795 707.13 -ACCELERATING ADMIXTURES FOR CONCRETE :
707.13.1 Acceptance Requirements for Approval of Accelerators: Accelerating
admixtures for concrete shall be non -chloride and shall be tested by NTPEP (National Transportation Product Evaluation Program). The NTPEP testing results shall meet the requireme nts of AASHTO M 194, Type C.
707.13.2 Performance Requirements for Concrete Accelerators:
707.13.2 1 -The effects of using accelerating admixtures may vary widely with different
types of cement, cement from different mills, aggregate proportions, aggr egates from different sources and of different gradation, and changes in water -cement ratio. Therefore, no accelerator shall be used until the concrete of the specified class, designed in accordance with these Specifications and made with the ingredients proposed for use by the Contractor, including Type C admixtures as specified or permitted under this Specification, is shown to meet the requirements of AASHTO M 194 for compressive strength at ages 3, 7, and 28 days.
707.13.2 2 -The mix shall contain the quantity of admixture recommended by the
manufacturer at the prevailing temperature.
707.13.3 Certification of Accelerating Admixtures: When a Contractor proposes to use
an approved accelerating admixture, the procedure set forth in subsection 707.2.4 shall apply.
707.13.4 Additional Test Requirements for Accelerating Admixtures (Optional):
Either prior to or at any time during construction, the Engineer may require the selected admixture to be tested further to determine its effect on the strength of the concrete. When so tested, the accelerator shall meet the requirements specified in subsection 707.13.2.
707.14 Water -Reducing and Accelerating Admixtures for Concrete :
707.14.1 Acceptance Requirements for Approval of Water -Reducing and
Accelerating Admixtures: Water -reducing and accelerating admixtures for concrete shall be tested by NTPEP (National T ransportation Product Evaluation Program). The NTPEP testing results shall meet the requirements of AASHTO M 194, Type E.
707.14.2 Performance Requirements for Concrete Water -Reducing and Accelerating
Admixtures:
707.14.2 1 -The effects of using water -reducing and accelerating admixtures may vary
widely with different types of cement, cement from different mills, aggregate proportions, aggregates from different sources and of different gradation, and changes in water -cement ratio. Therefore, no water -reducing accelerator shall be used until the concrete of the specified class, designed in accordance with these Specifications and made with the ingredients proposed for use by the Contractor, including Type E admixtures as specified or permitted under thi s 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.
707.14.2 2 -The mix shall contain the quantity of admixture recommended by the
manufacturer at the prevail ing temperature. 796 707.14.3 -Certification of Water -Reducing and Accelerating Admixtures: When a Contractor proposes to use an approved water -reducing and accelerating admixture, the procedure set forth in 707.2.4 shall apply.
707.14.4 Additional Test Requirements for Water -Reducing and Accelerating
Admixtures (Optional): Either prior to or at any time during construction, the Engineer may require the selected admixture to be tested further to determine its effect on the streng th of the concrete. When so tested, the water -reducing accelerator shall meet the requirements specified in 707.14.2.
707.15 Hydration Control Stabilizing Admixtures for Concrete :
707.15.1 Acceptance Requirements for Approval of Hydration Control Stabilizing
Admixtures: Water -reducing and accelerating admixtures for concrete shall be tested by NTPEP (National Trans portation Product Evaluation Program). The NTPEP testing results shall meet the requirements of AASHTO M 194, Type B or D .
707.15.2 Performance Requirements for Concrete Hydration Control Stabilizing
Admixtures:
707.15.2 1 -The effects of using hydrat ion control stabilizing admixtures may vary
widely with different types of cement, cement from different mills, aggregate proportions, aggregates from different sources and of different gradation, and changes in water -cement ratio. Therefore, no hydration control stabilizing admixture shall be used until the concrete of the specified class, designed in accordance with these Specifications and made with the ingredients proposed for use by the Contractor, including hydration control stabilizing 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.
707.15.2 2 -In order for a concrete mix design, containing a hydration control stabilizing
admixture, to be considered for the allowable concrete discharge time extension for excessive haul time, as outlined in Section 601.7, the additional following extended discharg e time testing is required in that subject mix design. Upon completion of the mixing of at least one of the trial batches at the minimum cement factor, for the subject mix design, as required in MP 711.03.23, air content and slump tests in accordance wi th Section 601.4.1 shall be performed on that trial batch of plastic concrete. A test to establish the initial and final times of setting of the concrete mix shall also be performed, in accordance with ASTM C403. The air content and slump tests shall the n be repeated at 45 -minute intervals, until a period of 3 -hours after the completion of mixing has elapsed. The value obtained by any of the air content tests during the 3 -hour period shall not vary, from the value obtained by the initial air content tes t, by more than 2.5 percentage points. The value obtained by any of the slump tests during the 3 -hour period shall not vary, from the value obtained by the initial slump test, by more than 1.75 inches. The results of all these tests shall be included, al ong with all the other information required in MP 711.03.23, when the subject mix design is submitted for approval. When more than one mix design, for the same Producer/Supplier, is submitted for approval on the same day, only one set of extended discharg e time tests, as outlined in