Tan Haoyu, Ji Henggang, Yuan Peilong, Fan Xiang
CCCC-SHEC Dongmeng Engineering Co., Ltd., Xi'an 710076, China.
School of Highway, Chang'an University, Xi'an 710064, China.
Materials (Basel). 2025 Feb 17;18(4):874. doi: 10.3390/ma18040874.
Steel slag powder (SS), ground granulated blast-furnace slag (GGBS), and flue gas desulfurization gypsum (FDG) are environmentally friendly and cost-effective substitute materials for ordinary Portland cement (OPC). This study investigated the use of industrial solid wastes, including SS, GGBS, and FDG, as auxiliary materials in OPC to stabilize pretreated recycled concrete aggregate (pretreated RCA). The use of pretreated RCA, mixed cementitious materials, and water at the optimum content created a mixture designated recycled cement-stabilized macadam (RCSM). A series of mechanical tests were conducted to clarify the performance of the RCSM, and microscopic tests were performed to elucidate the microcharacteristics of the mixed cementitious materials. With a curing time from 3 days to 28 days, the unconfined compression strength (UCS) of the mixed cementitious materials (A4) composed of SS, GGBS, FDG, and OPC increased by 5.94-10.79% compared with that of the cementitious material of OPC (A0). The UCS of the mixture composed (C4) of SS, GGBS, FDG, OPC, and pretreated RCA was greater than that of the mixture composed (C0) of OPC and RCA from 7 days to 90 days, increasing by 4.26-8.35%. The total drying shrinkage coefficient of C4 was lower than that of C0, whereas the temperature shrinkage coefficient of C4 was higher than that of C0, indicating that the use of A4 can effectively reduce drying shrinkage cracking in C4. The hydration products of A4 primarily consisted of flocculent calcium silicate hydrate (C-S-H) gel, fibrous calcium aluminate hydrate gel, and needle-like ettringite crystals. The interlocked growth of C-S-H gel and ettringite crystals continued and promoted an increase in the UCS of the cementitious system. The test results provide a reference for the application of similar materials.
钢渣粉（SS）、磨细粒化高炉矿渣（GGBS）和烟气脱硫石膏（FDG）是普通硅酸盐水泥（OPC）的环保且经济高效的替代材料。本研究调查了将包括SS、GGBS和FDG在内的工业固体废物用作OPC中的辅助材料，以稳定预处理再生混凝土骨料（预处理RCA）。以最佳含量使用预处理RCA、混合胶凝材料和水，制成了一种名为再生水泥稳定碎石（RCSM）的混合物。进行了一系列力学试验以阐明RCSM的性能，并进行了微观试验以阐明混合胶凝材料的微观特性。养护时间从3天到28天，由SS、GGBS、FDG和OPC组成的混合胶凝材料（A4）的无侧限抗压强度（UCS）与OPC胶凝材料（A0）相比提高了5.94 - 10.79%。由SS、GGBS、FDG、OPC和预处理RCA组成的混合物（C4）的UCS在7天至90天内大于由OPC和RCA组成的混合物（C0），提高了4.26 - 8.35%。C4的总干燥收缩系数低于C0，而C4的温度收缩系数高于C0，表明使用A4可有效减少C4中的干燥收缩开裂。A4的水化产物主要由絮状硅酸钙水化物（C - S - H）凝胶、纤维状铝酸钙水化物凝胶和针状钙矾石晶体组成。C - S - H凝胶和钙矾石晶体的相互联锁生长持续进行，并促进了胶凝体系UCS的增加。试验结果为类似材料的应用提供了参考。
