What air content is required for concrete on Michigan DOT projects?

"Air content (a) <5.0% or >9.0%" [1] "(a) Action limits for air content must be defined in the Contractor ’s QC plan and cannot be <5.5 % or >8.5 %." [1] "testing will be conducted whenever there is a change in QC ’s or QA ’s equipment or testing personnel for the project, or if the Engineer determines that there is a significant difference between the QC and QA test results. If the air content results of the side- by-side tests conducted by the QC and QA testers and equipment differ by more than 0.8% air by volume of concrete, a referee air content test must be conducted by a third party, des ignated by the Engineer but independent of the project, before the beginn ing or continuation of concrete placement in order to resolve issues associated with non-correlation." [5] "If the difference in m easured air content between the two test locations for the same concrete is greater than 1.5% air by volume of concrete, suspend operations and administer corrective action." [5]

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