THE EFFECT OF ASPHALT PROPERTIES ON THE FATIGUE CRACKING OF ASPHALT CONCRETE ON THE ZACA-WIGMORE TEST PROJECT

AGENCIES RESPONSIBLE FOR PUBLIC HIGHWAYS ARE CONCERNED WITH THE POSSIBLE INCREASE IN LIFE OF ASPHALT CONCRETE PAVEMENTS OBTAINED BY SELECTING THE MOST DURABLE ASPHALTS. NEW ASPHALT TEST METHODS ARE BEING SOUGHT TO IMPLEMENT THIS SELECTION OF BETTER QUALITY ASPHALTS. TWO NEW DURABILITY TEST METHODS ARE PRESENTED AND THEIR FUNCTIONALITY AND PRECISION COMPARED WITH TWO TEST METHODS IN COMMON USE. THE TESTS IN COMMON USE ARE THE THIN FILM OVEN (TFO) TEST, AND THE ROLLING THIN FILM (RTF) TEST, WHICH PREDICT THE HARDENING OF THE ASPHALT DURING MIXING WITH HOT AGGREGATE. THESE TWO TESTS PREDICT LONG-TERM PAVEMENT LIFE WITH A REASONABLE DEGREE OF CONFIDENCE. A SLIGHTLY BETTER CORRELATION IS OBTAINED BETWEEN RECENTLY DEVELOPED MICROFILM DURABILITY TESTS AND THE LIFE OF THE VARIOUS EXPERIMENTAL TEST SECTIONS IN THE ZACA-WIGMORE (Z-W) TEST PROJECT. THE THREE ALTERNATIVE MICROFILM DURABILITY TESTS, THE THIN FILM PLATE DURABILITY TEST (TFP), THE ROLLING MICROFILM (RMF), AND THE ROLLING MICROFILM ON ORIGINAL ASPHALT (RMFO) APPEAR TO CORRELATE EQUALLY WELL WITH THE PAVEMENT LIFE OBTAINED ON THE Z-W TEST PROJECT. THESE CORRELATIONS ARE SHOWN TO BE SLIGHTLY ALTHOUGH SATATISTICALLY NOT SIGNIFICANTLY BETTER THAN ARE OBTAINED FROM PROJECTIONS OF THE TFO OR THE RTF OVEN EXPOSURES. THE THREE MICROFILM DURABILITY TESTS ARE QUITE DIFFERENT IN THEIR EASE OF DETERMINATION AND PRECISION. AN APPENDIX PRESENTS THE ROLLING MICROFILM (RMF AND RMFO) TEST PROCEDURES. THE TFP TEST HAS GIVEN AN ASTM REPEATABILITY OF 138%; THE RMF, 65%, AND THE RMFO, 43% ON A SINGLE OVEN EXPOSURE AND A SINGLE MICROVISCOSITY TEST. THE RMF AND RMFO EXPOSURES GIVE ENOUGH RESIDUE SO THAT DUPLICATE VISCOSITIES CAN BE MADE. CONSEQUENTLY, THEIR PRECISION IMPROVES TO 54% AND 34%, RESPECTIVELY. WHEN DUPLICATE EXPOSURES AND DUPLICATE VISCOSITIES ARE AVERAGED, THE PRECISION IMPROVES TO 35% AND 23%, RESPECTIVELY. THIS LEVEL OF PRECISION APPEARS TO BE APPROACHING THE LEVEL REQUIRED FOR ROUTINE TESTING. THE RMFO TEST WAS FOUND TO BE THE MOST CONVENIENT, ECONOMICAL, AND AT THE SAME TIME THE MOST RELIABLE OF THESE MICROFILM TESTS. THE ENGINEERING SIGNIFICANCE OF THE ABILITY OF THESE TESTS TO DEFINE FOR SPECIFICATION PURPOSES ASPHALTS WHICH RESIST FIELD HARDENING APPEARS TO VARY DEPENDING ON THE PAVEMENT STRUCTURE.

• Supplemental Notes:
  • Vol 38, pp 39-64, 15 FIG, 4 TAB, 16 REF, 1 APP
• Authors:
  • Santucci, L E
  • Schmidt, R J
• Conference:
  • Association of Asphalt Paving Technologists Proc
• Publication Date: 1969-2

Subject/Index Terms

• TRT Terms: Asphalt; Asphalt concrete; Asphalt pavements; Concrete hardening; Durability; Fatigue (Physiological condition); Hardness; Microforms; Oven tests; Pavement cracking; Pavements; Properties of materials; Rolling; Service life; Test procedures; Thin films
• Uncontrolled Terms: Thin film oven test
• Old TRIS Terms: Microfilms
• Subject Areas: Design; Highways; Materials; Pavements;

Filing Info

• Accession Number: 00211500
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 27 1970 12:00AM