EXPANSION OF PRESTRESSED STRAND CORROSION PRODUCTS AND CONCRETE CRACKING PREDICTION

Strand corrosion would induce the cracking of prestressed concrete. An experimental study is conducted to investigate the corrosion-induced cracking of concrete under various prestress. The expansion ratio of prestressed strand corrosion products is studied based on the infrared (IR) spectroscopy and the thermal gravimetry (TG) analysis. The effects of prestress on the critical time of cover cracking and crack widths are discussed. An analytical model is proposed to predict the concrete cracking from corrosion initiation to crack propagation. The model can consider the combined effects of the prestress, rust-expansion ratio and residual strength of cracked concrete. The model was verified by experimental data. The predicted results show that prestress can accelerate the corrosion-induced cracking process. When the prestress is 75% strand tensile strength, the critical time of cover cracking decreases 22% and the crack propagation rate increases 9%. The model can reasonably predict the corrosion-induced cracking of prestressed concrete.