An experimental study on the effect of thickness and connection type of precast ultra-high-performance fiber-reinforced geopolymer concrete plates on the load–deflection capacity of one-way concrete slabs

•The connection of precast plates to one-way reinforced concrete slabs increased their bearing capacity.•The connection of precast plates to one-way reinforced concrete slabs reduced their deflection.•The increase in the thickness of the precast plates prevented the slabs and plates from acting in an integrated manner. This experimental research addressed the reinforcement of one-way concrete slabs using ultra-high-performance fiber-reinforced geopolymer concrete (UHPFRGC) based on ground granulated blast furnace slag (GGBFS) and silica fume. So, five 1000*300*70 mm one-way slabs were fabricated by uniform mix design. One slab was selected as the control specimen, and the other specimens were reinforced by 25-mm and 35-mm thick precast ultra-high-performance fiber-reinforced geopolymer concrete plates (PUHPFRGCP). The precast plates were connected to the tensile zone of the slab once with ultra-high-performance geopolymer concrete (UHPGC) and the other time with epoxy adhesive. The results revealed that the use of 25-mm thick PUHPFRGCS increased their bearing capacity and reduced their deflection significantly. Increasing the plate thickness to 35 mm prevented the slab and plate from acting in an integrated manner and significant debonding was observed in some parts between the slab and the plate, so the bearing capacity did not significantly increase in these specimens. Also, debonding was responsible for failure in none of the specimens. Finally, the specimen that was reinforced with the 25-mm plate and connected to the slab with epoxy adhesive was promising for structural applications.