Use of Cantabro Test to Reduce Raveling in Patching Mixes

For decades, the Texas Department of Transportation has used a stockpiled, dense-graded, cold-mix, cold-laid maintenance material. This mix is used throughout the state for blade-on repairs and has a typical stockpile life of 4 to 6 months. Several districts had placement issues and premature failures at the beginning of 2010. Most of the reported problems were from one of two suppliers and were regarding the material being too “dry” and raveling prematurely. The materials met all quality control testing requirements including asphalt content, lab-molded density, and gradation and none of these tests were identifying the deficiencies seen in the field. Maintenance mixes in Texas are also required to meet a Hveem stability requirement of more than 35 to ensure a rut-resistant mix. While this test is a still a good detector of an unstable mix, it does not indicate when a mix is too dry. In fact, the drier the mix, the better the Hveem stability. This test also does not provide an indication of when the binder in the mix is of an effective quality. The cause of the failures in 2010 appeared to be related to the type of binder/flux oil that was used in the mix. And while the mix and binder met all specifications, the mix raveled severely in many locations where it was shipped around the state. Researchers looked at different mixture tests to try to improve the resistance of the mix to raveling: Modified Cantabro Test; Indirect Tensile Strength Test; Modified Wet Ball Mill Test. It was important that any new test implemented be simple and quick since TxDOT laboratory personnel at the production facilities could not support significant increases in testing requirements. The Cantabro test was selected for implementation because it appeared to be sensitive to not only the binder quantity but also distinguished between a good and bad binder. This test is very simple and can be performed on the same specimen that was tested in Hveem Stability (which is a nondestructive test). By balancing both a Hveem stability and Cantabro Loss requirement, both rutting and raveling performance requirements will be met.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AHD20 Standing Committee on Pavement Maintenance.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Estakhri, Cindy K
  • Kassem, Emad
  • 0000-0002-4331-6692
  • Arambula, Edith
  • Scullion, Tom
• Conference:
  • Transportation Research Board 96th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2017-1-8 to 2017-1-12
• Date: 2017

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 19p
• Monograph Title: TRB 96th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Bituminous binders; Cold mix paving mixtures; Flux oil; Laboratory tests; Stripping (Pavements)
• Identifier Terms: Texas Department of Transportation
• Subject Areas: Highways; Maintenance and Preservation; Materials; Pavements;

Filing Info

• Accession Number: 01627798
• Record Type: Publication
• Report/Paper Numbers: 17-05967
• Files: TRIS, TRB, ATRI
• Created Date: Feb 27 2017 5:12PM