ABSTRACT
Based on the existing fatigue evaluation methods and evaluation indexes of asphalt, Fatigue Factor test, Time Sweep test controlled by constant strain and Liner Amplitude Sweep test were conducted on different recycled asphalts. Fatigue properties and applicability of fatigue evaluation methods and indexes of recycled asphalt were investigated. Also difference mechanism of anti-fatigue performance of recycled asphalts was analyzed by conducting FTIR test and analyzing master curves results. Results showed that fatigue factor test and Fatigue factor couldn’t be recommended as the fatigue evaluation method and index of recycled asphalt. Considering definite physical meaning and sensibility to regenerant content, Nf3 -fatigue performance parameter index was recommended as the fatigue evaluation index of recycled asphalt and fatigue life could be considered to determine the regenerant content, so an optimal and a maximum regenerant content were from 2% to 4% and 6% respectively; FTIR results suggested that there were existing obvious distinctions between regenerant and asphalt but no chemical reaction between them. And the difference of fatigue property of recycled asphalt was influenced by alkanes stretching vibration absorption peak area from 2923 cm−1 to 2924 cm−1 and alkanes bending vibration absorption peak area at 1461 cm−1 and 1671 cm−1. Also Complex modulus and phase angle significantly influenced the fatigue property of recycled asphalt. A better fatigue life would appeare when complex modulus was at an intermediate range, smaller phase angle at intermediate frequency segment meant a better fatigue life.
