ZL Research Group

Welcome to Dr. Zhen Leng's Research Group

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Sustainable Pavement Materials


Sustainable Pavement Materials and Technologies


Recycled from waste tires, crumb rubber modifier (CRM) is added into bitumen to produce the rubberized asphalt with superior performances and several environmental benefits. Rubberized asphalt pavement can be categorized in to dry process and wet process, which can be further divided into the Asphalt Rubber (AR) and Terminal Blend (TB). Our research group has paved one trial sections of warm asphalt rubber pavement in Fo Tan Road, Hong Kong, which has shown outstanding performance and noise-reduction effect. Our research group now is focusing on the aging and recycling mechanisms of asphalt rubber pavement and the development of more advanced rubberized asphalt technologies.


Reactive resins, such as epoxy resin and polyurethane, are widely used in composites, coatings, and high-end functional materials. In pavement engineering, epoxy resin has been used to manufacturing high-performance paving material for airfield runways and steel bridge decks. Polyurethane recently has emerged as a strong modifier or bonding material in pavement construction. Both epoxy resin and polyurethane can improve the high-temperature performance, resistance to moisture damage, and fatigue properties of asphalt pavement. Our research team is devoted to the development of a new generation of high-performance paving material for steel bridge paving, pavement anti-skid sealing, etc., which will significantly improve the durability and resilience of the transportation


Waste plastic pollution is one of the most pressing environmental problems worldwide, and this problem is especially prominent in high-density cities like Hong Kong. Among various waste plastic recycling methods, reusing them or their derived products in roadway construction has recently emerged as an attractive option. Our recent research mainly focuses on the advanced recycling of waste plastic (e.g. PET bottle, PP mask, PE film) and value-added additive development for asphalt pavement and their environmental assessment. We also explore the impact of environmental factors, such as moisture, high temperature, UV, and oxidation on the modified asphalt, to find a better way to improve the anti-strip, high-temperature, and long-term fatigue life of asphalt pavement.