Influence of Metakaolin on Strength Contribution Rate of Pozzolanic Effect in Cement Paste

By using the quantitative analysis method of metakaolin pozzolanic effect proposed by Professor Pu Xincheng,the authors of this paper conducted a research on the influence of metakaolin on the strength contribution rate of pozzolanic effect in cement paste.The results show that,the strength contribution rate of pozzolanic effect on cement paste increases as the amount of metakaolin increases;the strength contribution rate of pozzolanic effect on cement paste decreases and then increases with the increase of the curing age,and its lowest value occurs during 7days;with smaller particle metakaolin(2.5 and 3.75 μm),the strength contribution rate of pozzolanic effect on cement paste during 3 days is obviously higher than during 7 days.This shows that in paste there is the higher physical filling and pozzolanic effect contributed by metakaolin during early aging(3 days);but the larger particle metakaolin and supplement of calcium and aluminum source may improve the medium-term(7days) strength of the paste.