RU2136624C1 - Concrete mix - Google Patents

Abstract

FIELD: building materials industry, more particularly preparation of heat-insulating concrete used for manufacture of safety structures having high heat- insulating properties. SUBSTANCE: composition comprises peat, sawdust, clay, portland cement and water, ratio of components being as follows, wt %: peat 12-16; sawdust, 4-8; clay 17-18; portland cement, 9-10; and water, the balance. EFFECT: simplified composition and reduced cost price thereof due to maximum use of local raw material having sufficient building properties.

Description

 The invention relates to the building materials industry and can be used to obtain heat-insulating concrete used for the manufacture of building envelopes with high thermal insulation properties.

Known peat composition for obtaining insulating concrete (see RF patent N 2005701, C 04 B 28/30, 01/15/94.), Including, wt.%:
Magnesium Oxide - 16 - 25
Lowland peat - 40 - 48
Portland cement - 14 - 27
Sodium Chloride - 1 - 3
Water - Else
The closest analogue in terms of essential features is concrete mix (see ed. St. USSR N 1244122, C 04 B 28/04, 07/15/86, 3 pp.), Including, wt.%:
Portland cement - 33 - 38
Peat deposits wood waste - 20 - 25
Peat - 4-12
Water - Else
A disadvantage of the known concrete mixes is the high consumption of expensive mineral binders (magnesium oxide, Portland cement).

 The present invention is aimed at solving the problem of simplifying the composition and reducing its cost due to the maximum use of local raw materials while maintaining sufficient construction and technical indicators.

The problem is achieved in that in the known concrete mixture, including Portland cement, lightweight aggregate containing peat, wood waste and water, sawdust is used as wood waste in the lightweight aggregate, and the concrete mixture additionally contains clay in the following ratio of components, wt.% :
Portland cement - 9 - 10
Peat - 12 - 16
Sawdust - 4 - 8
Clay - 17 - 19
Water - Else
Peat is taken in an amount of at least 12%, because otherwise, the technological properties of the mixture and not more than 16% will not be ensured in order to avoid warping of the material. Sawdust is taken in an amount of at least 4% to ensure the fibrous skeleton of the material and not more than 8% to maintain the desired technological properties. Clay is taken at least 17% to ensure sufficient strength of the material. Portland cement is taken at least 9% to fix the clay well, and not more than 10% so as not to increase the density of the material. The remaining amount of water is necessary for the normal consistency of the mixture.

 Example 1. The proposed composition was prepared as follows: took 70 g of sawdust, 212 g of peat, mixed for 2 minutes Separately, 300 g of clay, 159 g of Portland cement were mixed. Then, a mixture of sawdust and peat was added to the mixture of clay and Portland cement, mixed for 2 minutes, 1024 ml of water was added, mixed for 3 minutes.

The resulting mixture was placed in a pre-lubricated form until it was completely filled. Then it was sealed with a load on a vibrating platform for 2 minutes. After that, samples in the form were placed in a steaming chamber for 5-6 hours at 70 ^o C and W _rel = 100%. Then the deformed samples were placed in a drying chamber for 8-10 hours at 100 ^o C, after which their density and strength were determined by known methods.

Example 2. Used the same methodology, but took the following composition, g:
Peat - 230
Sawdust - 88
Clay - 318
Portland cement - 176
Water - 970
Example 3. Used the same methodology, but took the following composition, g:
Peat - 282
Sawdust - 141
Clay - 335
Portland cement - 177
Water - 830
The test results are shown in the table.

 A mixture of peat and sawdust is used as a filler, with sawdust playing an additional reinforcing role. During hardening of a binder made of clay and Portland cement with water, complex physical and chemical processes take place: hydration and hydrolysis of cement grains, hardening of hydrolysis products, exchange absorption of cement hydrolysis products with a finely dispersed part of clay, irreversible coagulation of clay under the influence of hydrolysis products, microreaction and cementation of particles. The formation of calcium hydrosilicates and hydroaluminates, which bind the fixed clay into a durable material.

Industrial applicability
The proposed concrete mixture was experimentally tested in laboratory conditions at the Department of Production of Building Products and Structures of TSTU, which confirms its industrial applicability.

Claims (1)

A concrete mixture comprising Portland cement, a lightweight aggregate containing peat and wood waste, and water, characterized in that the lightweight aggregate contains sawdust as wood waste, and the concrete mixture additionally contains clay in the following ratio, wt.%:
Portland cement - 9 - 10
Peat - 12 - 16
Sawdust - 4 - 8
Clay - 17 - 19
Water - Else

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