Abstract— 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-tocement
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.