Geopolymer Flat Slabs with Synthetic Coarse Aggregate under Punching

This paper experimentally analyzed the behavior of steel fiberreinforced geopolymer with red mud (RM) synthetic coarse aggregates. Eight flat slabs were manufactured and subjected to symmetrical punching tests until failure. The results were compared with the estimates of the prescriptions of seven models in the literature. The results show a considerable increase in the punching shear capacity in the group with steel fiber addition; the strength gains in steel fiber-reinforced concrete were 9% and 36% for natural and synthetic aggregates, respectively, and 3% and 27% in geopolymer reinforced concrete. However, the highlight of the post-peak behavior improvement was with the geopolymer concrete, while the slabs with synthetic aggregate showed similar behavior to conventional concrete slabs. Moreover, the theoretical models showed satisfactory predictions in favor of safety and can be applied to geopolymer concrete.