AN EVALUATION OF SHREDDED WASTE POLYETHYLENE TEREPHTHALATE BOTTLES LIGHTWEIGHT SORGHUM HUSK ASH BASED CONCRETE COMPOSITE

Abstract

ABSTRACT 3

Concrete is the most common material for human beings to use in construction in this research thesis, the use of shredded waste Poly-ethylene Terephthalate (PET) bottle flakes as a lightweight coarse aggregate in concrete was examined. Study was carried out on two groups of concrete samples, one made with only granite as coarse aggregate (control) and second made with a combination of PET and granite aggregate. The PET replaced the granite aggregate at varying percentage of 0%, 5%, 10%, 15% and 20%. Additionally, Sorghum Husk Ash (SHA) was also used as the replacement of cement on mass basis at the replacement ratio of 10% to reduce the amount of cement used and provide savings. The water–binder (w/b) ratio used in the mixtures was 0.55. It was observed that 5% PET was the optimum PET replacement for coarse aggregate that gave strength properties that is close to the control concrete. A compressive strength of 34.11 N/mm2 was achieved at 56 days, and a tensile strength of 3.94 N/mm2 was achieved also achieved at 56 days for concrete 5% PET concrete containing SHA. The results of the laboratory study and testing carried out showed that concrete comprising PET and SHA as cement replacement can be categorized into structural lightweight concrete in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET as aggregate in the production of structural lightweight concrete. The use of shredded waste PET due to its low unit weight reduces the unit weight of concrete which results in a reduction in the self-weight of a structural concrete member of a building. Reduction in the dead weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependent on the dead-weight. Furthermore, it was also concluded that the use of industrial and agricultural wastes such as PET flakes and SHA in concrete provides some advantages, that is, reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.