Abstract:

Concrete is commonly used in construction of chimneys, blast furnace lining, nuclear shielding, rocket launching pads and industrial structures subjected to high temperatures. Production of Ordinary Portland Cement consumes a lot of energy and results in large carbon emissions in the atmosphere. Geopolymer concrete made of Class-F fly ash is a low-carbon concrete that exhibits improved thermal stability. The SCGPC is a sustainable material that combines sustainability properties with self-compacting ability that is useful for congested reinforcement and no mechanical vibration. This study involved preparation of SCGPC mix containing Class-F fly ash as primary binder, Zone-II river sand as fine aggregates, crushed angular aggregates of sizes 10mm and 12mm as coarse aggregate, 12M sodium hydroxide with sodium silicate solution having 18% alkalinity as an activator and polycarboxylate ether based super plasticizer Conplast SP430 in 2% dose by binder weight. Beams of size 1200mm x 112mm x 240mm were cast. After 28 days ambient curing of SCGPC and conventional water curing of M30, beams were subjected to 100°C and 300°C in electric furnace for 60 minutes, allowed to cool down for 24 hours and loaded. Test results indicated SCGPC beams achieved residual flexural strength of 20.09 MPa at 100°C and 16.66 MPa at 300°C, exhibiting 17.04% reduction and 82.96% retention between temperatures. Conventional beams showed 17.11 MPa at 100°C and 14.88 MPa at 300°C with 13.04% reduction and 86.96% retention. SCGPC retained 17.39% higher strength at 100°C and 12.0% higher at 300°C compared to conventional beams. In terms of ductility, SCGPC exhibited 54.28% higher midspan deflection at 100°C and 28.20% higher at 300°C than conventional beams, confirming superior deformation capacity. Therefore, SCGPC can be considered sustainable thermally resilient alternative offering improved strength and ductility with reduced carbon footprint.