In April of 2021, after 6 years of balloting, the ASTM Subcommittee C09.40 on Ready Mix Concrete updated ASTM C94/C94M-21 Standard Specification for Ready-Mixed Concrete with two significant changes in respect to the time limit from the start of mixing to the completion of discharge.  The first was a revision to Section 12.9 and the second was the addition of Section 6.10. The sections in the current ASTM are as follows:

  • 9 Discharge of the concrete shall be completed within time limit as established in 6.1.10.  This limitation may be waived by the purchaser if the concrete is of such slump or slump flow after the specified time limit has been reached that it can be placed, without the addition of water to the batch.
  • 1.10 Purchaser shall state a time limit from the start of mixing defined in 12.3 or 12.5 to when the concrete discharge must be completed.  If no time limit is stated by Purchaser, the Manufacturer shall establish and communicate the limit to the Purchaser prior to delivery.  The time limit to complete discharge shall be stated on the delivery ticket.

ATL provides this summary to bring your attention to these important changes.  We have prepared a more technical explanation of these changes that can be found here: Quality Bulletin – Review of Technical Changes to ASTM C94.  Please contact our technical staff to discuss any implications this may have on your projects.