Combined Methods to Investigate the Crack-Bridging Ability of Waterproofing Membranes
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.
Josef Kaufmann, Frank Winnefeld, and Nikolajs Toropovs from EMPA are acknowledged for fruitful discussions. We thank Sebastian Dettmar for his careful sample preparation. CTI is gratefully thanked for financial support of project No. 18797.1 PFIW-IW.
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