硫铝酸钙基促强剂对复掺粉煤灰-矿渣水泥混凝土早期性能的影响

Influence of calcium sulfoaluminate-based accelerator on early-age performance of double mixed fly ash-slag cement concrete

为了改善复掺粉煤灰-矿渣-水泥的三元复合(F-S-C)混凝土的早期强度,使用了一种新型早强剂(硫铝酸钙基促强剂,CSA)。采用热重分析仪(TGA)、水化热、压汞法(MIP)、X射线衍射(XRD)和扫描电子显微镜(SEM)等方法来表征CSA对F-S-C混凝土的早期性能和微观结构的影响。结果表明,CSA的掺入使F-S-C三元复合混凝土早期强度提升,且不会对后期强度发展产生不利影响。掺入CSA明显加速F-S-C三元复合浆体早期的水化(前6 h内),改变了F-S-C三元复合浆体早期生成的AFt数量和形态,从而获得早期强度。

In order to improve the early strength of double mixed fly ash-slag cement(F-S-C)concrete,a new type of accelerator(calcium sulfoaluminate-based accelerator,CSA)was used in this work.The thermogravimetric analysis(TGA),isothermal calorimetry,mercury intrusion porosimetry(MIP),X-ray diffraction(XRD)and scanning electron microscopy(SEM)were used to characterize the early-age properties and of F-S-C concrete.Results showed that the incorporation of CSA improves the strength of F-S-C concrete in the early stage and does not adversely affect the strength development in the later stage.The addition of CSA significantly accelerated the early hydration of F-S-C composite slurry(within the first 6 h),changed the number and form of AFt generated in the early stage,and thus obtained the early strength.