Optimization of Calcined Bentonite Caly Utilization in Cement Mortar using Response Surface Methodology

Discovery of alternative to the pozzolanic materials generated from industrial wastes was needed because of its unavailability when the industries was shutdown permanently. This paper deals the optimization of calcined bentonite clay utilization in cement mortar using response surface methodology (RSM). The variables were taken as three levels of calcination temperature (room temperature, ۷۰۰۰C and ۸۰۰۰C) and seven levels of calcined bentonite (۰%, ۵%, ۱۰%, ۱۵%, ۲۰%, ۲۵% and ۳۰%). The compressive strength, workability, strength activity index and sorpitivity were taken as responses. The fresh and hardened properties of all determined for all mixes. Design Expert ۱۱.۰ version was utilized to carried out  modelling and optimization using RSM. Workability was decreased upon increasing the calcination temperature and bentonite content in cement mortar. This attributed to high water absorption capacity of bentonite. The peak compressive strength was displayed by ۲۰% replaced bentonite calcined at ۸۰۰۰C cement mortar after ۲۸ days curing. Strength activity was improved upon increasing the percentage of bentonite calcined at ۸۰۰۰C. The sorpitivity of cement mortar was improved by incorporation of bentonite calcined at ۸۰۰۰C. The generated models from RSM were significance in all the factors considered. Optimum performance of the responses was observed at ۱۵.۲۵ % bentonite substitution calcined at ۸۰۰۰C

Keywords:

Calcined bentonite , Workability , Compressive strength , Response surface methodology (RSM) , optimization