Analysis of IT-CY stiffness modulus of foamed bitumen asphalt concrete compacted at 95°C

Abstract

This study is to compare the results of temperature sensitivity tests of foamed bitumen asphalt concrete (AC 8) compacted at 95ºC with that of the reference mixture compacted at the conventional temperature of 140ºC. The tests and subsequent analysis confirm the advantageous effects the modification of bitumen 50/70 with 2.5% Fischer-Tropsch (FT) synthetic wax has on the characteristics of asphalt concrete. The characteristics investigated in this study included the air void content and moisture resistance of the specimens in one freezing cycle test (ITSR). Additionally, the relationships between air void content and stiffness moduli were investigated. The analysis of temperature sensitivity was conducted based on the measured indirect tensile stiffness modulus, Sm, (IT-CY) at -10ºC, 0ºC, 10ºC and 25ºC. The parameters of the asphalt concrete compacted at 95ºC made with FT wax modified foamed bitumen (FT=2.5%) are comparable to those of the reference mixture compacted at 45ºC.