Corrosion‐induced cracking characteristics of reinforced carbonated recycled aggregate concrete under short‐term load

Carbonated recycled aggregates can improve the durability of recycled aggregate concrete (RAC). In this paper, accelerated corrosion test and scanning electron microscope–energy‐dispersive spectroscopy (SEM–EDS) test were conducted on the carbonated recycled aggregate concrete (CRAC) to investigate the effects of the carbonated recycled coarse aggregate (CRCA), the carbonated recycled fine aggregate (CRFA), and the short‐term load on the corrosion‐induced cracking characteristics of CRAC. The results showed that the CRAC with high replacement ratio of both CRCA and CRFA exhibited comparable or even better corrosion resistance than the CRAC with low replacement ratio where only the recycled fine aggregate (RFA) was carbonated. The highly porous old mortar adhering to recycled coarse aggregate (RCA) was filled during carbonation by reaction products, but the efficacy of carbonation strengthening RCA was limited. Carbonation strengthening partially enhanced the performance of RFA, but the persistent microstructural deficiencies in CRFA resulted in inferior properties compared with the natural fine aggregate. When the CRFA replacement ratio increased from 30% to 50%, the CRAC exhibited a maximum increase of 4.63% in the average mass loss of steel bars, an increase of 87.64% in the total area of corrosion‐induced cracking, and an increase of 84.62% in the mean value of width of corrosion‐induced cracks. Under high short‐term load level, the CRAC with both CRCA and CRFA exhibited corrosion resistance comparable to that of CRAC treated only on RFA under low short‐term load level. The research findings can provide data support for the application of CRAC.