Abstract Shotcrete is a material frequently used in underground constructions such as tunnels, where Ca leaching and sulfate attack are important durability issues. In this study, two test methods were employed to investigate the sulfate resistance and leaching behaviour of dry- and wet-mix shotcretes in sulfate solutions on a time-resolved basis. Tests on powdered samples showed the dissolution of AFm, portlandite and C-A-S-H, subsequently followed by the precipitation of calcite and ettringite. The extent of sulfate expansion of drill cores corresponded to the chemical response of the powder materials, particularly on the reactivity of Ca- and Al-containing hydrated cement phases. The use of high-purity metakaolin (7–10 wt%) in the shotcrete binder significantly decreased the sulfate durability, while high amounts of other SCMs such as blast-furnace slag and silica fume (>20 wt%) had a positive effect on the durability of shotcrete.

中文翻译：

---

干湿混合喷射混凝土混合物的硫酸盐耐久性和浸出行为

摘要 喷射混凝土是一种经常用于隧道等地下建筑的材料，其中钙浸出和硫酸盐侵蚀是重要的耐久性问题。在这项研究中，采用两种测试方法来研究硫酸盐溶液中干混和湿混喷射混凝土在时间分辨基础上的硫酸盐耐受性和浸出行为。对粉状样品的测试表明 AFm、硅酸盐和 CASH 溶解，随后方解石和钙矾石沉淀。钻芯的硫酸盐膨胀程度对应于粉末材料的化学反应，特别是含钙和铝的水合水泥相的反应性。在喷射混凝土粘合剂中使用高纯度偏高岭土（7-10 wt%）显着降低了硫酸盐耐久性，