Pavement

This report is the final output of the Austroads project T+E.P.N.528 - `Development of Pavement Structural Condition Parameters for Estimation of Remaining Life`. Currently in Australasia different parameters are used to represent pavement strength at the project and network levels and the use of different pavement strength parameters at project and network levels could result in inconsistencies in pavement structural assessment. The major objective of this project, therefore, was to improve consistency of pavement strength assessment by comparing performance predictions using project level and network level systems. This report: outlines the origins of project and network level pavement strength parameters in common use in Australasia; compares allowable loadings predicted using Austroads procedures for the design of new pavements with HDM-4 predictions of allowable loading; and compares allowable loadings predicted using Austroads overlay design procedures for assessing structural adequacy of existing pavements with HDM-4 predictions of allowable loading. It was found that HDM-4 calibration factors can be modified such that predictions of pavement rutting for sprayed seal granular pavements and asphalt surfaced granular pavements are consistent with Austroads new pavement design procedures for permanent deformation. It was also found that HDM-4 predictions were improved when initial densification and plastic deformation components of rutting were excluded and HDM-4 rutting predictions were based on the structural deterioration component of rutting only.