3.1         Introduction

As was shown in chapter two, a number of experimental studies have been performed on EPS geofoam to identify the mechanical properties of this material under various conditions. Most of the work has been done in Europe and in Japan and very few from the United States. This chapter highlights some of the physical properties of EPS geofoam manufactured in the United States. Most of the common EPS types were used in this study.

First density variations within a block are discussed and presented. Monotonic uniaxial compression tests were performed on different specimen sizes and under different loading rates. The effect of the rate of loading on both the stiffness and the strength of the material is shown. Most of the tests were done in strain-controlled mode. Empirical equations for both the strength and the stiffness of EPS are presented. The effect of the loading rate on the behavior of the stress strain curve is examined.

The effect of the dimensions of the specimen on both the initial modulus and the strength are shown. The distribution of strain over the height of the specimen is presented.

Little is known from previous about Poisson’s ratio. Reported values in previous studies range from 0.05 up to 0.5, as mentioned in chapter two. Poisson’s ratio is experimentally obtained in this study with an explanation of what errors were encountered in previous research works. The value of the initial modulus of EPS geofoam specimens is studied under cyclic compression. The chapter ends with a quick overview on both the isotropic behavior and the creep behavior of EPS geofoam under compression loading.