Concrete is the most-used manufactured material on earth, and almost all of it arrives on site in a rotating drum, mixed to order, with a few hours of useful life. This site is an independent reference for the people who order that concrete, place it, inspect it or specify it: a plain-language guide to how ready-mixed concrete is proportioned, produced, delivered, tested and cured, written for practitioners rather than for a sales department.
Nothing here is for sale. There is no supplier behind this reference, no product catalogue and no quotation service. The material is organised the way the work actually happens, from the pit and the cement silo through the batch plant and the truck to the slab, the cylinder break and the curing blanket.
Where to start
If you are new to the subject, read concrete mix design first. Proportioning is the decision that governs everything downstream: strength, durability, workability, cost, and how much trouble the crew has on placement day. Once the proportions make sense, the rest of the reference reads as a set of consequences.
If you already work with concrete and want a specific answer, the sections below are self-contained.
Materials
- Mix design and proportioning — water-cement ratio, the absolute volume method, trial batches and why the strength you specify is not the strength you design for.
- Aggregates — gradation, particle shape, absorption and moisture correction, and the reactivity problems that only appear years later.
Production and delivery
- Plant types — central-mix, transit-mix and dry-batch operations, and what each one implies for consistency and haul distance.
- Delivery geography — haul time, the discharge window, and why a plant network map is really a map of drive times.
- Ordering — the information a supplier genuinely needs before a truck can be loaded.
- Commercial terms — unit pricing, short-load charges, standby time and the cost of an unprepared site.
On site
- Curing and protection — the cheapest strength available to any project, and the one most often skipped.
- Testing — slump, air content, temperature, cylinders, and how a badly made test specimen fails a good load of concrete.
- Safety data — alkaline burns, respirable crystalline silica, and the controls that actually reduce exposure.
Context
- Regional practice — why the same specification produces different concrete in North Texas, on the Gulf Coast and in central Arkansas.
- Industry structure and the roles inside an operation.
- The standards that govern the material, and the certifications people working with it hold.
What makes ready-mixed concrete different
Most construction products are finished when they arrive. Ready-mixed concrete is not: it is delivered as a chemically active suspension that begins to stiffen from the moment water meets cement, and its final properties are decided partly at the plant and partly by what happens in the ninety minutes after the truck leaves. That shared responsibility is the source of nearly every dispute on a concrete job.
The supplier controls proportions, materials, batching accuracy and mixing. The contractor controls placement rate, consolidation, finishing timing, protection and curing. The specifier controls what was asked for in the first place, which is frequently the real problem — a mix specified for strength alone, with no exposure class and no thought about placement method, will meet its cylinder breaks and still produce a slab nobody is happy with.
The National Ready Mixed Concrete Association publishes industry guidance on exactly this division of responsibility, and the purchase specification for the material itself, ASTM C94, is written around it: the producer certifies what was batched, the purchaser accepts what is discharged, and the two are separated by a documented delivery ticket.
How this reference is written
Every number in these pages is either a documented limit from a published standard, or is flagged as typical practice rather than a rule. Where a value is jurisdictional — cover requirements, exposure classes, aggregate acceptance — the page says so and points at the primary source. The authoritative documents live with the American Concrete Institute, ASTM International, and the state transportation departments; nothing here substitutes for them.
The reference is deliberately conservative about site-specific advice. Concrete failures are usually local: a particular aggregate, a particular subgrade, a particular week of weather. What a general reference can do is tell you which variable to look at, what a normal value looks like, and where the governing document is.