Natural and accelerated weathering evaluation of granite and marble waste paints

Abstract

Recent studies have highlighted the potential for using waste generated from the processing of granite and marble as pigments in sustainable and low-cost paints. To evaluate the durability of these paints, this work presents an assessment of the resistance to weathering (natural and accelerated) of different formulations of PVA (polyvinyl acetate) latex paints produced with pigments of granite and/or marble waste, with and without the addition of biocidal and/or dispersant additives. Natural weathering tests were conducted in the Brazilian city of Viçosa, Minas Gerais, where mortar slabs covered with paint samples were exposed to a natural weathering process for one year. Accelerated weathering tests were also performed using a weathering chamber that simulates UV radiation, high temperatures, and condensation mechanisms. The specimens were evaluated based on calculations of the delta-E parameter to determine color changes, pull-out tests, and visual and microscopic analyses of possible pathologies in the paint film. The results indicated that the paints only underwent significant color changes, possibly due to resin degradation after exposure to UV radiation and/or bacterial growth. Furthermore, the accelerated weathering chamber was able to replicate one year of natural weathering results in just 17 days.