海水环境下矿物掺合料对硫铝酸盐水泥的水化影响

研究了海水环境下掺入硅灰、粉煤灰、矿渣对硫铝酸盐水泥抗压强度、化学收缩和水化产物的影响规律.结果表明:当硅灰的掺量为2.5%时,水泥浆体的抗压强度比空白组高.矿渣掺量为10%的水泥浆体28 d抗压强度明显超过掺入硅灰和粉煤灰时的强度,60 d强度高于空白组.掺入2.5%硅灰后,水泥浆体的化学收缩增大;在水化早期,粉煤灰和矿渣的火山灰活性很低,导致水泥浆体的化学收缩降低.掺入10%硅灰加快了硫铝酸盐水泥3 d水化反应,钙矾石生成量增多,水泥浆体早期强度比掺其它掺合料有所提高,但体积过快膨胀会破坏其内部结构,对水泥浆体的强度发展不利.

Effect of Mineral Admixtures on the Hydration of Sulphoaluminate Cement under Seawater Condition

The influence of silica fume, fly ash and ground granulated blast furnace slag on the compressive strength, chemical shrinkage and hydration products of sulphoaluminate cement under seawater condition were investigated.The results show that the compressive strength of cement paste is higher than the control sample when the dosage of silica fume is 2.5%.The compressive strength of cement paste with 10% of slag at 28 d evidently surpass that of silica fume and fly ash.The compressive strength at 60 d is even higher than the control sample.The chemical shrinkage of cement paste increase with 2.5% of silica fume, while the low pozzolanic activity of fly ash and slag during early hydration decrease the chemical shrinkage of cement paste.The hydration reaction of sulphoaluminate cement during 3 d is accelerated when the content of silica fume reached 10%, and the amount of ettringite is increased, which enhanced its early strength compared to others, but the rapidly volume expansion will destroy its internal structure and has a negative effect on the strength development.