Aggregate
Proportional Caliper Device
Meets ASTM D-4791 specification.
The proportional caliper is a timesaving device used for rapid determination of percentages of flat and elongated particles in coarse aggregate fractions of .375" or larger. The device consists of a 6 x 16" base plate with two fixed posts and a 13" pivoting arm mounted between the posts so there is an opening at the end of each arm.
