RU2254310C1 - Method of manufacturing heat-insulation products - Google Patents

Abstract

FIELD: manufacture of building materials.

SUBSTANCE: invention relates to manufacture of polystyrene-concrete parts for use in construction as wall and heat-insulating material. Manufacture of heat-insulation products comprises preparation of molding mix from Portland cement (60.0-65.6%), water, and granulated foamed polystyrene with loose density 10-20 kg/m³ (2.2-4.4%), molding, and heat treatment of products. Invention resides in that molding mix additionally includes microsilica (6.6-12.0%) and superplasticizer S-3 (0.6-0.66), starting mix Portland cement/microsilica/foamed polystyrene is first stirred for 2-3 min, then water containing superplasticizer is added, resulting mix is stirred for further 3-5 min and loaded into molding boxes. Molding involves vibrocompaction and pressing followed by unloading of products from molding boxes and heat treatment: 2 h at 15-25°C, 8 h at 40-60°C, and 1 h at 15-30°C.

EFFECT: reduced consumption of cement, improved placeability and moldability of mix, increased strength of products, and increased productivity.

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Description

The invention relates to the production of building products and building structures, namely polystyrene concrete products intended for use in construction as a wall and heat-insulating material.

In world practice, polystyrene concrete has been known since the 50s of the last century, and in the USSR the first developments belong to the 70s, however, polystyrene concrete was widely used only in the 90s. The widespread use of this material in construction is due to high consumer properties. Polystyrene concrete, the so-called lightweight concrete, can be used in construction not only as building envelopes, but also as load-bearing structures of buildings, which can reduce the weight of building structures, lower the ground load, reduce heat loss, increase the fire resistance of buildings, and increase the number of storeys. Building material, which is a foam concrete with polystyrene foam filler and special additives, is produced in the form of blocks and slabs. Blocks, depending on the brand, have different load-bearing capacity and are used for laying self-supporting walls and for the construction of load-bearing walls in low-rise construction. Plates are solid insulation and can be used for insulation of walls, floors, ceilings. Walls erected from polystyrene concrete blocks do not require the use of additional insulation and are 2-2.5 times lighter than from traditional materials.

A known method of manufacturing polystyrene foam (RF patent No. 2201907, class MKI C 04 B 38/08, priority 02.03.2001) from cement, water, foam and polystyrene granules, which consists in the fact that the prepared cement mortar is first served 0 , 1-0.3 m ^{3 of} foam per 1 m ^{3 of} concrete and the mixture is stirred for 0.5-5 minutes, then styrene foam granules are fed in an amount of 0.2-0.6 m ³ per 1 m ^{3 of} concrete and the mixture is mixed 0, 5-5 minutes, then foam is fed in an amount of 0.3-0.1 m ³ per 1 m ^{3 of} concrete and mixed for 0.5-5 minutes. Effect: increased strength and reduced manufacturing time.

The disadvantage of this method is the low strength of manufactured products.

The composition of concrete is known (Pat. EP No. 1189853, class MKI C 04 B 38/08, priority 10.04.2000). According to this, an additive is used to produce lightweight concrete. This additive is a mixture of 40-99% organic polymeric material and 1-60% air-entraining agent. The additive is suitable for the production of lightweight concrete containing polystyrene aggregate for excellent dispersion of the polystyrene aggregate and improve its binding to the surrounding binder.

A known method of wall cladding of especially lightweight concrete (US Pat. RF No. 2197583, class MKI E 04 F 13/08, priority 05.07.2000). Cladding for the walls of buildings is made of particularly lightweight concrete, in particular polystyrene concrete blocks, lightweight slabs of fine-grained concrete. Effect: increasing the reliability of attaching lightweight large-sized slabs to walls made of especially lightweight concrete, reducing the complexity of installing the cladding and ensuring fire safety when using combustible materials in the wall structure. Wall cladding made of especially lightweight concrete contains a layer of slabs made with holes for accommodating fasteners. The plates are installed with mutual overlap and gaps, metal fasteners are made flexible in the form of rods with tails and anchors, each anchor is made in the form of a rod whose axis is perpendicular to the plane of the shank. Shanks and rods are fixed in adhesive seams between blocks of especially lightweight concrete, for example polystyrene concrete, each of the slabs being connected with blocks of especially lightweight concrete by means of an adhesive seam.

A known method of manufacturing environmentally friendly lightweight polystyrene concrete products (US Pat. RF No. 2082695, MKI C 04 B 38/00, priority 02/11/94, priority), comprising preparing a concrete mixture containing polystyrene granules, a polymer additive, cement, water, laying the mixture in the form and heat treatment, while the polystyrene granules are preliminarily thermostated, and the mixture contains components in the following ratio, wt.%:

cement - 67.0-75.0 granules of thermostatic expanded polystyrene - 4.75-5.55 polymer additive - 0.25-0.45 water - the rest.

Thermostatting of polystyrene granules is carried out in a stream of heated air at 60-87 ° C for 2.5-5 hours at a coolant flow rate of 0.5-2.5 m / s. After temperature control, polystyrene granules are treated with a polymer additive containing a mixture of dicarboxylic acids and saponified wood resin in the following ratio of components, wt.%:

mixture of dicarboxylic acids - 35-60 mixture of salts of dicarboxylic acids - 25-30 saponified wood resin - 15-38.

Then the granules are mixed with cement and a homogeneous molding mixture is prepared, which is molded into products and subjected to further processing.

The disadvantage of this method is the low strength of the products and the complexity of manufacturing.

A known method of preparing a building mixture (US Pat. RF No. 2201412, MKI C 04 B 40/00, priority July 20, 2000), including preliminary joint grinding of Portland cement, quartz sand and superplasticizer and subsequent mixing of the grinding product with building sand. In this case, the grinding is carried out to a specific surface of 4500-5500 cm ² / g, and the grinding product is first mixed for 3-4 minutes. with silica fume, and then with ordinary building sand or a mixture of it with crushed stone fractions of 5-20 mm in the following ratio of components, wt.%:

Portland cement - 14.7-22.5 quartz sand - 1.7-2.5 superplasticizer - 0.22-, 034 silica fume - 0.7-1.1 crushed stone fractions 5-20 mm - 0-0.51 ordinary building sand - 22.56-82.68.

The manufactured products had strength, MPa: R _bend 8.1-10.7; R _compression 68.7-82.0.

The disadvantage of this method is the limitation of its use.

A known composition (US Pat. RF No. 2182141, MKI C 04 B 38/08, priority 20.03.2000) for the manufacture of lightweight concrete products, including cement, sand, expanded polystyrene foam granules, water and a complex additive consisting of 0.015 wt.% Sulfate soap and 0.15 wt.% technical lignosulfate, calculated on the weight of the composition in the following ratio of components, wt.%:

cement - 50-51 sand - 3-31 expanded polystyrene granules - 2.1-2.2 complex supplement - 0.165 water - the rest.

EFFECT: increased adhesion of granules to a binder, plasticization of concrete mix, increased strength and decreased density of finished products.

The disadvantage of this composition is the limited capabilities. The closest technical solution is a method of manufacturing heat-insulating products (US Pat. RF No. 2080311, MKI C 04 B 38/08, priority January 31, 1996) by preparing a molding mixture of cement, water and polystyrene foam, molding and heat treatment of products at a temperature not higher than 70 ° C. Moreover, to prepare the molding mixture, first mix 2 vol. parts of cement with 1 vol. part of water for 15 seconds to obtain a gel-like cement ligament, then 5-10 vol. parts of expanded polystyrene and produce final mixing for 16.5 seconds to obtain a molding mixture. Portland cement 400 is used in accordance with GOST 10178-85, water in accordance with GOST 23792-79 and self-extinguishing foaming polystyrene (PSV-S pre-foamed type in accordance with GOST 30105-202-92. Preparation of polystyrene-concrete mixture is carried out on a standard concrete mixer - forced-action concrete mixer C-256, cement 600 / AD-600-2VS (DVTs-600) water dispenser 600 2AD-400-2VSh (DBZh 400) Heat and humidity treatment is carried out in pit type chambers according to the following mode: exposure without steam for 4 hours, temperature rise to 50 ° C 2 hours, holding at 50 ° C for 2 hours, temperature rise about 70 ° C 3 hours isothermal heating at 70 ° C 3 hours, cooling to 60 ° C 3 hr.

EFFECT: thermal conductivity of expanded polystyrene concrete with a volume weight of 500 kg / m ³ is 0.19 W / m * ° C or 0.13 kcal / m * g * ° C. In this case, expanded clay concrete has 0.57 kcal / m * g * ° C, and brickwork of ordinary clay brick on a cement-sand mortar of 0.48 kcal / m * g * ° C.

The disadvantage of this method is the limited technical capabilities and insufficiently high strength of manufactured products.

The objective of the proposed method for the manufacture of heat-insulating products is to eliminate the above disadvantages, as well as reducing the consumption of Portland cement, improving workability, formability, increasing the strength of concrete, its frost resistance and productivity.

To achieve this goal, a molding mixture is prepared from Portland cement grade 400-500, water and expanded polystyrene granular PVG grade at a bulk density of 10-20 kg / m ³ , additionally, silica fume and S-3 superplasticizer are introduced into the molding mixture. First, the specified Portland cement is mixed with silica fume and the specified foamed PVG for 2-3 minutes. Then, water containing C-3 superplasticizer is added to the mixture and mixed again for 3-5 minutes. After that, the mixture is loaded into molding boxes, forming by vibration compaction and pressing is carried out, followed by extraction of products from molding boxes before heat treatment, which is carried out in the following mode:

2 hours at a temperature of 15-25 ° C;

8 hours at a temperature of 40-60 ° C;

1 hour at a temperature of 30-15 ° C.

The components for the manufacture of thermal insulation products are taken in the following proportions, wt.%:

specified portland cement - 60.0-65.6 silica fume - 6.6-12.0 specified PVG - 2.2-4.4 superplasticizer C-3 - 0.6-0.66 water - the rest.

Introduction to the molding sand mixture of silica fume allows you to reduce cement consumption, increase the volume of cement paste, increase density, strength and durability. Silica fume is a small spherical particles with an average specific surface area of about 20 m ² / g, the average particle size is about 0.1 microns, about 100 times smaller than the average grain size of cement. The density of silica fume is approximately 2.2 g / m ³ (Portland cement 3.1 g / m ³ ), and the bulk density in the loose state is 130-430 kg / m ² (cement 1500 kg / m ² ).

The silica fume used easily reacts with calcium hydroxide released during cement hydration, increasing the amount of hydrated silicates such as CSH, which have the ability to attach other ions, especially alkalis, which is essential to reduce the expansion caused by reactions between alkalis and aggregate. The silicate gel formed during the hydration period subsequently passes into morphological silicates of the CSH type, which is a factor in increasing the strength of concrete with silica fume. It was experimentally established that in the hardening cement mass, silica fume in an amount from 0 to 20% by weight of Portland cement reduces the amount of Ca (OH) ₂ from 33 to 5%. In addition, the compaction of the cement mixture contributes to the filling of the space between the particles of Portland cement and the products of hydration by particles of silica fume.

By bonding free lime and compacting the cement mixture, silica fume enhances corrosion resistance. The addition of silica fume in an amount of 10-20% by weight of Portland cement increases the strength of concrete by 30-35%, water resistance by 25-50% and sulfate resistance by 90-100%. When substituting up to 5% of Portland cement with silica fume, the quality of the resulting concrete changes very slightly, with an increase in the amount of silica fume, the physical indicators of concrete increase intensively, but when the silica content in the concrete is 20-30%, changes in physicomechanical characteristics were not observed or changed slightly. At the same time, the water demand of the mixture increased, which led to a decrease in strength.

The use of S-3 superplasticizer as a plasticizer provides increased concrete strength and improves molding properties, accelerates the hardening process. The indicated amounts of C-3 superplasticizer were established experimentally and its overdose leads to an unjustified rise in price of the mixture.

The presence in the concrete mixture of polystyrene allows you to get building material used for thermal insulation of walls, roofs, ceilings, for thermal insulation of buildings in monolithic and cottage construction. The resulting material has a high degree of sound absorption, which allows it to be used as sound absorbing material.

The proposed method uses polystyrene expanded granular foamed PVG, representing a product of single or multi-stage suspension foaming of polystyrene (GOST 301-05-202-92E), having a mark in bulk density from 10 to 20 kg / m ³ fine fraction size 2.5-10 mm

The use of polystyrene for the manufacture of articles in the indicated quantity allows obtaining polystyrene concrete characterized by grades in density D200-D250, and in strength M2-M3.5. The use of polystyrene less than the lower limit does not provide polystyrene concrete with specified technical characteristics. When using polystyrene more than the upper limit, the quality of polystyrene concrete is deteriorated, especially strength and thermal conductivity. Portland cements used in the method are characterized by grades 400, 500, without additives (DO) in the amount necessary for the technological process (180-250 kg / m ^{3 of} polystyrene concrete).

A specific example of execution.

Pour Portland cement grade M500DO in the amount of 180 kg into the mortar mixer, add silica fume in the amount of 36 kg and foamed granular polystyrene PVG grade in bulk density of 20 kg / m ³ fractions of 2.5-10 mm in the amount of 13.4 kg. Mix the dry mass for 2-3 minutes and gradually introduce mixing water in the amount of 68.5 liters with the addition of superplasticizer C-3 in the amount of 1.8 kg (1% by weight of Portland cement). Mix the molding mixture for 5 minutes until a homogeneous mixture is formed. Then the mixture is loaded into the molding boxes of the press and vibrocompressed, followed by pressing with a force of 35 g / cm ² for 1 minute, then we remove the force, remove the items from the molding boxes and place them in the heat treatment chamber with the processing mode:

2 hours at a temperature of 15-25 ° C;

8 hours at a temperature of 40-60 ° C;

1 hour at a temperature of 30-15 ° C.

The obtained products from polystyrene concrete with a size of 100 × 200 × 400 are characterized by a strength grade of M2, a density of 200 kg / m ³ , a thermal conductivity coefficient of 0.064 W / (m * ° C), and an operating humidity of 4%.

Other examples are given in table 1.

Thus, the proposed method for the manufacture of heat-insulating products allows to obtain high-quality products (some of its physical and mechanical characteristics are given in table 2), which can be used in construction as a wall, heat-insulating and soundproof material.

Table 1

Example No. The quantitative content of the components, per 1 m ³ polystyrene concrete Manufacturing parameters Portland cement, kg Silica fume, kg Polystyrene, kg Superplasticizer S-3, kg Water, l 1st stirring, min 2nd stirring, min Heat and moisture treatment 1 2 3 4 5 6 7 8 nine 1 Grade 500 TO 180 (60%) 36 (12.0%) Brand 20
13.4 (4.4%) 1.8 (0.6%) 68.5 (23%) 2-3 5 at 15-25 ° C -2 hours
40-50 ° C -8 hours
15-20 ° C -1 hour 2 Brand 500 to 200 (62.72%) 30 (9.41%) Brand 15
10.9 (3.413%) 2.0 (0.627%) 76.0 (23.83%) 2-3 3-5 at 15-25 ° C -2 hours
40-50 ° C -8 hours
15-20 ° C -1 hour 3 Grade 400 TO 250 (65.634%) 25 (6.563%) Brand 10
8.4 (2.205%) 2.5 (0.656%) 95.0 (24.942%) 2-3 5 at 15-25 ° C -2 hours
40-50 ° C -8 hours
15-20 ° C -1 hour Prototype 2 vol. parts 260 kg 5-10 about. parts 300-400 kg / m ³ 1 about part 105l fifteen 16.5
2 minutes 4 hours without steam
2 hours at 50 ° C
2 hour exposure
3 hours at 70 ° C,
3 hours isothermal exposure
3 hour cooling

table 2 №№p / p Example Compressive strength grade according to GOST 10180 The density of polystyrene concrete, kg / m ³ Coefficient of thermal conductivity in the dry state, W / (m * ° С) Sorption humidity according to SNiP 11-3-79 *,% 1 2 3 4 5 6 1 1 M2 200 0,064 W-4 2 2 M2.5 250 0,070 W-5 3 3 M3.5 250 0,075 W-6 4 Prototype 500 0.190

Claims (1)

A method of manufacturing heat-insulating products by preparing a molding mixture of Portland cement, water and expanded polystyrene, molding and heat treatment of products, characterized in that they use Portland cement grade 400-500, expanded polystyrene granular PVG grade at a bulk density of 10-20 kg / m ³ in molding the mixture is additionally injected with silica fume and C-3 superplasticizer, and first, said Portland cement is mixed with silica fume and said foamed PVG for 2-3 minutes, then water and soda are added holding C-3 superplasticizer, mix for 3-5 minutes, load the mixture into molding boxes, perform molding by vibration compaction and pressing, followed by removal of products from 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, in the following ratio of components, wt.%: specified portland cement - 60.0-65.6 silica fume - 6.6-12.0 specified PVG - 2.2-4.4 superplasticizer C-3 - 0.6-0.66 water - the rest.