Examples of Successful Practices with State Implementation of Balanced Design of Asphalt Mixtures

Abstract

State departments of transportation (DOTs) are at various stages of implementation of their balanced mix design (BMD) program. Some states have not yet started and may still be exploring the feasibility of integrating BMD within their asphalt pavement program, while others have already moved forward with implementation activities and are currently at different stages of the implementation process. The latter have valuable experience and lessons learned that could facilitate the implementation of a BMD program into practice to improve long-term pavement durability and performance. Thus, an effort was initiated to identify and put forward positive practices from state DOTs when implementing BMD and performance testing of asphalt mixtures. To accomplish this objective, information was collected through virtual site visits, and other means made necessary by the coronavirus pandemic, with seven key state DOTs. As a result of this effort, it was identified that five state DOTs out of seven use Approach A for the BMD process as defined in AASHTO PP 105-20, and one state DOT uses a combination of Approach A and Approach B. One state DOT also allows for Approach C while another state DOT allows for Approach D. Eight major tasks for the overall process for implementing BMD as part of mixture design approval and acceptance are established, and positive practices with examples for each task are provided. Those successful efforts used by state DOTs could be considered by other state DOTs in their effort to implement BMD within their asphalt pavement program.