Comprehensive Balanced Mixture Design Protocol: Design Phase through Production Quality Assurance

Abstract

The objective of this study was to develop a comprehensive balanced mix design (BMD) protocol for a state highway agency (SHA) using one of the four approaches presented by both the National Asphalt Pavement Association (NAPA) and the American Association of State Highway and Transportation Officials (AASHTO). This comprehensive BMD was to ensure that a mixture design continues to be balanced from the mixture design phase to the production quality assurance (QA) phase. While existing publications by NAPA, AASHTO, and others provide a good initial framework for developing a BMD protocol, many important questions arise that are left for each SHA to answer when developing a comprehensive BMD protocol. This paper outlines these questions and how each of them was addressed. Also, a new approach for developing a pass/fail criterion for bottom-up fatigue cracking using AASHTOWare® pavement mechanistic-empirical design (PMED) predictive models is presented. Twenty-one SHA-approved plant-produced mixtures were obtained and tested to aid in the development of this pass/fail criterion. A similar approach as presented in this paper can be used by other SHAs. A comprehensive BMD protocol is presented at the end of this paper along with recommendations for future studies needed for further refinement.