Calcium bentonite and sodium bentonite as stabilizers for roads unbound

Abstract

Several technologies are currently available to stabilize the unbound layers of road pavements. The use of these solutions, often manufactured by means of chemical processes, is steadily increasing worldwide. As an alternative natural resource, the use of bentonite represents a valid option when it comes to road stabilization and its application in this context is still relatively unexplored. This study characterises the use of calcium based bentonite and sodium based bentonite to stabilize a typical road base layer. Considering two types of aggregates with different geological origin, the laboratory investigation is performed on dry specimens by means of repeated load triaxial tests, which assess the enhancement in stiffness and resistance to permanent deformation. The findings show that both the investigated types of bentonite are suitable for road stabilization. Even if negligible from a road engineering standpoint, the performance stemming from calcium bentonite was slightly better than the one pertaining to sodium bentonite when it came to the increase in resilient modulus. • Bentonite clay is a natural effective resource to stabilize unbound layers of roads. • Repeated load triaxial tests evaluate modifications in stiffness and deformation. • The performances related to calcium bentonite and sodium bentonite are compared.