Study on rheological properties of asphalt binders for seamless expansion joints of bridges

ABSTRACT The seamless expansion joint has received considerable attention as a new type of bridge expansion joint owing to its good integrity and driving comfort. To satisfy the requirements of both deformation and road use, the high-temperature stability and low-temperature crack resistance of the asphalt binder for the seamless expansion joint are particularly important. In this study, a temperature scanning test, high-temperature creep test, and low-temperature stress relaxation test of Matrix 502 and Colas, as the asphalt binders in the seamless expansion joints of bridges, were performed before and after ageing using a dynamic shear rheometer. An analysis of the test results revealed that both asphalts had an outstanding stress-relaxation ability and resistance to high-temperature deformation. The maximum stress relaxation of modified asphalt coals with good performance was 83%, and the permanent deformation after short-term ageing was only 0.48%. Additionally, the technical indicators according to the Swiss Federal Road Office for seamless expansion joint road guidelines and the United States Strategic Highway Research Program applicable to the asphalt binder used in the seamless expansion joint of bridges were examined with focus on the development of cost-effective bituminous mixtures for seamless expansion joints.