RU2102356C1 - Concrete mix - Google Patents

Abstract

FIELD: manufacture of building materials, more particularly concrete mixes containing wood filler. SUBSTANCE: concrete mix comprises (wt %): 20.5-29.7 cement; 25.2-39.1 wood filler, 6.0-12.1 powdery lime; 0.01-0.02 bischofite of higher fatty C₆-C₂₀ alcohols; and the water balance. The claimed concrete mix solidifies at accelerated rate and the resulting products have strength of not greater than 3.2 kgf/sq cm. EFFECT: improved properties of the resulting products. 2 tbl

Description

 The invention relates to building materials, and in particular to compositions of concrete mixtures containing wood aggregate.

 Known concrete mixture, including cement, wood aggregate, chemical additives and water (1).

 Closest to the invention in technical essence and the achieved result is a concrete mixture including wood aggregate, mineral binder and additives of the following composition, wt.

Shredded wood 24.7 38.0
Mineral binder 21.5 30.3
Powdered lime 7 5.0 11.5
Calcium Chloride 2.5 4.8
Water 24.2 37.5
However, this concrete mixture slowly hardens and has a low grade strength of concrete.

 The solution to the technical problem is aimed at speeding up the hardening process of concrete mix on wood aggregate and increasing the brand strength of concrete.

This is achieved by the fact that the concrete mixture, including cement, wood aggregate, powdered lime, additives and water, contains bischofite and still bottoms from the production of higher fatty alcohols of the C ₆ -C ₂₀ fraction as additives, in the following ratio, wt.

Cement 20.5 29.7
Wood aggregate 25.2 39.1
Powdered lime 6.0 12.1
Bischofite 3.5 6.1
VAT residues of the production of higher fatty alcohols "ALFOL" fraction C ₆ -C ₂₀ 20 0.1 0.02
Water Else
As a wood filler, sawdust, wood crushed, chopped wood can be used.

 When wood aggregate is introduced into the concrete mixture, the strength of concrete usually decreases and hardening processes are slowed down due to the presence of water-soluble extractive substances of monosaccharides in the wood.

 Introduction to the concrete mixture as additives of bischofite, powdered lime and bottoms production of higher alcohols solve the problem of accelerating the hardening of the mixture and increase the brand strength of concrete.

 The mechanism of interaction of the composition of the additives with the concrete mixture is as follows.

Use a natural bischofite solution with a density of 1.3 1.32 g / cm ³ , pH 5-6, the following chemical composition, wt.

Magnesium chloride 41.0 42.0
Magnesium Bromide 0.7 0.8
Potassium chloride 1.6 1.7
Calcium Chloride 4.0 4.1
Calcium sulfate 0.56 0.60
Calcium carbonate 0.44 0.50
Calcium bicarbonate 0.25 0.30
Water Else
When additives are added to the wood aggregate, bischofite magnesium chloride and calcium chloride react with water-soluble extractive substances (monosaccharides) of wood to form calcium and magnesium sugars, which slow down the hardening of the concrete mixture to a lesser extent.

 However, during the reaction of magnesium chloride and calcium chloride with extractive substances of wood, foaming of the mixture is caused and the strength of concrete is reduced.

Reduces foaming and increases the strength of concrete additive bottoms residues production of higher fatty alcohols "Alfol" fraction C ₆ -C ₂₀ .

 The reaction of powdered lime with bischofite promotes the formation of calcium hydroxylate, which accelerates the hardening of the concrete mixture and is a preservative of wood material.

 For experimental verification of the claimed composition of the concrete mixture were prepared four composition of the concrete mixture, three within the claimed ratios of the components, the fourth known composition. The ratio of the components of concrete mixtures are shown in table 1.

 All materials included in the proposed concrete mix are regulated by regulatory documents that reflect their properties and composition stability: Portland cement grade 400 corresponds to GOST 10178-85, softwood sawdust, fractions 0.0 5.0 mm GOST 18320 78, bischofite GOST 7759-73, powdered lime GOST 9179-77, calcium chloride GOST 450-77, bottoms of the production of higher fatty alcohols TU 38.107119-77.

 The concrete mixture is prepared in the following sequence: sawdust is mixed with additives, cement is added to the mixture and the mixture is mixed, water is gradually introduced and the mixture is mixed again.

From the prepared mixtures, vibro-densification was used to form cubes with a 10 cm rib, which were then subjected to heat and humidity treatment according to the following conditions: holding for 12 hours, raising for 2 hours, isothermal for 8 hours, cooling for 2 hours at 40 ^o C.

 After heat and moisture treatment, the compressive strength of concrete samples was determined in accordance with GOST 10180-74.

 Comparative test results of the obtained compositions and the known are presented in table 2.

 The obtained test results show that, in comparison with the known, the proposed composition of the concrete mix is 40% higher in strength.

 The advantage of the proposed concrete mixture is also the durability and fire resistance of concrete products and structures obtained from it.

 The proposed concrete mixture is recommended for the production of wall materials in low-rise construction.

Claims (1)

Concrete mixture including cement, wood aggregate, powdered lime, additives and water, characterized in that it contains bischofite and still bottoms from the production of higher fatty alcohols "Alfol" fraction C ₆ C _{8 0} in the following ratio of components, wt. Cement 20.5 29.7
Wood aggregate 25.2 39.1
Powdered lime 6.0 12.1
Bischofite 3.5 6.1
VAT residues of the production of higher fatty alcohols "Alfol" fraction C ₆ C ₈₀ 0.01 0.02
Water Rest

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