Bituminous Surface Treatment Protocol

This study used the HDM-4 software to test the average annual daily traffic (AADT) and equivalent single axle load (ESAL) levels appropriate as criteria for selecting the application of bituminous surface treatments (BST) to WSDOT pavements. It verified the feasibility of using BSTs to maintain pavements with higher traffic levels than have been applied in the past. It also determined the validity of alternating the application of BST resurfacings and 45-mm hot mix asphalt overlays. In addition, the research estimated the impacts that increased use of BST surfaces would have on the performance of the state-owned route system.

The basic recommendations are as follows:
  • ADT of up to 2,000: Apply BSTs unless they are specifically exempted (such as paving through cities, limited BST routes, etc.).
  • ADT of 2,000 to 4,000: Apply a combination of BST and HMA overlays used interchangeably, depending upon pavement condition. Exemptions are allowed for paving through cities, limited BST routes, etc.
  • ADT of greater than 4,000: Apply HMA overlays.
This report is the first of two planned for the study.
Publication Date: 
Sunday, April 1, 2007
Publication Number: 
WA-RD 652.1
Last modified: 
10/12/2016 - 15:41
Jianhua Li, Joe P. Mahoney, Stephen T. Muench, Linda M. Pierce,
Washington State Transportation Center (TRAC)
Number of Pages: 
Asphalt concrete pavements, Annual average daily traffic, Axle loads, Bituminous overlays, Computer models, Hot mix paving mixtures, Overlays (Pavements), Pavement maintenance, Pavement management systems, Pavement performance, Recommendations, Software. Traffic volume