Refining Volumetric Boundaries for Balanced Mix Design (BMD) Approaches

Volumetric parameters have played a foundational role in asphalt mix design, acceptance, and quality assurance (QA). In both the Marshall and the Superpave mix design methods, volumetric criteria guide the selection of materials, aggregate gradation, and binder content. In more recent balanced mix design (BMD) approaches, particularly Approaches A and B, the initial mix design still relies on traditional volumetric properties. However, the integration of performance-related testing in BMD has raised questions about the continued relevance and appropriate limits of volumetric criteria. Modern asphalt mixtures increasingly incorporate modified binders, additives, reclaimed asphalt pavement (RAP), and other recycled or innovative materials that may result in volumetric properties that differ from conventional hot mix asphalt. Strictly enforcing conventional volumetric criteria may unnecessarily restrict the design flexibility that BMD seeks to promote. At the same time, volumetric properties are relatively easy to measure, monitor, and adjust during mix design, production, and QA, and they provide an additional layer of assurance in mix consistency and constructability. There is currently no consensus on how volumetric boundaries should be defined to appropriately reflect mixture performance and support effective mix design within the BMD framework. As transportation agencies transition toward performance-related mix design specifications, there is a need to revise current volumetric boundaries to better align with modern materials, performance objectives, and QA practices. The objective of this research is to investigate the impact of variations in volumetric parameters on modern asphalt mixtures and determine the volumetric boundaries that are suitable for BMD approaches and QA.

• Record URL:
  • http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=6037
• Supplemental Notes:
  • Contract to a Performing Organization has not yet been awarded.

Language

• English

Project

• Status: Proposed
• Funding: $900,000.00
• Contract Numbers:

  Project 09-78

• Sponsor Organizations:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Project Managers:

  Khosravifar, Sadaf

• Start Date: 20260608
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Asphalt mixtures; Mix design; Quality assurance; Volume
• Subject Areas: Design; Highways; Materials; Pavements;

Filing Info

• Accession Number: 01992222
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 09-78
• Files: TRB, RIP
• Created Date: Jun 10 2026 11:05AM