Tack coat optimization for HMA overlays laboratory testing.

Details

• Creators:
  Al-Qadi, Imad L. ; Carpenter, Samuel H. ; Leng, Zhen ; Ozer, Hasan
• Corporate Creators:
  University of Illinois at Urbana-Champaign. Department of Civil and Environmental Engineering
• Corporate Contributors:
  Illinois. Department of Transportation. Bureau of Materials and Physical Research ; Illinois Center for Transportation
• Subject/TRT Terms:
  • Pavement design
  • Pavement components
  • Pavement cracking
  • Pavement layers Pavements
• Publication/ Report Number:
  FHWA-ICT-08-023;FHWA-ICT-08-023, UILU-ENG-2008-2010
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Corporate Publisher:
  Illinois Center for Transportation
• Abstract:
  Interface bonding between hot-mix asphalt (HMA) overlays and Portland cement concrete (PCC) pavements can be one of the most ; significant factors affecting overlay service life. Various factors may affect the bonding condition at the interface, including HMA material, ; tack coat material, tack coat application rate, PCC surface texture, temperature, and moisture conditions. The objective of this study is to ; quantify the impact of these parameters on the permanent deformation of the HMA overlay. This study includes three major components ; to achieve the objective: laboratory testing, numerical modeling, and accelerated pavement testing. This report presents and analyzes the ; laboratory testing results. ; A direct shear test device was built and utilized to investigate the characteristics of the HMA-PCC interface and to determine the ; interface shear strength in the lab. Tests were run in monotonic mode at a constant loading rate of 0.47 in/min (12 mm/min). Test ; specimens were prepared using field PCC cores, laboratory prepared HMA, and tack coat materials provided by the supplier. Parameters ; affecting the interface performance that were evaluated include HMA material type (SM-9.5 surface mix and IM-19.5A binder mix), tack ; coat type (SS-1h and SS-1hP emulsions, and RC-70 cutback), tack coat application rate, PCC surface texture, temperature, and ; moisture conditions. Test results showed that the asphalt emulsions SS-1h and SS-1hP produced greater interface bonding strength than ; the cutback asphalt RC-70. The SM-9.5 surface mix was found to have better interface strength than the IM-19.0A binder mix. ; The HMA tested produced the same trend of interface shear strength with tack coat application rate for various tack coat types. The ; optimum residual tack coat application rate for the SS-1hP emulsion using IM-19.0A binder mix was 0.04 gal/yd2 (0.18 L/m2) in the lab. ; The direction of tining on the PCC produced no effect on interface shear strength at 20 oC. However, the milled concrete surface ; provided greater interface shear strength than both tined and smooth PCC surfaces for the same tack coat application rate. At the ; optimum tack coat application rate, the smooth PCC surface produced higher interface shear strength than the tined surface. As ; temperature increased, interface bonding strength decreased. Moisture conditioning significantly decreased the interface shear strength. ; This reduction was more pronounced when a stripping-vulnerable binder mix IM-19.0B was used.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/16700/dot_16700_DS1.pdf
• File Type:
  [PDF - 954.59 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:32ae6a511232c9f8a1d5536cbf051df08637b4d2c0ea58360d586c6c4cd9e5505326957389c358271bdd70f01d644c9f387d1067691fc821fa530f5f2aa33c52