Homogeneous pore distribution in foam concrete by two-stage foaming

The article addresses the issues of investigating the homogeneity of foam concrete produced by three methods: the classical method (CM), dry foam mineralization (DM), as well as the proposed method of two-stage foaming (TSF). The study is necessary due to the impact of the manufacturing process on the homogeneity degree of foam concrete. Therefore, the TSF method is aimed at improving the homogeneity of the material structure by evenly distributing the pores through the sequential foam introduction. The homogeneity of the materials produced by the three methods was evaluated by comparing the results of discrete (point and localized) strength testing over the entire volume of the foam concrete blocks, as well as the results of thermal conductivity measurements. The test results obtained gave an understanding of the degree of materials homogeneity, and confirmed the impact of the foam concrete manufacturing process on its quality. Thus, the most homogeneous material structure throughout the entire volume is observed in TSF specimens, as evidenced by the minimum deviations of particular values of strength and thermal conductivity, ranging from 4.19 % (in the analysis of thermal conductivity) to 6.71 % (in the analysis of strength), while the same indicators for CM specimens are 22.4 % and 48.35 %, and for DM specimens are 11.05 % and 19.21 %, respectively.