Flexural performance of GGBS-based EGC layered reinforced cement concrete and geopolymer concrete beams: a retrofit perspective

An innovation that transforms the brittle nature of the concrete to behave almost like a metal with 100% eco-friendly binding materials is called as Engineered geopolymer composites. Researchers opted for fly ash and silica sand to prepare engineered geopolymer composites for applications and research; however, the effect of other major ingredients has to be studied to favour the advantage of local availability. Engineered geopolymer composites, with a material combination of GGBS, RHA and Copper slag, have been prepared and optimised with respect to mechanical, durability and microstructural considerations in a previous research study from which the optimised mix was considered as a retrofitting material over cement concrete and geopolymer concrete beams, in this research. Engineered geopolymer composites with the thickness of 10, 20 and 30% to the overall depth of beam was layered underneath the concrete beams which resembles the retrofit method of chipping and layering. Eight ‘Layered beam’ specimens were prepared and tested upon flexural load in terms of load-carrying capacity, flexural, ductility and cracking characteristics. Results revealed that layering with ductile material significantly enhances the load-carrying capacity and flexural strain capacity. 30% layering of developed composite around the tension zone of the beam imparts the strain hardening nature, improves the multiple micro-cracking mechanism and enhances the maximum load up to 40 and 60% of cement and geopolymer concrete beams, respectively. 10% layering which implies clear cover to beam, also showed significant enhancement in maximum load that connotes the pure ductile nature of the material.