CORRELATION BETWEEN ASPHALT CONTENT AND NEUTRON SCATTERING DATA IN BITUMINOUS PAVEMENT MIXES

A NON-DESTRUCTIVE ON-SITE DETERMINATION OF THE ASPHALT CONTENT OF BITUMINOUS PAVING MIXTURES USING THE THERMALIZATION OF FAST NEUTRONS INDICATES THAT THE SIZE OF THE SPECIMEN TO BE TESTED DEPENDS ON THE TYPE OF NUCLEAR DEVICE USED. THE STUDY WAS UNDERTAKEN FOR: THE DETERMINATION OF THE MOST EFFICIENT AND PRACTICAL GEOMETRY OF THE LABORATORY SAMPLE, THE CORRELATION OF DATA BETWEEN EXTRACTION TESTS AND THE NEUTRON SCATTERING METHOD ON LABORATORY BITUMINOUS MIXES, AND THE EVALUATION OF THE METHOD ON FIELD SAMPLES OBTAINED FROM ASPHALT PLANTS. THE EQUIPMENT USED WAS A RADIATION-SAFE NUCLEAR-CHICAGO MODEL P- 19 WHICH HOUSES A NEUTRON SOURCE AND A DETECTOR IN A SINGLE UNIT. COUNT READINGS AND ASPHALT CONTENTS FOR A GIVEN SPECIMEN SIZE AND ACCURACY, ARE RELATED THROUGH AN EQUATION DERIVED DIRECTLY FROM THE NEUTRON ATTENUATION AND THE ERROR IN COUNTING STATISTICS EQUATIONS. COUNT READINGS DO NOT SEEM TO BE INFLUENCED BY THE VARIATIONS IN THE UNIT WEIGHT OF ASPHALTIC MIXTURES BUT ARE SLIGHTLY AFFECTED BY BLEND AND PENETRATION OF ASPHALT. MOISTURE PRESENT IN ASPHALTIC MIXTURES HAS AN ADDITIVE LOGARITHMIC EFFECT IN THE COUNT READINGS AND HENCE, IN THE ASPHALT CONTENT DETERMINATIONS. BY USING A CYLINDRICAL MOLD WITH AN INSIDE SPACE OPENED AT BOTH ENDS, IT IS POSSIBLE TO TAKE READINGS IMMEDIATELY FOLLOWING PLACEMENT OF THE ASPHALTIC MIXTURE IN THE MOLD WITHOUT EXPOSING THE PROBE TO THE ADVERSE AFFECTS OF HIGH TEMPERATURE. THE ERROR INHERENT IN THE EXTRACTION TEST IS OBSERVED TO BE 0.2 PERCENT. THE ERRORS OBTAINED WITH A NUCLEAR SCATTERING METHOD DEPEND ON THE SIZE AND METHOD OF PREPARATION OF THE SPECIMEN. THE METHOD IS VERY EFFICIENT IN THAT IT GIVES THE ASPHALT CONTENT OF AN EQUIVALENT 125 GRAM SAMPLES IN A TIME OF ABOUT 10 MINUTES.

• Supplemental Notes:
  • Vol 35, pp 485-513, 16 FIG, 12 TAB, 7 REF
• Authors:
  • Laguros, J G
  • Reid, G W
  • Bonilla, U L
• Conference:
  • Assoc Asphalt Paving Technol Proc
• Publication Date: 1966-2

Subject/Index Terms

• TRT Terms: Asphalt content; Bituminous mixtures; Equations; Moisture content; Neutrons; Nondestructive tests; Nuclear radiation; Scattering; Sensors; Specimens
• Uncontrolled Terms: Neutron scattering
• Old TRIS Terms: Fast neutrons; Radiation counters /sensors/
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00210783
• Record Type: Publication
• Files: TRIS
• Created Date: May 13 1994 12:00AM