硅酸盐学报

对600℃焚烧的稻壳灰(rice husk ash,RHA)纳米尺度的显微结构进行了SEM/TEM(SAD)研究,首次发现稻壳灰由纳米尺度的SiO₂粒子(～50 nm)疏松地粘聚而成。稻壳灰结构中除了以往报道过的微米尺度的蜂窝孔外,还含有大量由SiO₂粒子非紧密粘聚而形成的纳米尺度孔隙(<50 nm)。纳米尺度的SiO₂粒子和纳米尺度的孔隙是低温稻壳灰具有巨大的比表面积和超高火山灰活性的根本原因。活性试验表明,低温稻壳灰火山灰活性超过造粒硅灰,对普通混凝土和高强混凝土都具有强烈的增强作用。当低温稻壳灰替代水泥量为10％～20％时,可提高高强混凝土抗压强度10 MPa以上。

The nano-structure of rice husk ash burned at 600℃ was investigated by using SEM and TEM. The results show that the rice husk ash contains some nano-particles of silica (SiO2) with a size of -50 nm, which stick loosely each other. Be-sides the micron-cellular pores, there are many nano-sized interstitial pores below 50 nm formed by the packing of the nano-particles. The rice husk ash possesses great specif ic surf ace and highly " superpozzolan" activity due to the existence of the nano-particles of silica and the nano-sized pores. It is indicated that the pozzolanic activity of the rice husk ash is higher than that of pelletized silica fume, resulting to increase of strength for ordinary concrete and high strength concrete. The compressive strength of concrete with 10% - 20% RHA to replace cement is increased by 10 MPa.