Improving Asphalt Mixture Testing Efficiency

Asphalt mixture design and quality assurance procedures that incorporate performance measures are essential for ensuring long-lasting pavements. However, many performance tests are constrained by time, equipment, and labor demands, which limits their practical application—particularly in quality assurance and quality control processes (collectively referred to as QA herein). Currently, the North Carolina Department of Transportation (NCDOT) specifies the Asphalt Pavement Analyzer (APA) for rutting assessment and the Tensile Strength Ratio (TSR) test for moisture damage evaluation. These tests are among the most resource-intensive asphalt mixture tests required by the NCDOT, in terms of time, labor, and equipment. Moreover, specifying the APA without an accompanying cracking test can unintentionally prioritize rutting resistance over cracking resistance. To address this issue, NCDOT RP 2023-02 is evaluating the IDEAL-CT test for incorporation into mixture design to balance rutting and cracking performance. However, adding the IDEAL-CT to existing tests further emphasizes the need for more efficient testing methods. Implementing efficient alternatives could allow additional performance measures to be integrated into mix design and increase the frequency of performance assessments in QA, despite the limitations of available resources. Monotonic indirect tensile (IDT) loading tests offer a promising, cost-effective alternative to the APA for assessing rutting. Furthermore, previous NCDOT research suggests that the Boil test, combined with Asphalt Compatibility Tester (ACT) measurements, may provide a faster method for evaluating moisture damage compared to the TSR. Additionally, the IDT testing used in TSR determination closely resembles the IDEAL-CT test, presenting a potential opportunity for dual-purpose testing. However, further research is needed to systematically evaluate these approaches within the context of NCDOT’s mixture design and QA practices, ensuring that more efficient methods can be implemented without compromising the accuracy of performance assessment. Accordingly, the objectives of this proposed research are to: (1) identify asphalt mixture testing methods that improve efficiency while accurately assessing performance and (2) provide recommendations for their implementation within NCDOT’s mixture design and QA procedures. These objectives will be achieved through the execution of the following six tasks: (1) Conduct a literature review to identify efficient, alternative test methods and their relationships to existing NCDOT tests in terms of correlation and sensitivity to mixture composition variables. (2) Select, sample, and verify plant-produced mixture and the component materials for six job-mix formulas (JMFs) encompassing different mixture classifications and volumetric properties. (3) Compare NCDOT tests to the efficient alternatives in terms of correlation, sensitivity to mixture composition differences, and precision (repeatability and reproducibility) and establish preliminary thresholds for acceptance. (4) Evaluate alternative scenarios for implementing the viable efficient tests into mixture design and QA using a Strengths, Weakness, Opportunities, and Threats (SWOT) analysis. The analysis will identify implementation scenarios with the highest likelihood of success, balancing potential benefits with practical constraints. (5) Propose changes to mixture design and QA procedures based on the findings of the previous tasks and input from the NCDOT. (6) Prepare a final report documenting the study methodology, findings, and recommendations. This research project aims to identify rutting and moisture damage tests that can be integrated into asphalt mix design and/or quality assurance practices to enhance efficiency without compromising performance assessment accuracy. Additionally, the study may offer a practical pathway for incorporating a cracking performance test into mixture design and, potentially, QA processes. Furthermore, in cases where additional testing is deemed unnecessary, the greater efficiency could lead to cost and time savings.

Language

• English

Project

• Status: Active
• Funding: $346,504.00
• Contract Numbers:

  RP2026-14

• Sponsor Organizations:

  North Carolina Department of Transportation

  Research and Development
  1549 Mail Service Center
  Raleigh, NC  United States  27699-1549
• Managing Organizations:

  North Carolina Department of Transportation

  Research and Development
  1549 Mail Service Center
  Raleigh, NC  United States  27699-1549
• Project Managers:

  Kadibhai, Mustansir

• Performing Organizations:

  North Carolina State University, Raleigh

  Department of Civil Engineering, Campus Box 7908
  Raleigh, NC  United States  27695-7908
• Principal Investigators:

  Castorena, Cassie

• Start Date: 20250801
• Expected Completion Date: 20270731
• Actual Completion Date: 0
• USDOT Program: Pavements and Materials
• Subprogram: Materials

Subject/Index Terms

• TRT Terms: Asphalt mixtures; Mix design; Pavement cracking; Performance tests; Quality assurance; Rutting; Test procedures
• Identifier Terms: North Carolina Department of Transportation
• Subject Areas: Design; Highways; Pavements;

Filing Info

• Accession Number: 01957964
• Record Type: Research project
• Source Agency: North Carolina Department of Transportation
• Contract Numbers: RP2026-14
• Files: RIP, STATEDOT
• Created Date: Jun 13 2025 12:39PM