Behaviour of epoxide resin used to protect the "Rupe di Tropea" (southern Calabria, Italy)

Fabio Ietto (a), Emilia Le Pera (a), Domenico Miriello (a), Silvestro Antonio Ruffolo (a) & Francesco Perri (a)
(a) Dipartimento di Biologia, Ecologia e Scienze della Terra, Università della Calabria, 87036 Arcavacata di Rende, Cosenza, Italy. Corresponding author e-mail: fabio.ietto@unical.it

The present work aims to study the behaviour of the protective resin tested on a small portion of sandstone rock along the "Rupe di Tropea". The "Rupe di Tropea", located on the northern coastal edge of the Capo Vaticano promontory (Southern Calabria, Italy), is characterized by frequent landslide phenomena involving large amounts of detritus related to the weathering processes of arenitic sediments. An experimental resin was used in a small portion (the tested surface) of the arenitic sediments of the "Rupe di Tropea", in order to check its behaviour against fast erosion processes during the intervention of slope consolidation in 1998. The study of resin was performed trough laboratory tests and petrographic analysis. The results of analysis shown that the resin type was epoxy resin and it has penetrated the rock to a depth of about 2 mm. The tested surface of the arenitic sediments has shown during the last 17 years a good resistance to erosion with only a slight opacization of the applied resin. However, the tested surface is characterized by higher content of soluble salts then the non-treated surface due to the infiltration of water enriched in soluble salts related to the marine aerosol. In these conditions the soluble salts crystallize in the rock pores and between the prismatic cleavage of the micas producing an increase of physical stress and consequent exfoliation processes of the resin surface layer. After a long period, this produces a rock breakdown when these soluble salts evaporate, leaving salt crystals behind. Thus, the epoxy resin improves the resistance to erosion only in a restricted period and without infiltration of water. Over time the infiltration of moisture may introduce dangerous soluble salts. Thus, if the treated surface is not well isolated from the water infiltration, the resin produces after a long period an increase of the crystallization of the soluble salts with consequent important exfoliation processes of the treated area.

epoxy resin, sandstone rock, slope consolidation, southern Calabria.