Statement of the problem. The problem of studying the compaction of the structure and characteristics of concrete samples made using urease bioadditives, such as density, porosity and strength and their interrelationships, is considered. Results. The results of experimental studies of the structural and strength properties of concrete are presented, taking into account the effect of dietary supplements based on urease strains of bacteria with urease activity. For formed cement systems with different content of bioadditive, type and quantity of coarse aggregate, the value of porosity and compressive and flexural strength was determined by the ratio W:C. The use of such dietary supplements leads to the formation of calcite inside the open pores and lobes, obtained by precipitation using the bacterial enzyme urease. Conclusions. The values of density, porosity and strength of concrete mixtures made using various types of crushed stone have been obtained, porosity values have also been established, and the compressive and flexural strength of the obtained concrete samples made using urease bioadditives has been determined. It has been found that the use of dietary supplements leads to a decrease in porosity to 5—15 %, as well as to an increase in compressive strength by at least 20 %, and bending strength by at least 10 %. Thus, it has been established that bioadditives improve the quality of the bond between the components of concrete, making it more durable and resistant to loads, as well as improve and compact its structure.
Dergunova et al. (Wed,) studied this question.