Evaluation of Properties and Microstructure of Cement Paste Blended with Metakaolin Subjected to High Temperatures
Evaluation of Properties and Microstructure of Cement Paste Blended with Metakaolin Subjected to High Temperatures
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DOI：
10.3390/ma12060941
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发表时间：
2019-03
期刊：
影响因子：
3.4
通讯作者：
Wenqiang Wang;Xinhao Liu;Liang Guo;P. Duan
中科院分区：
文献类型：
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作者：
Wenqiang Wang;Xinhao Liu;Liang Guo;P. Duan
研究了掺加10%偏高岭土对水泥石抗压强度、吸水率、收缩率和微观结构的影响。实验结果表明，与常温下相比，200 °C和400 °C下的抗压强度有所提高。高达800 °C，抗压强度迅速下降。添加10%的偏高岭土导致抗压强度的提高，而不管暴露温度。在400 °C热暴露后，抗压强度达到最大值。热暴露使孔结构退化。采用多项式方程描述了水泥净浆和偏高岭土水泥净浆的收缩随试验天数的变化规律。水泥浆体的力学性能、抗渗性能和收缩性能与其微观结构的发展密切相关。掺量为10%的偏高岭土在热暴露前后均比纯水泥浆体具有更好的耐热性、更低的收缩率和更致密的微观结构。
The effects of 10% metakaolin addition on compressive strength, water absorption, shrinkage and microstructure evolution of cement paste after elevated temperatures exposure from room temperature to 800 °C were evaluated. The experimental results show that compressive strength increases at 200 °C and 400 °C compared with that obtained at ambient temperature. Up to 800 °C, compressive strength decreases rapidly. The addition of 10% metakaolin leads to the enhancement of compressive strength regardless of exposure temperatures. After thermal exposure at 400 °C, compressive strength reaches the maximum value. Thermal exposure degrades pore structure. A polynomial equation was used to indicate the shrinkage of cement paste or metakaolin-blended cement paste with testing days. Mechanical properties, permeability resistance, and shrinkage in cement pastes are closely related to the microstructure development. 10% metakaolin addition presents better thermal resistance, lower shrinkage and denser microstructure compared with pure cement paste before and after thermal exposure.