Ternary　blended　cement　represents　a　promising　option　for　effectively　reducing　CO2　emissions　caused　by　cement　production.　This　study　examines　the　hydration　kinetics　of　ternary　cement　containing　ultrafine　steel　slag　(USS)　and　blast-furnace　slag　(BFS)　at　elevated　temperatures.　The　results　reveal　that　high-temperature　curing　significantly　accelerates　the　hydration　kinetics　of　the　ternary　cement.　The　governing　mechanism　of　the　hydration　reaction　evolves　with　increasing　temperature.　The　hydration　rate　at　60　℃　experiences　a　notable　acceleration,　accompanied　by　a　decrease　in　the　induction　period　and　an　enhancement　alumina　reaction,　transitioning　the　hydration　kinetics　from　NG→I→D　to　NG→D.　The　low　reactivity　and　inert　components　of　USS　lead　to　the　tendency　of　forming　a　relatively　loose　microstructure　of　hardened　paste.　In　contrast,　the　flocculent　C(-A)-S-H　gel　formed　after　incorporating　BFS　contributes　to　a　denser　and　more　uniform　microstructure,　owing　to　the　synergistic　hydration　effect　between　USS　and　BFS.　Moreover,　increasing　the　temperature　promotes　the　hydration　reactions　of　f-CaO　and　f-MgO,　thereby　enhancing　the　apparent　density　of　the　reaction　products　and　reducing　the　risk　caused　by　volume　instability.　The　findings　address　a　key　limitation　of　SS-based　binders　and　emphasizes　the　potential　of　USS-BFS　ternary　cement　as　a　sustainable　alternative　with　reduced　environmental　impact.　©　2025　Elsevier　Ltd