自由水对铝酸钙水泥水化产物之间转化的影响

Effect of free water on transformation of hydrates of calcium aluminate cement

为确定CAH_(10)向C_(3)AH_(6)和AH_(3)的转化机制是固态脱水分解还是溶解-沉淀,将铝酸钙水泥浆体在10℃分别养护1和3 d生成CAH_(10),再分别于60℃有水和无水条件下养护3 d,然后通过真空冷冻干燥法终止浆体水化,最后采用XRD和SEM研究水化产物的物相组成和显微形貌。结果发现:CAH_(10)在60℃养护过程中,有水存在时转化成C_(3)AH_(6)和AH_(3),无水存在时则未转化成C_(3)AH_(6)和AH_(3)。这表明,CAH_(10)向C_(3)AH_(6)和AH_(3)的转化属于溶解-沉淀机制。

To determine the transformation mechanism of CAH_(10)to C_(3)AH_(6)and AH_(3)solid-state dehydration decomposition or dissolution-precipitation,the calcium aluminate slurry was cured at 10℃for 1 and 3 d to form CAH_(10),and then the slurry was cured at 60℃in water and anhydrous conditions for 3 d,respectively,then the slurry hydration was terminated by vacuum freeze drying,and finally the phase composition and microstructure of the hydration products were studied by XRD and SEM.The results show that,with water,CAH_(10)converts to C_(3)AH_(6)and AH_(3),without water,CAH_(10)does not convert to C_(3)AH_(6)and AH_(3).This suggests that the transformation of CAH_(10)to C_(3)AH_(6)and AH_(3)belongs to a dissolution-precipitation mechanism.