparing the mixture, high strength of products, improving thermal insulation properties, high frost resistance, low vapor permeability and low water absorption.

The disadvantage of the analogue is the low content of polystyrene granules, as well as the low (less than 1 wt.%) content of saponified wood resin, which reduces the involvement of a sufficient amount of air in the mixture and ultimately leads to the weighting of the finished block and excess material consumption.

A METHOD FOR MANUFACTURING POLYSTYRENE CONCRETE PRODUCTS is known from the prior art [RU 2223931, published 20.02.2004], in which the air-entraining additive - saponified wood resin - is preliminarily diluted with water in a ratio of (1:5) - (1:10) to an 8-12% concentration of dry matter and kept for up to 48 hours at a temperature of 15-35°C. To wet granulated foamed polystyrene, having a bulk density of 25-30 kg/ ^m3 , fractions with a diameter of 3-5 mm, 1/3 of the mixing water is used and mixed for 0.5-1.5 minutes. After adding grade 400-500 Portland cement to the mixer, the mixture is stirred for 30-60 seconds, then the remaining 2/3 of the mixing water, pre-diluted saponified wood resin and a plasticizing additive - lignosulfonate or superplasticizer C3 are fed into the mixer, the mixture is stirred for at least 2 minutes and heated due to the heat of hydration of the cement to a temperature of 35-75°C and a cohesive porous homogeneous structure is obtained. During molding, the prepared polystyrene concrete mixture is fed using a screw pump into the formwork with a cellular framework installed in it made of reinforcing material - threads or rods with a diameter of (0.5-3)d, with a cell of (50-100) × (50-100) d in 2-4 layers and connecting transverse rods with a diameter of (1.0-4) d with a step of (100-200) × (100-200) d, where d is the average diameter of polystyrene granules. The protective layer between the reinforcement and the outer surface is at least 25 mm. The laid mixture is leveled and kept at a temperature of 15-35 ° C for at least 12 hours. After stripping the formwork, the resulting polystyrene concrete product is sprayed with water once every three days for 30 days, starting from the 8th day after laying the mixture in the formwork. The composition used includes, by weight %: Portland cement - 68-70; foamed polystyrene - 3-6; saponified wood resin (on dry matter) - 0.02-0.1; plasticizing additive (on dry matter) - 0.1-0.2; water - the rest, reinforcing material (over 100%) - 5-12. Technical result: reduction of bulk density and thermal conductivity of products, reduction of consumption of initial components.

The disadvantage of the analogue is the absence of sand in the composition, with the help of which it is possible to create the façade part of a concrete wall during gradient pouring.

Known is a RAW MIXTURE FOR MASONRY MORTAR AND A METHOD FOR ITS PRODUCTION [RU 2490233, published 20.08.2013], containing Portland cement, quartz sand, water, characterized in that the mixture is modified with polystyrene foam waste, crushed to granules of 2-7 mm in size, with a bulk density of 38-40 kg/ ^m3 , liquid sodium glass with a density of 1250 kg/ ^m3 and fly ash from the combustion of brown coal, the mixture contains the specified components in the following ratio, wt.%:

polystyrene foam waste crushed into granules size 2-7 mm, bulk density 38-40 kg/ ^m3 0.25-0.56 liquid sodium glass with a density of 1250 kg/ ^m3 0.415-0.9296 fly ash from brown coal combustion 4.14-9.38 Portland cement 18.76-20.70 quartz sand with the largest grain size of 2.5 and fineness modulus 2.37 56.29-62.10 water rest

The technical result is the production of masonry mortar with reduced density and thermal conductivity of grades M25-M100.

The main technical problem of this solution is the low (less than 2 wt.%) content of polystyrene granules and cement in combination with the high (more than 25 wt.%) content of quartz sand, which increases the density and weight of the finished product and can lead to a decrease in noise and heat insulation and the strength of concrete, as well as to an increase in moisture absorption. At the same time, the increased content of quartz sand does not allow, if necessary, to obtain a monolithic block with different body densities, when the highest density is formed precisely in the façade part, where a large amount of heavy filler - sand is concentrated, and the lowest density - in the back part, where a large number of light polystyrene granules are concentrated.

A composition for the production of expanded polystyrene concrete is known (patent RU2763568, published on 30.12.2021), including polystyrene granules, water, grade D0 (M500) cement, sand, characterized in that it additionally contains an aqueous solution of sodium silicate in a ratio of 1:10, as well as saponified wood resin in the form of a 10% aqueous solution, with the following ratio of components, wt.%:

polystyrene granules 2-3 cement grade D0 (M500) 69-72 sand 15-25 aqueous solution of sodium silicate in a ratio of 1:10 1.8-2.5 saponified wood resin in the form of 10% aqueous solution 1.2-1.6 water rest

This analogue claims to have a reduced material consumption, reduced construction and finishing time, no need to use additional insulation while maintaining thermal conductivity, reduced moisture absorption, increased concrete strength and resistance to dynamic loads.

However, this result is achieved due to the low content of polystyrene granules, as well as an increase in the proportion of cement, which increases the weight of polystyrene concrete products by the same volume and reduces their noise insulation in comparison with products where the proportion of polystyrene granules is many times higher.

In this regard, the indicated result of the analogue, associated with improved sound insulation, is questionable and is most likely stated in comparison with the solution RU 2490233.

The closest to the claimed invention is a polystyrene cement mixture (RU 2213076, published 27.09.2003), containing cement, expanded polystyrene granules and water; according to the invention, the filler "Politerms" is additionally introduced in the following ratio of components, wt.%:

magnesium stearate 9.5-11 calcium carbonate 18-20 animal protein 14.5-16 water rest,

with the following ratio of components of the polystyrene cement mixture, wt.%:

cement 58.0-60.4 polystyrene granules 11.0-12.5 filler 1.2-3.0 water rest

The prototype provides improved thermal insulation properties of the material and has optimal proportions of cement and sand in the mixture.

It should be clarified that the name of the filler "Polyterms" used in the prototype has changed over time to "Polyterm". "Polyterm" is granules of foamed polystyrene treated with a special EIA composition (produced by the Italian company EDILTECO).

"Mosstroy-31" (https://ms31.ru/politerm/) is the only company in Russia with the exclusive right to produce Politerm using Italian technology. "Politerm" is used as a filler for polystyrene concrete mixture: "Politerm" granules are mixed with cement and water directly on site, in accordance with the recommended recipe. A simple and quick mixing method helps reduce the time of preparation and pouring of the mixture. Concrete mixers of various volumes are used to mix the mixture. Also, for the production and laying of a large volume of mixture, it is advisable to use specialized mobile units with high productivity and the ability to deliver the mixture to the laying site - "Politerm machines".

Politherm fraction 3-7 mm is used for the preparation of polystyrene concrete, intended for monolithic thermal insulation of floors, flat roofs, walls (well masonry), and the production of polystyrene blocks.

Today, the disadvantage of all polystyrene mixtures and the mixture according to the prototype is the high fragility of the products due to the uneven distribution of polystyrene capsules. In addition, the uneven distribution of polystyrene capsules also leads to a deterioration in the quality of sound insulation.

High-impact polystyrene (HIPS) and copolymers of styrene with acrylonitrile and butadiene do not have the disadvantage of brittleness. When heated to a temperature of 300-400°C, PS depolymerizes to form a monomer [see https://www.chem21.info/page/104170029080016078068040241190060247021007120099/].

However, to obtain such a polystyrene mixture, special production conditions, high energy costs for heating and expensive additives are required. Thus, the resulting mixture is not economical and has low production volumes, compared to the traditional production method according to the prototype.

In addition, the UPS has worse sound insulation characteristics than the prototype.

The objective of the invention is to reduce the brittleness of the polystyrene cement mixture in the prototype by ensuring a more uniform distribution of polystyrene capsules and at the same time selecting such a percentage composition of the mixture that does not require a large proportion of cement and a large proportion of sand.

The technical result of the invention is an expansion of the range of polystyrene cement mixtures, as well as a more uniform distribution of polystyrene capsules in expanded polystyrene concrete, a reduction in the volume of expanded polystyrene granules in the mixture, an improvement in the soundproofing properties of expanded polystyrene concrete, while reducing the proportion of cement and sand in the composition of the mixture.

The specified technical result is achieved due to the fact that a composition for the production of expanded polystyrene concrete is declared, containing cement, expanded polystyrene granules and water, wherein the expanded polystyrene granules are treated with a mixture of magnesium stearate, calcium carbonate, animal protein and water in the following ratio of components, wt.%:

magnesium stearate 9.5-11 calcium carbonate 18-20 animal protein 14.5-16 water rest,

characterized in that the composition uses expanded polystyrene granules selected by diameter from the range of 3 to 7 mm, which are pre-sorted by size in such a way that more than 90% of the granules are granules of the same size within a deviation of ±0.3 mm, and the remaining 10% of the granules differ in size by no more than 1 mm, and the ratio of the components of the polystyrene cement mixture, wt.%:

cement 58.0-60.4 polystyrene granules 10.5-10.9 filler 1.2-3.0 water rest

Implementation of the invention

The invention describes a composition for producing expanded polystyrene concrete, containing cement, expanded polystyrene granules and water, wherein the expanded polystyrene granules are treated with a mixture of magnesium stearate, calcium carbonate, animal protein and water in the following ratio of components, wt.%:

magnesium stearate 9.5-11 calcium carbonate 18-20 animal protein 14.5-16 water rest

What is new is that the composition uses polystyrene foam granules selected by diameter from the range of 3 to 7 mm, which are pre-sorted by size in such a way that more than 90% of the granules are granules of the same size within a deviation of ±0.3 mm, and the remaining 10% of the granules differ in size by no more than 1 mm, and the ratio of the components of the polystyrene cement mixture, wt.%:

cement 58.0-60.4 polystyrene granules 10.5-10.9 filler 1.2-3.0 water rest

Sorting polystyrene granules by size is explained by the following example.

Example 1

The expanded polystyrene granules are separated by 90% within one selected size with a deviation of ±0.3 mm, for example, by sifting them in a cylindrical bin with mechanical blades of the vertical rotation axis, rotating the contents of the bin under the action of the electric motor shaft. In the lower part of the bin, there is a sieve in the form of a slotted grid with slits of a given size, exceeding the required sorting parameter by 0.5 mm. Under the action of the mass of the granules inside the bin, a slight pressure is created on the granules located near the sieve. Granules of the required size and smaller ones are sifted through the sieve, including 10% of the granules, which differ in size by 1 mm due to the oval shape of some granules.

Unscreened granules are repelled by the sieve and returned to the main mixing mass until complete sorting.

First, large granules (less than 7 mm) are sorted, then the sorted masses are moved to another similar bin, where a smaller sieve is installed (for sifting granules less than 6 mm). After sifting these, the collected mass is then sorted through a sieve for sifting granules less than 5 mm. The actions are repeated until the granules are completely sorted.

At each stage of sorting, starting from the second, a percentage of granules of the required size is obtained, strictly sorted according to the invention.

Manual measurements of 15% of randomly selected granules after experimental tests showed that it is possible to sift out polystyrene foam granules selected by diameter from the range from 3 to 7 mm, which are pre-sorted by size in such a way that more than 90% of the granules are granules of the same size within a deviation of ±0.3 mm, and the remaining 10% of the granules differ in size by no more than 1 mm due to their oval shape (see examples of the sorting result in Fig. 3, Fig. 4, which show granules of size 4 mm (Fig. 3) and 3 mm (Fig. 4) sorted by the specified method according to Example 1).

Better sorting quality cannot be achieved.

Nevertheless, even such indicators of 90% sorted polystyrene granulate allowed achieving better results for the resulting composition for the production of polystyrene concrete, which had better characteristics in the production of polystyrene concrete. Namely, a more uniform distribution of polystyrene capsules in polystyrene concrete was ensured, as well as improved soundproofing properties of polystyrene concrete, in comparison with the prototype.

The method of obtaining polystyrene concrete is explained with an example.

Example 2

The polystyrene foam granules sorted by size according to example 1 are treated with a special mixture of magnesium stearate, calcium carbonate, animal protein and water in the following ratio of components, wt.%:

magnesium stearate 9.5-11 calcium carbonate 18-20 animal protein 14.5-16 water rest

Next, two bags of 420 kg of sorted and processed polystyrene foam granules with the specified mixture are fed into the concrete mixer.

Then the polystyrene granules are mixed with 1/3 of the water for 30 seconds. After that, 200 kg of cement are loaded into the mixer and the mixture is mixed for another 30 seconds. Then the remaining portion of water is poured in and mixed for 10 minutes at maximum speed. This proportion is for the production of 1 ^m3 of the finished mixture.

Due to the fact that each polystyrene foam granule is treated with a mixture of magnesium stearate, calcium carbonate, animal protein and water, this allows, as with the prototype, to mix the balls with water so that they form a homogeneous mass without floating to the surface.

And due to the fact that 90% of the polystyrene granules are selected to be the same size, and the remaining 10% differ in size by no more than 1 mm, a minimum ratio of surface area to the occupied volume of the installation is ensured.

Thus, granules of similar diameter have the least shrinkage deformation and the least compaction, which gives the filler good flowability.

This can be seen from the example in the drawings (see Fig. 1, Fig. 2), where in the mixture according to the prototype (Fig. 1) the used polystyrene foam granules from 3 to 7 mm due to their different sizes (1 - medium, 2 - large, 3 - small) can be arranged completely chaotically, while forming compactions from the smallest granules 4.

Whereas in the mixture according to the invention (Fig. 2) a smaller number of granules fill the same volume due to the same type of granules 5, among which there are deviations (10%), in the form of granules 6, which, due to a slight deviation from the main granules 5 in size of no more than 1 mm, do not in the least change the situation of optimal uniform filling of the volume without compaction from the smallest granules.

The spreadability of the mixture according to the invention (Fig. 2) ensures a more uniform distribution of polystyrene capsules and improved soundproofing properties of polystyrene concrete (see Table 2 below). At the same time, the composition of the mixture according to the invention does not require a large proportion of cement and a large proportion of sand, and due to the uniform distribution of granules and the reduction of their compaction with each other, it was possible to reduce the volume of required polystyrene granules in the total mixture from 11-12.5% to 10.5-10.9%.

The pouring area must be cleaned of dust and any dirt. In warm, sunny weather, the coating hardens in 24 hours.

It is recommended to prepare the polystyrene cement mixture in forced-action concrete mixers with a horizontal shaft, which provide intensive turbulent mixing of the components.

Table 1 below shows examples of the composition of mixtures according to the prototype (mixtures 1, 2, 3) in comparison with the composition of mixtures according to the invention (mixtures 4, 5, 6).

Table 1

Mixture Composition, wt. % Cement Filler surfactants Microsilica Polystyrene granules Water Magnesium stearate Calcium carbonate Live protein Water 1 58.0 1,2 - - 11.0 Rest 10 18 15 57 2 59.0 1.8 - - 11.5 Rest 9.5 20 14.5 56 3 60.4 3.0 - - 12.5 Rest 11 20 16 53 4 58.0 1,2 - - 10.5 Rest 10 18 15 57 5 59.0 1.8 - - 10.7 Rest 9.5 20 14.5 56 6 60.4 3.0 - - 10.9 Rest 11 20 16 53

Table 2 shows the physical and mechanical properties of the compositions of mixtures according to the prototype (mixtures 1, 2, 3) in comparison with the compositions of mixtures according to the invention (mixtures 4, 5, 6).

Table 2

Physical and mechanical properties Composition of the mixture according to the prototype Composition of the mixture according to the claimed invention 1 2 3 4 5 6 Density, kg/ ^m3 250 300 350 250 300 350 Thermal transmittance (λ), kcal/m⋅°С 0.076 0.079 0.082 0.078 0.081 0.084 Pressure resistance (strength), N/ ^mm2 1.0 1.5 1.9 1,2 1.7 2.0 Reduction of noise of footsteps on the floor, dB 14 13 12.5 15.5 14.5 13.5 Adhesion (rigidity), kPa 105 127 149 117 134 155 Combustion (according to ASTM D1962-68) Non-flammable Non-flammable Non-flammable Non-flammable Non-flammable Non-flammable Water absorption μ 14.1 14.2 14.5 14.2 14.3 14.5

From Tables 1 and 2 it is evident that in the claimed invention, while improving the physical and mechanical properties for noise reduction, it was possible to reduce the volume of polystyrene foam granules used.

Claims (4)

A composition for the production of expanded polystyrene concrete, containing cement, expanded polystyrene granules and water, wherein the expanded polystyrene granules are treated with a mixture of magnesium stearate, calcium carbonate, animal protein and water in the following ratio of components, wt.%: magnesium stearate 9.5-11 calcium carbonate 18-20 animal protein 14.5-16 water rest, characterized in that the composition uses expanded polystyrene granules selected by diameter from the range of 3 to 7 mm, which are pre-sorted by size in such a way that more than 90% of the granules are granules of the same size within a deviation of ±0.3 mm, and the remaining 10% of the granules differ in size by no more than 1 mm, and the ratio of the components of the polystyrene cement mixture, wt.%: cement 58.0-60.4 polystyrene granules 10.5-10.9 filler 1.2-3.0 water rest