Light-weight deflectometers (LWDs) are increasingly being used for controlling the quality of compacted aggregate and soil layers as a partial or full replacement of conventional density testing. TRB hosted a webinar on Thursday, September 30, 2021 from 1:00-2:30 PM Eastern that identified the latest practices in using LWDs for construction. Presenters highlighted current modulus-based compaction quality assurance (QA) methods that state departments of transportation use, described the variety of LWDs in use, and identified the effect of the LWD’s configuration when measuring deflection. They also discussed the steps required to further implement LWDs as a tool for construction acceptance of unbound material layers.

This webinar was sponsored by the TRB Standing Technical Committee on Aggregates.

The slides and recording are available. 

Webinar agenda and presenters

1. Review of compaction QA methods: Charles Schwartz, University of Maryland, and Xiong Zhang, Missouri University of Science and Technology
2. Modulus-based compaction QA testing using LWDs: Charles Schwartz, University of Maryland
3. State department of transportations’  QA specifications and practices of applying LWDs: Xiong Zhang, Missouri University of Science and Technology
4. Indiana’s experience in construction QA and field performance: Nayyar Siddiki, Indiana DOT
5. Summary and conclusion: Andrew Dawson, University of Nottingham
6. Question and answer session: Moderated by Andrew Dawson, University of Nottingham

The first 60 minutes of the webinar will be for presentations and the final 30 minutes will be reserved for audience questions.

Learning Objectives

At the end of this webinar, participants will be able to:

1. Identify conventional methods of construction QA for compacted unbound material layers
2. Identify how to incorporate modulus-based methods in construction QA
3. Implement LWDs in construction QA

Professional Development Hours

Professional Development Hours (PDHs) earned on completion of this program were reported to the Registered Continuing Education Program (RCEP). Certificates of Completion are issued to all participants via the RCEP.net online system. Complaints about registered providers may be addressed to RCEP, 1015 15th Street, NW, 8th Fl., Washington, DC, 20005.