Zhu Jing, Qu Zijian, Liang Siqi, Li Baiping, Du Tao, Wang Hui
College of Civil Engineering and Architecture, Harbin University of Science and Technology, Harbin 150080, China.
School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Materials (Basel). 2022 Feb 20;15(4):1578. doi: 10.3390/ma15041578.
Carbon dioxide is the main component of greenhouse gases, which are responsible for an increase in global temperature. The utilization of carbon dioxide in cement-based materials is an effective way to capture this gas. In this paper, the influence of carbon dioxide curing on the setting time, the electrical resistivity, dry shrinkage ratio, water absorption by unit area and mechanical strengths (flexural and compressive strengths) were determined. The scanning electron microscope, X-ray diffraction and thermogravimetric analysis were obtained to investigate the mechanism of carbonation reaction of cement paste. Water-cement ratios of cement paste were selected to be 0.3, 0.4 and 0.5. Results showed that carbon dioxide curing could accelerate the setting of cement paste. The electrical resistivity decreased with the increasing water-cement ratio and increased with the carbon dioxide curing. Moreover, the evaluation function for the curing age and dry shrinkage rate or the mechanical strengths fit well with the positive correlation quadratic function. The water absorption by unit area increased linearly with the testing time. The carbon dioxide curing led to increasing the mechanical strengths and the dry shrinkage ratio. Meanwhile, the carbon dioxide curing demonstrated a decreasing effect on the water absorption by unit area. The mechanical strengths were improved by the carbon dioxide curing and increased in the form of quadratic function with the curing age. As obtained from the microscopic findings, that the carbon dioxide curing could accelerate the reaction of cement and improve the compactness of cement paste.
二氧化碳是温室气体的主要成分，温室气体导致全球气温上升。在水泥基材料中利用二氧化碳是捕获这种气体的有效方法。本文测定了二氧化碳养护对凝结时间、电阻率、干缩率、单位面积吸水量和力学强度（抗折强度和抗压强度）的影响。通过扫描电子显微镜、X射线衍射和热重分析来研究水泥浆体碳化反应的机理。选择水泥浆体的水灰比为0.3、0.4和0.5。结果表明，二氧化碳养护可加速水泥浆体的凝结。电阻率随水灰比的增加而降低，随二氧化碳养护而增加。此外，养护龄期与干缩率或力学强度的评价函数与正相关二次函数拟合良好。单位面积吸水量随试验时间线性增加。二氧化碳养护导致力学强度和干缩率增加。同时，二氧化碳养护对单位面积吸水量有降低作用。二氧化碳养护提高了力学强度，并随养护龄期呈二次函数形式增加。从微观研究结果可知，二氧化碳养护可加速水泥反应并提高水泥浆体的密实度。
