自制低温稻壳灰的火山灰活性及配置UHPC的强度研究

Experimental investigation on the pozzolanic activity of home-made L-RHA and its application in ultra high performance concrete

将自制低温稻壳灰(L-RHA)、纳米氧化硅(Nano-SiO2)、某厂家提供的稻壳灰(O-RHA)和硅灰(SF)分别进行氢氧化钙吸附试验、二次水化试验以及多种掺配制超高性能混凝土(UHPC)的力学性能实验.结果表明:火山灰活性关系为Nano-SiO2>L-RHA>SF>O-RHA;平均粒径为5.9μm的L-RHA微孔结构能够蓄水且在水泥水化过程中可提供水泥水化所需的部分水分,起到内养护的作用;SF颗粒小,填充效果好,而L-RHA火山灰效应好,二者共同作用要优于单一作用.

Tested were Ca（OH） 2 absorption, secondary hydration, and mechanical properties of ultra - high performance concrete （ UHPC ） of different blending with materials of low - temperature rice husk ash （L- RHA） made by authors, Nano -SiO2, ordinary rice husk ash （O -RHA） provided by a factory and silica fume （SF）. The results show that the ascending order of pozzolanic activity is Nano - SiO2 〉 L - RHA 〉 SF 〉 O - RHA and that the micro - cellular structure of L - RHA with an average diameter of 5.9μm can store water which can be used in hydration and internal curing. Furthermore, the combined effect of SF and L - RHA is better than a single one of them because of the good filling effect of SF and the high volcanic effect of L - RHA.