免蒸养混凝土用胶凝材料的性能研究

Study on Properties of Cementitious Materials for Non-steam Curing Concrete

将促强减缩剂与普通硅酸盐水泥组成复合胶凝体系,表征复合胶凝材料的凝结时间和其在不同水灰比时的强度变化,通过XRD、压汞法、SEM和水化热等测试方法研究复合胶凝体系的水化机理。结果表明:促强减缩剂的掺入可以促进硅酸盐水泥的凝结硬化,提高复合体系的水化速率,促进C_(3)S的水化程度,增加水化产物中AFt的生成,使结构更加紧密。在水灰比为0.3条件下,当促强减缩剂掺量为25%时,混凝土的8 h强度最高,为23.3 MPa;当促强减缩剂掺量为10%时,混凝土的28 d强度最高,为87.3 MPa。

The composite cementing system is composed of the strengthening and reducing agent and ordinary Portland cement,characterizes the setting time and the strength of the composite cementing material under different water-cement ratios,studies the hydration mechanism of the composite cementing system by means of XRD,MIP,SEM and hydration heat.The results show that the addition of strength enhancer and shrinkage reducer promotes the setting and hardening of Portland cement,improves the hydration rate of the composite system,promotes the hydration degree of C_(3)S,increases the generation of AFt in the hydration products,and make the structure more compact.Under the condition of water-cement ratio of 0.3,the 8 h strength of concrete is the highest at 23.3 MPa when the dosage of the strength-promoting and shrinkage-reducing agent is 25%,and the 28 d strength of concrete is the highest at 87.3 MPa when the dosage of the strength-promoting and shrinkage-reducing agent is 10%.