Falling/Heavy Weight Deflectometer (F/HWD) Equipment Round-Up

Introduction

In October and November of 2010 and April of 2011, the FAA hosted a Falling/Heavy Weight Deflectometer (F/HWD) Round-Up in the National Airport Pavement Test Facility (NAPTF) at the William J. Hughes Technical Center in Atlantic City, NJ.  F/HWD equipment and backcalculation techniques have proven useful in many areas of airport pavement design, construction, and management.  F/HWD equipment can be used to measure material properties needed for pavement evaluation and thickness design.  This same data, over time, can also be used within Pavement Management System databases for long-term evaluation of pavement structures and the development of maintenance and rehabilitation strategies.  With this in mind, the FAA created the F/HWD Round-Up project with the following objectives:

• Recognize the value of deflectometer equipment in pavement structural evaluation.
• Demonstrate the proficiency of the equipment.
• Compare collected F/HWD data to a static and rolling dynamic load using the NAPTF test vehicle.
• Compare collected F/HWD data amongst different manufacturers.
• Compare backcalculated pavement material properties using the different manufacturer's F/HWD data.
• Evaluate specifications and methodologies for existing F/HWD equipment for use in pavement design and construction.

The project required the development of a controlled test pavement within the NAPTF facility.  The Round-Up included a rigid and a flexible pavement section each 60' long by 15' wide.  Construction began in December 2009 and was completed in May 2010.  A standardized test pattern and recommended test loads were provided to each participant during the testing process.  The original participants came during the months of October and November of 2010 with a late participant completing their testing in April of 2011.  The FAA HWD equipment (KUAB) performed multiple test runs both before and after the other participants completed their testing.