% CRUSHED PARTICLES

Mn/DOT PROCEDURE – 1214 ASTM D 5821

Natural Aggregates vs Processed Aggregates Natural Aggregates: typically from river or glacial deposits. (Pit Run) Processed Aggregates: in most cases they are quarried. But can include natural aggregate that has been crushed and separated into size fractions

PURPOSE The intended purpose of crushing aggregates is to change the particle surface texture from smooth to rough and the particle shape from round to angular (cubical). These characteristics will aid in the aggregate particles interlock and adhesion.

FRACTURED FACE A fractured face is defined as being a broken surface, caused either by mechanical means or by nature Natural fractures, to be accepted, must be similar to fractures produced by a crusher. The fractured face should have sharp or slightly blunted edges. The surface of the fractured face should be rough (not smooth nor polished) in texture.

CRUSHED PARTICLE Defined as a particle of aggregate having at least one fractured face or two fractured faces, as required by the specifications.

CRUSHED PARTICLES Characteristics to Look For: Sharp Edges, Rough Surfaces Sharp Edges, Smooth Surfaces Slightly Blunted Edges, Rough Surfaces

NON CRUSHED PARTICLES Characteristics To Look For : Rounded Particles, Smooth Surfaces Rounded Edges, Smooth Surfaces

Mn/DOT’s Procedure Allows for CRUSHED PARTICLES UNCRUSHED PARTICLES QUESTIONABLE PARTICLES (not to exceed 20%)

Examples