Physical, mechanical, and thermal properties of concrete roof tiles produced with vermiculite.

This study aimed to evaluate the effect of using expanded vermiculite and its impact on the production of concrete roof tiles. The control treatment and replacement of 12.5, 25, 37.5, and 50% sand by vermiculite were evaluated. The concrete roof tiles were moulded by the simultaneous pressing and extrusion mechanical process. The control trace was comprised by 21.95% CPV-ARI cement, 65.85% sand, and 12.20% limestone. After production, the concrete roof tiles were cured for 28 days. The physical (roof tiles classification, samples dry weight, water absorption, and porosity), mechanical (splitting tensile strength), and microstructural properties were evaluated. All treatments were assessed before and after accelerated ageing. The thermal properties of the modification in the concrete roof tiles' composition were also analysed. The evaluated amounts of vermiculite significantly affected the physical, mechanical, and thermal properties of concrete roof tiles. The use of vermiculite in concrete roof tiles reduced their dry weight and thermal conductivity, not impairing their durability. The use of 31.0% vermiculite in concrete roof tiles was suggested for better thermal insulation optimization (20.29% reduction) and weight reduction (7.92% and 7.94% at 28 days of curing and after accelerated ageing, respectively), along with adequate physical, mechanical, and durability properties.