Effect of carbonation in supercritical CO2 on the properties of hardened cement paste of different alkalinity
Effect of carbonation in supercritical CO2 on the properties of hardened cement paste of different alkalinity
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DOI：
10.1016/j.conbuildmat.2016.07.040
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发表时间：
2016-10
影响因子：
7.4
通讯作者：
L. Urbonas;V. Leno;D. Heinz
中科院分区：
文献类型：
--
作者：
L. Urbonas;V. Leno;D. Heinz
众所周知，水泥基建筑材料的强度通过碳酸化而增加。在150巴下使用超临界二氧化碳scCO2加速该过程。硬化波特兰水泥浆体与不同的碱含量和水灰比为0.5和0.6处理后，初步储存在不同的相对湿度在scCO2 4小时。通过X射线衍射、扫描电子显微镜和压汞测孔仪对强度和显微结构进行了测量。scCO2中的碳酸化可显著增加强度，这有利于低水分含量和低碱水泥。通过热力学计算证实了碱对碳酸化反应的阻滞作用。
It is well-known that the strength of cementitious building materials is increased by carbonation. This process was accelerated using supercritical carbon dioxide scCO2at 150 bar. Hardened Portland cement pastes with different alkali contents and w/c ratios of 0.5 and 0.6 were treated for four hours in scCO2after preliminary storage at different relative humidities. Strengths were measured and the microstructure investigated by X-ray diffraction, scanning electron microscopy and mercury intrusion porosimetry. Carbonation in scCO2produces a substantial increase in strength which is favoured by low moisture contents and low-alkali cements. The retarding effect of alkalis on the carbonation reaction was confirmed by thermodynamic calculations.