ASTM C94/C94M
Standard Specification for Ready-Mixed Concrete
The commercial and technical rules for buying ready-mixed concrete: what the supplier must batch, how the load is documented, and how long it may stay in the drum.
Who needs it
Ready-mix producers, general contractors, concrete subs, inspectors, and owners writing or enforcing a purchase specification.
What the test involves
It defines the three ways concrete can be ordered — by performance, by prescription, or by a shared split of responsibility — and sets batching tolerances for each ingredient. It also requires a delivery ticket with specified information, limits how long concrete may be held before discharge, and lays out the conditions under which water may be added at the site and who bears responsibility when it is. Sampling and acceptance testing are tied to the test methods it references.
Common misconceptions
- The batch ticket is not a receipt. It is the contractual record of what was actually loaded, and it is the first document reviewed when a slab underperforms.
- 'Adding a little water' is not free. Water added beyond what the specification allows shifts responsibility for strength away from the supplier.
- Discharge time limits exist because concrete stiffens and gains temperature in the drum, not because suppliers want the truck back — a load held too long is a different material than the one batched.
Official source
We summarize scope and purpose only. The full text belongs to the issuing body — read it at the official source. ASTM International