Study on the Pozzolanic Activity of Diatomite

In this paper,the influence of calcined condition on the pozzolanic activity of diatomite was determined according to ICP-OES analysis.Phase transformation,microstructure of diatomite,and mechanism of pozzolanic activity during calcination were investigated using XRD,SEM,EDS and FT-IR methods.The results indicate that mircroporous structure and Si-OH cluster in diatomite favor the pozzolanic activity,especially when calcined at 800 ℃.Layered structure of clay minerals is destroyed as a result of removal of water,which leads to a lower pozzolanic activity.After being calcined at 800 ℃ for 1 h,the proportion of pozzolanic compositions increase from 22.15% to 37.21%.Marco-pore structure,surface structure and crystal structure of diatomite are changed in high temperature,resulting in the level of pozzolanic activity.