Thirty-six　pullout　tests,　including　twelve　groups　of　three　specimens,　were　performed　to　study　the　bond　behavior　of　steel　reinforcement　in　concrete　containing　ferronickel　slag　and　blast　furnace　slag　powder　(F-S　powder/concrete).　Test　parameters　considered　in　this　research　were　F-S　powder　replacement　percentages　(i.e.,　0%,　10%,　20%,　30%,　40%,　and　50%)　and　concrete　strength　grades　(i.e.,　C30　and　C35).　Unexpectedly,　the　results　showed　that　the　bond　quality　of　steel　reinforcement　in　F-S　concrete　was　inferior　to　that　of　normal　concrete　even　with　comparable　concrete　strength.　The　more　F-S　powder　content,　the　greater　the　inferiority.　Through　investigating　the　underlying　mechanism,　it　was　found　that　bleeding　adversely　affected　the　reinforcement-concrete　bond　quality　in　F-S　concrete.　Based　on　the　pullout　test　results,　a　bond　stress-slip　relationship　and　an　anchorage　length　modifying　factor　were　proposed　for　F-S　concrete　of　C30　and　C35　strength　grade.　The　conclusions　would　help　designers　assess　the　suitability　of　a　particular　F-S　concrete　for　use　in　a　given　structure.　©　2020　Elsevier　Ltd