Meng Yazi, Ling Tung-Chai, Mo Kim Hung, Tian Weihao
Key Laboratory for Green & Advanced Civil Engineering Materials and Application Technology of Hunan Province, College of Civil Engineering, Hunan University, Changsha 410082, Hunan, China.
Key Laboratory for Green & Advanced Civil Engineering Materials and Application Technology of Hunan Province, College of Civil Engineering, Hunan University, Changsha 410082, Hunan, China.
Sci Total Environ. 2019 Jun 25;671:827-837. doi: 10.1016/j.scitotenv.2019.03.411. Epub 2019 Mar 27.
Carbonation for the curing of cement-based materials has been gaining increased attention in recent years, especially in light of emerging initiatives to reduce carbon dioxide (CO) emissions. Carbonation method or CO curing is founded on the basis of the reaction between CO and cement products to form thermally stable and denser carbonate, which not only improves the physical and mechanical properties of cement-based materials, but also has the ability to utilize and store CO safely and permanently. This study aims to assess the effect of CO curing technology on the high-temperatures performance of cement blocks. Upon molding, dry-mix cement blocks were cured under statically accelerated carbonation condition (20% CO concentration with 70% relative humidity) for 28 days, followed by exposure to elevated temperatures of 300 °C to 800 °C in order to comprehensively study the principal phase changes and decompositions of cement hydrates. The results indicated that CO curing improved the performance of cement blocks, such as enhancement in the residual compressive strength and reducing the sorptivity. At 600 °C, the scanning electron microscopy (SEM) revealed a denser microstructure while thermal analisis and X-ray diffraction (XRD) analysis also clearly demonstrated that higher amounts of calcium carbonate were present in the cement blocks after CO curing, suggesting better high-temperature performance compared to natural cured cement blocks. In general, an improved high-temperature performance, specifically at 600 °C of the dry-mixed cement blocks was demonstrated by adopting the CO curing technology. This confirms the potential of utilizing CO curing technology in not only improving quality of cement blocks, new avenue for storing of CO2 in construction material can be realized at the same time.
近年来，用于水泥基材料养护的碳酸化技术越来越受到关注，特别是鉴于减少二氧化碳（CO₂）排放的新举措。碳酸化方法或CO₂养护是基于CO₂与水泥制品之间的反应，形成热稳定且更致密的碳酸盐，这不仅改善了水泥基材料的物理和力学性能，还具有安全且永久地利用和储存CO₂的能力。本研究旨在评估CO₂养护技术对水泥块高温性能的影响。成型后，干拌水泥块在静态加速碳酸化条件（CO₂浓度20%，相对湿度70%）下养护28天，然后暴露于300℃至800℃的高温下，以便全面研究水泥水化物的主要相变和分解。结果表明，CO₂养护改善了水泥块的性能，如残余抗压强度提高和吸水率降低。在600℃时，扫描电子显微镜（SEM）显示微观结构更致密，而热分析和X射线衍射（XRD）分析也清楚地表明，CO₂养护后的水泥块中存在更多的碳酸钙，表明与自然养护的水泥块相比具有更好的高温性能。总体而言，采用CO₂养护技术证明了干拌水泥块在高温性能方面有所改善，特别是在600℃时。这证实了利用CO₂养护技术不仅可以提高水泥块质量，同时还能实现建筑材料中储存CO₂的新途径。
