THE INFLUENCE OF MICA ON THE COMPACTION AND BEARING PROPERTIES OF BASECOURSE AGGREGATE

INVERKAN AV GLIMMER PAA PACKNINGS - OCH BAERIGHETSEGENSKAPER HOS BERGGRUS

Mica has an essentially negative influence on the compaction and bearing properties of road materials. In investigations, samples of 0-16 mm particle size were mixed with commercial muscovite mica of a grading similar to the 0-4 mm rock flour in the sample. Crushing by compaction is little affected by mica content; however, dry density decreases considerably and almost linearly with increasing mica content. Mica also counteracts formation of an optimum moisture content; compaction curves are quite flat. Bearing tests show that values of the modulus decrease as mica content increases, but are low even at slight degrees of saturation, probably due to resilience of mica. Admixture of only 2.5% mica has A surprisingly large negative influence; this is pronounced at low saturations. Bearing strengths were also determined on samples previously treated in an la abrasion machine without steel shot; bulk densities after compaction are higher and the modulus better at low saturations. It is evident that the small mica flakes produced by abrasion can fill the voids in the sample better than large particles; it appears large particles are main cause of inadequate compaction and low strength. Permeability is similar for different mica contents; mica flakes appear to reduce permeability. /TRRL/

• Corporate Authors:

  Swedish National Road and Traffic Research Institute

  Drottning Kristinas Vaeg 25
  S-11428 Stockholm,   Sweden 
• Authors:
  • HOEBEDA, P
  • Buenzow, L
• Publication Date: 1974

Language

• Swedish

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: 58 p.

Subject/Index Terms

• TRT Terms: Aggregates; Bearing capacity; Compaction; Crushing; Density; Grain size; Mica; Moisture content; Pavement base course; Percent saturation; Permeability; Quality control; Tests
• Uncontrolled Terms: Particle size distribution; Quality
• ITRD Terms: 4577: Aggregate; 2990: Basecourse; 3085: Bearing capacity; 3686: Compaction; 5176: Crushing; 5907: Degree of saturation (mater); 5908: Density; 4194: Mica; 5920: Moisture content; 6200: Particle size distribution; 5921: Permeability; 9063: Quality; 6255: Test
• Subject Areas: Construction; Geotechnology; Highways; I36: Aggregates;

Filing Info

• Accession Number: 00125640
• Record Type: Publication
• Source Agency: Swedish National Road and Traffic Research Institute
• Report/Paper Numbers: NR 55 R&D Rept.
• Files: ITRD, TRIS
• Created Date: Apr 7 1976 12:00AM