Evaluation of High-Temperature Creep Deformation Properties of Warm-Mix Recycled Asphalt Mixture Based on Improved Flow Number

Abstract

To calculate a more accurate flow number (FN) to evaluate the effects of temperature, long-term aging, and salt freeze-thaw cycles on the high-temperature creep deformation characteristics of warm-mix recycled asphalt mixture (WRAM). This paper uses WRAM with different recycled asphalt pavement (RAP) old material contents (0%, 30%, 50%, and 70%) as the research object. The shortcomings of the cut line minimum method were analyzed, and based on this, a two-step slope of the cut line minimum method based on different interval coefficients (P) was proposed. In addition, this method was also compared with the four common methods. The results show that all five methods can solve the FN accurately, but the two-step slope of the cut line minimum method is better than the four common methods. When the P value is 0.99, 0.97, and 0.95, the method can find the accurate and unique FN, which is easy to operate and practical. According to the high-temperature evaluation indexes (creep rate b and improved FN), temperature and salt freeze-thaw cycles reduce the high-temperature creep deformation resistance of WRAM, while long-term aging will promote the high-temperature creep deformation resistance ability. Compared with traditional hot-mix asphalt mixture (HAM), WRAM is more excellent in high-temperature creep deformation resistance, aging resistance, and salt freeze-thaw cycles damage resistance.