SU1645252A1 - Combined addition to the concrete mixture - Google Patents

Abstract

The invention relates to building materials, in particular, to the composition of complex additives modifying properties of concrete. The purpose of the invention is to increase the water resistance of concrete while maintaining its strength and frost resistance, increasing the ability of an additive to create fine, conventionally closed pores in the structure of concrete. The complex additive includes the following components, wt%: sodium salt of the naphthalene sulfoxlox condensation product with formaldehyde 84.7 - 90.9; och; gogoethoxy-2-ethylhexoxyisloxane 9.1- 15.3. The permeability of heavy concrete with the complex additive W12-W14, conditionally close the volume.x then 6.8-8.1%. 3 tab. c (O (L

Description

The invention relates to building materials, namely, compositions of complex additives that modify the properties of concrete.

The purpose of the invention is to increase the water resistance of concrete while maintaining its strength and frost resistance, increasing the ability of additives to create fine conditionally closed pores in the structure of concrete.

Portland cement M400, quartz sand with Мkn 2.0 mm, crushed granite FR. 5-20 mm tap water.

As the sodium salt of the condensation product of naphthapnic sulfonic acid with formaldehyde, the commercially available superplasticizer C-3 is used as the organosilicon siloxane compound, oligoethoxy-2-ethylhexoxy-syn-ocean.

Oligoethoxy-2-ethylhexoxysiloxane is a low viscosity colorless or slightly yellow liquid beta of mechanical impurities.

The physicomechanical indicators of the silicon-organic liquid are presented below.

Cfc

4 SP

to eat go

Kinematic viscosity at 20 ° C, cSt

Medium reaction Hydrophobicity, not less

Pour Point, ° C Structural Formulas

OE

OR

HO + Si-O-H-Si-O-l-B I OR

Jn

I

(F

m

 where R is CrHr-;

R - CaH

7

n 1-V;

t 9-i.

Toxic-2-ethylhexoxysiloxane oligog is produced by the chemical industry in the form of a 100% organosilicon liquid, and is also intended to be produced in the form of a 50% aqueous emulsion.

The silicone fluid is highly soluble in organic solvents, forms stable emulsions with water, and is diluted with water in any ratios.

The preparation of aqueous emulsions is carried out using a solvar in the amount of 2-4% by weight of the silicone fluid as an emulsifier. Solutions and aqueous emulsions of oligoethoxy-2-ethylhexoxysiloxane have a strong water-repellent effect.

The preparation of the additive is carried out as follows.

The sodium salt of the condensation product of formaldehyde with naphthalenesulfonic acid is dissolved in the gate water, then an aqueous emulsion of oligoethoxy-2-ethylhexoxysiloxane is added to the resulting solution. All components are mechanically mixed for 5 minutes. The water temperature of the shutter is 20 + 2 ° С.

The compositions of complex additives are given in table. one.

The prepared complex additive is introduced into the concrete mixture of composition C: P: S 1: 2.09: 3.39 by weight. (B: C of control, without additives, composition 0.42).

All prepared concrete mixes

had a cone draft of 3 cm. Samples

0

five

0

five

0

five

0

five

0

five

fine-grained concrete mix with a 115 mm cone melt of composition C: P 1: 2 is prepared at the same time.

Data on the composition of the concrete mix with additives are presented in table. 3, the physicomechanical properties of the samples are given in Table. four.

Recommended composition of complex additives are the compositions according to examples 2, 3 and 4, when introduced into the concrete mix in an amount of 0.6, respectively; 0.70; 0.8% by weight of cement.

Composition 1 is characterized by reduced water tightness and strength, and composition 5 is characterized by a low degree of formation of fine conditionally closed pores, which leads to a decrease in water resistance and frost resistance.

As follows from the above results, the introduction of the proposed complex additive into the concrete mix allows creating a system of fine conventionally closed pores, characterized by a volume of conditionally closed pores.

The volume of conditionally closed pores in the concrete structure when using the proposed additive in fine concrete is 1.23-1.35 times more than when using a prototype additive, when using an additive in heavy concrete - more than 1.04-1.09 times.

The water resistance of concrete with the use of the proposed additive is higher by 2-4 marks in comparison with the prototype, the frost resistance also increases and the strength of concrete is maintained high.

Claims (1)

Invention Formula Complex additive in concrete mixture, including sodium salt of naphthalene sulphonic acid condensation product with formaldehyde and silicon-organic siloxane compound, characterized in that, concrete structure, it contains oligoethoxy-2-ethylhexoxysiloxane as the silicone siloxane compound in the following ratio comrade, wt.%: The sodium salt of the condensation product of naphthalene sulfonic acid with formaldehyde. 84,7-90,9 Oligoethoxy-2-ethyl-hexoxy siloxane 9.1-15.3 Table 1 FineTable 2 Table 3 Note e. For samples of heavy concrete, the strength of the samples is measured under compression after HFO after 7 days. Continued table. 3