VKelly Slipform Paving Vibration Test

Project Details







Khyle Clute


Georgia Department of Transportation, South Dakota Department of Transportation, Iowa Department of Transportation, Idaho Department of Transportation, California Department of Transportation, Kansas Department of Transportation


Portable equipment, Slip form paving, Vibration tests, Workability

Project description

The aim of the work is threefold: (1) Make the test more user friendly and portable; (2) Understand the science behind the method to guide mixture proportioning and field operations based on test results; (3) Broaden the applicability to include structural and pumping mixtures. The long-term vision of this work is to develop an understanding of how mixtures can be proportioned that are relatively insensitive to vibration abuse or are ideal for the vibration system planned for use on a given site. In addition, it is desirable that a real-time test be available on a site so that as a mixture is delivered, it can be tested for workability variances due to batching or transport, thus providing the operator with guidance on how to tune the placing equipment for a truckload for a given workability. Data can also be provided to the batch plant to guide proportions for the next truck to maintain uniformity. At present, the output from the method is a so-called VKelly Index that has been tested in the field to assess upper and lower limits for slipform paving. Initial laboratory test data using a smart vibrator that also reports the voltage required to maintain a constant vibration frequency also indicates the potential to assess a number of other mixture properties. Based on this information there is a need to fully understand the mixture and equipment factors that influence the rate at which the ball sinks under vibration and how it can be used to guide mixture proportioning and construction processes.