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Water transport in recycled aggregate concrete under sustained compressive loading: Experimental investigation and mesoscale numerical modelling
Journal of Building Engineering ( IF 6.4 ) Pub Date : 2021-09-25 , DOI: 10.1016/j.jobe.2021.103373
Jiuwen Bao 1, 2 , Shuguo Li 2 , Zihao Yu 2 , Jun Xu 3 , Yanlong Li 1 , Peng Zhang 2 , Zheng Si 1 , Song Gao 2
Affiliation  

The durability properties of load-induced damaged concrete incorporating recycled concrete aggregates (RCAs) have previously been reported, but the investigation on water transport in recycled aggregate concrete (RAC) subjected to sustained loading remains to be limited, especially involving both numerical simulation and experimental aspects. This paper presents a comprehensive exploration on capillary water absorption in RAC under various sustained compressive stress levels (λc = 0, 0.1, 0.3, 0.5, 0.7). An improved experimental set-up was self-designed for realizing the coupled action of sustained compressive loading and water absorption by RAC, and then a series of water absorption tests for specimens with different replacement ratios of RCAs (0, 30%, 50%, 100%) were experimentally conducted. The coupled effects of sustained stress level and replacement ratio on the sorptivity of RAC were further discussed. The quantitative correlation between the sorptivity and stress level was obtained to derive the formula of hydraulic diffusivity. Based on the unsaturated flow theory and Mazar's damage variable, the prediction model of water transport in load-induced damaged concrete was established. A mesoscopic model of RAC modelled as a five-phase composite material by considering the old and new interfacial transition zones (ITZs) as interphases was developed and employed to numerically simulate the process of water transport in load-damaged concrete. The mechanical and hydraulic parameters for multiple ITZs of RAC were determined by summarizing the previous studies. The visual numerical results indicate that the distribution of water content and wetting front of penetration depth were remarkably affected by the stress level and the content of RCAs. The comparison of cumulative amount of water absorption indicates that the numerical results agreed well with the obtained experimental measurements, fairly validating the feasibility and accuracy of the developed models. It further illustrates the mesoscopic numerical modelling can be practically adopted to simulate water transport process coupled with sustained loading and also visually exhibit the wetting front of water penetration in RAC.



中文翻译:

持续压缩载荷下再生骨料混凝土中的水运移:实验研究和中尺度数值模拟

先前已经报道了掺入再生混凝土骨料 (RCA) 的载荷诱导损坏混凝土的耐久性能,但对承受持续载荷的再生骨料混凝土 (RAC) 中的水传输的研究仍然有限,特别是涉及数值模拟和实验方面。本文对不同持续压缩应力水平 ( λ c = 0, 0.1, 0.3, 0.5, 0.7)。自行设计了改进的实验装置以实现 RAC 的持续压缩载荷和吸水的耦合作用,然后对不同 RCA 替代率(0、30%、50%、 100%) 是通过实验进行的。进一步讨论了持续应力水平和替代率对 RAC 吸附性的耦合影响。获得了吸着性和应力水平之间的定量相关性,以推导出水力扩散系数的公式。基于非饱和流动理论和Mazar的损伤变量,建立了荷载诱导损伤混凝土中水分输送的预测模型。通过将新旧界面过渡区 (ITZ) 视为相间,开发了一种建模为五相复合材料的 RAC 细观模型,并用于数值模拟荷载损坏混凝土中的水传输过程。RAC 的多个 ITZ 的机械和液压参数是通过总结以前的研究确定的。可视化数值结果表明,水含量的分布和渗透深度的润湿前沿受应力水平和RCAs含量的显着影响。累积吸水量的比较表明,数值结果与获得的实验测量结果吻合良好,充分验证了所开发模型的可行性和准确性。

更新日期:2021-09-27
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