EFFECTS OF MODIFIED HIGH CALCIUM FLY ASH ON VOLUME STABILITY OF CEMENT-BASED MATERIALS

In this paper, effects of modified high calcium fly ash(HF) on hydration heat and shrinkage deformation of cement-based materials are studied. By mercury intrusion method, the mechanism of HF on volume stability is disclosed. Results show: equivalent replacement of cement by HF can obviously reduce the pore radius, while the effect of reducing porosity ratio is not obvious. The fining effect on pore radius distribution does not increase with increment of addition, instead, there is an optimum range. The replacement can reduce hydration temperature rising, this is advantageous to the massive volume concrete. Adding certain addition of HF exerts compensation on shrinkage, especially in dry environment.