Abstract The natural weather aging test (NWAT) for asphalt binders is an essential benchmark aging test used to investigate the aging evolution of asphalt binders under actual weather conditions. This study assessed the aging rates of olive pomace–modified asphalt binders and the control neat binder under NWAT. Instead of aging days, weather factors were proposed as metrics to correlate with the aging evolution of the rheological properties of asphalt binders. The test results showed that the olive pulp–rich fraction-modified asphalt binders after the rolling thin-film oven (RTFO) test had lower aging susceptibility than the RTFO-aged control binder. The RTFO-aged binders exhibited lower aging rates than the corresponding unaged asphalt binders under NWAT. The sums of weather indexes such as the sum of the daily maximum ultraviolet index are rational field metrics to correlate with the rheological aging properties of natural weather–aged asphalt binders. Caution shall be taken when using aging days to interpret the aging rates of asphalt binders under NWAT.
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