Volume 22, Issue 2 (March 1994)
Determining Asphalt Concrete Properties via the Impact Resonant Method
Various publications have demonstrated that the results from the resilient modulus test (see ASTM D 4123, Method for Indirect Tension Test for Resilient Modulus of Bituminous Mixtures) display a wide range of variability. Considering this, an alternate testing method that produced more consistent results with a simpler test setup was pursued. A standardized vibrational test procedure for Portland cement concrete (ASTM C 215, Test Method for Fundamental Transverse, Longitudinal, and Torsional Frequencies of Concrete Specimens) was modified to measure the material properties of asphalt concrete. The impact resonant method provided three separate, independent tests, two measuring the elastic modulus and one the shear modulus. Poisson's ratio was obtained by comparing moduli results. Unlike the semi-nondestructive nature of the resilient modulus test, the impact resonant method was a true non-destructive test. The method also allowed for a possible laboratory link to nondestructive analysis of in-situ pavement. Experimental test results demonstrated that the impact resonant method provided precise and reproducible results. Further experiments revealed that the impact resonant method could detect different magnitudes of microcrack healing.