Acid mine drainage (AMD) is detrimental to concrete cut-off walls due to acid and sulfate attacks. As a recently developed fiber reinforced cement-based composite with high tensile ductility and intrinsically tight crack width, Engineered Cementitious Composites (ECC, also known as Strain-Hardening Cementitious Composites, or SHCC) has potential advantages in resisting transport of water and contaminant if applied to the mine cutoff walls. The durability of ECC exposed to AMD, however, has not been previously studied, and is the main objective of this research. Mechanical properties of ECC exposed to AMD wet-dry cycles were investigated. In addition, MgO was added in ECC to improve self-healing performance. It was found that AMD wet-dry cycles coarsened pore structure and led to ECC’s mass loss and compressive strength reduction. The AMD exposure also reduced ECC’s first cracking strength, ultimate tensile strength and tensile strain capacity by 23.7%, 17.8% and 36.5%, respectively. Addition of MgO was found effective in enhancing ECC’s resistance to AMD attack, by moderating the reductions in compressive strength, tensile ductility and mass loss. Further, the addition of MgO densified ECC’s microstructure and improved self-healing behavior. We conclude that ECC containing 6% MgO retains the desirable tensile ductility and possesses acceptable durability against AMD for cutoff wall applications at mining sites.

由于酸和硫酸盐的侵蚀，酸性矿山排水（AMD）对混凝土防渗墙有害。作为最近开发的具有高拉伸延展性和固有裂缝宽度的纤维增强水泥基复合材料，工程胶凝复合材料（ECC，也称为应变硬化胶凝复合材料或SHCC）在施加水和污染物时具有潜在的优势到防雷墙。但是，以前没有研究过ECC暴露于AMD的耐久性，这是这项研究的主要目标。研究了暴露于AMD干湿循环的ECC的机械性能。另外，在ECC中添加了MgO，以提高自我修复性能。发现AMD干湿循环使孔结构变粗，并导致ECC的质量损失和抗压强度降低。AMD暴露还使ECC的首次开裂强度，极限抗拉强度和抗拉应变能力分别降低了23.7％，17.8％和36.5％。通过抑制压缩强度，拉伸延展性和质量损失的降低，发现添加MgO可有效增强ECC对AMD的抵抗力。此外，MgO的添加使ECC的微观结构致密，并改善了自愈性能。我们得出的结论是，含6％MgO的ECC保留了理想的拉伸延展性，并且在采矿现场的防渗墙应用中具有抗AMD的可接受的耐久性。通过缓和抗压强度，拉伸延展性和质量损失的降低。此外，MgO的添加使ECC的微观结构致密，并改善了自愈性能。我们得出的结论是，含6％MgO的ECC保留了理想的拉伸延展性，并且在采矿现场的防渗墙应用中具有抗AMD的可接受的耐久性。通过缓和抗压强度，拉伸延展性和质量损失的降低。此外，MgO的添加使ECC的微观结构致密，并改善了自愈性能。我们得出的结论是，含6％MgO的ECC保留了理想的拉伸延展性，并且在采矿现场的防渗墙应用中具有抗AMD的可接受的耐久性。