Thermo-mechanical and durability properties of expanded perlite aggregate foamed concrete

The thermal conductivity of a material is a measure of its capacity to conduct heat and is a major factor influencing heat transfer in buildings. For better thermal insulation, construction materials should possess low thermal conductivity. The feasibility of expanded perlite aggregate as a thermal insulation material in foamed concrete was examined. Mechanical, thermo-mechanical and durability properties were assessed and compared. A base mix was designed to have 1100 kg/m³ density, a water-to-solids ratio of 0.3 and a cement-to-sand ratio of 1:1. Expanded perlite aggregate was used as a substitute for fine aggregate in the foamed concrete mix at contents of 0, 10, 20 and 30% by volume. The work was extended by replacing cement with 60% by weight of fly ash to study an eco-friendly mix. The test results showed that the strength values increased with an increase in fly ash and decreased with an increase in perlite. The reverse trend was observed for thermal conductivity and durability, which was also affected by the addition of perlite. The test results showed that expanded perlite is an excellent replacement for sand as a thermal insulation material. The efficiency of the developed material was assessed by an analytical model using the Comsol Multiphysics software program.