石膏基复合胶凝材料的物理力学性能研究

在石膏基复合胶凝材料优化配合比的基础上,研究了石膏原料煅烧温度、萘系减水剂、聚羧酸减水剂、养护条件等因素对其性能的影响,借助扫描电镜SEM、X射线衍射的表征手段,分析石膏基复合胶凝材料水化过程特点、凝结硬化作用机理.结果表明:当脱硫建筑石膏、粉煤灰、水泥、熟石灰用量分别为52%、25%、20%、3%,复合激发剂适量,基准水胶比0.40时,常温自然养护条件下该复合材料28 d和56 d抗压强度分别为24.25 MPa和26.20 MPa,软化系数0.816.常温下粉煤灰水化反应条件不同于一般水泥基材料的情况,关键是控制碱性激发剂用量应适中.适宜蒸养工艺参数为70℃、24 h,还需再经适当龄期常温养护,可以显著加快CSH凝胶和AFt的生成数量.

Physical and Mechanical Properties of Gypsum Based Compound Cementing Materials

The effects of calcining temperature of raw gypsum, naphthalene-based reducer, polycarboxylate superplasticizer, curing styles on properties were studied with optimization mixing proportion of gypsum based compound cementing materials. Meanwhile,the characteristics of hydration process and mechanism of setting and hardening for the cementing materials were characterized by using scanning electron microscope and X-ray diffraction. The results show that the optimum formula proportion is 52% of flue gas desulphurization (FGD)building gypsum,25% of fly ash,20% of cement and 3% of hydrated lime,an appropriate quantity of compound exciting agent,standard at weight rate of 0. 4 water per compound cementing materials. By the way of normal atmospheric temperature of nature curing,the compressive strength of 28 d and 56 d of cementing materials are 24. 25 MPa and 26. 20 MPa,softness coefficient is 0. 816 as well. The situation of fly ash hydration of compound cementing materials is worse than the situation of fly ash hydration of normal cement based at the normal atmospheric temperature. The key question of moderate proportion of alkaline exciting agent is controlled from beginning to end. The appropriate processing parameters of steam curing for the cementing materials are 70 ℃ and 24 h,in addition,a suitable age of normal atmospheric temperature of curing is required. The rapidity of generating quantities of calcium silicate gel and ettringite (AFt)is significantly accelerated and then.