Mechanochemical activation: an ecological safety process in the restoration of stone materials

The aim of this work is the assessment of the possibility to produce geopolymeric materials for the specific use in the field of consolidation of stone materials or as restoration mortars, through mechanochemical activation of two solid precursors, quartz and kaolin. These starting materials were modified by grinding at different times and then the degree of reactivity of the obtained products was verified by studying the changes induced by the mechanical treatment on the crystalline structure and by determining the specific surface. Moreover the solubility and kind of alkaline solutions classically used for the production of geopolymeric materials (NaOH and KOH) was investigated together with other aqueous solutions at variable pH. The mechano-chemical activation process can achieve the result to reduce the use of alkaline solutions as activators of the starting raw materials in the production of consolidating solution for monument stone materials and to utilise natural materials in the production of restoration mortars compatible with the substrates to be restored.