The National Academies

SHRP 2 R06(D) [Completed]

Nondestructive Testing to Identify Delaminations between HMA Layers

  Project Data
Funds: $899,937
Research Agency: Auburn University
Principal Investigator: Michael Heitzman
Effective Date: 2/20/2009
Completion Date: 8/1/2013

Project snapshot. More details below.

(Project Number)
Impact on Practice
Product Status

Guidelines for using two new technologies to detect subsurface delamination in asphalt pavement. Both ground- penetrating radar and impact echo and seismic analysis of surface waves accelerate data acquisition.
Single-pass and full-lane coverage techniques significantly increase testing efficiency, reduce the time that technicians are exposed to traffic, and reduce data collection costs. These NDT techniques improve the ability to detect a key cause of pavement failure faster, with less manual analysis, and less risk to drivers and technicians.
Two prototypes are in development and pilot-test sites will be identified. Guidelines for using the technologies are being refined. The equipment is expected to be available for commercial use in 2014.

The final report is available at www.trb.org/Main/Blurbs/167281.aspx.  
Staff Responsibility: James Bryant

Several types of pavement surface distress can be attributed to delamination between hot-mix asphalt (HMA) layers. Longitudinal cracking in the wheel path and tearing in the surface are two common types of visual distress that are caused by delamination between layers, which is primarily due to layer debonding or stripping. Debonding occurs when there is improper tack between paved HMA layers or between an HMA overlay and concrete pavement. Stripping develops when the aggregates and asphalt binder are incompatible, adhesion is lost, and water separates the asphalt binder from the aggregate. These conditions cannot be detected by visual inspection of the pavement, particularly in the early stages of the problem. The distress—cracking or tearing—is usually the first indicator that delamination may be occurring within the pavement layers.

The objective of this project was to identify and develop nondestructive testing (NDT) techniques that are capable of identifying and determining the extent and depth of delaminations and discontinuities in HMA pavements.

This project evaluated NDT technologies to detect the extent, depth, and severity of delamination in HMA pavements, and it evaluated the ability of the technologies to operate full-lane width at safe traveling speed. The evaluation included theoretical modeling, controlled laboratory and full-scale pavement testing at the National Center for Asphalt Technology, and uncontrolled field evaluation in Florida and Kansas. The technologies evaluated included ground-penetrating radar, infrared thermography, mechanical waves, and deflectometers. Technical briefs were developed for the most promising systems.

The results of Renewal Project R06D will be incorporated into an electronic resource for practitioners, known as the NDToolbox, which will provide information regarding recommended technologies for the detection of a particular deterioration. The NDToolbox is being created by SHRP 2 Renewal Project R06A: Nondestructive Testing to Identify Concrete Bridge Deck Deterioration.

Renewal Project R06D is one of seven follow-on projects to SHRP Renewal Project R06: A Plan for Developing High-Speed, Nondestructive Testing Procedures for Both Design Evaluation and Construction Inspection.

Project Status: This project is complete.

Product Availability: Nondestructive Testing to Identify Delaminations Between HMA Layers, Volume 1 - Summary, SHRP 2 Report S2-R06D-RR-1, was published in June 2013.  It is available as an Adobe PDF.  A printed version is available through the TRB bookstore.  An e-book version of this report is available for purchase at Google, iTunes, and Amazon.  A fact sheet and project brief are also available.

Volumes 2 through 5 of the report provide more detailed technical information and are available only as Adobe PDFs via the following links:
Nondestructive Testing to Identify Delaminations Between HMA Layers: Volume 2 - Theoretical Models
Nondestructive Testing to Identify Delaminations Between HMA Layers, Volume 3 - Controlled Evaluation Reports
Nondestructive Testing to Identify Delaminations Between HMA Layers, Volume 4 - Uncontrolled Evaluation Reports

Nondestructive Testing to Identify Delaminations Between HMA Layers, Volume 5 - Field Core Verification


This page was last modified on March 19, 2014.



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