In　this　paper,　three　alkaline　activators,　namely　sodium　hydroxide　(SH),　calcium　oxide　and　sodium　carbonate　(COSC),　calcium　hydroxide　and　sodium　sulfate　(CHSS),　and　the　influence　of　different　alkali　equivalents　on　the　carbonation　resistance　of　alkali-activated　slag　concrete　(AASC)　were　investigated.　By　testing　the　mechanical　properties　at　different　carbonation　ages　of　AASC　with　three　types　of　activators　at　varying　alkali　equivalents　(4%,　6%,　and　8%),　along　with　the　changes　in　carbonation　depth,　this　study　aims　to　characterize　hydration　products　and　porosity　through　microstructural　analysis.　The　objective　is　to　explain　the　mechanism　by　which　carbonation　affects　the　AASC　structure.　The　findings　showed　that　the　carbonation　rate　(i.e.,　the　growth　rate　of　the　carbonation　depth)　of　AASC　was　CHSS　＞　COSC　＞　SH　when　the　exciter　dosages　were　the　same,　and　the　carbonation　rate　of　all　samples　tended　to　slow　down　as　the　alkali　components　increased.　Calcite　and　spherulite　were　the　calcium　carbonate　morphologies　after　SH,　COSC,　and　CHSS　carbonation　according　to　XRD,　TG/DSC,　and　pore　structure　tests;　the　calcium　carbonate　content　decreased　with　increasing　alkali　equivalent　after　carbonation.　Since　the　pore-increasing　effect　of　carbonation　due　to　the　destruction　of　C–S–H　is　weaker　than　the　filling　effect　produced　by　calcium　carbonate,　the　total　pore　volume　of　SH,　COSC,　and　CHSS　decreased　due　to　the　activator　effect　after　carbonation.　Specifically,　the　calcium　carbonate　created　by　carbonation　repairs　pores　and　cracks　of　matrix,　but　its　presence　also　reduces　the　calcium　hydroxide　concentration,　leading　to　a　decrease　in　the　alkalinity　of　the　pore　solution,　which　disrupts　the　structure　of　the　hydration　products　and　loosens　the　matrix.　The　focus　is　on　which　aspect　is　more　decisive.　Interestingly,　small　pores　however　decreased,　while　there　was　an　increase　in　larger　pore　sizes　resulting　in　a　change　in　pore　size　distribution.　However,　this　negative　impact　on　pore　distribution　decreased　with　increasing　alkali　dosage.　©　2024　Elsevier　Ltd