The　effect　of　different　aggregate　treatment　methods　on　the　properties　of　both　the　recycled　aggregate　and　the　recycled　concrete　was　studied.　In　this　work,　the　compressive　strength,　dynamic　elastic　modulus,　dry　shrinkage　rate,　and　chloride　ion　migration　coefficient　for　five　types　of　recycled　concretes　were　investigated.　Moreover,　the　Vickers　hardness　index　and　micro-morphology　of　new　and　old　interfaces　were　analyzed.　The　results　showed　that　＂carbonation＂　significantly　improved　the　mechanical　properties　and　the　dry　shrinkage　resistance　of　the　recycled　concrete.　However,　＂slurry　wrapping＂　greatly　enhanced　the　chloride　ion　penetration　resistance.　Different　aggregate　treatment　methods　had　different　mechanisms　to　strengthen　the　interface.　The　influence　of　＂carbonation＂　on　the　old　interfacial　zones　(ITZ)　was　more　significant　than　that　on　the　new　ITZ.　A　contrary　influence　of　the　＂slurry　wrapping＂　on　both　old　and　new　ITZs　was　observed.　The　old　interface　had　an　obvious　effect　on　the　compressive　strength　and　dynamic　elastic　modulus,　while　the　new　interface　with　different　treatments　had　a　non-negligible　influence　on　the　chloride　penetration　resistance.　Besides,　in　this　study,　two　optimization　methods　were　proposed　based　on　the　improvement　of　＂carbonation＂　and　＂slurry　wrapping＂　treatment,　respectively.　These　optimized　methods　can　further　improve　the　quality　of　recycled　aggregate　and　the　performance　of　recycled　concrete.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.