Investigation of Properties of Plant-Produced Reclaimed Asphalt Pavement Mixtures

TLDR

The study examined how varying reclaimed asphalt pavement (RAP) content influences the complex moduli of plant‑produced hot‑mix asphalt mixtures and recovered binders. RAP was incorporated at 15 %, 25 %, and 40 % (PG 64‑22) and at 25 % and 40 % (PG 58‑28) into plant‑produced HMA, with control samples; compacted specimens were tested for complex dynamic and shear moduli, low‑temperature creep compliance, and indirect tensile strength across three temperatures to estimate critical cracking temperature. Statistical analysis showed no significant differences in mean strength or complex modulus at 15 % and 25 % RAP, while 40 % RAP mixtures differed from controls only at higher test temperatures.

Abstract

The influence of reclaimed asphalt pavement (RAP) content on the mixture and recovered binder properties of plant-produced hot-mix asphalt (HMA) was examined by studying the complex moduli of RAP mixtures and binders. RAP was added at 15%, 25%, and 40% levels to HMA with PG 64-22 and at 25% and 40% levels to HMA with PG 58-28 binder. In addition, control mixture samples with PG 64-22 and no RAP were also collected and tested for comparison. Compacted specimens were tested to determine the complex dynamic moduli (|E * |) at three temperatures. Complex shear moduli (|G * |) of the binders recovered from these HMA samples, RAP samples, and original binders were determined at the same test temperatures. Low-temperature creep compliance and indirect tensile strength of the mixtures were also determined, and these results were used to estimate the critical cracking temperature of the pavement. Statistical analysis indicated that there were no differences in mean strength and |E * | of the mixtures at the 15% and 25% RAP levels. Some differences between the control mixture and the 40% RAP mixtures were found only at the higher test temperatures.