This　paper　experimentally　investigated　the　bond　behavior　of　concrete-filled　square　steel　tubes　using　manufactured　sand　and　recycled　coarse　aggregate　(referred　to　as　MS-RCA-CFT).　A　total　of　48　specimens　were　tested　to　study　the　effect　of　the　following　parameters:　(i)　concrete　compressive　strength,　(ii)　widthto-thickness　ratio,　(iii)　stone　powder　content,　and　(iv)　type　of　sand.　The　test　results　indicated　that　MS-RCA-CFT　members　had　similar　bond　behavior　as　conventional　CFT　members.　The　bond　strength　increased　with　increasing　concrete　compressive　strength　and　decreasing　width-to-thickness　ratio.　Specimens　with　a　stone　powder　content　of　5%　to　10%　had　the　highest　bond　strength,　while　a　higher　stone　powder　content　(15%　and　20%)　had　a　negative　impact　on　the　bond　strength.　Specimens　with　manufactured　sand　exhibited　higher　bond　strength　compared　with　specimens　with　natural　sand.　The　bond　strength　of　MS-RCA-CFT　tested　in　this　research　was　compared　with　the　bond　strength　of　conventional　CFT　from　literature.　Applicability　of　several　design　codes　in　calculating　the　bond　strength　of　MS-RCA-CFT　members,　RCA-CFT　members,　and　conventional　CFT　members　was　evaluated.　Lastly,　an　analytical　model　for　the　bond-slip　curve　was　also　evaluated.　(C)　2020　Elsevier　Ltd.　All　rights　reserved.