Performance Evaluation of HMA Treated with Hydrated Lime and Liquid Antistrip Agents

Colorado Department of Transportation (CDOT) has been using the test procedure CP-L5109 - Resistance of Compacted Bituminous Mixture to Moisture Induced Damage – (based on AASHTO T-283) to report the percentage of remaining asphalt mixture tensile strength after immersion saturation and one freeze-thaw cycle. This test has worked well as a basic screening for the potential of stripping mixtures and is often the first indicator on a construction project that the required hydrated lime is not being properly added to the contractors asphalt mixture. Pavements in Colorado are typically subjected to between 50 and 200 freeze thaw cycles during an average year. Hydrated lime has proven successful in mitigating moisture damage over the typical life span of Colorado pavements statewide. It is proposed that approximately five asphalt mixtures be selected to represent typical materials across Colorado. These mixtures shall be composed of recently crushed aggregates and, as available, recycled asphalt pavement in mixtures designed for use on active or recent CDOT construction projects. When possible, known sources of moisture sensitive aggregate sources will be intentionally targeted for inclusion in the study mixtures. Each mixture will be tested for the tensile strength remaining (TSR) in accordance with CP-L5109 at the AC content for which it was designed for project use. Each mix will be tested for TSR with no antistrip agent, with Lime, and with each liquid antistrip (LAS) additive. Testing will compare the unconditioned sample strength with the strength after five freeze-thaw cycles. Aggressive climate conditions in Colorado are the justification for the use of 5 conditioning cycles in this testing regimen to represent conditions pavements will face over their performance life. This study will leverage the ongoing testing and data analysis being conducted by the Utah DOT to make lab comparisons between Lime and LAS impact on mixture resistance to moisture damage over long periods of time. Study results will be used to compare the performance of Lime and available LAS agents on Colorado asphalt mixtures with the goal of determining if alternatives to Lime can be viable additives to combat moisture damage. Potential secondary outcomes will be a methodology to approve and specify requirements for LAS alternatives on CDOT projects.

Language

• English

Project

• Status: Active
• Sponsor Organizations:

  Colorado Department of Transportation

  Applied Research and Innovation Branch
  Denver, CO  United States  80204
• Managing Organizations:

  Colorado Department of Transportation

  Applied Research and Innovation Branch
  Denver, CO  United States  80204
• Project Managers:

  Tran, Thien

• Start Date: 20231211
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Antistrip additives; Calcium hydroxide; Freeze thaw durability; Hot mix asphalt; Moisture damage; Pavement performance; Tensile strength
• Geographic Terms: Colorado
• Subject Areas: Design; Highways; Materials; Pavements;

Filing Info

• Accession Number: 01930636
• Record Type: Research project
• Source Agency: Colorado Department of Transportation
• Files: RIP, STATEDOT
• Created Date: Sep 16 2024 9:35AM