AASHTO TP 129:18(2020) Standard Method of Test for Vibrating Kelly Ball (VKelly) Penetration in Fresh Portland Cement Concrete.
SUMMARY OF TEST METHOD
This test method comprises a two-part measurement to assess static and dynamic behavior of plastic concrete mixtures.
3.2. First, the consistency of fresh concrete is assessed by measuring the depth of penetration of a metal mass into concrete under the force of gravity.
3.3. Second, the rate of penetration of the metal mass under vibration energy of 98 J (72 lbf) at 8,000 vibrations per minute (vpm) is measured and recorded for up to 36 s. The rate of penetration in cmls”2 (in./s2) is determined and reported as the VKelly index. This parameter indicates the responsiveness of a mixture to vibration.
SIGNIFICANCE AND USE
This test method is intended to assess consistency and responsiveness to vibration of low slump concrete mixtures for applications such as slipforrn paving. Such a mixture should be mobile while under vibration, making it easy to move the mixture through a paving machine and to achieve full consolidation, but static and resistant to edge slump after the paver has moved on. The slump test only addresses the latter parameter. The approach here is to take the Kelly Ball test and modify it by adding vibration energy.
4.2. This test method is not considered applicable to non-cohesive concrete and maximum aggregate size greater than 37.5 mm (1.5 in.) or for mixtures with a slump greater than 75 mm (3 in.).
VKelly test apparatus is shown in Figure 1. The test apparatus is available in a kit from the National Concrete Pavement Technology Center. Alternatively, a Kelly Ball is commercially available. It will have to be modified to clamp the vibrator onto it, to add a graduated shaft, and to allow for the mass of the vibrator head. A frame is desirable to hold the system vertically during the test and to facilitate depth measurement.AASHTO TP 129 pdf download.