Feasibility of using plasticisers for producing heat insulation foam concrete

Abstract

Based on the audit findings of raw materials used in concrete manufacture, this study aimed to opti-mise the composition of non-autoclaved heat insulation foam concrete (grade D300). When planning an experiment, a strength characteristic of foam concrete was taken as a parameter, while the cement water factor (W/C) of the cement mortar (matrix) and the concentration of a foam solution were taken as determinant factors. The research area was chosen based on the foam concrete’s ability to form the structure and ensure its stability. The "W/C" factor was considered within the following values: 0.60 ÷ 0.84 for foam concrete without a plasticiser, 0.54 ÷ 0.78 - with a plasticiser. The concentration of the work foam solution was varied across the range from 1 to 9%. Samples of heat insulation foam con-crete with dimensions of 100x100x100 mm were moulded using a foam concrete mixture prepared according to the conventional technology. The compressive strength of the samples was determined by the destructive method. In the course of the work, the influence of W/C of cement mortar and the concentration of foam work solution on the strength of foam concrete with and without polycarbox-ylate-based plasticiser was determined. The optimal amount of water was defined and substantiated to obtain the porous structure of foam concrete with an average density of 300 kg/m3 using a synthetic foaming agent, ensuring the maximum strength. It was concluded that using a superplasticiser for the production of low-density foam concrete is impractical. The compressive strength of heat insulation foam concrete increases with increasing W/C. The following correlation was observed between the investigated factors: the change in strength in the function of W/C is less prominent at a low concen-tration of the foam solution. To manufacture heat insulation foam concrete with a density of D300 based on synthetic foaming agent and general Portland cement, the optimal W/C (including water in the foam) should amount to 0.8.