Optimization synthesis geopolymer based mixture metakaolin and fly ash activated by alkaline solution

Abstract

The geopolymer materials have been widely studied because of their environmental positive impact and their potential use as a sustainable building material. It is in this context that this work has registered to optimize the synthesis geopolymer by improving their compressive strenght, from a mixture of three components, metakaolin, fly ash and activating alkaline solution. The methodology chosen in this study is a mixture design, in order to establish a models between two responses, setting time responses and the mechanical compressive strength, and the three constituents of the mixture, taking into account their interactions.The variance analysis of established models showed that Fisher experimental values are higher than critical value of Fisher-Snedecor, which allowed us to say that the factors used for modeling are significant overall. Thus, model validation showed that there is no difference statistically significant between the experimental and predicted values, which confirmed the validation of the established models, with very high values of determination coefficients (R2 = 95% for setting time and 96% for compressive strength). The graphical representation of models in the space of variables allowed us to determine the optimal constituent conditions, leading to a geopolymer with a compressive strength equal to 20.58 MPa.