Influence of gradation on volume characteristics and engineering performance of asphalt mixture

Extending the service life of asphalt pavements was an effective way to be a green environment and conserve resources. Gradation significantly affects the service life of asphalt mixtures. This paper aimed to investigate the influence of gradation on micro properties and the engineering performance of the mixture. Four representative gradations in the gradation range of AC-16 were selected. The fractal dimensional was used to characterize the quality distribution properties of the aggregates. The sensitivity of the Marshall index of the different graded mixtures to the asphalt aggregate ratio was investigated. CT scan tests were carried out to study the distribution pattern of microscopic properties. The high-temperature performance, low-temperature performance, water stability performance, indirect tensile strength, and fatigue performance of the four mixtures were also tested. The findings suggest that the effective asphalt aggregate ratio range differed for different gradation mixtures. The optimum asphalt aggregate ratio should be determined by settings the appropriate asphalt aggregate ratio step size. The fractal model can well characterize the quality distribution of aggregates. The larger the fractal dimension value, the smaller the air voids, and the higher the number of contact points of the mixture, hightemperature performance, strength, and fatigue performance. The low-temperature performance showed the opposite pattern. The water stability performance was not linearly related to the fractal dimension value. The performance of the mixture can be preliminarily predicted by analyzing the fractal dimension of the gradation.