Abstract The inferior durability of recycled aggregate concrete (RAC) is causing hindrance in the application of recycled concrete aggregates (RCA) in structural concrete. This research focuses on the influence of different treatment methods of RCA on the freeze-thaw and sulfate resistance of resulting concrete. For this reason, freeze-thaw and sulfate resistance tests were conducted on carbonated RAC (C-RAC), lime carbonated RAC (LC-RAC), acetic acid immersed RAC (A-RAC), acetic acid immersed and rubbed RAC (AR-RAC) and acetic acid immersed and carbonated RAC (AC-RAC). Furthermore, mechanical properties and porosity of all the specimens were also explored. The results of this study showed improved mechanical performance and porosity of treated RAC. Enhanced frost and sulfate resistance was also observed for the treated RAC specimens. For example, 23, 17, and 21% reduction in the weight loss was noticed for LC-RAC, AR-RAC, and C-RAC after the freeze-thaw test than RAC specimens, respectively. Similarly, 24 and 19% less reduction in compressive strength was observed after sulfate exposure for LC-RAC and AR-RAC than RAC specimens, respectively. Scanning electron microscopic images of specimens after freeze-thaw test also showed lesser microcracks and denser interfacial transition zone for AR-RAC and LC-RAC than RAC supporting the improved frost resistance due to RCA treatment. Based on the results obtained in this study, LC-RAC and AR-RAC may be used in colder and sulfate-rich environments leading towards sustainable construction. Furthermore, regression models developed in this study show that the durability performance of concrete can be estimated through the physical properties of aggregates leading towards the durable and eco-friendly design of concrete structures.

中文翻译：

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不同骨料处理工艺对再生骨料混凝土抗冻融和抗硫酸盐性能的影响

摘要 再生骨料混凝土（RAC）的耐久性较差，阻碍了再生混凝土骨料（RCA）在结构混凝土中的应用。本研究重点研究RCA的不同处理方法对所得混凝土的抗冻融性和抗硫酸盐性的影响。为此，对碳酸RAC（C-RAC）、碳酸钙RAC（LC-RAC）、醋酸浸渍RAC（A-RAC）、醋酸浸渍和摩擦RAC（AR- RAC) 和醋酸浸渍和碳酸化 RAC (AC-RAC)。此外，还研究了所有试样的机械性能和孔隙率。该研究的结果表明，经处理的 RAC 的机械性能和孔隙率有所提高。还观察到处理过的 RAC 样本具有增强的抗霜冻和抗硫酸盐性。例如，在冻融试验后，LC-RAC、AR-RAC 和 C-RAC 的重量损失分别比 RAC 样品减少了 23、17 和 21%。类似地，在硫酸盐暴露后，LC-RAC 和 AR-RAC 的抗压强度降低分别比 RAC 试样少 24% 和 19%。冻融试验后标本的扫描电子显微图像也显示，AR-RAC 和 LC-RAC 的微裂纹更少，界面过渡区更密集，支持由于 RCA 处理而提高的抗冻性。根据本研究中获得的结果，LC-RAC 和 AR-RAC 可用于较冷且富含硫酸盐的环境，从而实现可持续建筑。此外，