Investigating the influence of aging and filler type on the fatigue behavior of bitumen mastics

In this study, the effects of 0.6, 0.8 and 1 wt ratio of limestone and silica fillers on the bitumen fatigue life were investigated using different dissipated energy parameters. Pure bitumen and mastics were prepared prior to fatigue test using RTFO and PAV devices for short and long term aging. Fatigue test was carried out using a time sweep method with a dynamic shear rheometer device at a temperature of 20 degrees, a frequency of 10 Hz and under strain loading of 2, 3.5 and 5 percent. Four criteria including; N-f50, N-p20, Nmax-delta and Nmax-S x N were used to examine fatigue damage of the laboratory samples as well as a sessile drop test to determine the surface energy. The results show that by adding limestone and silica fillers to bitumen, based on all criteria, fatigue life of the base bitumen is reduced and as a result dissipated energy is diminished. Due to increase in cohesion energy, lime mastics also have longer fatigue life than silica mastics at all strain levels and based on all fatigue criteria. The initial dissipated energy (IDE) in both cases of aging is a suitable criterion to predict fatigue life of bitumen mastics. Assessing the relationship between the plateau value (PV), the ratio of dissipated energy change (RDEC) and fatigue life of the samples, based on the N-f50 criterion, reveals that such relationship is completely unique and independent of the loading strain level, type of the bitumen mastic and how aging is applied. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The study investigated the effects of limestone and silica fillers on the fatigue life of bitumen, showing that the addition of fillers can reduce fatigue life and dissipated energy. Lime mastics have longer fatigue life than silica mastics due to an increase in cohesion energy. The initial dissipated energy (IDE) is a suitable criterion for predicting fatigue life of bitumen mastics.