The insulation properties of foam concrete with the use of foam-agent and fly-ash

Abstract

Foam concrete is an alternative wall material that can be used in tropical buildings because of its insulation properties, good thermal conductivity, and sound absorption coefficient when compared with the normal concrete. The percentage of foam agent used in its production affects density and compressive strength. Furthermore, the use of fly-ash also has an effect on its mechanical and insulation properties. In this study, 40 units of foam concrete specimen (200x200x20) mm were tested for thermal conductivity, and cylinder (dia-100x20) mm for sound absorption. The mixture used for the concrete includes cement/sand ratio of 1:2.75 with w/c 0.425 and addition of 20% fly-ash as a cementitious material and foaming agent (ratio fa/w 1:20) at 1%, 2%, 3% and 4% by weight of cement paste, respectively. The result showed that foam concrete with 20% fly-ash and 2% foaming agent or more has a density below 2000 kg/m3 with a maximum compressive strength of 13.24 MPa. The highest sound absorption coefficient was obtained to be a = 0.89 at 20% fly-ash and 4% foaming agent. The thermal conductivity (k) of foam concrete was found to have increased using a 20% fly-ash and 1% foaming agent compared to the mixture without fly-ash at a value of 0,898. It was discovered that the use of fly-ash on foam concrete has the ability to improve thermal conductivity and sound absorption.