The aging level of asphalt mix due to short-term aging (STA) during delivery was analyzed using aging quantity (AQ) model based on temperature (T) and time (t) of STA. AQ values for various STA conditions were computed and used for estimating absolute viscosity (AV) of the binder as aging index. The estimated AV (EAV) and measured AV from recovered binder showed an excellent correlation (R2 >0.9). Raising T of mix to maintain compaction T in cold weather was found to be a significant cause of expedited aging. Extended STA t due to traffic delay was another significant cause of aging. The AV of HMA binder for 1 h STA at 160oC was 400pa.s, which is identical to RTFO-run level. The AV was 801pa.s when the mix was kept for 1 h at 180oC, and AVs were 2,024 and 4,436 pa.s when the mix was kept for 2 and 3 h at 180oC, respectively. The AV levels are much higher than the AV (1,108 pa.s) of PAV-run binder. Therefore, if T of mix is elevated to 180oC, the STA time should not be over 1 h before paving. Since the result of over aging by STA is detrimental, the t and T should be controled to prevent premature service life reduction.

Asphalt, short-term aging, absolute viscosity, aging quantity model