Effect of Coarse Plastic Waste Aggregates on the Performance of Concrete-Filled Steel Tube Columns and Their Life Cycle Assessment

This paper investigates the effect of a series of concrete mixes that contain plastic waste aggregate on the behavior of concrete-filled steel tube columns under axial load. Two groups of specimens, with a total of ten columns were prepared. Hollow steel columns and columns with concrete mix were used as reference specimens for each group. In other mixes, natural coarse aggregate was partially replaced with coarse plastic waste aggregate in ratios of (2.5-5) % and a different ratio of water cement content. Ultimate axial load capacity, ductility, and failure mode are discussed for all specimens. Besides, environmental impacts by applying the life cycle assessment methodology are discussed. The results also indicated that increasing the plastic waste aggregate ratio led to decreased ultimate axial load capacities and ductility for both square and circular columns, while decreasing the water-to-cement ratio with the same plastic waste aggregate ratio resulted in an increase in ultimate axial load. The failure mode of the square columns was local buckling, which occurred near the ends of the columns, while for the circular columns, local buckling occurred near mid-height. In general, circular columns were more ductile than square columns. The results of life cycle impact assessment promote the use of concrete-filled steel tube columns with recycled aggregate. The experimental results illustrated the feasibility of using plastic waste aggregate to partially replace coarse aggregates. concrete-filled steel tube columns concrete-filled steel tube columns. Generally, the proposed concrete-filled steel tube columns have comparable performance in some characteristics with the reference columns.