Protective performance of polyurethane waterproofing membrane against carbonation in cracked areas of mortar substrate

This study uses experiments and numerical analysis to evaluate carbonation in the cracked area of mortar substrate by particularly focusing on the deterioration of polyurethane waterproofing membrane due to aging. The results of outdoor exposure tests conducted over a period of 5 years and accelerated carbonation tests indicate that deterioration of waterproofing membranes on the substrate’s cracked area occurs faster than that on the non-cracked substrate area. In addition, protective performance against carbonation deteriorates as the thickness of the membrane decreases. Furthermore, numerical simulations are performed by considering carbon dioxide permeability of the waterproofing membrane and carbon dioxide diffusion in the cracked area of mortar. Finally, after verifying the validity of the numerical simulations against the experimental results, the substrate carbonation behavior upon long-term exposure of the waterproofing membrane is predicted and the membrane thickness required for suppressing carbonation is estimated.