Determining Bond Strength of Micro-surfacing Mixes-Phase 2

This report summarizes results of a project that was completed to determine the benefits and drawbacks of using tack coat in micro-surfacing applications and identify the tack coat application rate that will result in the optimum interface bond strength and better performance for micro-surfacing applications using different tack coat materials. The project included conducting comprehensive field and laboratory testing programs. The field-testing program constructing a total of 25 test sections in two micro-surfacing projects to examine the effect of different factors on the bond strength between micro-surfacing mixes and existing asphalt surfaces. The evaluated effects included: the tack coat material type and application rate, the micro-surfacing mix residual binder content, and the existing surface type and condition (on existing pavement or on micro-surfacing leveling course). The laboratory testing program included preparing samples using materials collected from the field during the construction of test sections. The program was focused in examining the effect of the tack coat type, application rate, the residual asphalt binder content of the micro-surfacing mix, and existing pavement texture on micro-surfacing bond performance. The results of bond strength tests conducted on the samples obtained from the field test sections indicated that the sections with no tack coat had significantly lower bond strength than those with tack coat with at least 0.042 gsy total application (0.0068 gsy residual application rate). Furthermore, the results indicated that the use of 0.75% lower residual asphalt binder content in micro-surfacing mixes resulted in significantly lower bond strength between the micro-surfacing and existing pavement. Based on the results of this study, it is recommended that ODOT continue using the current specification for micro-surfacing (Item 421) that requires placing a tack coat with a total application rate of 0.06 to 0.12 gallon per square yard (0.25 to 0.45 L/m²) on existing pavement surfaces prior to the application of a micro-surfacing layer.

• Record URL:
  https://ohiomemory.org/digital/collection/p267401ccp2/id/21239/rec/1
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/60416
• Corporate Authors:

  Ohio University

  Department of Civil Engineering
  Athens, OH  United States 

  Ohio Department of Transportation

  1980 W. Broad Street
  Columbus, OH  United States  43223

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  U.S. Department of Transportation

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Nazzal, Munir D
  • Kim, Sang Soo
  • Abbas, Ala
  • Al-Hosainat, Ahmad
  • Talha, Sk Abu
  • Hudaib, Ala
• Publication Date: 2021-8

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Maps; Photos; References; Tables;
• Pagination: 101p

Subject/Index Terms

• TRT Terms: Asphalt mixtures; Asphalt pavements; Bituminous binders; Bond strength (Materials); Surface course (Pavements); Tack coats
• Identifier Terms: Ohio Department of Transportation
• Geographic Terms: Ohio
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 01789981
• Record Type: Publication
• Report/Paper Numbers: FHWA/OH-2021-29
• Contract Numbers: SJN 135920
• Files: NTL, TRIS, ATRI, USDOT, STATEDOT
• Created Date: Dec 1 2021 9:35AM