A comparison of the thermal conductivity of oil palm shell foamed concrete with conventional materials

Foamed concrete (FC) is characterized by its low self-weight and insulation properties. This paper reports on the thermal conductivity of structural and non-structural grade foamed concretes developed using locally available waste materials – oil palm shell (OPS) – as lightweight coarse aggregate. Six mixes of oil palm shell foamed concrete (OPSFC) of oven-dry density ranging from 1100 to 1600 kg/m3 were prepared and tested for thermal insulation and compared with the non-foamed oil palm shell concrete (OPSC) as the control concrete and conventional materials, such as brick and block. Non-structural grade OPSFC with a density of 1100 kg/m3 showed the lowest thermal conductivity of 0.40 W/m K, which is 33% and 56% lower than the conventional materials – block and brick – respectively. OPSFC with 1500 and 1600 kg/m3 can be considered as structural and insulating concrete as per the RILEM classification. The tiny air pores created in the concrete act as an insulator and it was found that the thermal conductivity of OPSFC with densities of 1100 and 1300 kg/m3 are similar to those of pumice concrete and expanded perlite aggregate concrete (EPAC), respectively.