Thermal conductivity and compressive strength of expanded perlite aggregate concrete with mineral admixtures

This paper studies the influence of two admixtures on expanded perlite aggregate concrete. Both silica fume and fly ash were added as replacement for cement by decreasing the cement weights in the ratios of 10, 20 and 30% by weight. The binder dosage was kept constant at 200 kg/m3 throughout this study. Superplasticizer was used 1.5% by weight of Portland cement to reduce w/c ratios. The obtained results showed that: the thermal conductivity decreased with the increase of silica fume and fly ash as replacement for portland cement up to 14 and 18%, respectively. Densities of all samples decreased from 522 to 483 kg/m3 with the increase of both admixtures. Silica fume and fly ash decreased the density of samples. The compressive strengths decreased 12, 19, 29 for 7 days, and increased 9, 13%, 4%, for 28 days due to 10, 20 and 30% silica fume, respectively. Fly ash induced to reductions in the compressive strength up to 36% at 7 days and 27% at 28 days.