Non-destructive mechanical and physical in-situ testing of rendered walls under natural exposure

Abstract

Building façades are significantly influenced by the wall renders’ performance, since they are the first protection layer against degradation agents. During their service life, façades undergo a continuous performance reduction until they are unable to meet their demanded functions, such as protecting and waterproofing the façade. Therefore, the application of in-situ testing has great importance to evaluate in-service performance of wall renders under natural conditions. This study focuses on testing the physical and mechanical behaviour of rendered façades, taking into account different render colourings and roughness and natural exposure conditions according to the wall orientation. Physical (Karsten tube and moisture meter) and mechanical in-situ tests (pendulum rebound hammer and ultrasound pulse velocity) were performed on eight walls at a natural ageing station. The in-situ tests were used to detect the factors affecting the results of these techniques, and the evolution of the rendered walls’ performance over time was investigated. The relationships between the testing techniques were also assessed.