Lime based mortars for ceramic tile application: the influence of the lime, the use of a metakaolin and the curing

Intern.Conference AZULEJAR, Univ. Aveiro, 10-12 October 2012Bearing in mind the need to repair ceramic tile facade, that were traditionally applied by a lime-based mortar, an experimental campaign was held in order to characterize over time mortars made with two types of lime - an air lime EN 459-1 CL90-S and a recently classified EN 459-1 NHL3.5. The influence of different binder: aggregate proportions on mortars with air lime, of different percentages of a metakaolin substituting the same weight of air lime or of natural hydraulic lime and of different curing conditions are tested and discussed. Mortars used to apply glazed ceramic tiles will have a low contact with the carbon dioxide of the environment and the hardening of pure air lime mortars will be difficult. For that reason the addition of a metakaolin on air lime-based mortars can be advantageous. But natural hydraulic lime mortar NHL3.5 have registered higher mechanical strength but comparable capillary suction and drying characteristics to air lime mortars; that is why NHL mortars, without or with a low amount of metakaolin, can also be a possibility to intervene glazed ceramic tile façade when the mechanical resistances are compatible