Coating mortars with improved physical properties, economic cost, and carbon footprint

In recent years there has been renewed interest in innovative solutions for coating mortars. Previous research has clarified the importance of substituting a percentage of cement by other binders, and thus focused on a good balance between structural and thermal properties. However, the effect on the economic cost and the carbon footprint is yet to be fully understood. In this context, the present study aimed at investigating the role of hydraulic lime as a partial substitute for cement and expanded perlite in the structural and thermal properties of mortars while considering the economic cost and the carbon footprint as fundamental variables. We employed a combination of laboratory tests and theoretical calculations to clarify the optimal balance between all considered variables. The findings showed that thermal conductivity can be reduced up to 87.25% and density up to 78.94% if compared with a standard mortar; on the contrary, mechanical properties are compromised yet sufficient for rendering purposes. The final product is affordable, and its carbon footprint is remarkably lower than other alternatives. We concluded that these mortars can deliver optimal properties for rendering purposes, except for the mechanical resistance, which demands further research. In turn, our findings provide evidence for devising feasible options to maintain or repair buildings on a constrained budget, as in the case of social dwellings.