Sun Qi, Wei Xueda, Li Tianlong, Zhang Lu
School of Civil Engineering, Liaoning Technical University, Fuxin 123000, China.
Materials (Basel). 2020 Feb 13;13(4):855. doi: 10.3390/ma13040855.
A new type of cemented paste backfill (CPB) was prepared by using the bottom ash (BA) from a thermal power plant as an aggregate, alkali-activated slag as a binder, and an air-entraining agent as an admixture. Based on the central composite design (CCD) response surface method, the mix ratio was optimized, and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) was performed on the optimal mix ratio. ImageJ software was utilized to determine the porosity of the experimental samples at various curing ages. The results indicate that the optimal mix ratio of the aggregate-binder ratio is 3.28, the alkali dosage is 3%, the solid content is 67.44%, and the air-entraining agent dosage is 0.1%. As the curing age increases, the porosity of CPB gradually decreases. A calcium aluminosilicate hydrate (C-A-S-H) gel is the main hydration product of alkali-activated slag. At the beginning of the hydration reaction, the slag gradually dissolves, and the C-A-S-H product binds the BA together. At 14 d, complete calcium hydroxide (CH) crystals appeared in the hydration product. Finally, the degree of C-A-S-H crystallization increased further to form a dense structure.
一种新型胶结膏体充填材料（CPB）以热电厂的底灰（BA）为骨料、碱激发矿渣为胶凝材料、引气剂为外加剂制备而成。基于中心复合设计（CCD）响应面法对配合比进行了优化，并对最优配合比进行了扫描电子显微镜-能谱分析（SEM-EDS）。利用ImageJ软件测定了不同养护龄期实验样品的孔隙率。结果表明，骨料与胶凝材料的最优配合比为3.28，碱用量为3%，固体含量为67.44%，引气剂用量为0.1%。随着养护龄期的增加，CPB的孔隙率逐渐降低。钙铝硅水化物（C-A-S-H）凝胶是碱激发矿渣的主要水化产物。在水化反应开始时，矿渣逐渐溶解，C-A-S-H产物将BA粘结在一起。在14 d时，水化产物中出现了完整的氢氧化钙（CH）晶体。最后，C-A-S-H的结晶程度进一步提高，形成致密结构。
