Qin Wei, Fan Xinhui, Jiang Xiaohui
School of Economics and Management, Chongqing Jiaotong University, 66 Xuefu Road, Nan'an District, Chongqing 400074, China.
National Engineering Research Center for Inland Waterway Regulation, School of River and Ocean Engineering, Chongqing Jiaotong University, 66 Xuefu Road, Nan'an District, Chongqing 400074, China.
Materials (Basel). 2024 Jul 18;17(14):3567. doi: 10.3390/ma17143567.
The increasing demand for concrete reduces natural resources, such as sand and gravel, and also leads to a sharp increase in the amount of waste concrete produced. Due to the fact that the physical and mechanical properties of waste concrete made of recycled aggregates (RAs) differ greatly, it is difficult to use directly as a raw material for reinforced concrete (RC) components, which greatly restricts the popularization and application of RAs in actual projects. Utilizing the alkali aggregate properties of RAs to capture CO from industrial waste gases is an innovative way of enhancing their properties and promoting their application in real projects. However, the extent of the influence of original concrete strength (OCS) and coarse aggregate size (CAS) on the accelerated carbonation modification of RA is not clear, and a quantitative description is still required. For this purpose, accelerated carbonation tests on recycled coarse aggregate (RCA) samples under completely dry condition were carried out, and the variation laws for the physical property indicators of RCA samples before and after accelerated carbonation versus the OCS and CAS were revealed. Moreover, the influence degrees of the two factors, OCS and CAS, on the property enhancement of RCAs after accelerated carbonation were clarified, and the results of OCS and CAS corresponding to the best accelerated carbonation effects of RCAs were determined. By analyzing the micromorphology of RCA before and after accelerated carbonation, the reasons for property enhancement of RCAs with various OCSs and CASs under the best carbonation modifications were clarified. The findings will contribute to the development of basic theoretical research on accelerated carbonation modification of RA and have important scientific value.
对混凝土不断增长的需求减少了自然资源，如沙子和砾石，同时也导致废弃混凝土的产量急剧增加。由于由再生骨料（RAs）制成的废弃混凝土的物理和力学性能差异很大，很难直接用作钢筋混凝土（RC）构件的原材料，这极大地限制了再生骨料在实际工程中的推广和应用。利用再生骨料的碱骨料特性从工业废气中捕获二氧化碳是一种提高其性能并促进其在实际工程中应用的创新方法。然而，原始混凝土强度（OCS）和粗骨料尺寸（CAS）对再生骨料加速碳化改性的影响程度尚不清楚，仍需要进行定量描述。为此，对完全干燥条件下的再生粗骨料（RCA）样品进行了加速碳化试验，揭示了加速碳化前后RCA样品物理性能指标随OCS和CAS的变化规律。此外，明确了OCS和CAS这两个因素对加速碳化后RCA性能增强的影响程度，并确定了RCA最佳加速碳化效果对应的OCS和CAS结果。通过分析加速碳化前后RCA的微观形貌，阐明了在最佳碳化改性条件下不同OCS和CAS的RCA性能增强的原因。这些研究结果将有助于再生骨料加速碳化改性基础理论研究的发展，具有重要的科学价值。
