Evaluation of Balanced Mixed Design in Kansas

AASHTO PP 105-20 defines balanced mixed design (BMD) as "an asphalt mix design using performance tests on appropriately conditioned specimens that address multiple modes of distress considering mix aging, traffic, climate, and location within the pavement structure.” BMD is slowly getting acceptance as states become more familiar with the mixed design process. Traditional process (volumetrics-based) of the selection hot-mix asphalt (HMA) mix design may not provide the optimum mixture. It may not fully capture the effect of RAP, RAS, or other additives. Also, such mixtures tend to be drier and may not be sensitive to the location within the pavement structure. In contrast, BMD results in a mix that can be used as an interlayer or a reflective-resistant overlay. The latter application is beneficial to KDOT as the resurfacing mileage has recently increased. This new approach involves performance testing using a cracking test (IDEAL-CT) and a rutting test involving Hamburg Wheel Tracking Tester (HWTT). Some preliminary IDEAL-CT tests conducted by Kansas State University on KDOT resurfacing mixtures have shown that the test results are susceptible to the RAP or RAP & RAS content. The coefficient of variation of the test output is also low. Another candidate test for rutting is the IDEAL-RT test for rutting. Despite promotion from various entities, the states are cautiously approaching this new development of HMA mixture design. The states implementing this approach have also had this process for a long time. A similar study is needed in Kansas. The potential effects on acceptance using the current KDOT PWL/QC-QA specifications must also be evaluated. The objective of this research is to evaluate the balanced mix applications in Kansas critically. The following tasks are proposed to achieve the aim of this study: Task 1. Critically evaluate the IDEAL-CT results that KDOT and KSU have generated for the Kansas HMA mixes. Task 2. Select two "shadow" projects in the three KDOT districts, collect samples for the IDEAL-CT and IDEAL-RT tests and perform these tests. The test specimens shall be compacted after reheating the loose materials to the compaction temperature. Enough material should be sampled for 24 Lottman samples (150 mm dia x 95 mm thick, 7 ±0.5% air voids) for three consecutive days for the IDEAL-CT tests, and for three samples (150 mm dia x 62 mm thick) a day for three days for the IDEAL-RT tests. Analyze the test results to understand the impacts of these test results and simulated results via Monte Carlo simulation. Task 4. Develop recommendations for potential pilot projects. Task 5. Study the potential effects on the current KDOT QC/QA process.

Language

• English

Project

• Status: Active
• Funding: $76660
• Contract Numbers:

  K-TRAN: KSU-24-3

  RE-0876-01

  C2225

• Sponsor Organizations:

  Kansas Department of Transportation

  Eisenhower State Office Building
  700 SW Harrison Street
  Topeka, KS  United States  66603-3754
• Performing Organizations:

  Kansas State University Transportation Center

  Kansas State University
  Department of Civil Engineering
  Manhattan, KS  United States  66506
• Principal Investigators:

  Hossain, Mustaque

• Start Date: 20230701
• Expected Completion Date: 20250131
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Asphalt mixtures; Hot mix asphalt; Mix design; Performance tests; Quality assurance; Quality control; State departments of transportation
• Geographic Terms: Kansas
• Subject Areas: Design; Highways; Materials; Pavements;

Filing Info

• Accession Number: 01894618
• Record Type: Research project
• Source Agency: Kansas Department of Transportation
• Contract Numbers: K-TRAN: KSU-24-3, RE-0876-01, C2225
• Files: RIP, STATEDOT
• Created Date: Sep 26 2023 2:50PM