硫酸铝对喷射混凝土钙溶蚀过程的影响及作用机理

Influence of Aluminum Sulfate on Calcium Leaching Process of Shotcrete and Its Mechanism

摘要:

为研究硫酸铝（AS）对喷射混凝土钙溶蚀过程的影响及作用机理，分析了含AS水泥砂浆试样在6 mol/L氯化铵溶液中的性能变化.结果表明：AS掺量对水泥砂浆试件的钙溶蚀过程有显著影响，掺2%AS有利于延缓砂浆试样在加速溶蚀过程中的性能退化；钙溶蚀过程导致水泥水化产物中的氢氧化钙（CH）溶解，水化硅酸钙（C-S-H）凝胶和钙矾石（AFt）脱钙，生成易溶的氯化钙，加速水泥石解体；加入AS会改变水泥水化产物的组成与结构，以及水泥石的微观结构，进而影响喷射混凝土的钙溶蚀过程.

Abstract:

By investigating the performance changes of mortar samples containing aluminum sulfate（AS） in 6 mol/L NH₄Cl solution， the influence and mechanism of action of aluminum sulfate on the calcium leaching process of shotcrete were analyzed. The results show that the use level of AS has a significant impact on the calcium leaching process of mortar samples. The addition of 2% AS is beneficial in delaying the performance degradation of mortar samples during accelerated leaching. The leaching process leads to the dissolution of calcium hydroxide in the cement hydration products， the decalcification of calcium silicate hydrate gel and ettringite， and the formation of soluble CaCl₂， which accelerates the disintegration of cement stone. The addition of AS alters the composition and structure of cement hydration products， as well as the microstructure of cement stone， thereby influencing the calcium leaching process of shotcrete.