SU1636386A1 - Raw mix for producing light concrete - Google Patents

Abstract

The invention relates to building materials, namely lightweight concrete mixtures for the manufacture of building products. The purpose of the invention is to create a given constant degree of porisation, improving the workability of mixtures, reducing vapor permeability while maintaining the strength, density and thermal conductivity of concrete. For this purpose, the raw mix for the manufacture of lightweight concrete includes stagnant, coarse and fine porous slag aggregates, a sizing agent and water, and contains a polystyrene fraction of 4O4, 4 mm, as a foaming agent, a polystyrene concomitant pulverized product in boiling 5% aqueous solution of technical ligosulfonate in the following ratio of components, wt.%: slag Portland cement 11.4- 12.4, large porous slag aggregate - crushed stone crushed stone fraction 5-20 mm 51.6-51.7 crayons Porous slag aggregate — schapam-pemzez sand of fraction 5 mm 20.7–22.7, polystyrene pre-foamed in boiling 5% aqueous solution of technical lignosulfonate 4,1-fi, 2. The concrete preparation technology does not change as compared with the known mixtures, the continuous porous concrete structure is preserved. The density of the concrete is 1323-1360 kg / m3, the workability of the mixture 30 minutes after preparation is 1) -16 s, the vapor permeability decreases to 0.092-0.082 g / (Pa) with a thermal conductivity coefficient of 0.304-0.318 W (m-K ) and compressive strength 5.3-5.7 MPa. 2 tab. in SS O oo OE with 00 o

Description

The invention relates to building materials, namely lightweight concrete mixtures for the manufacture of building wall products.

The purpose of the invention is to create a given constant degree of porosity, improving the workability of the mixture, reducing vapor permeability while maintaining the strength, density and thermal conductivity of concrete.

Raw mix for making

lightweight concrete includes Slag Portland cement, goshkopemzovy crushed stone of a fraction of 5–20 mm, slag – clay sand of a fraction with 5 mm, a pore-forming agent and water, and contains as a pore-forming agent polystyrene of 0.4 mm fraction obtained by treating a coarse pulverized product of pre-foamed polystyrene in boiling 5% - nominal aqueous solution of technical lignosulfonate (LST), in the following ratio of components, wt.%:

Slag Portland cement 11,4-12S4 Slag-and-crushed crushed stone fraction 5-20 mm 51,6-51, / Slag-and-sand sand of a fraction 5 mm 20,7-22,7

A 0.4 mm polystyrene fraction obtained by treating a concomitant pulverized product of a pre-expanded polystyrene in boiling aqueous solution of LST, 1-6.2 Water8.1-11.1

The characteristics of the pre-expanded polystyrene, which is the starting material for the production of polystyrene — a pore-forming agent, existing in the form of grade 5 (fraction less than 0.4 mm), as an accompanying pulverized product, which is not suitable for the preparation of polystyrene foam products are the following: Apparent density, kg / m330 , 0

Strength at compression, kgf / cm2 2.5 Modulus of elasticity at compression, kgf / cmg 73.0 Heat conductivity coefficient, W / (m (K)

Shrinkage in 24 hours Water absorption in 30 days, kg / me Form-resistance at 70 ° C for 24 hours Frost-resistance, C

0.046 0.1

0.07

Resistant to -60

By foaming the concomitant pulverized polystyrene product by boiling LST additive in a 5% aqueous solution, microscopic films and flakes of this additive are formed on the surface of the expanding polystyrene granules in an amount sufficient for

0

five

0

five

changes in the plastic properties of the concrete mix. The plasticizer, when introduced together with the polystyrene granules, improves the workability of the mixture, liquefying the mortar part, which at the same time becomes more connected with the presence of the granules introduced into it. In this case, less plasticizer is required, its losses are minimal, and the effect is higher, since it is not absorbed by coarse aggregate, as with the known introduction into the concrete mixture in the form of an aqueous solution. Exhausted polystyrene granules do not electrify and lose their volatile properties, they are easier to dose and enter into the mixer, and they are evenly distributed in the concrete mix.

The raw mix contains polystyrene of 0.4 mm fraction as a blowing agent, obtained by treating the accompanying pulverized product of refracted expanded polystyrene in boiling 5% aqueous solution of LST.

Each mixture is prepared separately in a concrete mixer with a forced action according to the following technical procedure.

In the concrete mixer, in the case of the prototype, slag-and-pelt crushed stone, slag-and-grit sand, slag-portland cement, shutter water (from the condition of concrete mixture of a given workability of 23 s) and 5% aqueous solution of an adhesives wood saponified resin (SLO), In the case of the proposed mixture, slag-and-gravel crushed stone, slag-pemzez sand, polystyrene of 0.4 mm fraction obtained by treating the accompanying pulverized product of pre-expanded polystyrene in boiling 5% aqueous solution of LST, Slac Portland nt and mixing water (based on the same condition for obtaining a given workability 10 - 15 s).

In order to obtain concrete, three compositions of the proposed raw mix and one known compound are prepared, containing slag-and-ground crushed stone (slag pumice) as a coarse aggregate. Characteristics of the compositions are given in table. one.

Mixing time of each concrete mix 3 min. Determine the degree of orizatsiya mixtures and their comforters

five

0

five

0

five

vaemost (stiffness according to technical viscometer) immediately after preparation and after 30 min. From the resulting mixtures, cubes with an edge of 15 cm, plates of 25x25x5 cm and cylinders with a diameter of 10 cm are molded on a standard vibrating table to determine respectively the strength at the age of 28 days and the density in the dry state of concrete, its thermal conductivity and vapor permeability by standard methods. The molded specimens are heat-treated according to the (4) + 3 + 8 + 3 h mode at an isothermal heating temperature of 95 ° C.

The compositions of the proposed mixtures of compositions and known with the results of tests on the main physical and mechanical indicators are given in Table. 2

As can be seen from the table. 2, the proposed raw material mixture, while maintaining the strength, density and thermal conductivity of lightweight concrete obtained from it, is characterized by a given constant degree of porosity, improved workability, and the concrete structure is consistent with the known composition with minimal consumption of mixture components and without replacing the polystyrene filler used. (fractions 0.4 / / 3.2 mm) to a previously unknown - fr, 0.4 mm, obtained by treating a concomitant pulverized product, pre-expanded polystyrene in boiling water ohm solution of 5% concentration

years old.

The density and heat conductivity coefficient of concrete in the dry state of the proposed composition are reduced by 3.7-7% and 3.1-8.6%, respectively, and vapor permeability - by 6, 7 - 19.5%. At the same time, the preset (9–12%) degree of the mixture’s porning remains, and its workability in the same time interval (30 minutes) practically does not deteriorate, unlike the known mixture, here the degree of porosity decreases to

1636386

ti twice, and workability, estimated in seconds, instead of 20 s is 45 s.

The consumption of fine aggregate in the proposed concrete mix is reduced, compared with the known one by 27.3-40%, and the continuous porous structure of the concrete is preserved.

Claims (1)

Invention Formula Raw mix for the production of lightweight concrete, including slag-portland cement, 5–20 mm fraction of crushed granite as a coarse aggregate, 5 mm fraction of speckled grain sand, foaming polystyrene, an air entraining agent and a plasticizing agent containing technical lignosulfonate and water, which in order to create a given constant degree of porosity, to improve the workability of the mixture, to reduce the steam reproducibility while maintaining the strength, density and thermal conductivity of concrete, it tends to honors vozduhovovlekakntsey additives polystyrene fractions .0,4 mm, obtained by treating concomitant chenny py- | levidnogo predvspenennogo polystyrene product in boiling 5% aqueous solution of technical lignosulfo- nata in the following ratio compo- nents, wt.%: Slac Portland Cement 11.4-12.4 Slag clay crushed stone fraction 5-20 mm51.6-51.7 Slag clay sand fraction 5 mm20,7-22,7 A 0.4 mm polystyrene fraction obtained by treating a concomitant pulverized precursor polystyrene product in a boiling 5% aqueous solution of technical lignosulfonate4.1-6.2 Water. l8,1-11,1 Table 2 The content of the components of the mixture, wt.%: slag portland cement slag-and-cale-gravel crushed stone of fraction 5/20 mm slag-and-creem sand of fraction 6 5 mm polystyrene of fraction 0.4.4 mm, obtained by treating the accompanying pulverized product of pre-expanded polystyrene polystyrene foaming fraction 0.4 / 3.2 mm i.d. LMS of 5% concentration plasticizing agent (LST) water The degree of porosity of the concrete mix,%: after preparation in 30 minutes, the workability of the concrete mix, with: after cooking after 30 minutes Concrete strength at compression for 28 days after TVO, MPa The density of concrete in a dry state, kg / m3 Structure of concrete The coefficient of thermal conductivity of concrete in a dry state, W / (m-K) Permeability of concrete, g / (m h-Pa) 6.2 5.7 5.2 5.4 4.1 5.3 5.3 5.1 1360 1340 1318 1360 1320 SLITNA SLITNA SLITHNA SLITNA 0.318 0.312 0.304 0.318 0.304 0.082 0.086 0.092 0.095 0.098 5.2 4.1 5.4 5.3 5.3 5.1