Flexural performance of steel-reinforced geopolymer concrete one-way slabs: Experimental and numerical investigations

This paper investigated the out-of-plane flexural performances of ambient-cured steel-reinforced slag and fly ash-based geopolymer concrete one-way slabs, in which the activator was the blend of NaOH and sodium silicate solutions (SiO₂/Na₂O = 3.1–3.3). Twelve specimens were prepared and tested, which included six OPC concrete specimens. The test parameters were concrete type (i.e., geopolymer and ordinary Portland cement (OPC) concrete), concrete compressive strength (i.e., 30 MPa, 40 MPa, and 50 MPa) and longitudinal tensile reinforcement ratio (i.e., 0.82 % and 1.20 %). The failure modes, crack patterns, load–deflection relationships and load–strain relationships of all specimens were carefully studied and reported. Further, a two dimensional (2D) finite element (FE) analysis was conducted to validate the test results. The results of the study indicated that: (1) the geopolymer concrete specimens presented lesser crack width and crack spacing owing to the improved bond between rebar and geopolymer concrete; (2) the cracking load and initial stiffness of geopolymer concrete specimens were slightly lower than that of OPC concrete counterparts; (3) the current Codes of Practice GB50010-2010 and ACI 318-19 provided reasonable predictions of the cracking load and flexural load capacity of the steel-reinforced geopolymer concrete specimens; (4) the developed FE model provided a good prediction of the flexural performance of the tested slabs, and could be used for further parametric investigation.