Thickness Estimation of Existing Pavements Using Nondestructive Techniques: Matching Accuracy to Application

Accurate estimates of layer thickness are considered critical for pavement evaluation. Traditionally, layer thickness is assessed using cores taken from the existing pavement. However nondestructive testing (NDT) techniques, such as ground penetrating radar (GPR), ultrasonic, and spectral analysis of seismic waves (SASW) are being implemented by highway agencies. Inevitably, there are questions concerning the accuracy of NDT systems. It is proposed that the required accuracy of an NDT-based system be considered from the perspective of the application in which thickness data will be used. Four typical applications, including construction quality control/quality assurance (QC/QA), layer moduli estimation (using an elastic layered approach), estimation of remaining service life (using procedures contained in the 1993 AASHTO Guide), and overlay design (using one AASHTO-based empirical procedure and the mechanistic-empirical procedures in the new MEPDG), are examined to assess the relative sensitivity to variations in surface layer thickness. It is demonstrated that the required accuracy of layer thickness estimates varies by application. Specifically, it is suggested that construction QC/QA requires highly accurate thickness estimates (±2.5-5%); layer moduli determination requires moderate accuracy (±5%); overlay design – considering both empirical and mechanistic-empirical procedures – requires lower accuracy (±10%); and remaining life determination requires the lowest accuracy (>±10%). Agencies seeking to implement NDT-based techniques for estimating layer thickness of existing pavements should carefully consider the uses for which the data will be used, and develop their measurement systems accordingly.


  • English

Media Info

  • Media Type: DVD
  • Features: Figures; Photos; References; Tables;
  • Pagination: 14p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01152415
  • Record Type: Publication
  • Report/Paper Numbers: 10-2480
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 11:10AM