碾压混凝土中高掺石灰石粉与粉煤灰的耦合作用

Combination of high content limestone powder and fly ash used in RCC

以占胶凝材料总量60%的石灰石粉与粉煤灰进行不同比例复掺,开展了不同胶凝材料碾压混凝土的抗压强度、抗冻性能和抗渗性能试验研究,利用水化热、扫描电镜以及压汞法对不同比例石灰石粉与粉煤灰胶凝体系的水化过程与微结构形成进行了分析。研究发现,当石灰石粉与粉煤灰总量占胶凝材料总量的60%且石灰石粉取代粉煤灰比例为50%时,由于早期石灰石粉促进水化加上粉煤灰的填充效应、后期粉煤灰的火山灰活性以及石灰石粉的密实效应,二者的耦合作用可使得碾压混凝土形成密实的微结构,获得良好的力学性能和耐久性能。

Combined with limestone powder and fly ash which is taking 60% of the total replacement of cement, compressive strength, freeze-thaw resistance and impermeability performance of roller compacted con- crete（RCC） with different proportion of limestone powder content to replace fly ash were investigated, With help of micro calorimeter, scanning electron microscope and mercury intrusion, the hydration process as well as microstructure of pastes was also analyzed. The results indicate that, when the replacing ratio of limestone powder was 50% in composite paste,the mechanical property and durability of RCC were satisfactory. The coupling effect of limestone powder and fly ash led to hydration promotion and formation of denser microstructure, which resulted in great improvement in RCC performance.