In order to develop projects that are environmentally friendly, economically viable and sustainable, binders based on geopolymers are favoured. Geopolymer synthesis follow the reaction between aluminosilicate sources with an alkaline solution. Some applications require materials that could be used at high temperature for instance to avoid or resist to fire. The objective of this work is to understand the effect of alkaline content and iron additives on the geopolymer behaviour at high temperature (1150 °C).
In this study, different alkaline solution concentrations and two iron sources have been investigated. Firstly, physico-chemical characteristics of the mixture are presented, such as initial viscosity, Raman spectroscopy and solution density. Then, characterisation of thermal analysis, dilatometry and mercury porosity were evaluated. Finally, features and mechanical resistance changes before and after a high temperature (1150 °C) cycle were discussed according to structural characterisation.
Silicate alkaline nature and concentration govern properties from fresh state to consolidated one. The iron precursors are promising additives to reach materials to be used at high temperature.