Avaliação em obra da resistência superficial de revestimentos de argamassa

Abstract

This study aims to evaluate the surface tensile strength (STS) of mortar renderings on site. The test for evaluating this property is not yet standardized in Brazil, therefore, it deserves studies towards its standardization, considering that it is one of the most relevant properties concerning the performance of renderings. The evaluations were conducted in two different construction sites in the city of Goiânia (Goiás, Brazil), which analyzed the influence of the operator of the test, the mortar mix proportions, age and site of rendering application, as well as the influence of ergonomics factors during render production. The results were analyzed using statistical procedures, estimating the sample size and performing an analysis of variance, as well correlations between the STS and other tests. It was found that the sample size compatible with the variability obtained in the test was 10 to 15 samples per individual condition of analysis. It was also noted that the factors (mix proportion of mortar, age of the rendering and bad weather action) exert significant influence on the results of STS. Satisfactory correlations between the STS and the results of bond strength (r = 0.87), water permeability (r = 0.81) and sclerometric index (r = 0.99).