Abstract: Compound intended to be added to concrete mass for entraining air in the concrete, thus increasing frost-resistance of the hardened concrete. The compound consists of: cereal storage proteins from wheat, triticale, barley or rye; a reducing agent preferably in the form of FeSO.sub.4 in an amount adapted to the original properties of the cereal storage proteins to entrain air in the concrete mass during its mixing; an inert substance, preferably Portland cement or mineral powder in an amount adapted to the original capacity of the cereal storage proteins to entrain air in the concrete. By means of the reducing agent and the inert substance the compound is normalized to its effect to entrain air in the concrete irrespective of said original properties and capacity of the cereal storage proteins to entrain air in the concrete.