Combined Methods to Investigate the Crack-Bridging Ability of Waterproofing Membranes

Abstract

Polymer modification of dry mortars with redispersible polymer powders is a common approach to increase the mortar's mechanical properties. The use of polymer-modified mortars (PMMs) as waterproofing membranes requires a well-performing crack-bridging ability (CBA) to avoid infiltration of water into the construction owing to shrinkage or expansion. In order to evaluate the performance of PMMs, we present below a combination of crack-bridging tests with optical analysis. The latter is exerted with digital image analysis on photos acquired during the tensile tests and pictures of CBA-samples, which have been fixated after a certain displacement. Additionally, thin sections of fixated CBA-samples are investigated using transmitted light, UV light, and SEM microscopy. These methods are developed to understand the (micro)mechanical initiation and evolution of cracks in order to improve the crack-bridging ability of waterproofing membranes.