Evaluation of the performances of the ethyl silicates for the consolidation of stone material: the stone "peperino"

The aim of the research is the evaluation of the various commercial ethyl-silicate consolidation products on a silica stone substrate: the stone “peperino”. This rock, employed for artefacts of historic-artistic, archaeological and monumental interest in Central Italy, has its origins in the area of Viterbo. The effect of the consolidation agent is due to the precipitation in the pores of the stone of amorphous silica. The following parameters have been evaluated: absorbed consolidation agent; water absorption by capillarity, water absorption by total immersion, colorimetry, mechanical strength, apparent porosity and pore size distribution. The consolidation treatment induces, for each tested product, a marked reduction of the water absorption, both by capillarity and total immersion. After 30 days from the treatment, the product showing on the whole the best results has been single out.