Search

Asphalt materials including binder, mortar, and mixture are extensively used in the field of pavement engineering considering their obvious viscoelastic properties. To study the phase-transition temperature (Tp) of asphalt materials, we apply dynamic mechanical analysis (DMA) to conduct several temperature-sweep mode tests and compare the Tp values among these materials with similar sizes. Meanwhile, 27 AC5 mixtures are tested to determine the impact of binder type, gradation and, binder content on Tp. Results indicate that the Tp of binder and mortar is negative, but that of mixture is positive. Good correlations among Tp of binder, mortar, and mixture with the same binder type are observed, showing that binder quality is the key factor affecting Tp. Gradation type also affects Tp, and the mixture with a finer gradation has a lower Tp. Among the AC5 asphalt mixtures, the Tp of AR mixture is lower than those of the others, thereby demonstrating better low-temperature performance.

Corresponding experiments were designed and accomplished to obtain the authentic mechanical response mechanism of pavement under different loading conditions. Replicability and reproducibility of the experiments were discussed in this paper. Meanwhile, the response mechanism for three typical pavement structures was analyzed. Results show that mechanical response test method for pavement structure has characteristics of good replicability, reproducibility, and reliability. The method can also be used as an effective way to investigate the mechanical response of pavement structures. The mechanical states of different pavement materials under the same test condition are quite different. For cement bound granular and asphalt concrete, radial strain changes as alternative compression-tension with obvious mechanical response characteristic. However, the situation is different for cement concrete. The region of pavement that is close to the surface is in compressive state. By contrast, the far region is in tensile state. Top-down cracking of pavement developed from top surface crack may appear when load is too heavy. The working state of pavement can be reflected by utilizing the mechanical response test method. The mechanical response test method is a good reference when calculating mechanical state and determining parameters of pavement material.