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789 SECTION 707 CONCRETE ADMIXTURES, CURING AND COATING MATERIALS 707.1 -AIR-ENTRAINING ADMIXTURES FOR CONCRETE : 707.1.1 -Acceptance Requirements for Air -Entraining Admixtures: 707.1.1.1 -In the event that the Contractor elects to use an air -entraining admixture, evidence based on testing by NTPEP (National Transportation Product Evaluation Program) shall be submitted to the Division to show that the material conforms to the requirements of AASHTO M 154. Tests for bleeding, bond strength and volume change will not be required unless specifically called for in the Plans. 707.1.1.2 -An exception to the requirements in the preceding paragraph is the case of air-entraining admixtures which are manufactured by neutralizing Vinsol resin with caustic soda (sodium hydroxide). When the Contractor proposes to use such an admixture, the Contractor shall submit a certificate concerning the admixture is the following form: "This is to certify that the product (trade name) as manufactured and sold by the (company) is an aqueous solution of Vinsol resin that has been neutralized with sodium hydroxide. The ratio of sodium hydroxide to Vinsol resin is one part of sodium hydroxide to (number) parts of Vins ol resin. The percentage of solids based on the residue dried at 221F is (number). No other additive or chemical agent is present in this solution." 707.1.1.3 -When the Contractor proposes to use a air -entraining admixture which has been previously app roved, the Contractor shall submit a certification stating that the admixture is the same as that previously approved. If an admixture offered for use is essentially the same (with only minor differences in concentration) as another previously approved ma terial, a certification will be required stating that the product is essentially the same as the approved admixture and that no other admixture or chemical agent is present. 707.1.2 -Optional Acceptance Requirements for Air -Entraining Admixtures: 707.1. 2.1-The Division may elect to approve air -entraining admixtures as satisfactorily meeting acceptance requirements as outlined. If the Division chooses to exercise this option, then the acceptance requirements specified in subsection 707.1.1 above shall be modified as noted. 707.1.2.2 -The Division may develop a spectroscopic standard for an air -entraining admixture if such air -entraining admixture has previously been approved by the Division as satisfactorily meeting all the specification requirements as set forth in subsection 707.1.1. 707.1.2.3 -When a Contractor proposes to use an air -entraining admixture for which a spectroscopic standard has been developed, then the air -entraining admixture may be approved without further certification being made if a special analysis made on a representative sample of the admixture proposed for use on the project compares satisfactorily with the standard related thereto. 790 707.1.3 -Additional Test Requirements for Air -Entraining Admixtures (Optional): 707.1.3.1 -Either prior to or at any time during construction, the Engineer may require that the admixture selected by the Contractor be further tested to determine its effect upon the strength of the concrete. When so tested, the seven -day compressive strength of concrete made with the cement and aggregates in the proportions to be used in the work and containing the admixture under test is an amount sufficient to produce from four to seven percent (4-7%) entrained air in the plastic concrete shall be not less than 88 percent (88%) of the strength of concrete made with the same materials and with the same cement content and consistency but without the admixture. 707.1.3.2 -The percentage reduction in strength shall be calculated from the average strength of at least five (5) standard six (6) by twelve ( 12) inch cylinders of each type of concrete. Specimens shall be made and cured in the laboratory in accordance with the requirements of ASTM C192 and shall be tested in accordance with the requirements of ASTM C39. The percentage of entrained air shall be determined in accordance with the requirements of ASTM C231. 707.1.3.3 -Admixtures failing to meet the above requirements will be rejected. 707.2 -WATER -REDUCING AND RETARDING ADMIXTURES FOR CONCRETE : 707.2.1 -Acceptance Requirements for Approval of Retarders: Water reducing and retarding admixtures for concrete shall be tested by NTPEP (National Transportation Product Evaluation Program). The NTPEP testing results shall meet the requirements of AASHTO M 194, Type D or Type G. 707.2.2 -Performance Requirements for Concrete Retarders: 707.2.2.1 -The retarding effect caused by water -reducing and retarding admixtures may vary widely with different types of cement, cement from different mills, aggregates from different sources and of different gradatio n, and changes in water -cement ratio. Therefore, no retarder shall be used until the concrete of the specified class, designed in accordance with the Specifications and made with the ingredients proposed for use by the Contractor, including Type D or Type G admixtures as specified or permitted under this specification, is shown to meet the requirements of AASHTO M 194 for water reduction and compressive strength increases at ages 3, 7 and 28 days. When a Type G admixture is used for the sole purpose of in creasing the slump of the subject concrete mix (no water is removed when this admixture is added), the requirements of AASHTO M 194 for water reduction and compressive strength increases will be waived. When a Type G admixture is used for the sole purpose of increasing the slump of the subject concrete mix (no water is removed when this admixture is added), the requirements of AASHTO M 194 for water reduction and compressive strength increases will be waived. 707.2.2.2 -The mix shall contain the quantity of admixture recommended by the manufacturer at the prevailing temperature. 791 707.2.3 -Optional Performance Requirements for Concrete Retarders: 707.2.3.1 -The Division may elect to approve water -reducing and retarding admixtures as satisfactorily meeting performance requirements as outlined. If the Division chooses to exercise this option, then the performance tests specified in subsection 707.2.2 will be waived. 707.2.3.2 -The Division's testing laboratory may design concrete mixes in which various types and gradings of aggregates and various types of cements are used and in which water -reducing and retarding admixtures are used, the admixtures first havi ng met the acceptance requirements for approval of concrete retarders as specified in subsection 707.2.1. The water -reducing and retarding admixtures used in laboratory design mixes may be subjected to a spectral analysis, and a spectroscopic standard or a standard spectrograph may be developed if the admixture in combination with the particular type and grading of aggregate and the particular type of cement has met the performance requirements for water -reducing admixtures as specified in subsection 707.2 .2. 707.2.3.3 -When a Contractor proposes to use a water -reducing and retarding admixture with a type of grading of aggregate and a type of cement which was previously used in a laboratory design mix and for which a special standard is available, the reta rder may be approved on the basis of a spectral analysis made on a representative sample of the admixture proposed for use on the project if: