ABSTRACT:

The behavior of EPS block under dynamic loading remains one of the main concerns in geotechnical applications for this material. Laboratory tests were carried out to determine the resilient modulus of elasticity of EPS material, which is one of the most important properties needed in mechanistic methods of pavement design. The resilient modulus is usually determined in the laboratory from cyclic triaxial tests. However, because the confining pressure has little effect on the behavior of EPS material (Zou and Leo, 1998, Horvath, 1995, Preber et al. 1994, and Eriksson and Trank, 1991), a series of cyclic unconfined compression tests of EPS specimens were carried out instead. Cylindrical specimens with 50mm diameter and 50 mm height, and with a density of 20 kg/m3, were used for the tests. The effects of static and dynamic stress level, and load cycles on the resilient modulus and deformation of EPS material, were investigated. Test results indicated that the resilient modulus of EPS decreases with an increase in static stress, but remains constant as the dynamic stress increases.

INTRODUCTION

A rigid closed-cell cellular plastic foam, Expanded Polystyrene (EPS), has been used successfully as a subgrade replacement material for pavement construction, especially for poor quality subgrade. In flexible pavement structures, the mechanical properties of the asphalt concrete, the base course, and the soil subgrade, have a considerable influence on the response of the whole pavement to dynamic traffic loading. The design procedures for flexible pavements presented in the AUSTROAD (APRG Report No.8, 1993) and AASHTO Guide for Design of Pavement Structures (AASHTO Guide 1993) utilize the mechanical properties of the asphalt concrete, base course and soil subgrade. This is considered to be a required input for determining the stress-strain characteristics of pavement structures subject to traffic loading.

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