An Investigation of the Bond Performance of Reinforced Fly Ash-Based Geopolymer Concrete under Simulated Wet-Dry Environmental Conditions

This paper investigates the bond performance of fly ash-based Geopolymer Concrete (GPC) reinforced with steel bars under accelerated corrosion conditions. The study aimed to evaluate the bond strength of GPC when subjected to forced corrosion in a sulfate solution. Cylindrical specimens of three GPC mixtures, cured under different conditions, were prepared with 12 mm (d12) and 20 mm (d20) diameter rebars. These specimens were subjected to an accelerated corrosion test consisting of wet-dry cycles in a 1 M sodium sulfate solution for up to 8 weeks. The results indicated that the compressive strength of all GPC mixtures initially increased, peaking at 72 cycles, before steadily decreasing with a further exposure to corrosion. Similarly, the bond strength for both rebar diameters also showed an initial increase, peaking at 72 cycles, followed by a decline. The GPC cured for a longer duration exhibited higher compressive and bond strengths throughout the corrosion exposure. Furthermore, the 20mm diameter bars (d20) generally demonstrated better bond strength retention and durability under corrosive attack than the 12mm diameter bars (d12).