Quantifying the Impact of Plastic Shrinkage Cracking on the Corrosion of Reinforced Concrete to Improve Service Life Prediction

摘要

Several service-life modeling approaches have been advocated for performance prediction of reinforced concrete structures. However, they are commonly developed based on the assumption that no premature cracks exist in structure. In field applications, plastic shrinkage cracking may occur, which could substantially influence modeling assumptions and prediction reliability. Experiment is designed to investigate the impact of plastic shrinkage cracking on the corrosion of steel reinforcement. Plastic cracks were quantitatively assessed using image analysis. The slabs with premature cracking are then exposed to wetting/drying cycles for corrosion test. The width of surface cracks and the concrete cover thickness are correlated to the time-to-corrosion initiation measurements. Experimental results show that the size and distribution of plastic shrinkage cracks that are developed in an end restrained slab are influenced by fiber type, fiber volume, and concrete cover thickness. A reduction in crack width always leads to a delayed corrosion initiation time, while a reasonable cover thickness combines with the reduction in surface crack width may significantly improve corrosion resistance. Fiber reinforcement can substantially delay the corrosion initiation time.