THE DURABILITY OF TAR CARPETS
A BRIEF HISTORY IS PRESENTED OF THE DEVELOPMENT OF OPEN- TEXTURED BITUMEN MACADAM CARPETS. STUDIES ON THE FOLLOWING ASPECTS ARE DISCUSSED: (1) THE WEATHERING OF ROAD TARS, (2) THE EFFECT OF THE AGGREGATE COMPOSITION AND THE VISCOSITY OF THE TAR ON THE LIFE OF TAR CARPETS, AND (3) THE HARDENING OF TARS ON EXPOSURE. THE CONCLUSIONS REACHED AFTER EXPERIENCE ON THE DEVELOPMENT OF SUCCESSFUL MEDIUMTEXTURED WEARING COURSES WITH ROAD TAR ARE: (1) THE VISCOSITY OF THE TAR SPECIFIED MUST BE SUCH THAT AFTER LAYING AND COOLING TO ROAD TEMPERATURE IT IS SUFFICIENTLY FLUID TO PERMIT ADEQUATE COMPACTION OF THE AGGREGATE STRUCTURE BY ROLLING AND SUBSEQUENT TRAFFIC, (2) THE MIXING TEMPERATURE SHOULD NOT BE SO HIGH THAT THE TAR HARDENS UNDULY, (3) THE TAR MUST BE RELATIVELY SLOW HARDENING SO AS TO ALLOW FURTHER DENSIFICATION OF THE WEARING COURSE UNDER THE ACTION OF TRAFFIC, (4) THE AGGREGATE GRADING MUST BE SUCH AS TO GIVE A FAIRLY CLOSE TEXTURE IMMEDIATELY AFTER ROLLING, (5) THE COMPOSITIONS MUST GIVE A CONSISTENT APPEARANCE AND MUST CONFORM TO THE SPECIFICATIONS, AND (6) THE COMPACTED THICKNESS MUST BE NOT LESS THAN TWICE THE NORMAL SIZE STONE. IF THESE REQUIREMENTS ARE MET, THERE IS EVIDENCE THAT THE SOURCE OF THE TAR HAS LITTLE EFFECT ON THE LIFE OF THE SURFACING MATERIAL.
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Supplemental Notes:
- Vol 22, No 4, PP 7-11, 1 FIG, 3 TAB
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Authors:
- Cantlay, L F
- Publication Date: 1968-12
Media Info
Subject/Index Terms
- TRT Terms: Aggregate gradation; Aggregates; Bituminous macadam; Bituminous materials; Compaction; Concrete hardening; Densification; Durability; Hardness; Mixing; Rolling; Surface treating; Tar; Temperature; Texture; Thickness; Viscosity; Weathering
- Old TRIS Terms: Aggregate characteristics; Bituminous surfacing; Mixing temperature; Thickness design
- Subject Areas: Geotechnology; Highways; Materials;
Filing Info
- Accession Number: 00211405
- Record Type: Publication
- Files: TRIS
- Created Date: Sep 15 1994 12:00AM