ABSTRACT
Geofoam is a popular lightweight material block, used for the structural filling for the construction of vertical approach embankments of road bridges over soft subsoils. The design of such embankments is driven by the differential settlement, as the overall settlement of the geofoam blocks is lower than the fascia wall. Thus, the critical interface is the geofoam blocks with the concrete fascia wall. In the present study, an attempt has been made to determine the geofoam-concrete interface characteristics using a series of interface tests in a direct shear box. Geofoam with varying densities and concrete with varying roughness were utilised for the study. Based on the observed test results, a non-linear model for predicting interface friction angle with the roughness index was derived. This study can be utilised for the design and site quality assurance based on the roughness index of the concrete retaining wall cast at the site.
