In any case in which special assessments have been made, or shall hereafter be made, upon property for the construction of any improvement authorized by this Charter or previous statutes and several kinds of material have been named in the ordinance or ordinances providing for the same, and bids have been received for the construction of said improvements with any, either or all of said material, said assessments shall be valid and binding assessments, on the property so assessed. In the case of the construction of sewers required under the provisions of this Charter, notice of the passage of said resolution therefor, as provided for in Section sixty-four of this Charter, shall be given in the manner provided for in said section of this act.