Empirical models for permanent deformation of cement-grouted bituminous mixes

Abstract

Cement-grouted bituminous (CGB) mix is a semi-flexible type of pavement comprising an open-graded (porous) bituminous mix grouted with a cementitious mortar. CGB mixes have the advantages of both flexible and rigid pavements. This hybrid material of bituminous mix and cement grout offers better rut resistance and is more resistant to fuel and oil spillage compared to conventional bituminous mixes. This paper presents the details of different investigations carried out for the evaluation of the permanent deformation characteristics of different CGB mixes. A conventional bituminous concrete mix was also tested for comparison. The permanent deformation susceptibility of different CGB mixes was evaluated in a wheel tracking test facility. The rut depth developed after 20 000 load applications in the specimens conditioned at 60°C was correlated to different porous bituminous mix and CGB mix parameters. The empirical models presented in this paper will be useful for estimating the relative rutting performance of different CGB mixes in terms of their design parameters such as aggregate gradation, binder content and air voids in the mix.