Fatigue test setups and analysis methods for asphalt mixture: A state-of-the-art review

Fatigue performance evaluation on asphalt mixture provides an essential reference for asphalt mixture design and pavement structure design.Laboratory fatigue test has been widely used by researchers and engineers to assess the fatigue performance of asphalt mixture,due to its low cost,high efficiency,and strong operability.To ensure performance assessment reliability,fatigue test operated in the laboratory needs to simulate the loading and environmental conditions occurring in the field asphalt layer.As a result,loading setups in laboratory fatigue tests,including loading mode,loading frequency,loading waveform,temperature,and the controlled mode,have been carefully devised by researchers.This paper reviews the above common setups in fatigue tests,which aims to illustrate the classical and latest considerations as well as ideas proposed by researchers for improving fatigue test procedures.As fatigue response data of asphalt mixture is measured from fatigue test,an analysis method is required to process the data and identify fatigue behaviors of the material.Presently,the frequently-used fatigue data analysis methods include the fatigue life model,stiffness-modulus-based method,energy-based method,and viscoelastic continuum damage(VECD)method.This paper also provides a review survey on the main concepts,indicators,and models included in those methods to facilitate their applications.Meanwhile,the latest research progress and outputs related to the four methods are also introduced and discussed to reveal the state-of-the-art developments in this research area.

Research progress on supramolecular structures of asphalt

The properties of asphalt binder play an essential role in the design life of asphalt pavement.Analysis of asphalt mechanical behaviors based on the chemical structures provides the theoretical basis for the improvement of asphalt performance in service life.Intermolecular interactions have a significant impact on the macroscopic properties of asphalt,a colloidal material,resulting in the parameters characterizing asphalt molecular structures fail to directly connect with mechanical properties of asphalt.This paper introduces the supramolecular theory,presents a brief review of existing supramolecular models and research methods of asphalt,aiming to explore a new methodology for the investigation between asphalt microstructures and macroscopic properties.Results showed the supramolecular theory focuses on the intermolecular interactions,providing more accurate indicators for the investigation on the asphalt supramolecules.Supramolecular analysis of asphalt has proposed feasible methods and established favorable connections with asphalt properties,giving a new view of understanding asphalt microstructure and a new approach to capture mechanical behaviors of asphalt.