In order to study the effect of fly ash content in cemented paste backfill (CPB) on its anti-sulfate erosion, the apparent phenomenon, strength development, and hydration products change the law of CPB with different fly ash content under long-term soaking of 5% sodium sulfate solution were studied by the macrotest and microanalysis, in addition, the mechanism of CPB anti-sulfate attack was analyzed by combining with a scanning electron microscope (SEM). The results indicated that the effect of sulfate environment on the strength of fly ash cemented paste backfill (FCPB) was mainly determined by the hydration products in the FCPB at different soaking times. In the early soaking stage, the formation of ettringite (AFt) in FCPB could improve its compactness, which was conducive to improving the strength of FCPB. In the late soaking stage, there were ettringite-type erosion damage and gypsum erosion-type damage internal of the FCPB with low content fly ash, resulting in microfracture, cracking of the FCPB, and reducing the strength. CPB with an appropriate content of fly ash could improve the internal structure of the FCPB to achieve the purpose of anti-sulfate erosion.

为了研究水泥浆回填中粉煤灰含量对其抗硫酸盐侵蚀的影响，在长期浸泡下，表观现象，强度发展和水合产物改变了不同粉煤灰含量的CPB的规律。通过宏观试验和微观分析研究了5％硫酸钠溶液，并结合扫描电镜（SEM）分析了CPB抗硫酸盐侵蚀的机理。结果表明，硫酸盐环境对粉煤灰水泥浆回填土（FCPB）强度的影响主要取决于FCPB在不同浸泡时间下的水合产物。在早期浸泡阶段，在FCPB中形成钙矾石（AFt）可以提高其致密性，有利于提高FCPB的强度。在浸泡的后期 粉煤灰含量低的FCPB内部存在钙矾石型侵蚀破坏和石膏侵蚀型破坏，从而导致微裂纹，FCPB破裂和强度降低。含有适量粉煤灰的CPB可以改善FCPB的内部结构，从而达到抗硫酸盐侵蚀的目的。