石灰石粉对水泥浆体水化特性及孔结构的影响

来源期刊:中南大学学报(自然科学版)2010年第6期

论文作者:肖佳 金勇刚 勾成福 王永和

文章页码:2313 - 2320

关键词:石灰石粉;碳铝酸钙水化物;孔结构;水化特性

Key words:ground limestone; calcium carboaluminate hydrate; pore structure; hydration characteristic

摘    要:通过 X线衍射分析、热重-差热分析、压汞孔结构分析和量热微观测试分析研究水泥-石灰石粉浆体的水化特性及孔结构。研究结果表明:石灰石粉可促进水泥的早期水化,阻碍了其后期水化;石灰石粉导致新相半碳铝酸钙水化物(C3A·0.5CaCO3·0.5Ca(OH)2·11.5H2O)和单碳铝酸钙水化物(C3A·CaCO3·11H2O)的形成;半碳铝酸钙水化物不稳定,形成后便全部转变成单碳铝酸钙水化物;随着石灰石粉掺量增加,单碳铝酸钙形成提前并稳定存在;石灰石粉一方面延迟了钙矾石的生成,另一方面对钙矾石的存在起到了稳定作用;石灰石粉改变水泥水化历程,与纯水泥水化放热相比,石灰石粉的掺入致使第1放热峰明显增高和前移,使诱导期缩短,提前进入加速期;随着水化龄期增长,石灰石粉使水泥浆体孔结构由小孔向大孔转变,产生了孔粗化效应。

Abstract: The hydration characteristics and pore structure of the cement-ground limestone pastes were studied by X-ray diffractrometry, thermogravimetric-differential scanning calorimeters, mercury intrusion poremeasurement and calorimetry analysis. The results indicate that ground limestone promotes the earlier hydration of cement, and inhibits the later hydration of cement. Ground limestone causes the formation of C3A·CaCO3·11H2O and C3A·0.5CaCO3·0.5Ca(OH)2· 11.5H2O. C3A·0.5CaCO3·0.5Ca(OH)2·11.5H2O is unstable and totally transfers to C3A·CaCO3·11H2O after the formation. With the increase of ground limestone amount, C3A·CaCO3·11H2O advances its generation and exists stably. Ground limestone defers the formation of ettringite and improves the stability of ettringite. The hydration process of cement is changed by the ground limestone. The first exothermic peak of the cement containing ground limestone appears in advance, which shows higher and earlier than that of the pure cement. The addition of ground limestone shortens the induction period of cement hydration, and causes the cement hydration to advance the entering into the acceleration period. With the increase of the hydration time, the addition of ground limestone results in the pore structure of cement pastes changing from little pore to larger pore due to the addition of ground limestone, which is known as the pore coarsening effect.

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