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t PORTLAND CEMENT CONCRETE — ACCEPTANCE SAMPLING FREQUENCY . (REV 6-2540) (FA 7-540) (141 ) SUBARTICLE 346 - 9 . 2 ( of the Supplemental Specifications) is deleted and the following substituted : 346-9 . 2 Sampling Frequency for Quality Control Tests : As a minimum , sample and test concrete of each design mix for water to cermentitious materials ratio , air content, temperature , slump and compressive strength once per LOT as defined by Table 8 . When more than one concrete production facility is used for the same mix design , describe the method of sampling , testing and LOT numbering in the QC Plan . The Engineer will randomly verify one of every eight consecutive LOTs of each design mix based on a random number generator, and may perform additional Independent Verification tests . All QC activities , calculations , and inspections will be randomly confirmed by the Department . TABLE 8 Class Concrete Maximum LOT Size I one day ' s production 250 lane ft, or one day ' s production , whichever is I (Pavement) less II, II (Bridge Deck) , III, IV, V (Special) , 50 yd3 , or one day ' s production , whichever is less V , VI IV (Drilled Shaft) 50 yd3 , or two hours between placements , whichever I s less III ( Seal) Each Seal placement 346-9 . 2 . 1 Reduced Frequency for Acceptance Tests : When ten consecutive strength test results from the same mix design for a Class IV or higher class of concrete are produced at the same concrete production facility, on a given Contract have all been verified and have attained an average strength greater than two standard deviations above the specified minimum , then the LOT may represent a maximum production quantity of 100 yd 3 . When five consecutive strength test results from the same mix design for a Class III or lower class of concrete is produced at the same concrete production facility on a given Contract have all been verified and have attained an average strength greater than two standard deviations above the specified minimum , the LOT may represent a maximum production quantity of 100 yd 3 . The average of the consecutive compressive strength test results , based on the class of concrete , can be established using historical data from a previous Department project . The data must also represent the same prune/ subcontractor . The tests from the previous Department project must be within the last 60 calendar days or may also be established by a succession of samples on the current project . Only one sample can be taken from each LOT . Test data must be from a laboratory meeting the requirements of Section 105 . If at any time a strength test is not verified and/or the average strength of the previous ten or five consecutive samples based on the class of concrete described above , . 17 - FPID ( S ) : 423186 - 1 - 58 - 01