Special features of porosity of low cement concretes having chamotte fillers

摘要

The effect of microsilica content in low-cement concrete with a chamotte filler on the density and open p0rosity of the concrete is studied at firing temperatures to 1300°C. It is shown that an increase in the microsilica content in concrete above 10% results in an increase in the open porosity after firing at 1200 - 1300°C due to formation of thick silica glass films in the concrete structure, The gas phase present at a temperature of glass melting (1100°C) expands thus forming large pores. Thelargest amount of large pores in the structure cement-microsilica composition is observed after firing at 1300°C at the microsilica content 16%. The results obtained makes it possible to optimize the microsilica content in the composition of low cementconcrete with porous chainotte fillers. The optimal content is about 10%.