The present study proposes to improve the performance of recycled aggregate concrete (RAC) subjected to the internal steel corrosion by conducting the pre-treatment on recycled aggregate (RA). A sulfoaluminate cement (SAC) slurry and a diluted water glass (WG) solution were taken for the RA pre-treatment, respectively. Test results show that the RAC as modified by both the two RA treatments presented a better resistance to the steel corrosion as accelerated by the chloride ingress and the direct current (DC) power simutaneously. The corrosion of steel bars embedded in the modified RAC was found to be postponed, moreover, the width development of the cracks induced by the steel corrosion on the concrete surface was retarded, compared to the reference RAC. Microscopic measurements showed that the microhardness of the new ITZ formed between the new cement mortar and the treated RA by both two techniques was improved, moreover, the new ITZ presented a sandwich-like structure by using the SAC-treated RA. Likely due to the more significant enhancement in the new ITZ, the improvement in RAC’s resistance to the internal steel corrosion was more significant with the SAC treatment than with the WG treatment. Also considering the potential risk of a large early-age shrinkage caused by the high alkaline content introduced by the WG treatment, to pre-treat RA with the SAC slurry was suggested to be more beneficial than that with the WG solution to extend the service life of the reinforced RAC structures serving in severe environments with high risks of steel bar corrosion.

本研究提出通过对再生骨料 (RA) 进行预处理来提高受到内部钢筋腐蚀的再生骨料混凝土 (RAC) 的性能。分别采用硫铝酸盐水泥 (SAC) 浆料和稀释的水玻璃 (WG) 溶液进行 RA 预处理。测试结果表明，通过两种 RA 处理改性的 RAC 表现出更好的抗钢腐蚀能力，因为氯化物进入和直流 (DC) 电源同时加速。发现嵌入在改良 RAC 中的钢筋的腐蚀被推迟，而且，与参考 RAC 相比，混凝土表面钢筋腐蚀引起的裂缝的宽度发展被延缓。显微测量表明，两种技术在新型水泥砂浆和处理后的RA之间形成的新型ITZ的显微硬度都有所提高，而且，使用SAC处理后的RA，新型ITZ呈现出夹层状结构。可能是由于新 ITZ 的改进更显着，SAC 处理比 WG 处理更显着提高了 RAC 对内部钢腐蚀的抵抗力。还考虑到 WG 处理引入的高碱含量导致大早期收缩的潜在风险，建议使用 SAC 浆料预处理 RA 比使用 WG 溶液更有益，以延长使用寿命在钢筋腐蚀风险高的恶劣环境中使用的增强型 RAC 结构。