Composite Binders for Concretes with Improved Impact Endurance

Resumo

The chemical engineering principles of optimization of the physical and mechanical properties and performance characteristics of dispersed reinforced composite materials are proposed which consist in the integrated effect of a composite binder consisting of jointly ground Portland cement, rice husk ash, a complex of inert fillers, and a hyperplasticizer on the processes of structure formation of cement stone. Here, the effect of increasing the impact endurance increases up to sixfold. It is found that dispersed reinforced concretes with an increased ratio of static tensile strength to static compressive strength R_tens/R_compr and ductility possess the best endurance to dynamic action. It is proved that this ratio can be increased by using dispersed reinforcement of concretes (so-called fibrous concretes). In experimental studies on penetration of both unreinforced and fiber-reinforced concrete slabs, it is noted that samples of unreinforced concrete are completely fractured into large and small pieces, while samples of fiber-reinforced concrete are not completely fractured, and only through penetration at the impact site was observed; that is, fibrous concrete possesses better impact resistance. These results can be applied to the design of various special structures, such as defense structures of civil defense and emergency situations, fortifications of the Russian Ministry of Defense, and concrete structures of nuclear power plants.