Improving the thermal and mechanical performance of cement-based mortars for reinforcing masonry structures: computational and experimental methods

With an increasing energy deficit, improving the thermal properties of building materials is nowadays a priority. The incorporation of expanded polystyrene (EPS) and expanded perlite (EP) into cement mortar has shown enormous potential to improve overall thermal performance. This study aims to numerically evaluate the efficiency of using EPS and EP reinforced composites as coating mortars. First, several reinforced mortars were prepared by adding different proportions of EPS and EP to the cement mortar. The thermal, mechanical and microstructural performances of EPS and EP mortars were subsequently analyzed using Hot Disk and MATEST instruments as well as FTIR spectroscopy and XRD analysis. COMSOL Multiphysics software was then used to simulate the inner temperature variation of a hollow brick coated on both sides with the optimal reinforced mortar mix. The results showed that an increase in the amount of reinforcing material led to a reduction in both mechanical strength and thermal properties of the mortar. Optimum performance could be achieved by incorporating 2.5% expanded polystyrene into the mortar, which resulted in approximately 37%, 15%, and 26% reduction in thermal conductivity, thermal diffusivity, and volumetric heat capacity, respectively, compared to standard mortar. This thermal improvement was achieved while ensuring a satisfactory mechanical and chemical properties. By applying varying thicknesses of this reinforced mortar to the brick, the internal surface temperature was reduced by approximately 0.2–1.8 °C during periods of maximum flux exposure. Therefore, the application of these composites as a thermally enhanced coating mortar on building walls seems to be an adequate solution.

Graphical abstract