New Insights into the Layer Bond of Traffic Pavements Using a 2D and 3D Imaging Method
摘要
Hybrid construction methods consisting of asphalt and concrete layers are used as traffic reinforcement in the mass transit sector, highway construction, bridge construction, and airports. The bond between the layers is a decisive factor in transferring traffic loads. A lack of bond at the layer boundary can reduce the load-bearing capacity and therefore service life. Mechanical test methods are used to determine the quality of the bond. However, it is not possible to evaluate the effects of gluing and interlocking separately, which mainly affect the bond. For a complete understanding, it is important to quantify the components. This study uses imaging techniques to analyse the bond between concrete and asphalt. In particular, the structural composition of the bond is to be analysed, and the glueing is to be quantified. The 2D imaging method of asphalt petrology will be used to analyse the structure, and the 3D imaging method of high-resolution X-ray computed tomography (CT) will be used to quantify the contact surfaces between the layers. The investigations are carried out on test specimens with different base textures and different quantities of bitumen emulsions. The results show that the highest effect of glueing is achieved with the variant with a smooth texture and a high quantity of bitumen emulsion. The structural analysis results show that the void content at the layer boundary is dependent on the quantity of the bitumen emulsion. Overall, the two methods provide new insights into the structural composition of the composite and, for the first time, allow the effect of glueing to be quantified independently of other influencing factors. The findings can further develop the materials and provide a better understanding of the material behaviour at the layer bond.