Abstract: Steel-concrete composite structures is one of the most explosive rapidly developing, cost-effective,
and environmentally sustainable processes frequently utilised in high-rise structures and medium-span
bridge decks. This research presents an experimental work to investigate the performance of a composite,
concrete-filled steel tube (CFST) specimens manufactured by self-compacting concrete (SCC) under a pushout
test. Ten CFST specimens have been considered in the experimental tests with a combined two concrete
slab. Two variables have been considered in the experimental tests: thickness of tested tube (5 mm and 6 mm)
and concrete slab strength (25, 35,45, 55, and 65 MPa). For comparison, all concrete slabs are made with normal
concrete and steel tubes filled with SCC. The ultimate shear strength, load-slip behavior, failure load, crack
pattern, and failure mode were studied. The experimental results present that the ultimate shear capacity
and specimens stiffness improved by increased concrete block strength from 25 to 65 MPa. In addition, it was
found, that at the slab concrete strength reduction from about 65 to 25 MPa, it decreased by 4.45%, 9.75%,
14.44%, and 18.34% for 5 mm tube thickness, however, for 6 mm thickness tested specimens, it decreased by
5.36%, 9.35%, 16.04%, and 19.6%, respectively. The specimen with the 6 mm-thick steel tube had better ultimate
force capacity and specimens stiffness than the one with the 5 mm-thick tested tube. The perfobond rib
is utilised as an effective shear connection in composite or hybrid structures due to its adequate ductility and
enhanced shear capacity.