关键词: 工程水泥基复合材料, 聚乙烯醇纤维, 尾矿砂, 力学性能, 粉煤灰, CO₂排放量

Abstract: The high proportion of cement used in traditional engineering cementitious composites (ECC) leads to high costs and high carbon emissions, hindering the industrial application of ECC in transportation infrastructure. To overcome these limitations, while ensuring the mechanical properties of ECC, tailing sand was used as an alternative aggregate with increased fly ash content to develop an economical and green tailing sand ECC. Nine groups of ECC specimens with different mix proportion were designed for uniaxial compression and uniaxial tensile tests, employing varying aggregate types (tailing sand, a mixture of tailing sand and quartz sand, quartz sand) and ratio of fly ash and cement content (2.4, 3.4, and 4.4) to investigate their effects on mechanical properties, microstructure, and material sustainability. The tests revealed the failure process and deformation characteristics of ECC under loading stages. The results indicate that tailing sand, due to the angular morphology and micro-aggregate effect, exhibits excellent tensile strength and tensile ductility. The fly ash content has a dual effect on mechanical properties: as the ratio of fly ash and cement content increases, both the tensile and compressive strengths of ECC decrease, while the ultimate tensile strain significantly improves. By comparing sustainability indicators with traditional ECC, the results demonstrate that the novel ECC with tailing sand as aggregate can effectively reduce costs, energy consumption, and carbon dioxide emissions. This study validates the sustainability of utilizing industrial solid waste tailing sand as aggregate to produce green ECC, providing guidance for the application of environmentally friendly tailing sand ECC.

Key words: engineered cementitious composite, polyvinyl alcohol fiber, tailing sand, mechanical property, fly ash, CO₂ emission