Review of Hot Bituminous Surface Treatments in Washington State

This report reviews the construction and performance of 11 hot bituminous surface treatment (HBST) projects installed between 2014 and 2017. The HBST used AC-15P binders and either 3/8” to No. 8 or 3/8” to No. 4 aggregates pre-coated with PG binder. The pre-coated chips are dropped onto the hot binder and rolled with a series of pneumatic rollers which are followed by a steel wheel roller to further embed the aggregate into the binder.  The HBST is open to normal speed traffic when the binder has taken a set.

The performance of the HBST’s has been good on all of the projects with the exception of two, one built in 2015 and the other in 2017. The poor performance on these projects is attributed to poor chip seal placement practices. 

Recommendations are provided for the successful construction of HBST projects.

Publication Date: 
Monday, January 14, 2019
Publication Number: 
WA-RD 887.1
Last modified: 
02/27/2019 - 15:50
Keith W. Anderson, Jeff S. Uhlmeyer, Mark Russell, Kim Willoughby, Tim Moomaw, Joe Mahoney, Casey Fraisure.
Washington State Department of Transportation. State Materials Laboratory.
Number of Pages: 
Reviews, Surface treating, Demonstration projects, Bituminous overlays, Chip seals, Bituminous construction, Adaptation and use of bituminous materials, Pavement performance, Recommendations.