硅灰对硬化水泥浆体早期收缩的影响

Effect of the Silica Fume on the Early Shrinkage of Hardened Cement Paste

研究了硅灰对硬化水泥浆体早期收缩的影响 .结果表明 :在 2 0℃封闭的水化环境中 ,硬化水泥浆体净浆试样收缩主要发生在水化初始期 ,水化 5d后试样的收缩趋于稳定 ;试样 2 9d的收缩率为 0 .1 2 5% .掺加硅灰混合材料后 ,硬化水泥浆体试样的收缩显著增加 ;掺加 1 0 % (质量分数 )硅灰试样 2 9d的收缩率达到 0 .2 3 8% .探讨了硅灰引起试样收缩增加的主要原因 。

In 20 ℃ sealed situation, shrinkage of hardened cement paste(HPC) increases in the first few days and becomes steady after 5 d. It shows 0.125% early shrinkage at 29 d hydration. The early shrinkage is markedly increased when silica fume is in HPC. It is up to 0.238% at 29 d hydration when silica fume replaces 10% of cement in HPC. The relationship between HPC's early shrinkage and content of silica fume is studied and a hypothesis is proposed.