Effect of fly ash on properties of magnesium potassium phosphate cement paste
1.Department of Architectural Engineering, Jiangsu Radio and TV University, Nanjing, Jiangsu 210017, China; 2.Nanjing Construction Group Company Limited, Nanjing, Jiangsu 210012, China; 3.College of Civil and Engineering, Yancheng Instiute of Technology, Yancheng, Jiangsu 224051, China
Abstract：Magnesium potassium phosphate cement (MKPC) pastes with different contents of fly ash(FA) and ratio of acid to base were discussed through testing compressive strength, residual ratio of compressive strength after water curing and hydration temperature rise. The micro morphology and the phase composition of hardened MKPC pastes were also analyzed. The results indicate that compared to the MKPC paste with borate retarders, the optimum proportion of acid component is decreased above 50％ because of the effective delaying effect of composite retarder on the early hydration rate of MKPC paste. Some fly ash can obviously improve the water stability of hardened MKPC paste. The residual ratio of compressive strength of hardened MKPC paste with mass ratio of acid to base of 1.0∶3.0 and 20％ ash fly in water curing condition is over 90％. The dissolution of phosphate and hydrolysis in hydrates can be alleviated by the decrease of acid component content in MKPC. The micro structure of hardened MKPC paste is compacted by the physical and chemical effects of FA to improve the water stability.
2013, Vol. 34 
