Service life model for alternative rendering mortar developed from granite cutting waste

Abstract

Evaluating the service life of rendering mortar is crucial for managing its interaction with the substrate in the building due to various degradation causing factors as it have a significant influence on its repair, maintenance and, life cycle analysis results. This study is intended to predict the service life of the conventional cement sand (GP0) and 20% granite cutting waste incorporated alternative mortar (GP20). The mortars are exposed to a standard accelerated aging environment to simulate the natural field conditioning. Parallelly, the adhesive strength testing is conducted on naturally known aged field mortar samples. The Weibull distribution technique is used to perform life data analysis. The scale and shape parameters are calculated for GP0, GP20, and field samples, respectively. The R² value determined from the goodness of fit analysis. Modifying factor has been identified to incorporate additional degradation-causing agents other than temperature and humidity. The adhesive strength of laboratory testing and field samples are correlated to predict the service life of the mortar. The finding shown that the strength degradation mechanism follows a non-linear variation of adhesive strength under accelerated and natural aging conditioning. The adhesive strength degradation for both the mixes are studied w.r.t. aging cycles. The GP0 and GP20 mortar mixes mortar-substrate bond failed after 156 and 168 cycles respectively and failed in brittle nature. The reference service life is taken at critical adhesive strength value of 0.3 MPa which is recorded as 17.4 years. However, it is observed that GP20 mortar faced higher aging cycles as compared to GP0, which qualitatively signifies a slight improvement in the service life.