§5-03 Approval of Prequalified Concrete Mixes

   (a)   Source of concrete mixes. Concrete proportioned according to prequalified mixes shall be produced only from batch plants, approved by the Commissioner pursuant to rules and regulations of the department.

   (b)   Mix designs not previously accepted. Each concrete producer or group of producers seeking approval of mix designs that have not been previously accepted by the Department shall file an application with the M.E.A. Division, Department of Buildings at the address provided in the City's website, http://www.nyc.gov, and shall furnish the following:

      (1)   A compilation of the proposed mix designs listing the batch weights, types of aggregates and other ingredients together with a numbering system that will provide identification of each mix for testing and recording purposes. Each compilation shall contain a title sheet upon which a master list of all the mixes shall be designated. Opposite each mix a space shall be provided for the signature of the examiner and the date of the approval of that particular mix. When a mix has been approved for use as a "PREQUALIFIED MIX," the examiner shall affix his signature and the date in the space provided, and then he shall affix the approval stamp of the Commissioner of Buildings.

      (2)   For each mix utilizing a different combination of aggregates, admixtures, cement type, water-cement ratio, etc., a report of preliminary trials made by a testing laboratory licensed under §26-200 together with an attestation by the Architect or Engineer who supervised the making of the preliminary tests.  The laboratory report shall include the following information:

         (i)   Fine and coarse aggregate.

            Type (natural or manufactured sand, gravel, stone, etc.).
            Weight per. cu. ft. dry rodded.
            Specific gravity.
            Percentage of voids.
            Percentage of absorption.
            Fineness modulus (see ASTM Definitions C125).
            Gradation and comparison to ASTM C-33; also size of coarse aggregate.

         (ii)   Cement-type.

         (iii)   Batch weights.

         (iv)   Admixtures-type and amount.

         (v)   Test results of each particular mix design being submitted for approval. Separate tests shall be made for each compressive strength.

         (vi)   Attestation of the Architect or Engineer engaged by the producer or producers to supervise the tests.

         (vii)   Board of Standards and Appeals Cal. No. for items requiring Board approval, such as lightweight aggregate admixtures, etc.

         (viii)   Such other information required by §§27-605(a)(1), (2) and (3).

      (3)   Each concrete producer or group of producers that submits for approval the information required hereabove, shall be assigned an application number which is to be known as the "PREQUALIFIED MIX REFERENCE NUMBER." This REFERENCE NUMBER shall be valid only for the calendar year for which it is issued. All applications shall be submitted before November 1 of each year for review and for prequalification for the calendar year next following.  When the concrete proposed for use is to be produced using the mix designs from a summary compilation that has been approved, the architect or engineer who has been retained to make or supervise the Controlled Inspection shall verify that the mixes have been approved as "PREQUALIFIED MIXES" and shall file a statement for each project setting forth the PREQUALIFIED MIX REFERENCE NUMBER from which the concrete mix proportions are to be selected.

   (c)   Mix designs previously approved and used.

      (1)   Each concrete producer making an application shall be assigned a PREQUALIFIED MIX REFERENCE NUMBER in the same manner as designated in 1 RCNY §5-03(b)(3).

      (2)   The application shall set forth the details of location, date and laboratory that pertained to the previous project. It also shall include a statement setting forth the average strength obtained from tests made at the job, together with a summary of the total number of tests made and, of those tests, how many fell below the specified strength.

      (3)   A copy of the laboratory report that was originally accepted shall be submitted. It shall contain the information listed under 1 RCNY §5-03(b)(2). (Reports with the water-cement ratios selected at a point on the curve established by preliminary mix tests corresponding to a strength of concrete 15% higher than the minimum ultimate strength called for on the plans shall not be accepted, unless the water-cement ratio complying with §27-605(a)(2) can be determined.)

      (4)   The Architect or Engineer retained for the Controlled Inspection shall file a statement similar to the one mentioned in 1 RCNY §5-03(b)(3).