Wang Kai, Ren Liang, Yang Luqing
School of Civil and Architecture Engineering, East China Jiaotong University, Nanchang, 330013, China.
Materials (Basel). 2018 Aug 19;11(8):1474. doi: 10.3390/ma11081474.
Pure rankinite (C₃S₂) was prepared by calcining a C-S-H gel precursor at a temperature of 1300 °C. The carbonation hardening behavior of the resulting rankinite was revealed by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, thermogravimetry and differential thermal analysis (TG/DTA), and scanning electron microscope (SEM) coupled with energy dispersive spectrum (EDS). The results indicate that the pure rankinite can be easily prepared at a lower temperature. The cubic compressive strengths of the resulting rankinite samples reach a value of 62.5 MPa after 24 h of carbonation curing. The main carbonation products formed during the carbonation process are crystalline calcite, vaterite and highly polymerized amorphous silica gels. The formed carbonation products fill the pores and bind to each other, creating a dense microstructure, which contributes to the excellent mechanical strength. These results provide a novel insight into potential recycling of waste concrete powders for prefabricated building products with lower CO₂ emissions.
通过在1300℃的温度下煅烧C-S-H凝胶前驱体制备了纯硅灰石（C₃S₂）。通过X射线衍射（XRD）、傅里叶变换红外（FT-IR）光谱、热重分析和差示热分析（TG/DTA）以及结合能谱（EDS）的扫描电子显微镜（SEM）揭示了所得硅灰石的碳酸化硬化行为。结果表明，纯硅灰石可以在较低温度下轻松制备。所得硅灰石样品在碳酸化养护24小时后的立方体抗压强度达到62.5MPa。碳酸化过程中形成的主要碳酸化产物是结晶方解石、球霰石和高度聚合的无定形硅胶。形成的碳酸化产物填充孔隙并相互结合，形成致密的微观结构，这有助于提高优异的机械强度。这些结果为废弃混凝土粉末用于低CO₂排放的预制建筑产品的潜在回收利用提供了新的见解。
