Abstract: Fluidizing agents for hydraulic bonding materials such as, for example, concrete, cements, anhydrites, plasters, limes, or others. The fluidizing agents comprise the water soluble condensation reaction products of aminosulfonic acids, having one or more aromatic nuclei, or a mixture thereof; polyamino products including polyamino acids, polyamides, or polythioamides, or their mono- or polymethylol derivatives, and polyamino derivatives of triazine; and formaldehyde or compounds which generate formaldehyde under reaction conditions. The water soluble fluidizing agents permit a reduction of the quantity of water required for mixing the bonding materials and provide an increased mechanical resistance thereto. The invention includes the bonding materials containing the fluidizing agent, the method of using the fluidizing agents in bonding materials, and method of forming the bonding materials.