Study on Thixotropic Properties of Asphalt Mastics Based on Energy Viewpoint

Abstract

An asphalt mastic has thixotropic characteristics that significantly influence its fatigue and healing performance. Therefore, understanding the thixotropy of an asphalt mastic is clearly of great importance. However, research in this area is still in the early stages. This study focuses on self-heating as one of the biasing performances of asphalt material by analyzing the viscosity, stress, and hysteresis loops the of asphalt mastics under cyclic shear loading. Twelve types of asphalt mastics fabricated with asphalt, as well as different types of mineral filler, were selected to examine thixotropy. In addition, the filler/asphalt ratio was examined via the hysteresis technique to analyze the hysteresis loop and the viscosity–shear rate. The thixotropic potential function was also studied from the energy viewpoint. The results show that asphalt mastics with different asphalt binders, mineral fillers, and filler volume fractions showed hysteresis loops for shear stress versus shear rate diagrams. With an increase in the loading times of the cyclic load, the area of the hysteresis loop gradually decreases, and the hysteresis area most likely features a relatively stable value. The thixotropy of the asphalt can be significantly reduced by adding filler, and different types of mineral filler can slightly influence the thixotropy. The viscosity decreases with an increase in the shear rate, and it gradually recovers with a decrease in the shear rate. The greater the filler/asphalt ratio, the greater the viscosity, and the faster the viscosity’s descent is with the prolongation of time. Due to the existence of a higher amount of filler content, the recovery of a viscosity crack is more difficult. For asphalt mastics with high filler/asphalt ratios, the thixotropic mechanism can be explained via particle agglomeration and the depolymerization theory. For asphalt mastics with low and medium filler/asphalt ratios, the thixotropic mechanism can be explained via the particle chain theory. The damage and recovery of the internal structure of an asphalt mastic can be characterized by the structural failure potential function and the structural recovery potential function, respectively.

Mechanical Characterization of Asphalt Mixtures Based on Polymeric Resin and Thixotropic Filler as a Substitute for Bitumen

“…Due to the high percentage of mineral fillers, the effect of the thixotropy agent is reduced for formulations F1 to F7, and other filler-dominant effects are more pronounced. Moreover, the reduction of thixotropy in asphalt pavements was also shown in [25,26].…”

Feasibility of Carnauba Wax Rejuvenators for Asphalt Concrete with Vacuum Tower Bottom Binder

“…Its composition primarily consists of two components: asphaltene and maltene. Asphaltene, comprising 5%-25% of asphalt, is a high molecular weight compound with polar functional groups, such as carboxyl, alcohol, ketone, amine, and sulfur [13]. Maltene, on the other hand, has a relatively lower molecular weight and contributes to the workability of asphalt, being soluble in heptane [14].…”

Study on Thixotropy of Mastic Asphalt Binder and Asphalt Mastic

“…Virginie et al used cone-plate thixotropy test equipment to carry out the time scanning and stress scanning of asphalt, took composite modulus as the evaluation index of thixotropy, and studied the influence of test temperature, loading rate, and loading duration on thixotropy [22]. By analyzing the viscosity, stress, and hysteretic curve of asphalt mastic under cyclic shear load, Ma et al found that adding fillers can significantly reduce the thixotropy, and different types of mineral fillers have little effect on the thixotropy [23]. Hassan et al studied the thixotropy of two adhesives containing different fillers, and the thixotropy model of asphalt can be established by DSR [24].…”