Investigation of optimum alkaline activator ratio and geopolymerization rate of cattle bone ash-based geopolymer concrete

This study focused on the investigation of geopolymerization rate and optimum alkaline activator ratio for animal and industrial waste-based geopolymer concrete (GPC). To realize this, Sodium silicate (Na 2 SiO 3 ) and sodium hydroxide (NaOH) of 12 M were mixed at 2.0:1 and 3.0:1 proportions and used as alkaline activators to examine the strength development of cattle bone ash (CBA)/ground granulated blast furnace slag (GGBS)-based GPC. The GPC was batched by weight method and cast following necessary design standards. According to Tsutie et al. [95] , the use of the volumetric batching method in concrete production is a bad approach to concrete production and it accounts for a reduction in durability in terms of strength beyond 14 %. Slump tests were conducted on the fresh GPC samples to establish their workability. Compressive, flexural, and split tensile strength tests were conducted to examine the mechanical properties of the GPC, with the curing days being 7, 14, 28, 56, and 90 days. The Density of the hardened samples was also investigated on the 28th day of curing. The economic performance of the GPC was further checked using the cost-to-strength ratio approach, and prediction models were developed using regression analysis. This study further investigated the rate of geopolymerization by carrying out XRD analyses on CBA/GGBS-based geopolymer mortar. The results of the mechanical tests show that alkaline activators ratio of Na 2 SiO 3 and NaOH at 3.0:1 yielded better mechanical performance than alkaline activators ratio of Na 2 SiO 3 and NaOH at 2.0:1. The GPC samples produced with alkaline activators ratio of Na 2 SiO 3 and NaOH at 3.0:1 also exhibited lower cost-to-strength ratio (CSR) than the GPC produced with alkaline activators ratio of Na 2 SiO 3 and NaOH at 2.0:1. The developed models also exhibited high R 2 values, small root mean square error (RMSE), and mean absolute error (MAE), and the results of the XRD analyses validated the geopolymerization rate of GPC produced using CBA and GGBS. • CBA decreased the geopolymerization rate while GGBS increased the geopolymerization rate of CBA/GGBS-Based GPC. • Alkaline activator ratio of 3.0:1 exhibited better mechanical performance than alkaline activator ratio of 2.0:1. • The developed model exhibited high accuracy for the prediction of the GPC.