% CRUSHED PARTICLES. Mn/DOT PROCEDURE – 1214 ASTM D 5821.
-
Upload
blake-mooney -
Category
Documents
-
view
235 -
download
2
Transcript of % CRUSHED PARTICLES. Mn/DOT PROCEDURE – 1214 ASTM D 5821.
% 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