Environmental impact related to the energy consumption of materials has led to the development of more environmentally friendly materials such as geopolymers. Geopolymers are obtained by activating an aluminosilicate source with an alkali silicate solution at room temperature. These materials develop interesting properties (mechanical strength, thermal resistance, low thermal conductivity, etc.) depending on the choice of precursors. Several studies have been carried on the synthesis of geopolymers with different aluminosilicate sources and their properties of use. However, the control of the reactivity of metakaolin mixtures remains poorly understood. The objective of this work is to investigated the reactivity of different metakaolin mixtures on the use properties of geopolymers. 

Formulations of geopolymers selected out within a ternary of different metakaolins. The reactivity of the different metakaolin mixtures was highlighted by physicochemical and structural characterization techniques (zeta potential, wettability, 27Al NMR spectroscopy and X-ray diffraction). Afterwards, the geopolymerisation reactions of geopolymers was investigated from the fresh to the consolidated state with various techniques (infrared spectroscopy (FTIR), thermal analysis (DTA) and viscosity, water content, amorphous content) and the use properties such as, mechanical strength and extrusion workability.
Whatever the mixture, the results show that, it’s the aluminum moles number which governs the properties of the geopolymers. The viscosity of the mixtures shows that the setting time of the pastes is shorter for the geopolymers containing more reactive aluminum. The structural data evidence an increase of the Si/Al ratio from 1 to 1.7 on relation with heterogeneous networks displays a lower amorphous content. All these data permit to establish existence area on several ternary based on different metakaolin.