Influence of the incorporation of recycled coarse aggregate on water absorption and chloride penetration into concrete
Influence of the incorporation of recycled coarse aggregate on water absorption and chloride penetration into concrete
复制标题
再生粗骨料的掺入对混凝土吸水率和氯离子渗透的影响
DOI：
10.1016/j.conbuildmat.2019.117845
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发表时间：
2020-04-10
影响因子：
7.4
通讯作者：
Zhao, Tiejun
中科院分区：
文献类型：
--
作者：
Bao, Jiuwen;Li, Shuguo;Zhao, Tiejun
氯离子环境下再生骨料混凝土的传输特性是评估其耐久性和预测其使用寿命的关键。在这项研究中，粗再生混凝土骨料（RCAs）的掺入对水泥基胶凝材料的耐久性的影响进行了试验研究。得到两种类型的RCA以生产水与粘合剂比为0.33和0.39的RAC，并选择范围为0%、30%、50%和100%重量的不同取代度的RCA。对不同取代率的再生混凝土进行了抗压强度、吸水率、吸盐率和快速氯离子迁移试验。结果表明，RCAs的掺入通常会降低抗压强度，并相反地增加水和氯离子的传输系数相比，那些控制混凝土。再生混凝土的初始吸水系数随再生混凝土取代率的增加而增大，但随着再生混凝土质量的提高而减小。再生混凝土中氯离子含量和渗透深度随再生混凝土中氯离子含量的增加而显著增加，而再生混凝土质量的降低。不同置换率的再生混凝土中水与氯离子的渗透深度呈线性变化。这一发现揭示了RAC吸收测试中氯离子迁移过程滞后于水迁移的延迟效应。(C)2019爱思唯尔有限公司版权所有。
Knowledge of the transport properties for recycled aggregate concrete (RAC) exposed to chloride environment plays a critical role in assessing its durability and predicting the service life. In this study, the effect of the incorporation of coarse recycled concrete aggregates (RCAs) on the durability of cement-based cementitious materials was experimentally investigated. Two types of RCAs were obtained to produce the RAC with water-to-binder ratio of 0.33 and 0.39, and different substitutions of RCAs ranging from 0%, 30%, 50% and 100% by weight were selected. A series of experiments including compressive strength, water and salt absorption test, and rapid chloride migration (RCM) test for RAC with various replacement ratios of RCAs were conducted. The results indicate that the incorporation of RCAs generally decreases the compressive strength, and inversely increases water and chloride transport coefficient compared to those of the control concrete. An increasing trend can be found in the influence of RCAs replacement ratio on the initial coefficient of capillary water absorption, but it inversely decreases as the quality of RCAs is improved. The chloride content and penetration depth in RAC were remarkably increased as RCA content increases and its quality decreases. The linear changing behavior for the penetration depth between water and chloride ion in RAC with different replacement ratios was well exhibited. This finding reveals the retardation effect that the chloride transport process lags behind water migration for the absorption tests of RAC. (C) 2019 Elsevier Ltd. All rights reserved.