【摘要】 使用尾矿砂替代ECC中的细骨料,借鉴ECC技术制备了尾矿砂替代天然砂的比率达50%的纤维增强尾矿砂水泥基复合材料(FRTCC),采用立方体抗压、直接拉伸、薄板弯曲和双面剪切等不同加载模式的实验系统研究了FRTCC的压缩、拉伸、弯曲和剪切韧性以及PVA纤维的增韧机制,以及PVA纤维掺量和水胶比对FRTCC延性的影响。提出了完全韧性比的概念和定义,并采用韧性比和韧性指数双特征参数表征了FRTCC的韧性。结果表明,这种材料具有环保和延性双重特征。PVA掺量与水胶比存在着交互作用,对FRTCC的韧性有显著的影响。PVA掺量与水胶的适当配比明显提高了FRTCC的延性和能量吸收能力,使FRTCC具有多裂缝开裂、应变硬化和延性破坏等特征。更多还原

【Abstract】 A fiber reinforced tailing cementitious composite(FRTCC) was prepared via engineered cementitious composite(ECC) technology. By replacing 50% natural send with tailing sand, the prepared composite presents distinct ductility and environmental friendly-features. The tensile, compressive, flexural and shear ductility of FRTCC as well as the toughening mechanism of polyvinyl alcohol(PVA) fiber were systematically investigated by means of cube compression-, direct tensile-, thin plate bending-and double shear-test. The influence of the content of PVA fiber and the ratio of water to binder on the ductility of FRTCC was examined. The definition of complete toughness ratio was proposed, and the toughness of FRTCC was characterized with a set of double characteristic parameters i.e. the toughness ratio and the toughness index. The results show that the content of PVA fiber and the ratio of water to binder exhibit remarkable synergistic effect on the ductility of FRTCC. The proper mix proportion can significantly improve the ductility and energy absorption capacity of FRTCC, thereby ensure that the FRTCC possesses characteristics such as cracking with multi-cracks, strain hardening and ductile fracture etc.更多还原