Adaptation of the Austroads Pavement Design Guide for New Zealand conditions

The Austroads document 'Pavement Design – A Guide to the Structural Design of Road Pavements' does not specifically design for plastic deformation in the basecourse; however, both experiments and field observations demonstrate that, with sufficient traffic loading, plastic deformation accumulates in the basecourse, sub-base, and the subgrade. Furthermore, pavement design in New Zealand is critically dependent on subgrade strength, apparently neglecting the accumulation of plastic strain in the granular layers of the pavement. This study, initiated in 2004, examines the design methodologies presented in Austroads and evaluates them against available New Zealand research. Various subgrade strain criteria are examined for New Zealand conditions. The roughness model from HDM III has been used to generate a pavement design figure similar to ‘Figure 8.4’ of Austroads. The figure indicates that for lower design traffic levels Austroads is highly conservative; for high design traffic levels Austroads is not conservative enough. The results for design traffic between 1,000,000 and 10,000,000 equivalent standard axles (ESA) might help explain the observation that lives greater than 50 years are being achieved in New Zealand since, assuming the modelling is correct, in effect, these roads have been over designed. (a)

[1]  A Dodds,et al.  DYNAMIC LOAD PROPERTIES OF NEW ZEALAND BASECOURSE , 1999 .

[2]  P D Cenek,et al.  Prediction of road roughness progression , 1991 .

[3]  Andrew Dawson,et al.  Design of Granular Pavement Layers Considering Climatic Conditions , 2003 .

[4]  Per Ullidtz.  Modelling Flexible Pavement Response and Performance , 1998 .

[5]  Dr. Per Ullidtz.  ANALYTICAL TOOLS FOR DESIGN OF FLEXIBLE PAVEMENTS , 2003 .

[6]  Hechter L. Theyse,et al.  Pavement analysis and design software (PADS) based on the South African mechanistic-empirical design method , 2000 .

[7]  William D. O. Paterson.  Road Deterioration and Maintenance Effects: Models for Planning and Management , 1988 .

[8]  Ahmed A Auff,et al.  CONSTRUCTION VARIABILITY, LOCAL ROADS: THE KILMORE TRIAL. , 1995 .

[9]  B D Pidwerbesky,et al.  SUBGRADE STRAIN CRITERION FOR LIMITING RUTTING IN ASPHALT PAVEMENTS , 1997 .

[10]  Avijit Maji,et al.  Concepts of reliability in mechanistic-empirical bituminous pavement design , 2005 .

[11]  John E. Haddock,et al.  Determining layer contributions to rutting by surface profile analysis , 2005 .

[12]  M W Mclarin,et al.  MOISTURE IN PAVEMENTS: DIRECTIONS FOR NEW ZEALAND RESEARCH , 1998 .

[13]  Bryan Pidwerbesky.  Evaluation of Non-destructive in Situ Tests for Unbound Granular Pavements , 1997 .

[14]  F G Bartley.  A REVIEW OF AGGREGATE RESEARCH IN NEW ZEALAND , 1980 .

[15]  Walaa Eldin I Khogali,et al.  Novel Approach for Characterization of Unbound Materials , 2004 .

[16]  Keith Wallace,et al.  THE TENSILE RESPONSE OF AN UNBOUND GRANULAR PAVEMENT. , 1998 .

[17]  I. Collins,et al.  Geomechanical Analysis of Unbound Pavements Based on Shakedown Theory , 2000 .

[18]  G Youdale,et al.  CURRENT ISSUES FOR MECHANISTIC PAVEMENT DESIGN , 2003 .

[19]  G W Jameson.  ORIGINS OF THE AUSTROADS DESIGN PROCEDURES FOR GRANULAR PAVEMENTS. , 1996 .

[20]  J de Pont,et al.  THE RELATIONSHIP BETWEEN DYNAMIC WHEEL LOADS AND ROAD WEAR , 1999 .

[21]  G Salt,et al.  PAVEMENT PERFORMANCE PREDICTION: DETERMINATION AND CALIBRATION OF STRUCTURAL CAPACITY (SNP) , 2001 .

[22]  D Alabaster,et al.  CHARACTERISATION OF SOME NEW ZEALAND SUBGRADES , 2000 .

[23]  Andrew Dawson,et al.  PAVEMENT DESIGN MODEL FOR UNBOUND GRANULAR MATERIALS , 2004 .