To　study　the　damage　mechanical　properties　of　a　recycled　aggregate　concrete　(RAC)　prism,　several　two-dimensional　random　models　of　RAC　were　established.　The　numerical　models　were　subjected　to　uniaxial　compressive　loading　and　the　failure　mechanism　of　the　RAC　prism　was　analysed　based　on　the　base　force　element　method.　Further,　the　influence　of　the　prism　height　on　the　stress-strain　curves,　the　crack　pattern,　and　the　stress/strain　distribution　was　investigated.　In　addition,　the　effects　of　the　aggregate　content　and　the　old　cement　mortar　thickness　of　a　single　aggregate　on　the　crack　pattern　were　studied.　Simulation　results　demonstrate　that,　with　the　increase　of　the　prism　height　from　100　to　400　mm,　both　compressive　strength　and　peak　strain　are　reduced　by　9%;　however,　the　ultimate　strain　reduction　reached　56%.　The　stress/strain　distribution　was　discontinuous,　and　the　tensile　stress　concentration　phenomenon　appeared　in　the　cross-section,　especially　in　the　interfacial　transition　zones　(ITZs)　of　aggregate　dense　areas.　With　the　old　cement　mortar　thickness　increase,　the　aggregate　stress　decreased　and　gradually　transferred　to　the　old　cement　mortar　zone,　and　the　initial　crack　shifted　from　new　ITZ　to　old　ITZ.　Finally,　several　isolated　cracks　formed　in　the　old　cement　mortar　zones　instead　of　continuous　cracks　in　the　new　cement　mortar　zones.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.