Variability of Air Voids and Mechanistic Properties of Plant-Produced Asphalt Mixtures

Abstract

The results of a laboratory and field evaluation of the variability of physical and mechanistic properties of plant-produced asphalt mixtures are presented. Three asphalt mixtures from two overlay rehabilitation projects were selected. Comparison analyses were conducted on density measurements between two laboratory (AASHTO T166 and ASTM D6752-02, or CoreLok) and one in situ (pavement quality indicator) test methods. In addition, two laboratory mechanistic tests—indirect tensile (IDT)-strength and frequency-sweep-at-constant-height tests—and two field nondestructive tests with falling weight deflectometer (FWD) and light falling weight deflectometer (LFWD) were performed to characterize the variability of the plant-produced mixtures evaluated in this study. Superpaver gyratory compactor (SGC) samples and field cores were used in the laboratory testing program. A strong correlation was observed between the two laboratory bulk specific gravity test methods: AASHTO T166 and CoreLok. The IDT strengths of SGC samples were higher than those of field cores. A good correlation was found between the complex shear moduli of SGC samples and field cores. Field test results indicated that the LFWD test may be used as an alternative to the FWD test in pavement structure evaluation.