Fatigue properties of composite polyphosphoric acid modified asphalt mixture

The fatigue behavior of the polyphosphoric acid (PPA)-styrene-butaniene-styrene block copolymer(SBS) composite modified asphalt mixture was studied by considering the influence of different test temperatures and different strain levels. The fatigue behavior of the PPA-SBS modified asphalt mixture was compared with that of the SBS modified asphalt mixture. Results show that under the same conditions, the residual stiffness modulus of PPA-SBS modified asphalt mixture is smaller than that of SBS modified asphalt mixture.The same result is also shown in damage factor, the average change rate of dissipation energy in the stable stage and fatigue damage evolution, meaning the fatigue performance of PPA-SBS modified asphalt mixture is better; At the same temperature, the greater the strain level is, the smaller the residual stiffness modulus ratio is. Similarly, the large strain level brings a larger damage factor and average value of the stable rate of dissipation energy, which means severe fatigue damage evolution and worse fatigue resistance; At the same strain level, the anti-fatigue performance of the asphalt mixture specimen at the temperature of 10℃ is better than that of 15℃.