The　objectives　of　this　study　are　to　explore　the　mechanism　of　the　self-healing　or　flow　of　asphalt　binder　on　the　surface　of　the　aggregates　and　evaluate　the　contact　angle　between　the　asphalt　binder　and　aggregates.　The　mastic　samples　(small　size)　were　prepared　with　asphalt　binder　and　fine　aggregates　of　a　small　size　(below　0.3　mm).　The　microscale　dynamic　X-ray　tomography　was　used　to　observe　the　flow　of　asphalt　binder　in　the　mastic　sample　at　353.15　K　(80　degrees　C)　using　the　Advanced　Photon　Source　(APS)　beamline　2-BM　at　Argonne　National　Laboratory.　The　activation　energy　for　flow　of　the　asphalt　binder　and　the　contact　angle　between　the　asphalt　binder　and　aggregates　were　analyzed　to　explain　the　self-healing　characteristics　of　the　asphalt　binder　materials.　The　Molecular　Dynamics　(MD)　method　was　employed　to　simulate　the　flow　process　of　the　molecules　of　asphalt　binder　at　different　temperatures　and　mimic　the　contact　angle　difference　between　the　asphalt　binder　and　aggregate　models.　Simultaneously,　in　the　laboratory,　the　contact　angle　goniometer　was　selected　to　measure　the　contact　angle　between　the　asphalt　binder　droplet　and　aggregates　at　different　temperatures.　The　results　of　tests　and　MD　simulations　show　that　(1)　asphalt　binder　diffused　after　heating　from　the　X-ray　images,　and　the　stages　and　mechanism　of　the　flow　process　of　asphalt　binder　on　aggregates　were　investigated;　(2)　low　contact　angle　was　observed　in　the　interface　model　of　asphalt　binder　and　aggregates　at　high　temperatures　using　the　MD　method.　The　wetting　condition　changed　from　partial　non-wetting　to　wetting　after　heating　in　the　interface　model;　(3)　contact　angle　results　between　the　asphalt　binder　and　aggregates　demonstrated　flow　steps　of　the　asphalt　binder　material.　The　test　data　was　also　compared　with　the　MD　simulation　results　at　different　temperatures.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.