Multiphase pozzolanic reaction model of low-calcium fly ash in cement systems
Multiphase pozzolanic reaction model of low-calcium fly ash in cement systems
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DOI：
10.1016/j.cemconres.2019.04.015
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发表时间：
2019-08
影响因子：
11.4
通讯作者：
Tiao Wang;T. Ishida
中科院分区：
文献类型：
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作者：
Tiao Wang;T. Ishida
近几十年来，世界各地使用辅助胶凝材料（SCM）来改善混凝土性能的情况有所增加。然而，供应链管理的应用仍然受到其异质性和可变性的限制。工程实践需要一个统一的模型来预测和优化混合混凝土的性能。因此，在这项研究中提出了一个多相建模方案，涵盖各种SCM。根据这一建模方案，选择了三种低钙粉煤灰，并通过扫描电子显微镜-能量色散X射线能谱（SEM-EDS）全元素绘图和图像分析进行了全面研究。进一步研究了这三种粉煤灰在碱性和水泥体系中的火山灰活性。提出了一个考虑粉煤灰材料变化的温度依赖性两相火山灰反应模型（硅酸盐和铝硅酸盐玻璃），用于预测不同温度下的火山灰反应和反应程度。数值结果表明，所提出的多相模拟方案具有很大的潜力，以涵盖各种SCM。
The use of supplementary cementitious materials (SCMs) around the world to improve concrete performance has increased in recent decades. However, the application of SCMs remains limited by their heterogeneity and variability. Engineering practices demand a unified model for SCMs to predict and optimise the performance of blended concrete. A multiphase modelling scheme that covers various SCMs is therefore proposed in this study. Following this modelling scheme, three low-calcium fly ashes were selected and comprehensively studied by scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS) full-element mapping and image analysis. The pozzolanic reactivity of these three fly ashes was further investigated in alkaline and cement systems. A temperature-dependent two-phase pozzolanic reaction model (silicate and Al-silicate glass) considering fly ash material variations was proposed to predict the pozzolanic reaction and therefore the degree of reaction at different temperatures. The numerical results show that the proposed multiphase modelling scheme has great potential to cover various SCMs.