Optimization of mix design for cement mortar containing Nano silica using DOE approach

Cement mortar as a cement- based material is one of the pivotal ingredients of concrete due to have a significant effect on mechanical properties, i.e. compressive strength of concrete. Hence, modifying the properties of cement mortar is due to attain the most compressive strength of concrete. In that case, to achieve this desire conditionabout the highest compressive strength, the condition of effective parameters presents in mortar matrix must be on their optimal levels in the mix design. In this study, ۵۴ samples of cement mortar (۱۸ mix design) have been produced and experiments were analyzed as per the statistical Taguchi method. An L۱۸ ( ) orthogonal arrays (OA) used in order to determine the significance of each parameters on compressive strength of cement. To this end, the cement mortar specimens including three factors of water to cement materials (binder) ratio (W/B) at three levels of ۰.۳۵, ۰.۴, and ۰.۵, fine aggregate to binder (FA/B) at levels ۲, ۲.۵ and Nano-silica (NS) at levels of ۱%, ۲%, and ۳% by weight cement were prepared. The analysis of variance (ANOVA) method was used to determine the statistically effects of the factors. Results obtained from Taguchi method indicate that the W/B and NS has significant effect on the compressive strength of cement mortar. Additionally, the optimum levels of each factor in order to obtain the highest compressive strength of cement mortar are level of ۲ for FA/B, level of ۰.۳۵ for the W/B and level of ۳% for NS. The high statistical accuracy and close proximity of predicted results to the actual results prove that Taguchi statistical method is considered as a reliable method for optimization and analysis of the effect of input parameters on final result.

Keywords:

Cement mortar , water to binder , fine aggregate to binder , Nano-silica , Compressive strength , statistical Taguchi method