EXPERIMENTAL STUDY OF EFFECT OF NANO-SiO2 CONTENT ON THE PROPERTIES OF HIGH PERFORMANCE CONCRETE

Cement was replaced by the same amount of nano-SiO2 to prepare high performance concrete，it was tested the performance changes of concrete specimens in different admixture amounts of nano-SiO2 ． The results show that nano-SiO2 would reduce the workability of concrete． Cube compressive strength of concrete in 7 d was markedly increased with the increase of the admixture amounts of nano-SiO2 ． Compressive strength and elastic modulus in 28 d were first increased with the increase of the admixture amounts of nano-SiO2 then decreased，the maximum value was got when the admixture amounts nano-SiO2 was in the range of 2% to 3%，with the increasing range being 10% and 11% respectively． The impervious performance of concrete was improved with the increasing of the admixture amounts of nano-SiO2 ，and the increment of the impervious performance was also obvious in late period．