氯离子对G级水泥水化影响的化学机理研究

Chemical Mechanism Study of the Effect of Chloride Ions on the Hydration of Class G Cement

从硅酸盐工学和材料科学的角度,以盐水水泥浆为主要研究对象,利用X-射线衍射分析、微观电镜等实验手段,从化学机理方面研究了Cl-对G级水泥水化的影响,以期为抗盐水泥浆体系的设计提供理论依据。实验分析结果表明,Cl-参与C3A和C3S的水化反应,生成离子溶度积很小的氯盐(C3A.CaCl2.10H2O),加速水化从而缩短水泥浆稠化所需要的时间;水化反应产生的OH-与溶液中游离的Ca2+反应生成Ca(OH)2,使成形后的水泥石内部疏松且孔结构分布不均,其抗压强度小于不加盐所形成的水泥石;因氯盐引起的固相绝对体积的变化值为91.04%;加盐水泥石的固相体积相对不加盐的水泥石体积增大3.1%。

The effect of chloride ions on the hydration of Class G cement was studied using X-ray and SEM.The study showed that chloride ions play a role in the hydration reaction of C3A and C3S,producing a chloride(C3A·CaCl2·10H2O) of very low solubility product.The formation of the chloride accelerates the hydration of cement,thus shortening the time needed for the thickening of cement slurry.The hydroxyl ions,OH-,generated in the hydration reaction react with calcium ions to produce Ca(OH)2,making the set cement interiorly loose and irregular in structure.The set cement thus formed has a lower compressive strength than those formed with cement slurry having no salt in it.The Absolute solid volume change resulting from the presence of chloride is 91.04%.The solid volume of the set cement formed with cement slurry treated with salt is 3.1% greater than the solid volume of the set cement formed with cement slurry having no salt treatment.