Investigation of Factors Affecting Asphalt Pavement Recycling and Asphalt Compatibility

摘要

Both economic and environmental factors dictate that asphalt pavement be recycled. Many recycling projects have been completed using a variety of recycling additives, but little work has been done on the physiochemical aspects of pavement recycling. The present exploratory study was undertaken to better define the physiochemical variables of recycling. Objectives of the present study include: (1) to determine if molecular structuring in the asphalt binder could be observed in oxidized (air-aged) asphalt-aggregate briquets, and if so, how was structuring affected during briquits, and if so, how was structuring affected during briquet recycling and (2) to determine if recycling agents penetrate the strongly adsorbed asphalt layer on the aggregate surface. Differences were seen in asphalt component compatibility as judged by the state of peptization parameters. In extreme cases the values of the parameters correlated with properties of asphalts of known compatibility; however, a relationship between the parameters determined on a series of asphalts in pavements was not established. The parameters might be useful in evaluating additives for pavement recycling; however, more systems need to be studied to fully assess their potential usefulness. Finally, the parameters need to be correlated with performance-related measurements such as asphalt rheological and mix properties. Examination of the parameters and their changes on asphalt oxidative aging may also be informative with regard to asphalt durability inasmuch as oxidation-induced changes are a major cause of asphalt pavement failure. (ERA citation 08:025534)