Corrosion-induced mass loss of steel in concrete containing recycled coarse and fine concrete aggregates

This study examines the corrosion-induced mass loss of steel in concrete utilizing both fine and coarse recycled aggregates beside the mechanical properties as a part of ensuring circular economy by the construction industry. The corrosion mass loss of the reinforcing steel was determined using a non-destructive method for an accelerated corrosion process using 5% sodium-chloride solution by weight of cement. The results were then compared with the actual mass loss obtained by a destructive method. Furthermore, relationship between the actual mass loss of the steel vs. the crack width and electrical resistivity of the recycled aggregate concrete was initiated. Results revealed that estimated mass loss via non-destructive test was similar to the actual mass loss via destructive test. Results also indicate that substitution of natural aggregate with recycled aggregates for up to 50% can produce a similar mechanical property compared to the virgin natural aggregate in the concrete. In case of corrosion, the optimal range for the replacement level of recycled coarse and fine concrete aggregates lies between 50 and 75% of natural aggregates, while the corrosion rate is considerably influenced by resistivity and crack width. This study suggests that incorporating recycled concrete aggregates in new concrete is viable up to 50% replacement levels to strike a balance between mechanical properties and corrosion resistance.