Appraising the environmental friendliness of rice husk ash and oil palm shell as building materials from agricultural waste
The biggest challenge with concrete as the most expensive basic construction material made from cement and aggregate is that of creating a balance between economic constraints and environmental considerations with performance as the focal point. An appraisal of the environmental friendliness of Rice Husk Ash (RHA) and Oil Palm Shell (OPS) as emerging alternative building materials from agricultural waste to supplement and replace conventional cement and coarse aggregates in the production of concrete was conducted in order to guide their appropriate selection and utilisation. The embodied energy accrued during the production of RHA and OPS were assessed and compared with that of Ordinary Portland Cement (OPC) and crushed granite as coarse aggregate. Building Materials Green Feature Assessment criteria of Leadership in Energy and Environmental Design (LEED) was adopted in assessing the green features of both the materials. The appraisal concluded that the production processes and the behaviour of the materials at the construction and post construction stages were found not to have any significant negative impact on the environment in terms of pollution, resources depletion and ecological disturbance. The materials contain less embodied energy than the conventional materials i.e. OPC and coarse aggregate. There is however, the need to develop the necessary appropriate technologies for the local harnessing and utilisation of these emerging materials.
Keywords: Rice-Husk-Ash, Oil-Palm-Shell, Green Features, Agricultural Waste