Effects of various asphalt binder additives/modifiers on moisture susceptible asphaltic mixtures.

Details

• Creators:
  Al-Qadi, Imad L. ; Abuawad, Ibrahim M. ; Dhasmana, Heena ; Coenen, Aaron R. ; Trepanier, James S.
• Corporate Creators:
  University of Illinois at Urbana-Champaign. Department of Civil and Environmental Engineering ; Illinois. Department of Transportation. Bureau of Materials and Physical Research
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Asphalt concrete
  • Asphalt mixtures
  • Binders
  • Asphalt additives
  • Antistrip additives
  • Moisture damage
  • Calcium hydroxide
  • Styrene butadiene styrene
  • Surface energy
  • Tensile strength
  More +
• Publication/ Report Number:
  FHWA-ICT-14-004
• Resource Type:
  Tech Report
• Geographical Coverage:
  Illinois
• Corporate Publisher:
  Illinois Center for Transportation
• Abstract:
  Moisture damage of asphalt concrete is defined as the loss of strength and stability caused by the active presence of ; moisture. The most common technique to mitigate moisture damage is using additives or modifiers with the asphalt binder or ; the aggregate. Various additives and modifiers are used to enhance the performance of asphalt mixtures. However, some of ; these additives/modifiers may affect the moisture susceptibility of the asphaltic mixtures. The objective of this study was to ; investigate the effect, if any, of various additives and modifiers on the moisture susceptibility of asphalt concrete. Additives ; and modifiers included in this study were selected as those most commonly used in Illinois: liquid anti-strip (LAS), styrene ; butadiene styrene (SBS), polyphosphoric acid (PPA), and hydrated lime. Two mixtures exhibiting failed tensile strength ratio ; (TSR) results were selected for testing. Mixture-level lab tests were conducted including modified AASHTO T283 Lottman test ; with five freezing and thawing (FT) cycles, the Hamburg wheel tracking test, and a fracture test using semi-circular bending ; (SCB) specimens. The modified AASHTO T283 Lottman tests showed that LAS and hydrated lime improved moisture ; damage control of the asphalt mixes. In the wheel tracking tests, mixes with SBS-modified binder and mixes with hydrated ; lime provided the least rutting potential. The fracture tests generally showed that mixes with either hydrated lime or LAS had ; the best relative performance. Component-level tests were conducted including the direct adhesion test (DAT) and contact ; angle test to determine surface free energy (SFE). Results of SFE values and DAT parameters were in agreement with the ; results of mixture-level tests: LAS and hydrated lime generally help to mitigate a mixture’s susceptibility to moisture. Full-scale ; test sections were built and exposed to accelerated load testing. Although not all full-scale sections met the lab-mix design ; volumetrics, the control mix and the mixes with LAS and SBS had similar mixture composition compared with the labprepared ; mixes. This study found that LAS and hydrated lime might reduce moisture susceptibility of asphalt mixes. However, ; PPA may need to be used with another moisture control additive or modifier in order to avoid adverse effects on an asphalt ; mixture. The study also found that surface free energy values can be used to identify aggregate–binder compatibility with ; respect to moisture damage.
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• Format:
  PDF
• Funding:
  ICT-14-004;UILU-ENG-2014-2004
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/26947/dot_26947_DS1.pdf
• File Type:
  [PDF - 1.73 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:800e5b64aa273a780fd05d652b9c99c06b101369ec34147f665ac2aecfcc30ab5906b78369f0cc1f92c2c13eb9a79f1c1224e04ee2c6f76f5363dc1a778c6a05