ABSTRACT
The morphology and size of polymer phase affect the storage stability and engineering performance of polymer modified asphalt (PMA). Polymer phase in PMA is commonly investigated by using fluorescence microscopy (FM). However, some studies suggest that the two-dimensional (2D) images obtained from FM cannot reveal the real internal structure of polymer phase in PMA, because 2D images are formed by the projection of the three-dimensional (3D) polymer phase on a 2D plane. Using confocal fluorescence microscopy and image processing techniques, this study reconstructed the polymer phase in PMA of various polymer concentration. The research results indicate that the polymer phase likely increases to about 2.5 times by volume after being mixed with asphalt binder, and connected polymer network is not formed. Compared with the reconstructed 3D images, the 2D images would overestimate the swell effect and misinterpret the morphology of polymer phase in PMA.
