Characterisation of Polymer-based Wood-substitute for Sustainable Building and Construction

Abstract

Materials have always been used for the commodities and convenience of mankind. However, the recognition of the impacts of the global demand for materials and resources has been leading to a growing concern with regards to production and consumption patterns, resources scarcity and waste management. With the increase of plastic consumption by a factor of twenty in the past sixty years, packaging and packaging waste are one of the various factors accounting for these concerns. This research has reviewed the role of sustainability in relation to building and built environments, the need for sustainable construction, as well as waste management, its policies and directives, in order to evaluate current trends with regards to the use of waste as resource. This research has shown that the use of waste recycled polystyrene can be a suitable and sustainable wood-substitute in building and construction industries. Extensive laboratory work had been carried out to characterise the performance of the material under investigation. Recycled waste expanded polystyrene, converted into polymer decking material (B001, B002 and B003), typical softwood (TSW), hardwood decking (HWD) and softwood decking (SWD) have been assessed for comparative analysis. During the initial testing phase the polymer material was being analysed and compared to TSW. After the initial assessment it was evident that a thorough comparison would only be possible with specimens within the same characteristics (HWD and SWD). Results demonstrated that key parameters of density, water absorption, thermal conductivity and effects of weathering are within acceptable engineering standards. Results also shown that the polymer material has low compressive and flexural strength and experience variations under extreme temperatures (above 90˚C). The results obtained from the modulus of rupture suggest that for a construction of the same area, extra material would be needed to support the polymer decking. Overall, the results suggest that the polymer material is an attractive wood-substitute for a wide range of applications in building and construction industries. Nevertheless, there are limitations due to strength constraints. The polymer material would be more suitable than wood for outdoor applications such as decking, urban furniture, cladding, and playground structures. This research has demonstrated that the use of recycled polymer to substitute wood would reduce waste and provide a long lasting material, minimising costs and maintenance related to damages raised from weather exposition, temperature variations, root and fungi attack.

Date of Award	Oct 2013
Original language	English
Supervisor	John Kinuthia (Supervisor)