Analysis of Response and Development of Permanent Deformation of Unbound Granular Materials Using a Testing Box Technique

Sammanfattning: The main objective of this thesis is to study the response and development of permanent deformation in unbound granular materials, theoretically and experimentally. A testing box technique is used here to more closely simulate the behaviour of unbound aggregates subjected to external vertical loading. A small box device (800×800×800 mm) is employed to test both the response and permanent deformation characteristics of unbound granular materials (UGM) subjected to external pulsating loading. The response is measured with LVDTs within the tested materials. A subbase, 200 mm in thickness, is compacted in layers up to a desired degree of compaction, and thereafter a base course, 80 mm or 150 mm in thickness, is compacted, over the subbase material. After a series of tests of different quality of unbound base course materials, the material response and performance are modelled using a multilayer elastic approach and three different simple performance models. The principal conclusion is that the testing box method captures the main behaviour of the materials. Good correspondence is achieved between the calculated and the observed behaviours for different levels of applied stress.