Cement based foam concrete with aluminosilicate microspheres for monolithic construction

The present paper investigates cement foam concrete of natural hardening with aluminosilicate microsphere made from bottom ash waste from Seversk Heat and Power Station in Tomsk Region. The relevance of the given study is conditioned by the necessity to provide the required process parameters of mixture for transportation and laying the formwork, as well as providing strength and thermal and physical characteristics of wall structures for economy-class housing construction. Porous microsphere from bottom ash wastes applied within the technology of cement foam concrete of natural hardening contributes to ensuring increased microporosity and strength of interpore partitions of foam concrete. The study was conducted in the Laboratory of Tomsk State University of Architecture and Building which is accredited in accordance with the national standards requirements. The optimal content of microsphere in the cement foam concrete mixture was 5–10 % of the cement weight. Foam concrete mixture with microsphere possesses higher flowability and concrete has reduced plastic shrinkage by 40 %. The average pores diameter in foam concrete with microspheres is reduced from 308 to 210.2 µm, mean square deviation of the pores diameter is reduced from 23.6 to 14.2 µm. The maximum effect of reducing thermal conductivity coefficient up to the value of 33 % is observed with 5 % microsphere content of the cement weight. Inclusion of microsphere within the process of mixture formation enables to increase concrete strength at the age of 28 days by 40 % and its softening coefficient by 15 %. The elaborated composition and technology of foam concrete production with aluminosilicate microsphere is intended for use in the walls structures in monolithic construction.