The early hydration and rheological characteristics of cement paste containing co-combustion fly ash
The early hydration and rheological characteristics of cement paste containing co-combustion fly ash
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DOI：
10.1016/j.jobe.2023.107736
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发表时间：
2023-09
影响因子：
6.4
通讯作者：
Wei Liu;Hangyu Du;Peng Yi;Yongqiang Li;Yaoming Luo;Qian Chen;Feng Xing
中科院分区：
文献类型：
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作者：
Wei Liu;Hangyu Du;Peng Yi;Yongqiang Li;Yaoming Luo;Qian Chen;Feng Xing
采用等温量热法、低场核磁共振（LF-NMR）法和流变试验研究了掺混粉煤灰水泥浆体的早期水化和流变特性，分析了掺混粉煤灰水泥浆体与传统粉煤灰胶凝体系的差异。结果表明，掺烧粉煤灰对水泥的早期水化有一定的延缓作用。随着粉煤灰掺量从10%增加到30%，这种效果变得更加明显。此外，发现含有CCFA的样品的早期水化速率比含有CFA的样品更快，即使使用相同的混合物。T2谱分析表明，粉煤灰主要是通过影响毛细水的消耗量来影响早期水化特性。随着粉煤灰掺量的增加，水分损失减少。水分演化的模式表现出很强的相关性与水化热。在72 h时，发现CCFA和CFA样品的弛豫特性相似。此外，水泥浆体的流变性能还受粉煤灰种类、掺量、水化程度等因素的影响。随着粉煤灰掺量的增加，流变性能也有所提高。具体而言，CCFA样品显示出更高的可塑性相比，CFA样品，即使当使用相同的混合物的量。本研究中不同分析方法的结果一致。
In this study, the early hydration and rheological characteristics of cement paste containing co-combustion fly ash (CCFA) were studied by using isothermal calorimetry, low-field NMR (LF-NMR), and rheological tests, and the differences between CCFA/cement system and the traditional binding system made with coal fly ash (CFA) were analyzed. The results indicate that co-combustion fly ash has a retarding effect on the early hydration of the cement. This effect becomes more pronounced as the dosage of fly ash increases from 10% to 30%. Additionally, the early hydration rate of samples containing CCFA was found to be faster compared to samples with CFA, even when the same admixture was used. The T 2 spectrum analysis reveals that fly ashes primarily influence the early hydration characteristics by affecting the consumption of capillary water. As the admixture of fly ash increases, there is a reduction in moisture loss. The pattern of moisture evolution exhibits a strong correlation with the heat of hydration. At 72 h, the relaxation characteristics of both CCFA and CFA samples were found to be similar. Moreover, the rheological properties of the cement paste are influenced by factors such as the type and admixture amount of fly ash, as well as the degree of hydration. With an increase in the amount of fly ash blending, the rheological properties exhibit an increase as well. Specifically, CCFA samples display higher plasticity compared to CFA samples, even when the same admixture amount is used. The results of different analytical methods in the study were consistent.