Friction and fracture characteristics of engineered crumb-rubber concrete at microscopic lengthscale

Using small-scale depth-sensing techniques, we investigate the friction and hardness of engineered crumb rubber-reinforced concrete with applications into railway sleeper ties. The partial replacement of aggregates with crumb rubber particle leads to an increase in the friction coefficient and the fracture toughness, and a slight decrease in strength properties. Moreover, improper bonding at the cement/rubber interface is shown to result in poor strength characteristics. Furthermore, crumb rubber particles contribute to a higher durability as evidenced by sustained high values of the friction coefficient even in presence of surface lubrication with water or oil.