TRB Webinar: Materials for Unbound Granular Pavement Layers

TRB conducted a webinar on June 24, 2015, from 1:00pm to 3:00pm ET that presented material closely aligned with Chapters 2, 3, and 4 of NCHRP Synthesis 445: Practices for Unbound Aggregate Pavement Layers. Webinar presenters showed how natural mineral aggregate and recycled/by-product aggregate (as used in granular base and sub-base layers of pavements) is obtained, selected, characterized, and transformed into pavement layers that function in the desired manner.

This webinar was organized by the TRB Standing Committee on Mineral Aggregates.

A certificate for two Professional Development Hours (PDHs) were provided to attendees who registered and attended the webinar as an individual. Contact Reggie Gillum at RGillum@nas.edu for instructions on receiving a copy of the recorded webinar.


Webinar Presenters

• Erol Tutumluer, University of Illinois, Urbana-Champaign
• Debakanta Mishra, Boise State University
• Andrew Dawson, University of Nottingham
• Rick Boudreau, Boudreau Engineering

Moderated by: Rick Boudreau, Boudreau Engineering


Webinar Outline

1. Introduction
2. Aggregate types and material selection
• Selection on the basis of task
• Mineral consumption issues
• Types of aggregate, characteristics, and consequences for selection
• Relationship between aggregate constituents and granular material
• Recycled and by-product aggregates
3. Granular base and subbase construction practices
• Granular base defined
• Composition
• Segregation and degradation
• Stockpiling
• Transporting
• Spreading
4. Unbound aggregate base characterization for design
• Role of aggregate base
• Pavement design with unbound aggregate layers
• Unbound aggregate characterization needs
• Resilient behavior
• Stress and directional dependencies of modulus
• Permanent deformation behavior
5. Summary
6. Question and answer session

The first 90 minutes of the webinar will be for presentations and the final 30 minutes will be reserved for audience questions. The Registered Continuing Education Program (RCEP) categorizes this webinar activity as relating to health, safety, and welfare including core technical.


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

• Describe granular materials (as used in unbound pavement layers), in terms of both their constituent parts and their compacted, composite response;
• Explain the issues affecting aggregate availability and the basis of material selection;
• Discuss the fundamental ways in which unbound granular materials can be characterized in a scientific engineering manner and contrast this with traditional approaches; and
• Identify the test methods that are available to characterize these materials.

Registration Information
There is no fee for employees of TRB Sponsors or TRB Sustaining Affiliates who register using their work email address. In addition to employees of TRB sponsor organizations, the following are eligible to receive complimentary webinar registration:

• TRB and National Academies employees;
• Chairs of TRB standing committees, sections, or groups;
• Members of the media;
• Employees of tribal governments; and
• Members of Congress or their staff.

Other sites must pay $89 per site. View our pricing page for details.

After registering you will receive a confirmation email containing information about joining the webinar.


Professional Development Hour Information
A certificate for two Professional Development Hours (PDHs) will be provided to individuals who register and attend the webinar. For groups, only the person who registers and attends the session will receive a PDH certificate.

Individuals registered as Florida PEs are no longer required to email TRB with your license number to report your attendance. Instead, please use your certificate that TRB provides through RCEP.net as verification of your attendance to the Florida Board of Professional Engineers.

Please check with your licensing board to ensure that TRB webinar PDHs are approved by your board.

This webinar was developed in December 2013. TRB has met the standards and requirements of the Registered Continuing Education Program (RCEP). Credit earned on completion of this program will be reported to RCEP by TRB. Certificates of Completion will be issued to individuals who register for and attend the entire webinar session. Complaints about registered providers may be sent to RCEP, 1015 15th Street, NW, 8th Floor, Washington, DC 20005. Website: www.RCEP.net.

Registration questions? Contact Reggie Gillum at RGillum@nas.edu.