Investigation on mechanical properties of fly ash-ground granulated blast furnace slag based self curing bio-geopolymer concrete

Heat cured geopolymer concrete (GPC) normally catalyze the geopolymerization reaction and thereby the mechanical properties of the geopolymer concrete were improved. Because of the practical challenges in applying steam curing/heat curing process, the applications of geopolymer concrete were limited to precast elements alone. The objective of this research was to understand the positive impact of bio-additives such as Terminalia chebula and natural sugars (molasses/palm jaggery/honey) on the mechanical properties of the bio-geopolymer concrete under eco-friendly ambient curing conditions. In this study, both the bio-additives were added 0.8% by the weight of aluminosilicate minerals. Less concentrated alkaline solution (4 M sodium hydroxide) was employed. Experimental results confirmed that the bio-additives combination of Terminalia chebula and palm jaggery in fly ash-ground granulated blast furnace slag based self curing bio-geopolymer concrete improved 31.31% of compressive strength, 14.70% of splitting tensile strength, 27.59% of flexural strength when compared to control specimens cured at ambient condition for 28 days. Also the ultimate load of 83 kN and deflection of 11.99 mm was observed in load-deflection behaviour. Atomic force microscopy (AFM) studies confirmed that various surface roughness parameters were improved for bio-geopolymer concrete when compared to control specimens.