TRB Webinar: The Optimization of Tack Coat for Hot-Mix Asphalt Placement

TRB conducted a web briefing or "webinar" on January 12, 2012, from 2:00 p.m.-4:00 p.m. EST that will explore the findings of a forthcoming TRB’s National Cooperative Highway Research Program (NCHRP) report about the optimization of tack coat for hot-mix asphalt placement. The report will be published in the first quarter of 2012. Contact Reggie Gillum at RGillum@nas.edu to request a recording of the webinar.

The performance of an asphalt mixture overlay depends on the interface bond strength between the newly constructed asphalt mixture lift and the underlying pavement layers.  A tack coat, which typically consists of emulsified asphalt, has been commonly used to achieve the necessary bonding between pavement layers and to ensure that they behave as a monolithic system that withstands traffic and environmental stresses.  Poor interface bond strength may accelerate the appearance of distresses such as slippage and surface cracks.  Several factors have been considered to affect the bond performances.  Those are tack coat material type, tack coat application rate, pavement surface type, temperature, construction site conditions, and others. Participants will learn more about the development of field and laboratory devices for the evaluation of tack coat bond performance; field application of tack coat materials; evaluation of tack coat bond performance; and a summary of the research findings and recommendations.

At the conclusion of the webinar, attendees will be able to:

• Ascertain the importance of tack coat to pavement performance
• Determine the appropriate selection of tack coat materials and application rates
• Conduct measurements of total and residual tack coat materials spray application rates
• Recommend practices for tack coat material spray application

Presenters for this webinar include:

• Louay Mohammad, Louisiana State University and Louisiana Transportation Research Center
  Presentation: Results of NCHRP Project 9-40:  Tacking Your Way to Performance
  • Development of field and laboratory devices for the evaluation of tack coat bond performance
  • Field application of tack coat materials
  • Evaluation of tack coat bond performance
  • Summary of project findings and recommendations
    
    
• Joe Button, Texas Transportation Institute at Texas A&M University
  Presentation:  The Dos and Don’ts of Tack Coat Spray Application
  • The purpose of a tack coat
  • Types of tack coat materials
  • Conditions and preparation of the pavement surface
  • Tack coat break time and set time
  • Typical types of tack coat failures

Moderated by Ed Harrigan, Transportation Research Board

Request the recorded webinar: There is no fee for employees of TRB sponsors who request a webinar recording. In addition to employees of TRB sponsor organizations, the following are eligible to receive a complimentary webinar recording:

• TRB and National Academies employees;
• Chairs of TRB standing committees, sections, or groups;
• CRP panel members who were involved with developing the report or project that is the subject of the webinar;
• Members of the media; and
• Congressional staff members.

Others must pay $89 to receive the recording. View our pricing page for details.

Questions? Contact Reggie Gillum at RGillum@nas.edu.

This webinar was developed in December 2011. TRB has met the standards and requirements of the NCEES 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, PO Box 1686, Clemson, SC, 29633. Website: www.RCEP.net.