Hu Haibo, Yao Wu, Wei Yongqi
Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
Sci Total Environ. 2023 Dec 1;902:166008. doi: 10.1016/j.scitotenv.2023.166008. Epub 2023 Aug 5.
Waste dolomite powder (WDP) is a byproduct obtained from dolomite quarries during the preparation of dolomite products. To study the re-utilisation of WDP, an eco-friendly cement-based material was prepared using WDP as a micro-aggregate. The effects of WDP on the early hydration process, microscale characteristics, and life-cycle assessment of cement paste are discussed in this study. The isothermal calorimetry results showed that the incorporating WDP in cement paste accelerated the early hydration process of cement according to the degree of reaction. In this case, the setting time of the cement pastes with WDP was shortened, and the early compressive strength was significantly improved. The results of X-ray diffraction and scanning electron microscopy analysis at early curing ages (1 and 3 d) showed changes in the peak intensity of ettringite and portlandite and a denser microstructure. Mercury intrusion porosimetry tests showed that the middle and large capillary pores were refined by the nucleation and filling effects of WDP. Based on environmental and economic evaluations, the utilisation of WDP reduced energy consumption, CO emissions, and economic costs. Compared to the sample without WDP, the energy consumption, CO emissions, and economic cost indices were 42 %, 42.69 %, and 39.4 % lower, respectively. Our results may provide valuable references for the re-utilisation of WDP in low-carbonation cement-based materials.
废弃白云石粉（WDP）是白云石矿在制备白云石产品过程中产生的副产品。为了研究WDP的再利用，以WDP为微集料制备了一种环保型水泥基材料。本研究讨论了WDP对水泥净浆早期水化过程、微观特性和生命周期评估的影响。等温量热法结果表明，根据反应程度，在水泥净浆中掺入WDP可加速水泥的早期水化过程。在这种情况下，含WDP的水泥净浆的凝结时间缩短，早期抗压强度显著提高。早期养护龄期（1天和3天）的X射线衍射和扫描电子显微镜分析结果表明，钙矾石和氢氧化钙的峰值强度发生了变化，微观结构更加致密。压汞法测试表明，WDP的成核和填充作用细化了中、大毛细孔。基于环境和经济评估，WDP的利用降低了能源消耗、CO排放和经济成本。与不含WDP的样品相比，能源消耗、CO排放和经济成本指数分别降低了42%、42.69%和39.4%。我们的研究结果可能为WDP在低碳水泥基材料中的再利用提供有价值的参考。
