Determination of cement hydration and pozzolanic reaction extents for fly-ash cement pastes
Determination of cement hydration and pozzolanic reaction extents for fly-ash cement pastes
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DOI：
10.1016/j.conbuildmat.2011.07.007
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发表时间：
2012-02
影响因子：
7.4
通讯作者：
Q. Zeng;Kefei Li;T. Fen-Chong;P. Dangla
中科院分区：
文献类型：
--
作者：
Q. Zeng;Kefei Li;T. Fen-Chong;P. Dangla
本文旨在量化水泥颗粒与粉煤灰（FA）颗粒在混合水泥浆体硬化过程中的反应程度。为此，综合考虑FA颗粒的稀释效应、局部w/c增大效应和非均相成核效应，建立了水泥水化程度的综合模型。然后研究了两种w/b比（0.3、0.5）和四种FA含量（0%、20%、40%、60%）的水泥浆体的水泥水化和FA反应程度。采用热重分析（TGA）测定了非蒸发水（Wn）和氢氧化钙（CH）含量，采用选择性溶解法测定了FA反应程度。在这些实验数据的基础上，采用实验法和基于模型的方法确定了水泥水化程度和FA火山灰反应程度。结果表明，局部w/c、非均相成核效应和FA水化作用对混合膏体总Wn含量的贡献相当，而FA水化作用对CH含量的贡献最大。实验水化程度与模型水化程度吻合较好，验证了所建立的水泥混合膏体水化程度综合模型的有效性。
This article intends to quantify the reaction extents of cement grains and fly-ash (FA) particles in blended cement pastes during their hardening process. To this aim, a synthetic model for cement hydration extent in blended pastes is established taking into account the dilution effect, local w/c augmentation effect as well as heterogeneous nucleation effect of FA particles. Then the cement hydration and FA reaction extents of blended cement pastes with two w/b ratios (0.3,0.5) and four FA contents (0%, 20%, 40%, 60%) are investigated. The non evaporable water content (Wn) and calcium hydroxide content (CH) were measured by thermal gravity analysis (TGA) and the FA reaction extent was quantified by the selective dissolution method. On the basis of these experimental data, the cement hydration extent and FA pozzolanic reaction extent are determined from both experimental approach and model-based approach. From the results, it is observed that local w/c, heterogeneous nucleation effects and FA hydration have comparable contribution to the total Wn content in blended pastes while the FA hydration dominates in CH content. Furthermore, the good agreement between the experimental hydration extents and model-based extents validates the established synthetic model for cement hydration extent in blended pastes.