Drained ring-shear test data of wet silica powder-glass beads-PVC powder mixture “CM2” used for analogue modelling in the laboratory for experimental tectonics (LET) at RomaTre University, Rome, Italy

This dataset provides friction data from drained ring-shear tests on a wet (water saturated) silica powder-glass beads-PVC powder mixture (40:40:20 wt.%) “CM2”, used in analogue modelling of tectonic and erosion processes as a rock analogue for the earth’s upper crust (e.g. Conrad et al., 2023, Reitano et al., 2020, 2022. 2023). According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak, dynamic and reactivation friction coefficients of CM2 are µP = 0.66, µD = 0.58, and µR = 0.61, respectively. Cohesion of the material ranges between 60-230 Pa. The tested bulk material CM2 consists of a mixture of 40 wt. % silica powder, 40 wt.% glass beads and 20 wt.% PVC powder which has been saturated with water (Table 1). Specification of silica powder is “Ventilated Quartz VR16” (https://www.valligranulati.it/products-granules-quartz-marble-sands-premixed/sheet-m/ventilated-quartz) by the company Valli Granulati S.r.l. (Italy). Ventilated quartz is obtained by micronisation of quartz sands with a high content of SiO2 (around 96%), and used e.g. in paints and abrasives. It should be handled with care to omit generation of dust and a half mask (filter class FFA1P2 RD) should be worn because it can harm the human respiratory tract with the potential of causing silicosis. Glass beads used here have a size (diameter) of 700-110 µm and their individual properties are described in detail Pohlenz et al. (2020). The commercial name for the PVC powder is “PVC K.57 Inovyn 257RF” by the company TPV Compound (Italy). PVC powder is mainly used for cleaning industrial structures (as abrasives) or for the production of PVC tubing, plastic sheets etc. The composition of this PVC powder is the same of the common Polyvinyl chloride. According to the regulation CE n.1272/2008 (CLP), this type of PVC powder is classified as not dangerous for the supply, also thanks to its low value of density and round shape.