Assuming the digging mobs feature is working correctly zombies will dig through blocks to get to players after about ~30 seconds of not being able to reach them.
Here are the blocks (time is in seconds):
- - STONE:60
- - GRASS:30
- - DIRT:20
- - COBBLESTONE:60
- - WOOD:60
- - SAND:10
- - GRAVEL:10
- - HAY_BLOCK:600
- - LEAVES:10
- - GLASS:120
- - SANDSTONE:60
- - NOTE_BLOCK:120
- - PISTON_STICKY_BASE:600
- - PISTON_BASE:600
- - STEP:60
- - BOOKSHELF:600
- - WORKBENCH:60
- - WOOD_STAIRS:120
- - CHEST:300
- - COBBLESTONE_STAIRS:60
- - ICE:120
- - SNOW_BLOCK:10
- - NETHERRACK:5
- - SOUL_SAND:120
- - LOCKED_CHEST:120
- - THIN_GLASS:60
- - MELON_BLOCK:60
- - BRICK_STAIRS:60
- - SMOOTH_STAIRS:60
- - NETHER_FENCE:60
- - NETHER_BRICK_STAIRS:60
- - SANDSTONE_STAIRS:60
- - WOOD_DOUBLE_STEP:60
- - WOOD_STEP:60
- - SPRUCE_WOOD_STAIRS:60
- - BIRCH_WOOD_STAIRS:60
- - JUNGLE_WOOD_STAIRS:60
- - COBBLE_WALL:120
- - QUARTZ_BLOCK:600
- - STAINED_CLAY:60
- - ACACIA_DOOR:60
- - BIRCH_DOOR:60
- - DARK_OAK_DOOR:60
- - JUNGLE_DOOR:60
- - SPRUCE_DOOR:60
- - WOOD_DOOR:60
- - HARD_CLAY:600
