Foam　concrete,　as　an　inorganic　cellular　material　possessing　exceptional　thermal　insulation　and　fire　resistance　properties,　emerges　as　a　promising　candidate　for　thermal　insulation.　To　achieve　a　more　precise　evaluation　of　its　performance　under　elevated　temperatures,　the　present　study　comprehensively　investigates　the　thermal　characteristics　of　foam　concrete　with　a　combined　experimental,　numerical,　and　theoretical　approach.　Firstly,　a　high-temperature　test　is　conducted　to　investigate　the　influence　of　temperature　and　foam　concrete　density　on　its　macroscopic　appearance　and　internal　temperature　distribution.　Meanwhile,　the　thermal　conductivity　of　foam　concrete　at　various　densities　and　temperatures　is　directly　measured　with　a　thermal　conductivity　analyzer.　Subsequently,　to　acquire　comprehensive　specific　heat　and　thermal　conductivity　parameters　of　foam　concrete,　with　a　numerical　model　established　within　ABAQUS,　the　genetic　algorithm　is　applied　to　identify　these　thermal　parameters　based　on　the　measurement　data　from　the　elevated　temperature　test.　In　addition,　CT　scanning　and　3D　reconstruction　of　foam　concrete　before　and　after　exposure　to　elevated　temperatures　are　utilized　to　extract　pore　characteristics.　This　facilitates　the　thermal　conductivity　calculation　using　theoretical　models,　enabling　the　determination　of　the　thermal　conductivity　of　foam　concrete　above　600　°C.　Through　a　comparison　of　the　experimental,　numerical,　and　theoretical　results,　it　is　recommended　to　consider　the　variation　of　specific　heat　in　three　dehydration　stages　due　to　the　observed　notable　dehydration.　Due　to　the　effect　of　cracks,　the　numerically　determined　thermal　conductivity　is　slightly　higher　compared　to　the　experimentally　and　theoretically　determined　thermal　conductivity.　Based　on　the　analysis,　an　improved　formula　predicting　the　specific　heat　of　foam　concrete,　and　a　formula　determining　the　thermal　conductivity　of　foam　concrete　subjected　to　elevated　temperature　are　proposed.　©　2023　Elsevier　Ltd