CONCRETE

[:ru]Подмазова С. А.[:en]Podmazova S. A.[:] [:ru]к.т.н., в.н.с. НИИЖБ[:en]Cand. Eng. Sc., leading researcher, Scientific and Research Institute of Reinforced Concrete[:]

Alitinform №1 (08) 2009 г. 47-49 p.

Abstract

Concrete for manufacturing of reinforced concrete constructions intended for different purposes up to 1990s has been produced for precast iron concrete with compression resistance class, in general, as В15, В20, В25, seldom В30 (393 kgs/sm2) and even more rarely В35 (458 kgs/sm2). For premixed concrete mixtures compression resistance classes have been in the limits of В12,5-В15, and extremely rarely В20-В25.

After Russian economics had been shifted to market relations, the structure of concretes according to compression resistance classes started to change, on account of growing share of manufactured concretes with compression resistance classes В35, В40, В45, В50, В60 and even higher for concrete used in the sphere of monolithic construction, in general. It was caused with construction market demand – with increasing number of storeys and growing loads onto supporting structures. Increase in high-strength concretes’ production volume resulted in more careful attention to the quality and technical characteristics of its main component – cement.

Up to mid-1990s cements of PC D0 type had been manufactured in the amount of only 8% of the total production output. In 2004 this type of cement has been manufactured in the amount up to 32,5% already, i.e. reallocation in cement manufacturing took place with increase of share for cements without additives.