A L VELOSA(1) and M R VEIGA(2)
(1) Department of Civil Engineering, University of Aveiro
(2) National Laboratory of Civil Engineering (LNEC)

Renders are an extremely vulnerable part of constructions as they are constantly subject to atmospheric aggression. Although they act as sacrificial layers, over underlying walls and must have maintenance procedures, they must satisfy minimum durability requirements. In order to ensure that these requirements are fulfilled, artificial ageing tests are usually performed, simulating extreme conditions, both climatic and others. Inserted in a study of conservation mortars with pozzolanic additives, artificial ageing tests were developed on the basis of flexibility and adaptation to the national climate. A rain/heat cycle and a freeze/thaw cycle were performed and the state of mortars was assessed after each cycle by both visual evaluation and weighing. Water permeability and pull-off tests were performed on specimens with no severe degradation. Additional specimens were prepared and placed alternatively in a sodium chloride solution and in a conditioned atmosphere and mass alterations were registered.