Corrosion　of　steel　in　concrete　structures　is　one　of　the　main　causes　of　structural　durability　failure.　In　order　to　study　the　rust　cracking　behavior　of　the　concrete　protective　layer,　a　three-dimensional　meso-scale　model　of　concrete　was　established.　In　the　approach,　the　concrete　was　regarded　as　a　three-phase　composite　composed　of　coarse　aggregates,　mortar　matrix　and　the　interfacial　transition　zones　(ITZs).　The　non-uniform　radial　displacement　method　was　used　to　characterize　the　mechanical　effect　of　steel　rust　on　the　surrounding　concretes.　The　cracking　behavior　of　concrete　cover　caused　by　non-uniform　corrosion　of　corner　reinforcement　was　simulated　based　on　the　meso-scale　method.　The　rust　expansion　pressures　on　the　surrounding　concretes　due　to　non-uniform　corrosion　of　corner　rebar　were　explored.　Moreover,　the　influences　of　steel　bar　diameter,　cover　thickness　and　corrosion　distribution　mode　on　the　cracking　of　cover　concrete　were　investigated.　The　simulation　results　indicate　that　the　non-uniform　rust　pattern　of　the　steel　bar　makes　rust　expansion　pressure　smaller　than　the　uniform　rust.　The　random　distribution　of　aggregates　has　little　effect　on　the　cracking　mode　of　the　concrete　protective　layer.　With　the　increase　of　the　ratio　of　the　thickness　of　concrete　cover　to　the　diameter　of　steel　bar,　the　maximum　rust　expansion　pressure　of　concrete　increases.　Bar　diameter　has　a　negligible　influence　on　the　cracking　pattern　of　concrete.　(C)　2020　Elsevier　Ltd.　All　rights　reserved.