Compressive behaviour of middle and high strength concretes incorporating high density polyethylene at elevated temperatures
A rising interest has recently emerged for the use of post-consumer plastics as fillers to modify the properties of polymeric matrices. Little is however known about the mechanical behaviour of this new composites when subjected to elevated temperatures. This study investigated the compressive behaviour of superplasticised grades M25 and M50 concrete with (0, 0.25, 0.5, 0.75 and 1) percentages of pulverised high density polyethylene by weight of cement. Hydroplast-500 dosage in order of 1000litres/ 50kg by weight of cement was used throughout the study at constant water/cement ratio of 0.4 and 0.36 for requisite workability for grades 25 and grades 50 concretes respectively. After 28 days of curing in water, the150mm concrete cubes were subjected to elevated temperatures of 150, 300, 450 and 600 degrees for exposure duration of 1hour each. The results revealed that high density polyethylene admixture reduced explosive spalling of concrete up to 11.6% as a result of fibre bridging in the matrix and prevents spalling failure caused by high vapour pressure generated at high temperatures. It is therefore concluded that thermal stability could be achieved with pulverised high density polyethylene used as an admixture in concrete production.
Keywords: Concrete, Polyethylene, Elevated Temperatures, Compressive Behaviour