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

doi:10.3969/j.issn.1001-1935.2021.05.013

Abstract

Abstract:

To determine the transformation mechanism of CAH₁₀ to C₃AH₆ and AH₃ solid-state dehydration decomposition or dissolution-precipitation,the calcium aluminate slurry was cured at 10 ℃ for 1 and 3 d to form CAH₁₀,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,CAH₁₀ converts to C₃AH₆ and AH₃,without water,CAH₁₀ does not convert to C₃AH₆ and AH₃.This suggests that the transformation of CAH₁₀ to C₃AH₆ and AH₃ belongs to a dissolution-precipitation mechanism.

Key words: calcium aluminate cement, hydration, hydrates, transformation, dissolution-precipitation mechanism

摘要：

为确定CAH₁₀向C₃AH₆和AH₃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CAH₁₀,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:CAH₁₀在60 ℃养护过程中,有水存在时转化成C₃AH₆和AH₃,无水存在时则未转化成C₃AH₆和AH₃。这表明,CAH₁₀向C₃AH₆和AH₃的转化属于溶解-沉淀机制。

关键词: 铝酸钙水泥, 水化, 水化产物, 转化, 溶解-沉淀机制

CLC Number:

TQ175

Zhang Yang, Li Donghong, Wang Yi, Zhang Yanyan, Ye Guotian, Chen Liugang, Tian Xuekun. Effect of free water on transformation of hydrates of calcium aluminate cement[J]. Refractories, 2021, 55(5): 435-438.

张阳, 李东红, 王毅, 张岩岩, 叶国田, 陈留刚, 田学坤. 自由水对铝酸钙水泥水化产物之间转化的影响[J]. 耐火材料, 2021, 55(5): 435-438.

Figures/Tables 5

Tab.1 Curing conditions of specimens

试样编号	养护条件
S10	原始浆料在10 ℃养护1 d
S10-3	原始浆料在10 ℃养护3 d
S60ws	S10继续在60 ℃无水条件下养护3 d
S60-3ws	S10-3继续在60 ℃无水条件下养护3 d
S60ys	S10继续在60 ℃有水条件下养护3 d
S60-3ys	S10-3继续在60 ℃有水条件下养护3 d

Fig.1 XRD patterns of specimens cured at 10 ℃ for 1 day and further cured under different conditions

Fig.2 SEM micrographs of specimens cured at 10 ℃ for 1 day and further cured under different conditions

Fig.3 XRD patterns of specimens cured at 10 ℃ for 3 days and further cured under different conditions

Fig.4 SEM micrographs of specimens cured at 10 ℃ for 3 days and further cured under different conditions

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