A MICROBIAL INVESTIGATION OF ASPHALTS
MICRO ORGANISMS KNOWN TO ATTACK BITUMINOUS MATERIALS ARE ANALYZED AND DISCUSSED. THE AMOUNT OF GROWTH THAT THE BACTERIUM IS ABLE TO ACHIEVE WHEN USING THE BITUMEN AS A FOOD SUPPLY IS OBSERVED. EXPERIMENTS WITH DIFFERENT TYPES OF BITUMENS SHOWED THAT ONE BACTERIUM COULD ATTACK ALL OF THE BITUMEN MATERIALS EQUALLY WELL, AND ANOTHER WAS ABLE TO UTILIZE ONLY CERTAIN BITUMENS. FROM THESE OBSERVATIONS IT IS CONCLUDED THAT A DEFINITE SPECIFICITY OF BACTERIAL ACTIONS ON BITUMENS DOES EXIST. THIS SPECIFICITY OF ATTACK NOT ONLY INVOLVES THE NATURE OF THE BACTERIUM BUT ALSO SOME DIFFERENCE IN THE BITUMENS. EMULSIONS OF THREE ASPHALTS WERE EXPOSED TO MICROBIAL ACTION, FOR FOUR MONTHS AT 30 C. THE BITUMENS WERE THEN RECOVERED AND VISCOSITY DETERMINATIONS MADE AT 25 C WITH A HALLIKAINEN MICROGILM VISCOMETER. THESE TEST RESULTS INDICATE THAT BACTERIA AFFECT ASPHALTS IN A MANNER THAT DRASTICALLY CHANGES THEIR PHYSICAL CHARACTERISTICS. DUE TO THE CHEMICAL COMPLEXITY OF ASPHALTS, IT WAS NECESSARY TO OBTAIN YIELD FRACTIONS WHICH ARE LESS CHEMICALLY HETEROGENOUS FOR STUDY. ELEMENTAL ANALYSIS RESULTS ARE PRESENTED FOR BASE MATERIALS FROM THE THREE ASPHALTS. ALL THREE MATERIALS CONTAIN OXYGEN, NITROGEN AND SULPHUR IN ADDITION TO THE CARBON AND HYDROGEN. BASE MATERIAL AND TEN THERMAL DIFFUSION FRACTIONS WERE STUDIED BY INFRARED SPECTRAL ANALYSIS AND BY GROWTH RESPONSE FOR TWO TEST ORGANISMS. GROWTH DATA SUPPORTED BY THE INFRARED DATA LEAD TO THE ASSUMPTION THAT THERMAL DIFFUSION FRACTIONS ARE COMPOSED PREDOMINANTLY OF STRAIGHT CHAIN SATURATED OR UNSATURATED HYDROCARBONS CONTAINING 8 OR MORE CARBON ATOMS. IT IS CONCLUDED THAT THE FRACTIONS CONTAIN ALIPHATIC HYDROCARBONS OR HYDROCARBON DERIVATIVES OF A CHAIN LENGTH BETWEEN 8-22 CARBON ATOMS AS INDICATED BY INFRARED ANALYSES. THE MYCOBACTERIUM ASSAYS INDICATE THE PRESENCE OF SUBSTITUTE BENZYNE COMPOUNDS IN MOST OF THE FRACTIONS FROM THESE THREE ASPHALTS. SOME INDICATION IS GIVEN OF THE TYPES OF COMPOUNDS PRESENT IN ASPHALTS WHICH ARE SUSCEPTIBLE TO MICROBIAL ACTION. THE MODIFICATION OF SUCH COMPOUNDS WOULD EXERT AN EFFECT ON THE PHYSICAL PROPERTIES OF ASPHALTS AS SEEN BY THE VISCOSITY STUDIES. IT IS CONCLUDED THAT INFRARED DATA AND MICROBIOLOGICAL STUDIES ARE CONFIRMING TESTS OF THE NATURE OF THE THERMAL DIFFUSION FRACTION OF THESE THREE ASPHALTS.
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Supplemental Notes:
- Vol 34, pp 1-19, 14 FIG, 5 TAB, 5 REF
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Authors:
- Traxler, R W
- Conference:
- Publication Date: 1965-2
Subject/Index Terms
- TRT Terms: Aliphatic compounds; Asphalt; Benzene; Bitumen; Bituminous materials; Crash exposure; Emulsions; Food; Hydrocarbons; Infrared spectroscopy; Materials tests; Microorganisms; Microscopy; Physical properties; Thermal diffusion; Viscometers; Viscosity
- Uncontrolled Terms: Exposure
- Old TRIS Terms: Bitumen tests; Viscosity test
- Subject Areas: Highways; Materials; Safety and Human Factors;
Filing Info
- Accession Number: 00210808
- Record Type: Publication
- Files: TRIS
- Created Date: May 21 1994 12:00AM