Effect of Cl⁻-induced corrosion on the mechanical properties of reinforcing steel embedded in ternary concretes containing FA and UtSCBA

Mechanical properties of rebars embedded in ternary concretes with fly ash (FA) plus untreated sugarcane bagasse ash (UtSCBA) and immersed in a Cl⁻-solution for 3000 days were investigated. Reinforced concrete specimens containing Portland cement (PC) only, PC + FA, and PC + FA + UtSCBA were manufactured. The corrosion conditions of the rebars were evaluated by electrochemical testing; then the rebars were extracted and their mass loss estimated. Next, elemental mapping of the concrete/reinforcing steel interfaces using scanning electron microscopy was conducted. Rust was analyzed by X-Ray diffraction and infrared spectroscopy. Finally, the rebars were tested in tension to evaluate their yield and ultimate strengths, fracture loads, and ductilities. Results indicate that rebars from UtSCBA-ternary concretes experienced the lowest mass loss. Moreover, the yield strengths of all rebars were not affected by corrosion, while the ultimate strengths, fracture loads, and ductilities of rebars from UtSCBA-ternary concretes were larger than those from the control.