THE PERMANENT DEFORMATION OF PAVEMENTS WITH UNTREATED CRUSHED-STONE BASES AS MEASURED IN HEAVY VEHICLE SIMULATOR TESTS

Heavy vehicle simulators (hvs) were used to test a range of pavement structures with crushed-stone bases. These tests were done in different regions, covering most of South Africa. The quality of the crushed stone varied, as well as the type of subbase and subgrade. Tests were done at different moisture conditions. The permanent deformation behaviour of each structure was measured. The origin of the deformation was determined from trenches made through the test sections at the end of the tests. A relationship between the permanent deformation and the equivalent 80 kn axles was developed, and the ability of crushed-stone base pavements to carry very heavy traffic is clearly shown. The relationship between the calculated safety factors in the base and subbase layers and the permanent deformation behaviour is illustrated. The relationship between resilient deflection and permanent deformation was also investigated. The performance of the roads under real traffic was found to correlate with the behaviour observed during the hvs tests. Finally, the behaviour of pavements with crushed-stone bases is graphically summarised, showing typical trends and the factors which influence the behaviour (a). The number of the covering abstract of the conference is TRIS No. 368448. (TRRL)