Some special features of the porosity of low-cement concretes on chamotte fillers

Abstract

The effect of the content ofmicrosilica in low-cement concrete with a chamotte scrap filler on the density and open porosity of the concrete at a firing temperature of up to 1300~ is considered. It is shown that the open porosity of the concrete with the proportion of microsilica raised to over 10% increases after firing at 1200-1300~ due to the thick films of a silica glass formed in the structure. The gas phase present in the glass expands at the temperature of its melting (over I I00~ forming large pores. The greatest number of large pores appears in the cement-microsilica composition after firing at 1300~ at a content of microsilica equal to 16%. The results of the study make it possible to optimize the content of microsilica in the composition of low-cement concrete on porous chamotte binders. It should be about 10%.