Rheology, strength and durability performance of bentonite-enhanced high-performance concrete.

Bentonite has been widely studied as a cementitious additive in conventional concrete, but its integration into high-performance concrete has not been extensively explored. The present research aims to evaluate the rheological, strength, and durability of high-performance bentonite modified concrete (HPBC). Furthermore, the multi-objective optimization of the parameters was performed. The mix matrix design was developed using RSM through Design Expert software. The variables were considered bentonite substitution (0-30%) and superplasticizer dosage (1.5-2.7%). The responses were the slump value, fresh concrete density, compressive strength, resistance against Na2SO4, and resistance against MgSO4. The results for HPBC mixes were determined through experiments conducted using the mix matrix design. The model was developed, analysed, and validated using the responses determined by laboratory experiments through RSM. The equations were generated upon the analysis, and the model results were validated using ANOVA; a more than 90% significance level was found in the model. The optimal values for the responses were obtained by selecting the variables and validated with the experimental values. The variation between the laboratory results and predicted values of the HPBC mixes was within 10%, pointing to the model's accuracy. The present research assures the further development of HPBC due to its positive performance results.