How to Order Ready-Mix Concrete: Quantity & Delivery

Ordering ready-mix concrete is not just a matter of calling a plant and asking for a certain number of cubic yards.

The supplier also needs to know what concrete the project requires, where it will be placed, how it will be discharged, when each truck should arrive, and whether the site can safely accommodate a loaded mixer.

A good order connects three things:

Quantity + concrete requirements + delivery plan

If any one of them is wrong, problems can develop quickly. Too little concrete can interrupt a placement. The wrong mixture can conflict with the project specification. Trucks arriving faster than the crew can place concrete can create delays, while trucks arriving too slowly can disrupt continuity.

For engineered work, the drawings and project specifications control. For smaller residential work without a detailed concrete specification, the contractor and ready-mix producer should establish the required performance based on the application and exposure rather than relying on a generic “standard mix.”

This guide explains how to prepare a ready-mix concrete order, estimate quantity, communicate mixture requirements, coordinate truck delivery, check delivery tickets, and avoid common ordering mistakes.

Ready-Mix Concrete Ordering at a Glance

The purpose of an order is to translate the project requirements into information the producer can use.

What Is Ready-Mix Concrete?

Ready-mixed concrete is concrete produced under controlled batching conditions and delivered to the project in a fresh, unhardened state.

It is commonly transported in a truck mixer that keeps the concrete uniformly mixed until discharge.

Ready-mix is not one particular concrete recipe.

A producer can supply different strengths, aggregate sizes, air contents, consistencies, fibers, admixtures, colors, densities and other properties depending on the project.

That is why saying “I need six yards of concrete” is not a complete order.

In the United States, ASTM C94/C94M is the principal specification covering the manufacture and delivery of ready-mixed concrete. It addresses the concrete furnished to the purchaser; it does not replace the requirements for placement, consolidation, curing or protection after delivery.

The NRMCA Ordering Ready Mixed Concrete guide provides a practical overview of information purchasers should communicate.

Before Calling the Concrete Plant

Do not begin with the supplier until the basic project decisions are reasonably settled.

You should know what is being placed, its approximate dimensions, the specified concrete requirements, the planned placement method and the intended pour date.

If the project has drawings and specifications, have them available.

ASTM C94 requires applicable project requirements to be included in the order when a project specification applies.

Identify Different Placements Separately

A project does not necessarily use one mixture everywhere.

A residential project might include:

footings;

foundation walls;

a garage slab;

an exterior driveway;

steps.

These placements can have different exposure, strength, air, aggregate and workability requirements.

Do not assume that concrete specified for an exterior driveway is also appropriate for a hard-troweled interior floor or a reinforced foundation wall.

Where the project calls for different concretes, keep their mixture designations and placements clearly separated.

Step 1: Calculate the Concrete Quantity

Ready-mixed concrete is normally ordered by volume in cubic yards in the United States.

One cubic yard equals 27 cubic feet.

For a rectangular slab:

Cubic yards = Length (ft) × Width (ft) × Thickness (ft) ÷ 27

When thickness is measured in inches:

Cubic yards = Length (ft) × Width (ft) × Thickness (in) ÷ 324

Example: 20 × 24-Foot Slab, 4 Inches Thick

The theoretical volume is:

20 × 24 × 4 ÷ 324 = 5.93 cubic yards

That is the volume based on the planned dimensions.

It is not automatically the final order quantity.

Construction can require additional concrete because subgrade elevations are not perfectly uniform, forms vary, slab edges may be deeper, and some material may remain in handling or placement equipment.

How Much Extra Concrete Should You Order?

NRMCA recommends ordering approximately 4% to 10% more than the calculated plan volume to account for contingencies.

This is a planning range, not a mandatory waste percentage.

The appropriate allowance depends on how accurately the placement volume is known.

A carefully formed slab over a controlled base may involve less uncertainty than an irregular footing excavation or a slab with thickened edges.

For the 5.93-cubic-yard example:

4% additional volume gives approximately 6.17 cubic yards.

10% additional volume gives approximately 6.52 cubic yards.

The final order must also account for the supplier's ordering increments and delivery arrangements.

Do not automatically add 10% to every project.

A separate guide, How to Calculate Concrete Yardage, will cover walls, footings, irregular areas and quantity checks in more detail.

Step 2: Order Performance Requirements, Not Just a PSI Number

Compressive strength is one of the most familiar concrete requirements, but it is only one part of an order.

If the plans specify a concrete class, mixture designation or compressive strength, use that requirement.

Do not substitute another strength simply because it sounds stronger or because it is commonly used on a different project.

Specified Compressive Strength

Concrete strength is commonly specified in pounds per square inch, or psi, at a stated test age.

A 28-day compressive strength is common in conventional construction, but different ages may be specified.

The order should communicate the required strength and any other relevant performance requirements from the project documents.

Avoid relying only on phrases such as:

“Give me your driveway mix.”

A producer's standard mixture designation can be useful, but the purchaser still needs to confirm that it satisfies the project.

Performance Requirements vs. a Homemade Recipe

NRMCA identifies performance-based ordering as the preferred approach.

The purchaser communicates required performance, while the producer uses available cementitious materials, aggregates and admixtures to proportion an appropriate mixture.

Depending on the project, performance requirements can include:

specified compressive strength;

exposure requirements;

air content;

slump or slump flow;

density;

specialized durability or mechanical properties.

Prescriptive requirements can still be part of engineered specifications.

The key is not to invent unnecessary mixture proportions when the project can instead define the required result.

Step 3: Communicate Exposure Conditions

The producer needs to know where and how the concrete will be used.

An interior floor and an exterior driveway can require different concrete even when their specified compressive strengths are similar.

Communicate whether the concrete will be:

indoors or outdoors;

exposed to freezing temperatures;

wet during freezing conditions;

exposed to deicing chemicals;

subject to another documented aggressive environment.

Exposure can influence air entrainment, water-cementitious materials ratio, strength and other requirements.

Air-Entrained Concrete

Concrete subjected to relevant freeze-thaw exposure commonly requires a deliberately entrained microscopic air-void system.

Do not simply request “air” without knowing the project requirement.

Target air content depends in part on nominal maximum aggregate size and exposure severity.

Where the project specifies an air content, communicate that requirement directly.

Where no engineered specification exists, accurately describe the application and exposure so the contractor and producer can select an appropriate mixture.

Step 4: Communicate Slump or Slump Flow

Slump measures the consistency of conventional fresh concrete.

It is not a direct measurement of concrete strength, and it should not be interpreted simply as a measure of how much water is in the mixture.

Different construction methods can require different consistency.

Concrete placed in an open slab does not necessarily need the same slump as concrete pumped into congested reinforcement.

Do Not Select Slump From a Generic Chart

If the project specification establishes a slump, use it.

If the concrete will be pumped, tell the producer.

If access or reinforcement makes placement difficult, communicate those conditions rather than trying to solve the problem by ordering unusually wet concrete.

Water-reducing admixtures can increase workability without relying on uncontrolled additional water.

Self-Consolidating Concrete Uses Slump Flow

Self-consolidating concrete is evaluated using slump flow rather than the conventional slump measurement.

If SCC is required, order the designated mixture and specified fresh-concrete properties instead of trying to create extremely fluid ordinary concrete.

Step 5: Confirm the Aggregate Size

The nominal maximum size of coarse aggregate needs to suit the element and placement method.

Aggregate must be able to move through the available space.

Important constraints include:

section thickness;

spacing between reinforcing bars;

distance between reinforcement and formwork;

embedded items;

pump-line dimensions.

NRMCA notes that nominal maximum aggregate sizes of 3/4 inch and 1 inch are common in many applications, but neither should be specified automatically.

The actual project requirements control.

If concrete will be pumped, coordinate the mixture with both the producer and pump provider.

Step 6: Identify Fibers, Admixtures and Other Special Requirements

Ready-mix can be modified for different construction and performance goals.

Depending on the project, the order may include:

air-entraining admixture;

water reducer;

high-range water reducer;

accelerator;

retarder;

fibers;

integral color;

shrinkage-related admixtures;

corrosion-related admixtures;

other specified materials.

Each addition should have a defined purpose.

Do not add fibers simply because another project used them, or request an accelerator without considering its effect on placing and finishing.

Fibers Need a Defined Purpose

If fibers are specified, communicate the required fiber type and dosage or the designated producer mixture.

A small synthetic microfiber dosage intended for plastic-shrinkage crack control is not equivalent to a macrofiber system designed for post-cracking performance.

If the drawings require conventional reinforcement, do not assume fibers cancel that requirement.

Step 7: Tell the Producer How the Concrete Will Be Placed

The mixer truck does not necessarily discharge concrete directly into its final location.

Concrete may reach the forms by:

truck chute;

concrete pump;

conveyor;

powered buggy;

wheelbarrow;

crane bucket;

another planned method.

Placement method can affect workability, aggregate size, delivery rate and logistics.

If the Concrete Will Be Pumped

Coordinate the concrete producer, concrete contractor and pump company before the pour.

The producer should know the concrete will be pumped and any relevant requirements of the pumping system.

The pump also needs a safe setup location and a delivery schedule capable of maintaining the planned placement.

Do not wait until the first truck arrives to discover that the mixer cannot reach the forms.

Step 8: Plan the Delivery Rate

A start time alone is not a delivery plan.

The producer also needs to know how quickly the crew can place the concrete.

NRMCA recommends communicating the expected placement rate, delivery duration and project location.

Truck spacing depends on factors such as:

volume carried per truck;

crew size;

placement method;

pump capacity;

project geometry;

finishing sequence;

site congestion;

expected travel conditions.

Trucks arriving too quickly may queue at the site.

Trucks arriving too slowly can interrupt placement.

For multi-load pours, establish an expected delivery rate with the producer before the first truck is dispatched.

The NRMCA/ASCC Ordering and Scheduling Ready Mixed Concrete checklist provides a useful format for documenting these details.

Step 9: Understand Supplier Policies

Commercial policies vary by concrete producer.

Before confirming the order, ask about:

minimum delivered quantity;

short-load charges;

returned-concrete charges;

waiting or standby charges;

after-hours, weekend or holiday charges;

cancellation procedures;

cleanup or add-on loads;

advance-order requirements;

payment terms.

There is no single nationwide short-load threshold or fee.

A supplier may deliver a partial truck but charge more per cubic yard because much of the delivery cost exists regardless of load size.

The supporting guide Concrete Delivery and Short-Load Fees will examine these charges separately.

For the initial order, the important step is to understand the delivered-price structure before the pour.

Step 10: Check Truck Access and Site Safety

Ready-mix trucks are much heavier than ordinary residential vehicles.

NRMCA uses approximately 80,000 pounds (36,000 kg) as a planning reference for a loaded concrete truck.

That means truck access needs to be evaluated before delivery.

Consider:

road and driveway access;

gate widths;

turning room;

overhead wires and branches;

slopes;

curbs and sidewalks;

soft or recently filled ground;

buried tanks or structures;

underground utilities;

a safe exit route.

Do not direct a loaded mixer across an unverified lawn, septic system, buried structure or residential pavement simply because the truck physically fits.

The Truck Does Not Have to Reach the Forms

If direct mixer access is unsuitable, choose another conveying method.

A pump, buggy, conveyor or other system can allow the mixer to remain on a suitable surface.

This decision needs to be made before delivery because it can change mixture requirements, labor and truck spacing.

Fresh Concrete Can Cause Chemical Burns

Truck movement is not the only safety issue.

Fresh concrete and other wet cementitious materials are highly alkaline and can cause serious chemical burns to skin and eyes. Wet concrete trapped inside boots, gloves or clothing can continue damaging tissue without immediately causing severe pain.

People handling fresh concrete should use appropriate waterproof gloves, boots, eye protection and protective clothing.

Wash exposed skin promptly with clean water and keep children and unprotected bystanders away from the placement.

Step 11: Prepare the Site Before Dispatch

Ready-mixed concrete is a perishable construction material.

The crew should be ready before the first truck arrives.

A typical pre-placement check includes:

forms complete and secured;

subgrade or base prepared;

reinforcement and embeds installed where required;

vapor retarder complete where required;

required inspections finished;

placement crew on site;

pump or other conveying equipment ready;

screeds, vibrators and finishing tools available;

curing materials on hand;

weather plan established;

truck route clear;

safe washout area prepared;

testing personnel ready where specified.

If a critical part of the project is not ready, contact dispatch as early as possible.

A schedule change is easier to manage before concrete is batched.

What Happened to the 90-Minute Rule?

ASTM C94 historically required concrete discharge to be completed within 1½ hours after mixing began.

That default time limit was removed beginning with the 2021 edition.

Current ASTM C94 practice requires the purchaser to state a time limit from the start of mixing to completion of discharge.

If the purchaser does not state one, the producer establishes and communicates the limit before delivery.

The established limit must appear on the delivery ticket.

This does not mean ready-mixed concrete can remain usable indefinitely.

The appropriate delivery window can be affected by:

concrete mixture;

ambient temperature;

admixtures;

haul distance;

placement procedure;

project requirements.

Project specifications can also impose their own discharge limits.

Do not reject or accept a load based solely on an assumed universal 90-minute rule. Check the project specification and the time limit established for that delivery.

Step 12: Check the Delivery Ticket Before Unloading

The responsible person on site should review the delivery ticket before directing the truck into the placement.

Information worth confirming includes:

producer and plant;

ticket number;

truck number;

date;

purchaser and project;

mixture designation;

quantity delivered;

batching or loading information;

established discharge-time limit;

specified information required by the project;

documented jobsite adjustments where applicable.

Exact ticket requirements depend on ASTM C94 and any additional project specification.

Confirm the Mixture Designation

Projects may use multiple mixtures on the same day.

Verify that each truck contains the mixture intended for the location being placed.

Do not assume the correct concrete was dispatched simply because the truck arrived at the correct address.

Keep the Tickets

Delivery tickets provide a record of the placement.

For a multi-load pour, organize them by truck and placement area.

They can help resolve later questions about quantity, mixture designation, discharge limits and documented adjustments.

If the Wrong Concrete Arrives

Do not start unloading simply to keep the truck moving.

Compare the ticket and mixture designation with the project requirement.

If they do not match, contact the producer and the responsible project representative before placement begins.

Correcting a dispatch error before concrete enters the forms is far easier than addressing it afterward.

Jobsite Water Addition: Allowed, but Controlled

Water is sometimes added to concrete at the jobsite, but it should not be an informal way to make placement easier.

ASTM C94 permits controlled adjustment when concrete arrives below the allowable slump and the addition remains within the applicable maximum slump and water-cementitious materials ratio.

The NRMCA Jobsite Addition of Water guide summarizes the required controls.

Why Excess Water Is a Problem

Water beyond the permitted amount can:

delay setting;

reduce strength;

reduce durability;

increase segregation;

increase cracking potential.

Where additional workability is needed, an approved water-reducing admixture may be more appropriate than additional mixing water.

Water Addition Should Be Measured and Documented

Jobsite water additions should be measured and recorded on the delivery ticket.

NRMCA's guidance states that after all water or admixtures are added, ASTM C94 requires an additional 30 revolutions at mixing speed.

Water should be added before a significant amount of concrete has been discharged. Current NRMCA guidance advises against further water addition after more than about 1/4 cubic yard has been discharged.

The procedure should also establish who is authorized to request an adjustment.

These controls distinguish an approved slump adjustment from uncontrolled retempering.

Acceptance Testing

Where the project requires acceptance testing, responsibilities should be established before the pour.

Fresh-concrete testing can include:

slump or slump flow;

air content;

concrete temperature;

density where specified;

preparation of strength specimens.

Testing frequency and acceptance criteria come from the project documents and applicable standards.

Acceptance samples and tests should be obtained and performed using the applicable procedures by qualified personnel.

Homeowners and contractors should not invent rejection criteria after the truck arrives.

Likewise, visual appearance alone cannot confirm compressive strength or air content.

Manage Quantity During the Pour

The original quantity calculation is only the starting point.

On a multi-truck placement, compare actual concrete use with the remaining work.

If the early loads show that consumption is higher or lower than expected, communicate with dispatch before the final scheduled truck.

This can reduce both shortage and unnecessary excess.

If You May Run Short

Check:

the amount already delivered;

the area or form volume already filled;

the remaining placement;

any unexpected depth variation;

whether an additional load may be needed.

Calling early gives the producer more options for an add-on load.

Waiting until the last mixer is empty can create a longer interruption.

If You May Have Too Much Concrete

Do not create unplanned slabs or dump fresh concrete on the ground simply to empty a truck.

Ask about the producer's returned-concrete procedure and establish any legitimate secondary use before the pour.

Returned material may involve additional charges.

Accurate quantity monitoring is preferable to deliberately ordering a large surplus.

Weather and Delivery Scheduling

Weather affects both concrete and site logistics.

Hot conditions can accelerate slump loss and setting.

Cold conditions can affect concrete temperature and early strength development.

Rain can interfere with finishing or make the prepared site unsuitable.

When significant weather is expected, coordinate with the contractor and producer before batching begins.

Different mixture strategies and admixtures can be used for particular conditions, but they should be planned rather than improvised after delivery.

Detailed curing and cold- or hot-weather protection belong in the separate Concrete curing guide.

Common Ready-Mix Ordering Mistakes

Ordering by psi alone. Strength does not define the complete mixture. Exposure, air, workability, aggregate and placement can also matter.

Using a generic “driveway mix.” Residential concrete requirements vary with climate, project design and exposure.

Automatically adding 10% to every volume calculation. The contingency should reflect actual uncertainty.

Ignoring the placement method. Pumping and difficult access should be coordinated before delivery.

Scheduling only the first-truck time. Multi-load work also requires a realistic delivery rate and truck spacing.

Assuming the mixer can drive anywhere. A loaded truck can weigh about 80,000 pounds.

Adding water casually. Permitted adjustments need to remain within mixture limits and be documented.

Ignoring the delivery ticket. The ticket is the first check that the correct concrete reached the correct placement.

Applying the old 90-minute rule automatically. Current ASTM C94 requires an established project or producer time limit instead of a universal default.

Calling for additional concrete too late. Monitor actual consumption while there is still time to adjust delivery.

Ready-Mix Concrete Ordering Checklist

Before confirming the order, verify:

If several of these items remain unresolved, the project may not be ready for concrete delivery.

Frequently Asked Questions

How Do I Order Ready-Mix Concrete?

Provide the supplier with the project location, concrete quantity, applicable mixture or performance requirements, placement method, requested date and time, delivery rate and site-access information.

For engineered work, follow the project drawings and specifications.

How Many Cubic Yards of Concrete Do I Need?

For a rectangular placement, multiply length by width by thickness in feet and divide by 27.

Then evaluate an appropriate contingency for actual construction conditions.

NRMCA recommends approximately 4% to 10% above calculated plan volume as a general allowance for contingencies.

Should I Always Order 10% Extra Concrete?

No.

Ten percent is within the NRMCA planning range, but it is not a universal requirement.

The appropriate contingency depends on the accuracy of the project dimensions and uncertainty in the placement.

What PSI Concrete Should I Order?

Use the strength established by the project documents or other appropriate project requirements.

Do not select concrete strength solely from a generic residential chart.

What Slump Should I Order?

Use the slump appropriate to the specification and placement method.

There is no single ideal slump for every concrete project.

Pumping, reinforcement congestion and other placement conditions can change the required consistency.

Does Exterior Concrete Need Air Entrainment?

Concrete exposed to relevant freezing and moisture conditions commonly requires proper air entrainment.

The target air content depends on factors including exposure severity and aggregate size.

How Much Concrete Fits in a Ready-Mix Truck?

NRMCA's current CIP 31 guidance states that truck mixer capacity typically varies from approximately 8 to 12 cubic yards.

Actual supplier equipment and legal payloads vary.

How Much Does a Loaded Concrete Truck Weigh?

NRMCA uses approximately 80,000 pounds (36,000 kg) as a planning reference for a loaded concrete truck.

Actual weights vary by truck and load.

Can the Driver Add Water to the Concrete?

Controlled water adjustment is permitted under specific conditions when the mixture remains within its permitted slump and water-cementitious materials ratio.

The amount added should be measured and documented, followed by the required mixing.

Uncontrolled water addition should not be used merely to make concrete easier to place.

Does Ready-Mix Concrete Have to Be Discharged Within 90 Minutes?

Not as a universal current ASTM C94 requirement.

The default 1½-hour limit was removed beginning with the 2021 edition.

The purchaser now establishes the time limit, or the producer establishes and communicates one when the purchaser does not. The applicable limit should appear on the delivery ticket.

What Is a Short Load?

A short load generally means a delivery below the supplier's preferred or economically efficient truck quantity.

Minimum quantities and charges vary by producer.

Ask about them before confirming the order.

Should I Order Concrete Before Booking a Pump?

No.

The concrete order, pump requirements and delivery schedule should be coordinated.

The producer should know the concrete will be pumped before batching begins.

Final Ready-Mix Order Check

Before the order is released, confirm three things.

First, the concrete is correct. Strength, exposure, air, consistency, aggregate and any special requirements match the project.

Second, the quantity is realistic. Volume has been calculated from the actual placement and includes a justified contingency.

Third, the site can receive it. Access, crew, equipment, testing and delivery timing are ready before the first load leaves the plant.

Ready-mixed concrete is a perishable construction material. A well-prepared order reduces unnecessary changes after batching and gives the purchaser, producer and placement crew a shared plan.

The best concrete order is not the one with the longest list of specifications. It is the one that clearly communicates the requirements that matter to the project.

Technical References

Technical guidance in this article was checked against:

ASTM C94/C94M, Standard Specification for Ready-Mixed Concrete. ASTM listed C94/C94M-26C as the active edition on the technical review date.

National Ready Mixed Concrete Association, CIP 31 — Ordering Ready Mixed Concrete, revised 2023.

NRMCA, CIP 26 — Jobsite Addition of Water, revised 2023.

NRMCA/ASCC, Checklist for Ordering and Scheduling Ready Mixed Concrete.

NRMCA/ASCC, Concrete Pre-Construction Checklist.

Current industry guidance concerning the ASTM C94 change to discharge-time requirements.

Project drawings, specifications, applicable codes and qualified design requirements take precedence for an actual construction project.

Technical review: October 7, 2026.