Effect of expanded perlite aggregates and temperature on the strength and dynamic elastic properties of cement mortar

The residential market consumes nearly half of the world’s concrete production, and it is anticipated that 68 % of the global population will reside in urban areas by 2050. Researchers have focused their efforts on exploring alternative options to natural aggregates in concrete and mortar. In line with the principles of circular economy, construction and demolition waste has been repurposed for the manufacture of cement-based materials. Volcanic products, which are abundant but underutilized, have been identified as an alternative to recycled aggregates. They offer several advantages over natural river aggregates, including reduced weight, enhanced thermal and acoustic insulation, improved fire resistance and pozzolanic characteristics. While there has been a significant amount of research on the use of expanded perlite as a supplementary cementitious material, studies involving the use of expanded perlite aggregates (EPA) in cement-based construction materials are relatively limited. This paper seeks to address this knowledge gap by investigating the use of EPA in cement-based mortar at both room and elevated temperatures. The study examines the impact of varying replacement percentages (10 %, 20 % and 30 % - by volume) of natural sand with EPA having a maximum grain size of 4 mm, and the exposure temperature of mortar prisms at the age of 28 days. Specifically, temperatures of 100ºC, 150ºC and 200ºC were selected for analysis. The impact of these parameters on the flexural and compressive strength of mortar, as well as its dynamic elastic properties, was experimentally determined. The findings indicate that, at room temperature, higher replacement percentages of natural sand by EPA result in decreased flexural and compressive strengths, by as much as 50 % and 30.71 %, respectively. However, the dynamic moduli values for replacement percentages up to 20 % are similar to those of the reference mix. Conversely, when subjected to temperatures up to 200ºC, significant improvements were observed in the flexural strength values, e.g. over 20 % for temperatures of 150°C and 200°C, with only marginal improvements in compressive strength, 3 % ÷ 20 % for temperatures of 150°C and 200°C, compared to values obtained at room temperature. •Expanded perlite aggregates replace sand in cement-based mortar up to 30 % by volume.•Proposed equation correlates dynamic modulus of elasticity with compressive strength.•Flexural strength of perlite aggregate mortars increases at e