A Study of the Semi-Perpetual Pavement Performance in Queensland

This paper presents the characteristics of a long-term pavement performance site constructed with semi-perpetual materials. The design life of a perpetual pavement is normally specified as greater than 40 years. The design requires asphalt overlays at the tenth, 20th, and 30th year for extending the life of the pavement structure. A case study of a semi-perpetual pavement with an application of the stage construction technique will be presented. The study shows that the falling weight deflectometer (FWD) central deflection of the semi-perpetual pavement was reported to be between 230 to 240 microns and the deflection curvature is less than 100 microns. The horizontal tensile strain of the semi-perpetual structure varies from 102 to 187 micro-strains and the vertical compressive strain was analyzed to be between 65 to 98 micro-strains. For the structural overlay at the 30th year of service life would improve the tensile and compressive strains of the structure to the levels which would satisfy the fatigue endurance limit and limiting subgrade strains of that of a perpetual pavement. The non-linearity behaviour of the subgrade material of the semi-perpetual pavement was analyzed by computing the surface modulus using Boussinesq's equation and material constant of subgrade material model. The results obtained from both methods showed that the subgrade material of the semi-perpetual pavement exhibits linear elastic behaviour.