Correlating damage and cracking with air (gas) permeability in concrete using the Brazilian tension test

•Using acoustic emission and digital image correlation in the indirect Brazilian tension test, damage and cracking can be correlated to gas permeability in concrete.•A microcrack size of 40 µm can distinguish between pre-cracking and post-peak behavior of concrete.•Gas permeability of concrete increases to almost half an order of magnitude in the pre-peak region.•Gas permeability of concrete increases to about six orders of magnitude during the progression of cracking in the post-peak region.