Strain hardening cementitious composites (SHCCs) have been shown to have promising self-healing ability. Nevertheless, reliable healing performance only occurs for micro-cracks in relatively young SHCCs and requires several months of moisture exposure. To overcome these criteria for effective healing, this study explored the feasibility of using sodium sulfate solution to promote the healing performance of medium-term SHCCs. For this purpose, cracks were induced in SHCC specimens at the age of 180 days followed by a 28-day exposure to high sulfate ion concentrations. Four SHCC mixtures with different ratios of cement replaced by pozzolans were tested. In particular, the performance of the SHCCs containing an extremely high volume of granulated blast-furnace slag (GGBS) was studied. The healing behavior of the SHCCs was evaluated via multiple means, including uniaxial tensile tests, monitoring of the crack width, scanning electron microscopy, and energy dispersive x-rays. The results indicated that short-term exposure to sodium sulfate solution effectively promoted the healing performance of cracked SHCCs, especially for cracks with relatively larger widths. It was found that the newly formed healing precipitation within the cracks primarily consisted of calcium carbonate, calcium silicate hydrates, and ettringite. In addition, the SHCCs with 71% replacement of cement by GGBS had the highest recovery in terms of crack width and tensile response.

应变硬化水泥复合材料（SHCC）已被证明具有良好的自我修复能力。然而，可靠的愈合性能仅在相对年轻的SHCC中出现于微裂纹，并且需要几个月的湿气暴露。为了克服这些有效治愈的标准，本研究探索了使用硫酸钠溶液促进中期SHCC愈合性能的可行性。为此，在180天龄的SHCC标本中引起了裂纹，然后在高硫酸盐离子浓度下暴露28天。测试了四种不同比例水泥的SHCC混合物被火山灰替代。尤其是，研究了含有极高粒化高炉矿渣（GGBS）的SHCC的性能。通过多种方法评估了SHCC的愈合行为，包括单轴拉伸试验，裂缝宽度监测，扫描电子显微镜和能量色散X射线。结果表明，短期暴露于硫酸钠溶液可有效地促进破裂的SHCC的愈合性能，特别是对于宽度相对较大的裂缝。发现裂缝内新形成的愈合沉淀主要由碳酸钙，水合硅酸钙和钙矾石组成。此外，用GGBS替代71％水泥的SHCC在裂缝宽度和拉伸响应方面具有最高的回收率。结果表明，短期暴露于硫酸钠溶液可有效地促进破裂的SHCC的愈合性能，特别是对于宽度相对较大的裂缝。发现裂缝内新形成的愈合沉淀主要由碳酸钙，水合硅酸钙和钙矾石组成。此外，就裂缝宽度和拉伸响应而言，用GGBS代替水泥的SHCC的回收率最高，为71％。结果表明，短期暴露于硫酸钠溶液可有效促进破裂的SHCC的愈合性能，特别是对于宽度相对较大的裂缝。发现裂缝内新形成的愈合沉淀主要由碳酸钙，水合硅酸钙和钙矾石组成。此外，用GGBS替代71％水泥的SHCC在裂缝宽度和拉伸响应方面具有最高的回收率。