DYNAMIC MODULUS OF ASPHALT CONCRETE IN TENSION AND TENSION- COMPRESSION AND DISCUSSION

TEST PROCEDURES WERE DEVELOPED TO MEASURE THE DYNAMIC MODULUS OF ASPHALT CONCRETE IN TENSION AND IN TENSION--COMPRESSION. THE PROCEDURES ARE SIMILAR TO THOSE FOR DETERMINING THE DYNAMIC MODULUS AND PHASE LAG IN COMPRESSION. THE ASPHALTIC CONCRETE MIXES STUDIED WERE MADE WITH A DENSE-GRADED AGGREGATE AND TWO ASPHALT CEMENT CONSISTENCIES. IT WAS FOUND THAT BETWEEN DYNAMIC TENSION OR TENSION-COMPRESSION MODULI ON THE ONE HAND AND THOSE OF DYNAMIC COMPRESSION ON THE OTHER, DIFFERENCES ARE INSIGNIFICANT FOR TERMPERATURES OF 40--70 F AND LOADING FREQUENCIES OF 1--16 CPS, WHILE AT 70--100 F AND 1 CPS THE FORMER AVERAGE 1/2--2/3 THOSE OF THE LATTER. DIFFERENCES FOR PHASE LAG TENDED TO BE PRONOUNCED.