摘   要：研究了Ⅱ级粉煤灰-S75级矿粉复合掺合料的掺量（20%、25%、30%、35%）对核工程混凝土工作性、力学性能和耐久性能的影响，并与单掺和复掺Ⅰ级粉煤灰与S95级矿粉的混凝土进行了对比。结果表明：经超细粉磨后，Ⅱ级粉煤灰和S75级矿粉的颗粒形貌得到改善，趋于圆润光滑；相同掺量下，与单掺和复掺Ⅰ级粉煤灰与S95级矿粉的试验组相比，掺复合掺合料混凝土的工作性更好，力学、抗冻、抗氯离子渗透和抗硫酸盐侵蚀性能更优；随着复合掺合料掺量的增加，混凝土的坍落度、抗压强度、相对动弹性模量和抗压强度耐蚀系数均先增大后减小，质量损失率和氯离子扩散系数均先减小后增大，其最佳掺量为30%。

Abstract: The effects of the content(20%, 25%, 30%, 35%) of the grade Ⅱ fly ash and S75 slag powder composite admixture on the workability, mechanical properties and durability of nuclear engineering concrete were studied, and compared with the concrete mixed with grade Ⅰ fly ash or S95 slag powder. The results show that after ultrafine grinding, the particle morphology of grade Ⅱ fly ash and S75 slag powder is improved and tends to be round and smooth. At the same content, the workability of concrete mixed with composite admixture is better than that of the test groups mixed with grade Ⅰ fly ash and S95 slag powder, and the mechanical properties, frost resistance, chloride ion penetration resistance and sulfate corrosion resistance are better. With the increase of the content of composite admixture, the slump, compressive strength, relative dynamic elastic modulus and compressive strength corrosion resistance coefficient of concrete first increase and then decrease, and the mass loss rate and chloride ion diffusion coefficient first decrease and then increase,  and the optimum content of composite admixture is 30%.