Features of Calculation of Durability of Reinforced Concrete Structures Strengthened with Composite Materials

The article shows the influence of additionally entrained air on the properties of road cement concrete. The results of studies of various authors concerning the the effect of entrained air on the strength of concretes are analyzed. The existing contradictions in them are noted. New experimental results, which show that there are intervals of the content of entrained air, in which the strength of concrete is reduced by 14% per each percent of entrained air, are presented. It is found that the additional air can be engaged in concrete by using air-entraining additives or using polypropylene fibers at that, the pore structure of the concrete depends on the method of air entrainment. It is proved that in the pore structure of concrete with polypropylene fibers, but without air-entraining additives, smaller pores are present. Their distribution is more uniform, and the strength of the concrete is reduced less than in the case of pores which are formed by an air-entraining agent. This is confirmed by the results of microscopic analysis. Concrete properties are improved in this case. The article gives a theoretical justification of reasons for differences in the pore structure of concrete with fibrous additives

T.A. MUKHAMEDIEV, Doctor of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
A.I. ZVEZDOV, Doctor of Sciences (Engineering)

JSC Research Center of Construction (6, 2 nd Institutskaya Street, Moscow, 109428, Russian Federation)

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