In this study, to promote the chloride binding capacity of coal fired fly ash (RFA) in cementitious materials, wet grinding was employed and ultrafine fly ash (UFA) with D50 = 2.1 μm was prepared; SEM, XRD, TG, FTIR, and XPS were used to evaluate the chemical and physical change in the process of wet grinding. Then, two kinds of binders composed of cement and FA were designed, and the chloride immobilization was comparatively studied in terms of chemical binding, physical binding, and migration resistance. The hydration behavior and hydrates were investigated in terms of TGA, XRD, NMR, and MIP. Results revealed that UFA exhibited higher pozzolanic reactivity due to the increase of specific surface area, destruction of original molecular structure, and exposure of active reaction sites. And chloride immobilization in cement-UFA system was much greater than that in cement-RFA system at ages of 7 d and 28 d. The mechanism behind was discussed in three aspects: (a) chemical binding was promoted because of the more produced chloroaluminates facilitated by the release of aluminum from UFA; (b) physical adsorption was strengthened at 7 d but weakened at 28 d, resulting from the opposite influence on the amount of C-S-H gel at different ages; (c) migration resistance was improved by the reduction of pore volume and the increase in the complexity of pore structure. This investigation provided one new method for processing FA to promote the chloride immobilization of cement-FA system.

为了提高燃煤粉煤灰（RFA）在水泥质材料中的氯结合能力，采用湿磨法制备了D50 = 2.1μm的超细粉煤灰（UFA）。SEM，XRD，TG，FTIR和XPS用于评估湿磨过程中的化学和物理变化。然后，设计了由水泥和FA组成的两种粘结剂，并从化学结合，物理结合和抗迁移性方面对氯的固定化进行了比较研究。根据TGA，XRD，NMR和MIP研究了水合行为和水合物。结果表明，由于比表面积的增加，原始分子结构的破坏以及活性反应位点的暴露，UFA表现出更高的火山灰反应性。在7 d和28 d时，水泥-UFA系统中的氯化物固定化程度远大于水泥-RFA系统中的氯化物固定化。从三个方面讨论了其背后的机理：（a）由于从UFA释放铝而促进了更多的氯铝酸盐的产生，从而促进了化学结合；（b）物理吸附在7 d时增强，但在28 d时减弱，这是由于不同年龄对CSH凝胶量的相反影响；（c）通过减小孔体积和增加孔结构的复杂性来改善抗迁移性。这项研究提供了一种处理FA的新方法，以促进水泥-FA体系中氯化物的固定化。（a）由于从UFA释放铝促进了更多的氯铝酸盐的产生，从而促进了化学结合；（b）物理吸附在7 d时增强，但在28 d时减弱，这是由于不同年龄对CSH凝胶量的相反影响；（c）通过减小孔体积和增加孔结构的复杂性来改善抗迁移性。这项研究提供了一种处理FA的新方法，以促进水泥-FA体系中氯化物的固定化。（a）由于从UFA释放铝促进了更多的氯铝酸盐的产生，从而促进了化学结合；（b）物理吸附在7 d时增强，但在28 d时减弱，这是由于不同年龄对CSH凝胶量的相反影响；（c）通过减小孔体积和增加孔结构的复杂性来改善抗迁移性。这项研究提供了一种处理FA的新方法，以促进水泥-FA体系中氯化物的固定化。（c）通过减小孔体积和增加孔结构的复杂性来改善抗迁移性。这项研究提供了一种处理FA的新方法，以促进水泥-FA体系中氯化物的固定化。（c）通过减小孔体积和增加孔结构的复杂性来改善抗迁移性。这项研究提供了一种处理FA的新方法，以促进水泥-FA体系中氯化物的固定化。