BENDING TESTS ON BITUMINOUS PAVING MIXTURES

RESULTS OF EARLY BENDING TESTS ON BITUMINOUS PAVING MIXTURES SEEM TO INDICATE SOME RELATIONSHIP BETWEEN STIFFNESS OF THE MIXTURE AND CRACKING OF THE PAVEMENT IN SERVICE. FOR LATER TESTS, A SELF-CONTAINED BENDING APPARATUS WAS DEVELOPED TO STUDY THE EFFECT OF DIFFERENT VARIABLES UPON THE TEST RESULTS OBTAINED WITH LABORATORY SPECIMENS. WITH A CONSTANT RATE OF LOADING, THE MODULUS OF RUPTURE AND THE MODULUS OF ELASTICITY BOTH INCREASE AS THE RATE OF STRESS INCREASES. THE VALUE OF THE MODULUS OF RUPTURE IS NOT GREATLY INFLUENCED BY THE RATIO OF SPAN LENGTH TO THE DEPTH OF THE TEST SPECIMEN. FOR A GIVEN SPAN LENGTH THE VALUE OF THE MODULUS OF ELASTICITY DECREASES AS THE DEPTH OF BEAM INCREASES, AND THAT FOR A GIVEN DEPTH OF BEAM THE MODULUS INCREASES AS THE SPAN LENGTH IS INCREASED. THE MODULUS OF RUPTURE AND THE MODULUS OF ELASTICITY, CALCULATED BY USUAL FORMULAS, ARE SATISFACTORY MEASURES OF THE STRENGTH AND STIFFNESS OF BITUMINOUS MIXTURES. INCREASING THE DENSITY OF THE SPECIMENS BY INCREASED COMPACTION INCREASES THEIR STRENGTH AND STIFFNESS. DECREASING THE TEMPERATURE OF A MIXTURE INCREASES ITS STRENGTH AND STIFFNESS. INCREASING THE AMOUNT OF ASPHALT IN A MIXTURE UP TO THE AMOUNT REQUIRED TO FILL THE VOIDS INCREASES ITS STRENGTH BUT HAS LITTLE EFFECT UPON THE STIFFNESS OF THE MIXTURE. INCREASING THE AMOUNT OF DUST UP TO THE AMOUNT REQUIRED TO FILL THE VOIDS INCREASES BOTH THE STRENGTH AND STIFFNESS OF THE MIXTURE. THE INCREASE OF STIFFNESS WHICH FOLLOWS WITH THE INCREASE OF FILLER MATERIAL WOULD INDICATE THAT THIS FACTOR IS A POSSIBLE CAUSE OF PAVEMENT CRACKING.

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  • Supplemental Notes:
    • Vol 21, No 4, PP 69-78, 82
  • Authors:
    • Hillman, W O
  • Publication Date: 1940-6

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  • Accession Number: 00210861
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 13 1994 12:00AM