Effects of silicone hydrophobic additives on the durability of autoclaved cellular concrete and the aerated autoclaved concrete quality

Abstract

The article presents the results of a study of the effect of silicone hydrophobic additives on the main physical and mechanical properties of autoclaved aerated concrete with an average density of D400. The purpose of the work is to determine the effectiveness of silicone water-repellent additives on the durability of cellular concrete. Purpose of the article. According to the results of the studies, it was found that to improve the main physical, mechanical and operational characteristics of aerated concrete with an average density of D400, it is optimal to introduce an additive of silicone liquid PMS-50 in the amount of 1.5-2 % by weight of dry components into the composition of aerated concrete mixtures. In this case, the compressive strength of the material increases from 2.9 MPa to 3.8 MPa; water absorption decreases from 49.6 % to 4.2 % by weight, and frost resistance increases by 2 grades. The compositions containing PMS-50 and PMS-40 additives were characterised by a 3-5% reduction in average dry density with equivalent compressive strength values (3.7 MPa and 3.8 MPa, respectively). Samples of autoclaved aerated concrete modified with oligomethylhydrosiloxane and sodium methyl siliconate additives showed an increase in strength and frost resistance at an additive content of 3.5% and 2.5%, respectively. The strength of the cellular hydrophobic concrete of autoclaved curing is provided by the main low-base hydrosilicate phases and an increased number of elongated prismatic crystals of affilite