Cement is the most commonly used inorganic cementing material in construction engineering owing to its stable performance; however, cement production requires a considerable amount of energy. To reduce energy consumption, inorganic cementing materials were prepared by solid waste to replace parts of the cement. In this experiment, composite cementing material was prepared by mixing ultrafine fly ash, lime and gypsum; then, this material was hydrated at a calcium-to-silicon (C/S) ratio of 0.6-2.2. The effects of various C/S ratios on the properties of the prepared composite cementing material were investigated. The results showed that when the C/S ratio was 1.6, the compressive and flexural strengths of the composite cementing material reached their maximum. With the increase of C/S ratio, the production of C–S–H gel and ettringite increased; the two products got interwoven, filling the pores of hydration products and increasing the strength of the cementing material. When the C/S ratio was 2.0, the carbonization rate of the cementing materials increased. Calcite coated the surface of the fly ash, preventing the pozzolanic reaction of the fly ash and reducing the overall strength of the material.

水泥由于其性能稳定，是建筑工程中最常用的无机胶凝材料；然而，水泥生产需要大量能源。为了降低能源消耗，利用固体废弃物制备无机胶凝材料来替代部分水泥。本试验采用超细粉煤灰、石灰和石膏混合制备复合胶凝材料；然后，该材料以 0.6-2.2 的钙硅 (C/S) 比水合。研究了不同C/S比对制备的复合胶凝材料性能的影响。结果表明，当C/S比为1.6时，复合胶凝材料的抗压强度和抗弯强度均达到最大值。随着C/S比的增加，C-S-H凝胶和钙矾石的产量增加；两种产物交织在一起，填充了水化产物的孔隙，增加了胶凝材料的强度。当C/S比为2.0时，胶结材料的碳化速度加快。方解石包覆在飞灰表面，阻止了飞灰的火山灰反应，降低了材料的整体强度。