A GUIDE TO THE STRUCTURAL DESIGN OF PAVEMENTS FOR NEW ROADS
SEVERAL IMPORTANT CHANGES ARE CONSIDERED, PARTICULARLY IN THE METHOD OF ASSESSMENT OF TRAFFIC FOR DESIGN PURPOSES. TRAFFIC IS DEFINED IN TERMS OF THE CUMULATIVE EQUIVALENT NUMBER OF 8,200-KG (18,000- LB) AXLES TO BE CARRIED DURING THE DESIGN LIFE OF THE ROAD. SIMPLE MEANS OF ESTIMATING TRAFFIC ON THIS BASIS FROM NORMAL CENSUS DATA ARE PROVIDED. USING THIS APPROACH, THE CHANGES IN MINIMUM DESIGN THICKNESS ARE CONTINUOUS THROUGHOUT THE TRAFFIC RANGE FROM RESIDENTIAL ROADS TO MOTORWAYS. FROM THE INITIAL TRAFFIC INTENSITY AND ESTIMATED GROWTH RATE, DESIGNS CAN BE PREPARED WHICH ARE SUITABLE FOR ANY LIFETIME UP TO 40 YEARS. OTHER PRINCIPAL CHANGES ARE (1) THE ADDITIONAL THICKNESS OF SUB-BASE PREVIOUSLY RECOMMENDED UNDER DENSE COATED MACADAM AND ASPHALT BASES IN FLEXIBLE PAVEMENTS IS NO LONGER REQUIRED. (2) DENSE COATED MATERIALS WITH TAR BINDER AND GRAVEL AGGREGATES FOR ROAD-BASES ARE INCLUDED IN THE RECOMMENDATIONS FOR FLEXIBLE PAVEMENTS REGARDLESS OF THE TRAFFIC TO BE CARRIED. GRAVEL IS ALSO NOW INCLUDED IN THE AGGREGATES WHICH CAN BE USED FOR ROLLED ASPHALT BASE COURSES REGARDLESS OF THE TRAFFIC TO BE CARRIED. (3) THE RECOMMENDATIONS FOR UNREINFORCED CONCRETE PAVEMENTS HAVE BEEN BROUGHT INTO LINE WITH RRL REPORT LR 192. (4) PROVISION IS MADE FOR VARYING THE THICKNESS OF PAVEMENTS ACROSS THE WIDTH OF CARRIAGEWAYS CARRYING UNI-DIRECTIONAL TRAFFIC, SO THAT THE REDUCED COMMERCIAL TRAFFIC FLOW ON MIDDLE AND FAST LANES CAN BE TAKEN INTO ACCOUNT. (5) A DESIGN PROCEDURE IS INCLUDED FOR PRIVATE ROADS INTENDED TO CARRY SPECIALIZED TRAFFIC. (6) METRIC UNITS ARE USED. /TRRL/
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Supplemental Notes:
- 36 Pp, 17 FIG, 10 TAB, 10 REF
- Publication Date: 1970
Language
- English
Media Info
Subject/Index Terms
- TRT Terms: Base course (Pavements); Concrete pavements; Estimates; Flexible pavements; Pavements; Structural design; Thickness; Traffic
- Uncontrolled Terms: Pavement thickness
- Subject Areas: Highways; Operations and Traffic Management; Pavements;
Filing Info
- Accession Number: 00205675
- Record Type: Publication
- Source Agency: Transport and Road Research Laboratory (TRRL)
- Files: TRIS
- Created Date: May 16 1972 12:00AM