Abstract:

Waste tire ground （wTG）， recycled polyethylene （rPE）， and recycled polypropylene （rPP） are typical waste polymeric materials with large output. The applications of these waste materials in traffic construction not only can reduce their pollution to the environment but also improve the performance of asphalt pavement to a certain extent. In this sense， a ternary blending modifier （TM） was prepared by incorporating different amounts of wTG into the matrix of rPE and rPP at a mass ratio of 3/2. The effect of TM on the properties of modified asphalts and its mixtures （AC⁃13） was investigated. The experimental results indicated that the softening point of the TM⁃modified asphalts increased with an increase in the wTG content， but their penetration degree tended to decrease. Nevertheless， their ductility reached a maximum. The modification mechanism was analyzed by FTIR and microtopography. Furthermore， the high⁃temperature stability， low⁃temperature cracking resistance， water stability， and water permeability performance of the AC⁃13 modified asphalt mixtures with different contents of wTG were investigated. The results indicated that with an increase in the wTG content， the modified asphalt mixtures presented a rapid increase in the dynamic stability at first， and then the incremental rate tended to decrease. However， their low⁃temperature cracking resistance， water stability （freeze⁃thaw splitting strength ratio）， and water permeability resistance showed an increasing trend at first and then tended to decrease. In conclusion， the addition of 20 % wTG facilitates to improve the performance of the AC⁃13 modified asphalt mixtures under current experimental conditions. This study provides an important theoretical basis for the future engineering applications of this type of modified asphalt mixtures.

Key words: waste tire ground, recycled polyethylene, recycled polypropylene, asphalt, performance