Valorization of Altered Schist for Road Infrastructure Applications: A Case Study

¹ GERS-RRO, University Gustave Eiffel, IFSTTAR, University Lyon, F-69675 Lyon, France
² Laboratory for Research in Science and Engineering, Faculty of Technical Sciences of Fez, Sidi Mohamed Ben Abdellah University, Fez, Morocco, hicham.cherifi@univ-eiffel.fr

Abstract

In Morocco, the management of materials in the road sector is governed by a variety of technical and regulatory standards, including the Moroccan guide for road earthworks, established in 2002. This document, which is inspired by its French counterpart, provides guidelines for the reuse of soils in embankments, a critical component of pavement structures. However, it complicates the use of friable rocks (R category) and places the responsibility of determining the necessary precautions on the geotechnical engineer. This ambiguity often discourages administrative services from considering these materials as reusable, leading them to opt for more stable soils or rocks. This study presents the results of an experimental campaign conducted in the Taza and Taounate Provinces, focusing on several schistose massifs. The findings suggest that these materials can be reused by adapting them through secondary treatment. Furthermore, laboratory tests on samples from various sites indicate that these schists can be used as road aggregates for low-traffic roads. Additionally, treating this rock with hydraulic binders offers a promising and viable solution for its reuse in backfilling and subgrades. The results show that using reduced proportions of binders can significantly improve the behavior of schists and reduce their sensitivity to erosive factors.