Evaluation of Longitudinal Joint Densities of Asphalt Pavements in Kansas

The longitudinal joint between hot-mix asphalt (HMA) mats is often the weakest part of a bituminous concrete pavement. These joints often deteriorate fast under traffic because cracks in them allow water to ingress into the pavement, leading to further disintegration. Many studies, including one by the Federal Highway Administration (FHWA) and the Asphalt Institute in 2012, have fully recognized this. It is believed that the longitudinal cracks result primarily from the density gradient encountered across the joint during HMA construction. This density gradient can be attributed to low density at the unconfined edge when the first lane is paved and relatively high density at the confined edge when the adjacent lane is paved. The water infiltrates through the low-density area with high air voids and results in premature failures. The other causes of longitudinal cracks include loss in temperature during rolling; height differential due to poor construction (difficulty in compacting the unconfined edges) or differential settlements; residual stress (occurring at the wheel path as the HMA mat density increases) that exceeds the tensile strength of the HMA; and temperature and environmental forces. Asphalt pavement joints can be cold or hot. The cold joints occur where the first lane pavement has cooled overnight or longer, before the next lane is placed or where the first lane is carried so far ahead that the face has cooled to well below 120o F. Hot joints are produced by two pavers operating in echelon spaced close enough together so that the lane placed first does not cool significantly before the other lane is placed. There are many conventional joint compaction techniques such as rolling from the hot side, rolling from the cold side, and echelon paving. Various longitudinal joint construction techniques are being practiced now with varying results. Starting in October 2002 letting, the Kansas Department of Transportation (KSDOT) added longitudinal joint density (for HMA lift thickness greater than 1 in.) evaluation procedure to all bituminous pavements as a subsection 603.03(e)(2) in Special Provisions 90M-6917 following the specifications of the Texas Department of Transportation. The traveled way joint density was evaluated by taking two or three Nuclear Density Gauge readings in the transverse direction one paver-width wide. The traveled-way joint density, either one or two locations, is subtracted from the interior density and the difference in density compared to the allowable limits. The acceptable criterion for the joint density was interior density-joint density < 50 kg/m3. Since then, the specification has been modified as (Interior Density - Joint Density) ≤3.0 lb/ft3 or Joint Density ≥ 91.0% of Gmm, where Gmm is the theoretical maximum HMA specific gravity. Many agencies including the U.S. Army Corps of Engineers, Connecticut DOT, Michigan DOT, and Pennsylvania DOT have established pay schedules for joint densities. Thus, research on potential pay schedules for joint densities in Kansas to improve the quality of HMA pavement construction is worth pursuing.

Language

• English

Project

• Status: Active
• Funding: $34,450.00
• Contract Numbers:

  K-TRAN: KSU-26-2

  RE-0920-01

  C2252

• Sponsor Organizations:

  Kansas Department of Transportation

  Eisenhower State Office Building
  700 SW Harrison Street
  Topeka, KS  United States  66603-3754
• Performing Organizations:

  Kansas State University

  Manhattan, KS  United States  66506
• Principal Investigators:

  Hossain, Mustaque

• Start Date: 20251001
• Expected Completion Date: 20261231
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Asphalt concrete pavements; Hot mix asphalt; Longitudinal cracking; Longitudinal joints; Pavement design
• Geographic Terms: Kansas
• Subject Areas: Construction; Design; Maintenance and Preservation; Materials; Pavements;

Filing Info

• Accession Number: 01976238
• Record Type: Research project
• Source Agency: Kansas Department of Transportation
• Contract Numbers: K-TRAN: KSU-26-2, RE-0920-01, C2252
• Files: RIP, STATEDOT
• Created Date: Jan 13 2026 3:50PM