EVALUATION OF MODIFIED ASPHALT USING ACCELERATED PAVEMENT TESTING

Abstract

This paper introduces a full-scale accelerated pavement tester, HAPT (Hanyang Accelerated Pavement Tester), developed at Hanyang University in Korea. The first research using this tester, a comparison study of the resistance to permanent deformation between modified asphalt concrete and general dense grade asphalt concrete, was carried out. The objective of this test was to compare the resistance of general asphalt mixture and modified asphalt mixture to permanent deformation under the same experimental condition. One half of the test pit served as the control of this experiment, and it was paved with general asphalt mixture of 5cm in thickness. The other half of the test pit was paved with three different kinds of modified asphalt mixtures of the same thickness. The accelerated pavement testing evaluated the resistance to permanent deformation under three different temperature conditions (25-30, 40, 50℃). Additionally, DSR test, resilient test modulus, and wheel tracking test, were carried in the lab for the analyses. Results of the tests indicated that the most permanent deformation occurred in the control section of general dense grade asphalt mixture. Especially, the difference was more noticeable at higher temperature condition. The analyses of the resistance to permanent deformation revealed that it decreased rapidly as the temperature of the general dense grade asphalt increased. Additionally, G*/sinδ is verified as an important factor for permanent deformation. The result of the APT test and lab test showed that permanent deformation of general dense grade mixture was greater than that of modified asphalt mixture for all the case. Moreover, the difference was larger at higher temperature condition. However, the result was reversed for the resilent modulus in that the general dense grade mixture showed higher resilient modulus. From the result of this research, it can be confirmed that the resilient modulus can not be considered as a proper input variable for the estimation of layer coefficient in AASHTO pavement design guide