Abstract. The paper focuses on the problems of concrete for watertight tunnel lining. The theme iscurrently quite topical in the Czech Republic and abroad. The accent is put particularly ondetermination of level of dependence of different parameters of aeration of fresh and hardenedconcrete (determined in accordance with standardized procedures in common use) and durability ofthe concrete based on observation of properties of aerated concrete. Fluctuation of values of aircontent in hardened and fresh concrete are observed as well as influence of this fluctuation ondurability of concrete.