Abstract: To further modify the high cost and technical defects of asphalt separately modified with nano-calcium carbonate （nano-CaCO3） and waste polyethylene （WPE）， the nano-CaCO3/TTS/WPE composite modifier （CTW） and CTW-modified asphalt were prepared through melt extrusion using isopropyl triisostearyl phthalate （TTS） as a coupling agent. The influence of TTS content on the properties of CTW-modified asphalt was studied， and the modification mechanism was analyzed. The analysis of conventional indexes indicated that the softening point， elongation， and viscosity of the CTW-modified asphalt increased at first and then kept stable with an increase in the TTS content. However， the penetration degree exhibited an opposite change. According the investigation on the dynamic shear rheology and low temperature properties， a certain amount of TTS was conducive to improving the high- and low-temperature properties of the CTW-modified asphalt. Meanwhile， microtopography and mechanism analysis was carried out for the above-mentioned changes in the properties， and the results indicated that the physical and chemical interactions between different contents of TTS and nano-CaCO3/WPE/asphalt led to the performance changes of the CTW-modified asphalt.

Key words: nano-calcium carbonate, isopropyl triisostearoyltitanate, waste polyethylene, asphalt, property, mechanism