VKelly Slipform Paving Vibration Test
The VKelly test was developed to provide agencies and contractors a tool that reports how a slipform paving mixture responds to vibration. It has been noted in the past that the slump test was useful, but did not provide a complete picture of the workability of a mixture. Increased complexity of mixtures including the use of supplementary cementitious materials and chemical admixtures has reduced the usefulness of the information provided by the slump test. In addition, current construction tools call for more information about all of the rheological properties of a mixture that are not fully described by the slump test. Initial evaluation by agencies has shown that the VKelly does provide useful, numerical and repeatable data on how a mixture will perform in a paving machine and that it could distinguish between workability of mixtures with similar slumps. It has also been used by contractors to develop mixture proportions that were reported to be successful in the field. They were able to reduce the amount of cementitious materials in a mixture while improving workability without compromising engineering properties. A number of rigs were sent to agencies around the country for them to evaluate. Feedback indicated that while seemingly technically sound, the test was challenging to operate. The aim of the work is threefold: Make the test more user friendly and portable; Understand the science behind the method to guide mixture proportioning and field operations based on test results; 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.
- Record URL:
Language
- English
Project
- Status: Active
- Funding: $195000
-
Contract Numbers:
TPF-5(498)
-
Sponsor Organizations:
California Department of Transportation
1227 O Street
Sacramento, CA United States 95814Georgia Department of Transportation
600 West Peachtree St
Atlanta, GA United States 30308Idaho Department of Transportation
P.O. Box 7129
3311 W. State Street
Boise, ID United States 83707-1129Iowa Department of Transportation
800 Lincoln Way
Ames, IA United States 50010Kansas Department of Transportation
Eisenhower State Office Building
700 SW Harrison Street
Topeka, KS United States 66603-3754North Dakota Department of Transportation
608 East Boulevard Avenue
Bismarck, ND United States 58505-0700South Dakota Department of Transportation
700 East Broadway Avenue
Pierre, SD United States 57501 -
Managing Organizations:
Iowa Department of Transportation
800 Lincoln Way
Ames, IA United States 50010 -
Project Managers:
Clute, Khyle
- Start Date: 20230401
- Expected Completion Date: 0
- Actual Completion Date: 20250331
Subject/Index Terms
- TRT Terms: Portable equipment; Slip form paving; Vibration tests; Workability
- Subject Areas: Construction; Highways; Pavements; Vehicles and Equipment;
Filing Info
- Accession Number: 01855026
- Record Type: Research project
- Source Agency: Federal Highway Administration
- Contract Numbers: TPF-5(498)
- Files: RIP, STATEDOT
- Created Date: Aug 18 2022 5:02PM