Influence of Microbial Carbonate Biomineralization on the Strength of Cement Stone

Abstract

An intensive urbanization, renovation of housing stock, emergencies and natural disasters lead to difficulties arise in the management of concrete waste. In this regard, recycling construction and demolition waste is an effective solution for saving material and energy resources in the construction field. The article discusses the possibility of optimizing the structure and increasing the strength characteristics of concrete by selecting the grain composition of the aggregate based on recycled concrete scrap and the use of microbial carbonate biomineralization. The distribution of aggregate grains (0.315–5 mm), which is crushed ordinary stone SKTs, into fractions has an impact on the nature of the formation of contact zones between the cement matrix and the aggregate. This determines a decrease in strength characteristics according to the following relationship: with a decrease in the size of the aggregate, the strength of cement concrete increases. The addition of a biomineralizing solution to the cement mixture leads to improved adhesion of the cement paste to the surface of the aggregate due to the formation of additional crystallization centers in the area of the contact layer, clogging of the pore space with induced new formations, which increases the strength of concrete, both at brand age and in the forecast period.