Trass

Trass is rock that has transformed (rock metamorphism) due to pressure (meteor strike, Bavarian trass/suevit) or heat (volcanic activity, Rhenish trass). Trass reacts hydraulic, i.e. it cures/reacts with water. During the hardening process, construction materials containing trass (trass cement, trass cement mortar, trass lime, trass concrete) develop a solid and (water) tight structure. Due to their physical and chemical reactions they are not only used for waterproof objects but they also prevent/reduce the formation of efflorescence and other surface damages or impairments.