Shape characteristics of coarse aggregates are used for the rapid determination of percentages of flat and elongated particles in coarse aggregate fractions of 0.375in (9.5mm) or larger.
The base plate and pivot arms are constructed of 7 gauge steel, and the upright posts are constructed of steel. Posts, pivot arms, and base plates are yellow zinc plated. Caliper devices feature opening ratios of 1:2, 1:3, 1:4, and 1:5.
For shape determination of flat particle sizing, set the width of a particle in the larger end of the caliper, then tighten the pivot screw. Without adjusting the caliper, check the same particle in the smaller measuring end of the caliper. If the particle fits within the smaller gap, it is considered flat. Elongated particle determination follows the same steps. If the particle is larger than the small measurement in both situations, then the particle is considered neither flat nor elongated.
Budget Caliper adjusts by securing a pivot arm screw at one of four threaded positions to provide end opening ratios one at a time. Product dimensions are 16x6x3in (406x152x76mm), WxDxH.
Four-Station Caliper is similar but provides openings for all four ratios simultaneously without the need to reposition the pivot screw. Product dimensions are 16x8x3in (406x203x76mm), WxDxH.
- Calipers are precision-tooled for accuracy
- Meet the requirements of ASTM D4791
- Optimal for fractions of 3/8in (9.5mm) or larger
- The sturdy aluminum body is precision-tooled for accuracy
- Budget or Four-Station Caliper