2024 年 97 巻 3 号 p. 81-87
TPE/Asphalt gel shows a clear macroscopic structure and the corresponding characteristics that is quite suggestive to understand those of cross-linked rubber. TPE/Asphalt gel consist of co-continuous structure of TPE phase and asphalt phase, where the asphalts phases are enclosed in a thin eggshell-like bag of the TPE phases. In addition, the asphalt phases are bound together through small holes drilled on the surface of the eggshell-like bag (Fig.4). TPE/Asphalt gel has such characteristics that its stress-strain curve shows the S letter shape being similar that of the cross-linked rubber, where the stress increases greatly at a large extension ratio, called stress-upturn (Fig.5). The stress-upturn in the TPE/Asphalt gel is caused by the significant increase of the viscus effect generated when the asphalt flows through the narrow holes of the eggshell-like bag under large extension (Fig.11), where the compressed TPE bag makes the entrance and the exit of the holes much narrower (shown with dotted circles in Fig.12), which makes the flow of the asphalt faster and the viscosity of the asphalt higher significantly. Both the effects generate the drastic increase of the shear stress of the asphalt, resulting in the stress-upturn of the stress-strain curve of the TPE/ Asphalt gel (Fig.10 and Fig.13).
