Research On Pavement Performances Of TLA Modified Asphalt Mortar

In modern mortar theory, it is the asphalt mortar, rather than asphalt alone, that has the binding effect in asphalt mixture. TLA can significantly increase the performances of asphalt mixture through improving asphalt binder. Therefore, it is necessary to research the pavement performances of TLA modified asphalt mortar, such as high temperature performance, low temperature performance, construction performance, temperature susceptibility and aging property.The testing indexes of DSR are applied to stand for high temperature performance of TLA modified asphalt mortar. It can be inferred from the parameters impact of the DSR instrument on G*/sinδ, when deciding the experiment conditions,τandω, consideration should be given to the actual traffic circumstance. Under different experiment conditions, G*/sinδof different mortar are tested. It is found that G*/sinδincreases exponentially with the increase of mixing amount of TLA and the ratio of filler to bitumen, while TTG*/sinδand TTS quadraticly. Moreover, in the research of high temperature performance, the appropriate mixing amount of TLA and the ratio of filler to bitumen are 30% to 40% and 0.8 to 1.2 respectively.The results of BBR and force-ductility tests are used to demonstrate the low temperature performance of TLA modified asphalt mortar. With the increase of mixing amount of TLA and the ratio of filler to bitumen, S increases according to the formula S=AeBX, while changes in m is not obvious; ductility and toughness ratio decrease, while peak forces, tensile flexibility and yield strain energy increase. Moreover, in the research of low temperature performance, the appropriate mixing amount of TLA and the ratio of filler to bitumen are 30% to 40% and 1.0 to 1.2 respectively. Finally, it is found that BBR and force-ductility are well correlated and replaced each other.The analysis on viscosities of TLA modified asphalt mortar which is tested by Brookfield rotary viscometer, implied that the viscosities should be designated to be the initial value with no more than 1/200 attenuation. It is found that viscosities rise with the increase of rotating speed and temperature by power function, and with the increase of mixing amount of TLA and the ratio of filler to bitumen exponentially. The method of deciding the construction temperature of TLA modified asphalt mixture based on the mortar is produced accordingly. The construction temperature for different TLA modified asphalt mortar is calculated to obtain the linear regularity between the construction temperature and the mixing amount of TLA and the ratio of filler to bitumen. Therefore, the construction temperature for different TLA modified asphalt mixture can be forecasted with the regularity.The temperature susceptibility of TLA modified asphalt mortar is divided into high temperature sensitivity and low temperature sensitivity to evaluate, respectively. The viscosity temperature index VTS and the temperature sensitivity coefficient based on G*/sinδandηare used to represent the high temperature sensitivity. The optimal amount of TLA is 30%~40% based on the high temperature sensitivity. The force-ductility TS is used to represent low temperature sensitivity, and the most reasonable range of ratio of filler to bitumen is 1.0~1.2. Moreover, both of the high temperature sensitivity and the low temperature sensitivity decrease with the increase of the mixing amount of TLA and the ratio of filler to bitumen.Tests on the pavement performances of different TLA modified asphalt mortar after aging with RTFOT and PAV show that the influence ratio of the aging on performances increases at first and then decreases with the amount of TLA and the ratio of filler to bitumen. Therefore, the optimal amount of TLA and the ratio of filler to bitumen is 30% and 0.8~1.0 based on high temperature performance, 40% and 1.0 based on low temperature performance, 30% and 1.0 based on high temperature sensitivity, 40% and 1.0 based on low temperature sensitivity, respectively.Therefore, the researches of pavement performances on TLA modified asphalt mortar have great significances for the design and construction of the TLA modified asphalt pavement.