Influence of Accelerated Carbonation Conditions on the Physical Properties Improvement of Recycled Coarse Aggregate

作者：Nasir Mehmood, Pinghua Zhu, Hui Liu, Haichao Li, Xudong Zhu · 发表于：Materials · 年份：2025 · DOI：10.3390/ma18040901 · 被引用次数：8 · 研究领域：Recycled Aggregate Concrete Performance、Innovative concrete reinforcement materials、Tailings Management and Properties

The preparation of new-generation concrete from recycled coarse aggregate (RA) is an effective way to realize the resource utilization of construction waste. However, loose and porous attached mortar leads to RA showing low-density, high-water absorption, and high crushing value. However, carbonation modification treatment can effectively improve the performance of RA. This paper studied the effects of carbon dioxide (CO2) concentration, gas pressure, and moisture content on the RA physical properties (apparent density, water absorption, crushing value, and soundness) of waste concrete. The results showed that, when the (CO2) concentration increased from 20% to 60%, the apparent density of RA after carbonation increased by 0.23–0.31%, the water absorption decreased by 0.57–0.93%, the crushing value decreased by 0.36–0.61%, and the soundness decreased by 0.47–0.85%. When the (CO2) concentration was further increased from 60% to 80%, the apparent density of RA after carbonation was increased by 0.04–0.05%, the water absorption was improved by 0.15–0.31%, the crushing value was reduced by 0.06–0.07%, and the soundness was reduced by 0.09–0.11%. During the carbonation modification process, the performance of RA was significantly enhanced when the moisture content was 3.4% and the dissolution of hydration products was accelerated. The diffusion rate of CO2 and the carbonation reaction rate decreased with the high moisture content of RA. As gas pressure increases to 0.01 MPa, the p...