Li Yingying, Long Jia, Chen Xiang
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 Aug 24;17(17):4194. doi: 10.3390/ma17174194.
The poor properties of recycled coarse aggregate (RCA) and recycled coarse aggregate concrete (RCAC) are considered key constraints hindering the reuse of this waste resource in marine engineering. The CO-based accelerated carbonation method, which utilizes the alkali aggregate properties of RCA to achieve CO uptake and sequestration while significantly enhancing its properties, has attracted widespread attention. However, the degree of improvement in the properties of RCA under different initial moisture conditions (IMCs) and aggregate particle sizes (APSs) after CO-accelerated carbonation remains unclear. Moreover, the quantitative effect of carbonated recycled coarse aggregate (CRCA), which is obtained from RCA samples with the optimal initial moisture conditions, on the improvement of RCAC under optimal accelerated carbonation modification conditions still needs to be studied in depth. For this investigation, a CO-accelerated carbonation experiment was carried out on RCA samples with different IMCs and APSs, and the variations in the properties of RCA with respect to its IMC and APS were assessed. The degree of accelerated carbonation modification of RCA under different IMCs and APSs was quantified, and the optimal initial moisture conditions for enhancing the properties of the RCA were confirmed. By preparing concrete specimens based on the natural coarse aggregate, RCA, and CRCA with the best initial moisture conditions (considering the same concrete-water proportion), the effect of CRCA on the workability, mechanical properties, and durability of the corresponding concrete specimen was determined. The findings of this study can be used to effectively promote the sustainable development of marine science and engineering in the future and contribute to global dual-carbon goals, which are of great practical significance and scientific value.
再生粗骨料（RCA）和再生粗骨料混凝土（RCAC）性能较差被认为是阻碍这种废弃资源在海洋工程中再利用的关键制约因素。基于CO的加速碳化方法利用RCA的碱骨料特性来实现CO的吸收和封存，同时显著提高其性能，已引起广泛关注。然而，在CO加速碳化后，不同初始湿度条件（IMC）和骨料粒径（APS）下RCA性能的改善程度仍不明确。此外，从具有最佳初始湿度条件的RCA样品中获得的碳酸化再生粗骨料（CRCA）在最佳加速碳化改性条件下对RCAC性能改善的定量影响仍需深入研究。为此，对不同IMC和APS的RCA样品进行了CO加速碳化试验，并评估了RCA性能随其IMC和APS的变化。量化了不同IMC和APS下RCA的加速碳化改性程度，确定了提高RCA性能的最佳初始湿度条件。通过制备基于天然粗骨料、RCA和具有最佳初始湿度条件的CRCA（考虑相同的混凝土水灰比）的混凝土试件，确定了CRCA对相应混凝土试件工作性、力学性能和耐久性的影响。本研究结果可有效促进未来海洋科学与工程的可持续发展，为全球双碳目标做出贡献，具有重要的现实意义和科学价值。
