Thermal conductivity and mechanical properties of porous concrete materials

The aim of this research is to examine the effect of the water-binder (W/B) ratio, replacement of cement by fly ash and incorporation of water-reducing agent on the thermal insulation and mechanical properties of porous concrete with a density of 600 kg/m3. It was found that porous concrete achieved the optimum performance with a W/B ratio of 0.32, a fly ash replacement percentage of 30% and the addition of 0.65% of water-reducing agent. Under these optimal conditions, in the porous concrete specimen obtained the 28-day compressive strength up to 4.37 MPa, a 12% rate of water absorption and a heat conductivity coefficient of 0.116 W/(m·K). Overall, the findings show that the fabricated porous concrete (with a 150 mm thickness and a density of 600 kg/m3) fulfills the requirements of ultimate capacity and thermal insulation of the insulation layer for accessible flat roofing. More attractive, the product is cost-effective and may be useful in a wide range of applications.