% 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 PARTICLESCharacteristics to Look

For: Sharp Edges, Rough Surfaces

Sharp Edges, Smooth Surfaces

Slightly Blunted Edges, Rough Surfaces

NON CRUSHED PARTICLESCharacteristics 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