Characterization and Modeling of Photon Absorption in Asphalt Materials for Improved Accuracy and Consistency of Nuclear Density Measurement

Although the nuclear method has been widely used in the compaction measurement of both soils and asphalt pavements, its accuracy for asphalt pavements is not as good as that for soils. Due to this issue, many disputes have incurred in construction projects, which resulted in replacement of the nuclear test method with the core sample method in many state departments of transportation (DOTs) for quality assurance or acceptance including the Region II states, although most contractors still use it on quality control as a fast and economic test method. The previous investigation disclosed that the above disputes can mainly attribute to the effect of asphalt's chemical constitution on the nuclear gauge count readings. There are three basic types of photon interaction with matter, i.e., the Compton, photoelectric, and pair production effects. The first two effects are dominant in the existing nuclear test methods. Attenuation from the Compton effect is proportional to physical density; however attenuation from the photoelectric effect depends on atomic number or composition. Therefore, to accurately measure material density, the relative composition effect needs to be corrected. In other words, the Compton and photoelectric effects need to be decoupled. The goal of this project is to improve the accuracy and consistency of the nuclear test methods in asphalt pavement construction. To this end, we will first investigate the energy absorption difference between asphalt and aggregate materials. Experiments will be conducted to test the energy absorption rates of asphalt binders, mixtures, and soil materials using different nuclear sources. The nuclear gauge count reading changing with asphalt material density and microstructure will be characterized and modeled. The correlation between actual block densities and nuclear gauge count readings will be analyzed and understood, and photon absorption will be simulated through particle transmission analysis, and an appropriate calibration equation will be developed.

Language

  • English

Project

  • Status: Active
  • Funding: $77684.00
  • Contract Numbers:

    49198-13-26

    49198-14-26

  • Sponsor Organizations:

    Research and Innovative Technology Administration

    University Transportation Centers Program
    1200 New Jersey Avenue
    Washington, DC  United States  20590

    University Transportation Research Center

    City College of New York
    Marshak Hall, Suite 910, 160 Convent Avenue
    New York, NY  United States  10031
  • Project Managers:

    Eickemeyer, Penny

  • Performing Organizations:

    Manhattan College

    4513 Manhattan College Pkwy
    Riverdale, NY  United States  10471

    Columbia University

    610 SW Mudd
    500W 120th Street
    New York, New York  United States  10027
  • Principal Investigators:

    Wang, Qian

    Yin, Huiming

  • Start Date: 20140301
  • Expected Completion Date: 0
  • Actual Completion Date: 20150831
  • Source Data: RiP Project 36229

Subject/Index Terms

Filing Info

  • Accession Number: 01565933
  • Record Type: Research project
  • Source Agency: University Transportation Research Center
  • Contract Numbers: 49198-13-26, 49198-14-26
  • Files: UTC, RiP
  • Created Date: Jun 5 2015 1:00AM