RU2083523C1 - Concrete mix - Google Patents

Abstract

FIELD: preparation of concrete mixes used for manufacturing light-weight wall units. SUBSTANCE: concrete mix comprises (wt parts):1 portland cement; 3.6- 9.7 ash-slag mixture having bulk density of 1450 kg/cubic cm; 0.024-0.009 polyethylene foam crumb with particle size of not more then 10 mm and bulk density of 12 kg/cubic cm and 0.6-1.1 water. use of the claimed composition makes it possible to reduce water absorption of concrete to 5.2% and also to improved thermal and technical properties of wall materials. EFFECT: improved properties of the concrete mix. 1 tbl

Description

 The invention relates to building materials and can be used for the manufacture of lightweight wall blocks in low-rise construction.

 The composition of the concrete mixture is known, including the ash and slag mixture of the TPP and Portland cement [1]. This mixture provides concrete after hardening with physicomechanical properties corresponding to the properties of cement concrete on traditional aggregates, but the thermal conductivity decreases insignificantly and only in connection with the amorphous structure of slag in the ash and slag mixture.

Closest to the technical nature of the proposed is a concrete mixture, including Portland cement, ash and slag aggregate, crumb of polyethylene and water, acquiring reduced density and water absorption after hardening [2]
A disadvantage of the known composition is the increased water absorption and thermal conductivity due to the dense structure of the polyethylene introduced into the concrete mix.

 The solution to the technical problem is aimed at lowering the water absorption and thermal conductivity of concrete by introducing crushed polyethylene foam with closed micropores into the concrete mix.

This is achieved by the fact that the concrete mixture, including Portland cement, ash and slag aggregate, crumb of polyethylene and water, contains ash and slag aggregate of TPP with a bulk density of 1450 kg / m ³ , and as a crumb of polyethylene, a crumb of polyethylene foam with a particle size of up to 10 mm and bulk density of 12 kg / m ³ in the following ratio of components, parts by weight

Portland cement 1
Specified ash and slag aggregate 3.6-9.7
The specified crumb 0,024-0,009
Water The rest.

The feedstock for the production of polyethylene foam is high pressure polyethylene grades 15803-020, 16204-020. The raw material is ground to a powdery mass, to which powdery porophore is added, and depending on the expansion ratio, zinc stearate, zinc oxide, titanium dioxide, phenosan are added in a certain amount. After mixing, the mass is fed to extrusion. The material obtained after extrusion is irradiated in an electron accelerator, thereby achieving crosslinking of polyethylene molecules. After crosslinking, the material is fed into a foaming furnace at a temperature of 220 ^° C., where the porophore decomposes and directly swells. When preparing the concrete mixture, waste from the production of polyethylene foam with a closed pore structure is used.

 Analysis of the known concrete compositions used in the manufacture of wall building materials showed that polyethylene-like additives to the concrete mix are known, for example, polyurethane foam. However, their use in these compositions does not provide concrete with the properties that are manifested in the proposed mixture, namely, a significant reduction in water absorption and thermal conductivity with sufficient strength for wall materials.

 Preparation of concrete mix is carried out on a traditionally used set of concrete mixing equipment and includes dosing of concrete mixture components during the next mixing of dry components in a concrete mixer of the principle of operation. After achieving uniformity, the calculated amount of water is added to the dry mixture. In this case, the mobility of the concrete mixture corresponds to 4 cm of precipitation of a standard cone. Wall stones with a size of 190x190x390 mm, having 3 through voids, are formed from the resulting concrete mixture.

 Crushing of waste polyethylene foam produced in the installation of two-stage grinding to obtain crumbs oblong shape with a flat surface and a maximum particle size of 10 mm With large particles of polyethylene foam chips, the concrete mixture becomes heterogeneous. The developed surface of the crumb provides better adhesion of the polyethylene foam to the cement stone and ensures the elastic work of concrete when the ultimate stresses in the stone are reached under load.

For experimental verification of the claimed composition, a series of samples of concrete mixtures was prepared at a constant consumption of cement and at variable costs of ash and slag mixture, water and polyethylene. For the maximum strength of concrete in this series, the optimal consumption of polyethylene foam chips of 300 l per 1 m ^{3 of} concrete was established.

 Then, at a constant flow rate of the ash and slag mixture of the TPP and polyethylene foam chips, 6 concrete compositions were prepared.

The composition of 1 m ³ concrete and its properties are presented in the table.

Claims (1)

A concrete mixture including Portland cement, ash and slag aggregate, crumb of polyethylene and water, characterized in that it contains as an ash and slag aggregate a ash and slag mixture of a thermal power plant with a bulk density of 1450 kg / m ³ , and as a crumb of polyethylene, a crumb of polyethylene foam with a particle size of up to 10 mm and bulk density of 12 kg / m ³ in the following ratio of components, parts by weight Portland cement 1
Specified ash and slag aggregate 3.6 9.7
The specified crumb 0,024 0,009
Water 0.6 1.1x

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