Aperture distribution map.

This study reports the preparation of geopolymers with a mechanical performance similar to that of cement at room temperature by ground fly ash mixed with a small amount of cement. The grinding time of fly ash raw materials was 0,20,40 and 60 min, respectively. The influence of the grinding degree of the fly ash on the properties and the reaction degree of the geopolymer were investigated by XRD, SEM, EDS, and mercury compression tests. The reaction degree of the fly ash geopolymer was quantified by the selective dissolution method. Increasing the grinding degree of fly ash significantly increased the compressive strength of the geopolymer and the density of the microstructure of materials also increased. Furthermore, porosity and the average pore size decreased and the proportion of small holes in the pores gradually increased. The calculation results were in coincidence with the compressive strength test and the micro-performance test of the material, thus indicating that the selective dissolution method can reflect the influence of the grinding degree on the reaction degree of the geopolymer. Furthermore, the reaction degree of the geopolymer increased as the grinding degree of the fly ash increased. However, the growth rate of the reaction degree for the geopolymer slowed down when the fly ash was ground for more than 40 min.

本研究报道了通过将磨细粉煤灰与少量水泥混合，制备出常温下力学性能与水泥相近的地质聚合物（geopolymer）的方法。粉煤灰原料的粉磨时间分别设置为0、20、40和60 min。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、能量色散X射线光谱（EDS）及压汞法测试，探究了粉煤灰粉磨程度对地质聚合物性能及反应程度的影响。通过选择性溶解法（selective dissolution method）定量表征粉煤灰基地质聚合物的反应程度。研究发现，提高粉煤灰的粉磨程度可显著提升地质聚合物的抗压强度，材料微观结构的致密度亦随之提升；同时孔隙率与平均孔径降低，小孔在孔隙中的占比逐渐升高。计算结果与材料抗压强度测试及微观性能测试结果相符，表明选择性溶解法能够反映粉磨程度对地质聚合物反应程度的影响。此外，地质聚合物的反应程度随粉煤灰粉磨程度的提高而升高，但当粉煤灰粉磨时间超过40 min后，其反应程度的增长速率趋于放缓。