Field Measurements of Emulsion Application Rates and Pavement Absorption Rates in Tack Coats and Chip Seals

The emulsion application rate (EAR) is critical to the performance of both tack coats and chip seals. Typically, only the change in volume of emulsion in the distributor tank before and after construction is measured for acceptance, which cannot quantify local variability in the applied EAR. In addition, the current practice is to adjust the required target EAR to account for absorption into the existing pavement based on visual inspection, which is subjective. This study identifies suitable test frameworks for in-situ measurements of EARs. In tack coat projects, measurements of the applied EAR can be made by simply placing pre-weighed plates on the roadway prior to emulsion application. The mass of the plate after emulsion application is used to determine the applied EAR. In chip seal projects, the applied EAR can be measured by performing Tack Lifter tests on impermeable plates placed in the roadway prior to emulsion application. The Tack Lifter uses an absorbent sheet that is pressed onto the application surface with a weighted device to obtain spot checks of EARs. By conducting Tack Lifter tests directly on the pavement, the “effective” EAR (i.e., the amount of emulsion available after absorption) can be measured in both tack coats and chip seals; this can better inform target EAR selection. Residual binder rates can be obtained by collecting pre-weighed plates or Tack Lifter sheets in-situ and weighing after curing; this mitigates challenges with obtaining mass measurements in the field.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AHD18 Standing Committee on Pavement Preservation.
• Corporate Authors:

  Transportation Research Board

  ,    
• Authors:
  • Malladi, Haritha
  • Castorena, Cassie
• Conference:
  • Transportation Research Board 98th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2019-1-13 to 2019-1-17
• Date: 2019

Language

• English

Media Info

• Media Type: Digital/other
• Features: Photos; References; Tables;
• Pagination: 7p

Subject/Index Terms

• TRT Terms: Asphalt emulsions; Chip seals; Surface active agents; Tack coats
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 01697297
• Record Type: Publication
• Report/Paper Numbers: 19-02062
• Files: TRIS, TRB, ATRI
• Created Date: Mar 1 2019 3:50PM