Void Content Apparatus with Strike-off Guide Plate
Void Content Apparatus
AASHTO T-304 Standard Method of Test for Uncompacted Void Content of Fine Aggregate
- Analysis of AMRL Proficiency Test result data by David Jahn confirmed that the biggest cause of variability between labs conducting this test was the way in which the technician struck off the excess material at the top of the cylinder in an attempt to level it.
- Not everyone was doing it exactly the same way, every time. Some might not have the spatula blade perfectly perpendicular to the edge of the cylinder, which could push material back down into the cylinder or scoop it out at the end of the sweep.
- Others may have been holding the spatula higher at one end of the blade than the other, which would leave an angled top cone on top of the cylinder.
- What was needed was a way to position the edge of the spatula prior to the strike off to ensure that: A) The full edge of the spatula was horizontal, and B) Perpendicular to the edge of the cylinder.
- HMA Lab Supply is pleased to introduce our version of the Void Content Apparatus with the David Jahn Modification. It works, it’s easy to use, and it’s not expensive.
- The plate allows the technician to place the edge of the spatula flat on the plate and push it across the material on top of the cylinder without touching it and causing vibrations that would make the material in the cylinder compact.
- What the means is that there will be far less variability between agencies and contractors.
