Thermal characterisation of composite walls made from waste materials

Sustainable development has been an ever-growing global concern over the years, especially with respect to the environment. The construction sector is a major cause for concern due to the devastating effects traditional building materials, manufacturing processes and procurement, have on the environment. Inadequate housing in developing countries is also another major sustainable development challenge. These illustrate the cogent need for developing new methods of delivering sustainable housing that can be accessible to lowincome communities who have little or no access to finances. This study compares the thermal performance of low-cost building components made from incorporating waste materials in cement blocks, thereby reducing the quantity of new materials needed. Three samples (wall panels) were made. Each panel was 330mm × 330mm × 240mm and incorporated 25 × 500ml plastic bottles laid horizontally in rows. A sand and cement mixture (ratio 1:3) was used as a binder and filled the gaps between the plastic bottles. The bottles in the first sample were filled with sand, those in the second were filled with water, and those in the third with used plastic carrier bags. A guarded hot box was developed to experimentally measure the U-values of the samples following the BS EN ISO 8990 standards. It was observed that the samples with the plastic bags had the lowest Uvalue, about 60% lower than samples with sand. The results show a promising potential for low-grade plastic waste to be used as a means of improving the thermal performance of low-cost buildings.