ASPHALT SPECIFICATIONS IN BRITISH COLUMBIA FOR LOW TEMPERATURE PERFORMANCE

THIS PAPER OUTLINES A METHOD OF SPECIFYING ASPHALTS WHICH WILL BE ABLE TO MEET THE REQUIREMENTS OF THE VARIOUS SERVICE TEMPERATURES ENCOUNTERED IN THE PROVINCE OF BRITISH COLUMBIA. THE PAPER ALSO OUTLINES SOME OF THE PROBLEMS OF MIX DESIGN ENCOUNTERED WHEN SOFTER ASPHALTS ARE USED AS A RESULT OF THESE SPECIFICATIONS. THE VARIOUS CONCLUSIONS REACHED IN THIS INVESTIGATION ARE SUMMARIZED AS FOLLOWS: (1) TRANSVERSE PAVEMENT CRACKING CAN BE LARGELY CONTROLLED BY THE USE OF BITUMENS WHICH DO NOT EXCEED A CRITICAL STIFFNESS (ABOUT 2 TIMES 10 TO THE 8TH POWER N/SQ M) AS COMPUTED FROM THE VAN DER POEL DIAGRAM. (2) THE USE OF VAN DER POEL'S NOMOGRAPHIC METHOD OF CALCULATING THE CRITICAL STIFFNESS OF BITUMENS FROM THE PENETRATION-TEMPERATURE RELATIONSHIP OF THE BITUMEN APPEARS TO AGREE REASONABLY WELL WITH FIELD OBSERVATIONS OF CRACKING VERSUS THE PROPERTIES OF THE RECOVERED BITUMENS. (3) THE CRITICAL STIFFNESS CAN BE CONVERTED TO A RELATIONSHIP BETWEEN THE PENETRATION OF A BITUMEN AT ONE TEMPERATURE AND THE PENETRATION AT ANOTHER TEMPERATURE FOR ANY GIVEN VALUE OF LOW TEMPERATURE EXPECTED TO OCCUR IN SERVICE. (4) ALTHOUGH THE ABOVE RELATIONSHIPS BETWEEN LOW TEMPERATURE CRACKING AND THE PENETRATION-TEMPERATURE PROPERTIES OF A BITUMEN ARE BASED UPON DATA FROM RECOVERED BITUMENS, IT WOULD APPEAR THAT A REASONABLE ESTIMATE OF THE PROPERTIES OF THE AGED BITUMEN CAN BE MADE FROM THE RESULTS OF THE THIN FILM OVEN TEST. (5) IN REGIONS OF VERY LOW SERVICE TEMPERATURES (BELOW-40 C) BITUMENS IN GENERAL USE IN BRITISH COLUMBIA MUST BE USED AT VERY SOFT CONSISTENCIES IF CRACKING IS TO BE AVOIDED. FOR THE DESIGN OF MIXES USING THESE SOFT ASPHALTS, LOWER ASPHALT CONTENTS THAN PREDICTED BY THE MARSHALL DESIGN METHOD MUST BE USED. (6) ALTHOUGH MARSHALL METHODS OF DESIGN OF MIXES WITH SOFT ASPHALTS RESULT IN VERY LOW VALUES OF STABILITY, NO PROBLEMS HAVE BEEN EXPERIENCED IN THE FIELD AS A RESULT OF THESE LOW VALUES OF MARSHALL STABILITY PROVIDED ASPHALT CONTENTS ARE KEPT TO LOWER VALUES. (7) A SIMPLE METHOD OF DESIGN USING VIBRATORY COMPACTION OF MARSHALL SPECIMENS ENABLES OPTIMUM ASPHALT CONTENTS TO BE PREDICTED. (8) DURABILITY OF MIXES MADE WITH SOFT ASPHALTS IN BRITISH COLUMBIA HAS BEEN AT LEAST AS SATISFACTORY AS THOSE MADE WITH HARD ASPHALTS, BUT FURTHER OBSERVATIONS SHOULD BE MADE.

• Supplemental Notes:
  • 1 APP
• Authors:
  • Readshaw, E E
• Conference:
  • Association of Asphalt Paving Technologists Proc
• Publication Date: 1972

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 562-81
• Serial:
  • Volume: 41

Subject/Index Terms

• TRT Terms: Asphalt content; Asphalt pavements; Bitumen; Cold weather; Cracking; Durability; Low temperature; Mix design; Oven tests; Pavement cracking; Pavement performance; Pavements; Pendulum tests; Specifications; Stiffness; Thin films; Transverse cracking; Vibratory compaction
• Uncontrolled Terms: Cold cracking; Marshall mix design; Thin film oven test
• Old TRIS Terms: Asphalt pavement specifications
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 00211824
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 17 2002 12:00AM