ABSTRACT
Rocks tested in this work were obtained from two slopes located in two national roads at Idiazabal (IM-18) and Ormaiztegui (OM-9) sites in the North-East Spain (Guipuzkoa). It is interesting to note that similar stability problems have been reported during last decades despite both slopes are so far each other. Representative undisturbed samples where used to carried out a preliminary study aimed to evaluate the degradation potential of both materials. Rocks tested corresponds to argillites from the Upper Cretaceous period mainly composed by (Martinez-Bofill et al., 2011): quartz (OM-9:27%; IM-18:29%), clayey fraction (50%; 60%) being the illite-moscovite the predominant clayey mineral. The percentage of carbonates was around 20% (OM-9) and 9% (IM-18). From characterization tests (clayey fraction) liquid limit and plasticity index showed similar values in both cases (27% and 13%, respectively) whereas density of solids was around 2.78 Mg/m3.
