THE STABILITY OF AGGREGATES USED IN ROAD SUB-BASES
THE PROPERTIES OF ELEVEN TYPICAL AGGREGATES ECONOMICALLY AVAILABLE IN THE MIDLANDS FOR SUB-BASE CONSTRUCTION, ARE COMPARED WITH THE MINISTRY OF TRANSPORTS SPECIFICATION /1963/ FOR TYPE I GRANULAR SUB-BASE. IT IS SHOWN THAT CRUSHER RUN ROCK AGGREGATES GENERALLY DO NOT COMPLY WITH THE SPECIFICATION, BECAUSE THEIR FINES /NO. 200 B.S. SIEVE/ ARE PLASTIC. EXPERIMENTS INVESTIGATING THE INFLUENCE OF THE FINES CONTENT AND PLASTICITY ON THE STABILITY OF SOME CRUSHED STONE AGGREGATES ARE DESCRIBED. THE RESULTS INDICATE THAT A FINES CONTENT OF BETWEEN 4% AND 8% GIVES MAXIMUM STABILITY TO AGGREGATES COMPACTED TO DENSITIES ACHIEVED WITH MODIFIED A.A.S.H.O. COMPACTION. THIS, AND PRACTICAL CONSIDERATIONS SUGGEST THAT SUCH AGGREGATES ARE LIKELY TO PERFORM MOST SATISFACTORILY UNDER ADVERSE CONDITIONS, ALTHOUGH IT IS SHOWN THAT AGGREGATES HAVING NO FINES PASSING THE NO. 200 B.S. SIEVE MAY HAVE VERY HIGH STABILITY IF COMPACTED TO A HIGH DENSITY. TESTS ALSO INDICATE THAT THE HIGHEST STABILITY IS OBTAINED IF THE MATERIAL PASSING A NO. 36 SIEVE HAVE LOW PLASTICITY. IT IS SUGGESTED THAT THE MINISTRY OF TRANSPORT SPECIFICATION FOR TYPE I SUB-BASE MAY BE IMPROVED BY' SPECIFYING A FINENESS INDEX /%PASSING NO. 200 PLASTICITY INDEX/ AS A MEANS OF CONTROLLING THE PROPERTIES OF THE FINES CONTENT. A VALUE OF 40 WOULD BE SUITABLE, AND CARRYING OUT PLASTICITY TESTS ON MATERIAL PASSING THE NO. 36 SIEVE INSTEAD OF ON FINES PASSING THE NO. 200 SIEVE. /RRL/
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Supplemental Notes:
- Vol 44, No 519, PP 77-78, 79-81, 4 FIG, 3 TAB, 1 PHOT
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Authors:
- Dunn, C S
- Publication Date: 1966-3
Media Info
Subject/Index Terms
- TRT Terms: Aggregates; Coarse aggregates; Compaction; Fineness; Fines (Materials); Plasticity; Properties of materials; Road construction; Sieves; Specifications; Stability (Mechanics); Subbase materials
- Old TRIS Terms: Ungraded coarse aggregate
- Subject Areas: Construction; Geotechnology; Highways; Materials;
Filing Info
- Accession Number: 00217526
- Record Type: Publication
- Source Agency: Road Research Laboratory /UK
- Files: TRIS
- Created Date: Aug 10 2004 5:50PM