Comparison of Butt and Notched Wedge Longitudinal Joints Constructed in Connecticut
Proper construction of longitudinal joints in asphalt pavements significantly contributes to their longevity and reduces joint-related pavement distresses, such as surface raveling, joint cracking and opening. Despite the apparent importance of the joint, there is no single construction practice that is widely accepted in the US. Most states have their own approaches and requirements regarding the construction techniques and quality assurance (QA) activities associated with longitudinal joints. Recently, the Connecticut Department of Transportation and Federal Highway Administration sponsored a research study that investigated two types of longitudinal joints: traditional vertical butt joints and notched wedge joints. The data was collected from two re-surfacing projects in Connecticut that utilized both joint types. Each project was divided randomly into multiple sections and the density data was collected from each section. The density was measured at the joint location as well as on both sides of the joint immediately after compaction. Two methods were employed to determine the density. First, the in-place density was measured using the nuclear density gauge. Next, the cores were taken from the same locations to measure the density in the laboratory using the vacuum seal method. This paper presents the experimental setup and the construction details on both joint types. The collected data is statistically analyzed and factors influencing the final density for each project are discussed. Both density measurement methods are compared and the correction factor was established between the two methods using additional cores taken from the mat away from the joint.
Zinke, Scott
Shaffer, Gregg
TRT Terms: Asphalt pavements; Butt joints; Data collection; Longitudinal joints; Pavement cracking; Pavement distress; Stripping (Pavements)