Every contractor, including contracting owners, to whom is awarded a contract for street work hereunder, shall upon the execution of such contract file with said Director a bond, approved by him, in a sum not less than ½ of the total amount payable under the contract; such bond shall be executed by an authorized corporate surety able to justify in the manner provided by law; such bond must provide that if the contractor, or his, its or their sub-contractors, fail to pay for any materials or provisions, or the reasonable rental value of items, implements or machinery used in, upon, for or about the performance of the work contracted to be done, or for any work or labor of any kind done directly thereon or therefor, that the surety will pay the same, to an amount not exceeding the sum specified in such bond.