As　a　new　composite　material　by　adding　ceramsite　into　foam　concrete,　lightweight　aggregate　foam　concrete　(LWAFC),　mainly　composed　of　cement,　water,　performed　foam,　and　ceramsite,　exhibits　excellent　compressive　performance.　To　facilitate　its　application　in　structure　protection　where　energy　absorption　is　concerned,　the　responses　of　ceramsite　foam　concrete　were　investigated　experimentally　and　numerically　with　meso-scale　model.　First,　a　compression　test　(loading　rate　of　5　mm/min)　on　cubic　LWAFC　specimens　with　side　length　of　100　mm　was　conducted,　in　which　two　different　failure　modes,　namely　foam　concrete　failure　and　through-ceramsite　failure,　were　observed.　Meanwhile,　it　was　found　that　the　compressive　strength　of　LWAFC　specimens　increased　with　increasing　foam　concrete　density.　Based　on　synchrotron　radiation　CT　on　foam　concrete,　a　two-dimensional　meso-scale　numerical　model　with　size　of　100　x　100　mm　was　established.　The　failure　mode,　compressive　strength,　plateau　stress,　and　energy　absorption　capacity　of　the　LWAFC　with　an　averaged　loading　rate　of　1　m/s　were　systematically　investigated.　In　particular,　the　underlying　mechanism　for　the　two　distinctive　failure　modes　was　revealed　as　the　strength　match　between　the　foam　concrete　and　ceramsite.　Subsequently,　the　performance　of　LWAFC　was　significantly　improved　by　reasonably　designing　the　foam　concrete　and　ceramsite　with　optimized　strength　match.　(c)　2021　The　Author(s).　Published　by　Elsevier　Ltd.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(http://creativecommons.org/licenses/by-nc-nd/4.0/).