Testing and modelling of friction characteristics between concrete slab and subbase layers

Abstract

This paper presents the results of an analysis of the interlayer friction characteristics between a concrete slab and various types of subbases, which are commonly used in concrete pavement construction. The interlayer friction characteristics were examined by conducting push-off tests on concrete slabs placed on top of lean concrete, crushed stone, or asphalt subbase, with and without separation membranes, under a range of saturated conditions. Throughout the tests, the friction resistance force and horizontal displacement, along with different types of subbases, were measured during the first application of a load, steady conditions, and saturated conditions. The measured interlayer friction resistance force and horizontal displacement after applying the first load showed results similar to other studies. To incorporate the test results into an analysis, a simple method was developed to estimate the maximum friction resistance force, initial slip displacement, and friction stiffness based on bilinearisation from the field-measured nonlinear friction resistance force, displacement relationship using the energy method. The finite element programs, ABAQUS and EverFE, were incorporated to analyse a concrete pavement. The interlayer friction behaviour was considered both with nonlinear and bilinear models in finite element programs and the interlayer friction characteristics were modelled with connector elements. The maximum tensile stress and horizontal displacement under temperature loading conditions were calculated using analytical models and the results were compared with field data. The results of the bilinear model based on the energy method matched the field data.