Volumetric Concrete

What Is Volumetric Concrete?

Volumetric concrete — also called on-site concrete, mobile mix, or metered mix concrete — is concrete produced at the jobsite rather than at a central batch plant. A volumetric mixer truck carries all raw ingredients separately: cement, fine aggregates (sand), coarse aggregates (stone or gravel), water, and chemical admixtures. When the truck arrives at the pour site, the ingredients are combined in precise metered quantities directly from the truck's conveyor system — mixed fresh, on demand, right where the concrete is needed.

This on-demand batching method stands in contrast to ready-mix concrete, which is batched at a central plant and arrives at the jobsite already mixed with a fixed hydration clock running. Volumetric concrete has no such clock — because water doesn't contact cement until the moment of batching, there is no time pressure on delivery. The concrete is always fresh, regardless of travel distance or pour duration.

How a Volumetric Mixer Works

A volumetric mixer truck is essentially a mobile batch plant. The truck's compartments store dry and wet ingredients separately throughout transit. At the jobsite, a computer-controlled metering system measures and combines the ingredients in the correct proportions as they pass through the mixing auger at the rear of the truck.

The operator controls the mix design and output rate from a panel at the back of the truck. Multiple mix designs can be produced from a single load — for example, a foundation pour requiring 3,000 PSI mix can be followed immediately by a 4,000 PSI column mix, all from the same truck without returning to a plant.

Key components of a volumetric mixer include:

Material compartments — Separate bins for coarse aggregate, fine aggregate, cement, and water. Admixture tanks are mounted separately.

Metering system — Computer-controlled augers and gates measure precise material proportions per the programmed mix design.

Mixing auger — The final mixing stage where all ingredients combine before discharging as finished concrete.

Operator panel — Controls mix design selection, output rate, drum speed, and water adjustment at the point of pour.

In-cab display — Connects to dispatch software to receive the job manifest and transmit delivery confirmation and digital ticketing data.

Volumetric vs. Ready-Mix: Key Differences

Understanding the difference between volumetric and ready-mix concrete is essential for anyone involved in construction materials dispatch.

Batching location
Ready-mix: batched at a central plant, delivered pre-mixed.
Volumetric: batched at the jobsite, mixed on demand.

Time constraints
Ready-mix: subject to a 60–90 minute hydration window from the moment water contacts cement at the plant.
Volumetric: no hydration window — water contacts cement only at the moment of batching. The truck can sit on-site indefinitely without the concrete setting prematurely.

Mix design flexibility
Ready-mix: one mix design per load. Changing mix requires a new truck.
Volumetric: multiple mix designs from a single truck load. The operator adjusts proportions between pours.

Minimum order size
Ready-mix: drum trucks typically carry 8–11 cubic yards minimum per load. Small pours waste product.
Volumetric: batches exactly the quantity needed — from a fraction of a yard to the truck's full capacity. No waste, no short-load fees.

Remote jobsite suitability
Ready-mix: limited by travel distance from the batch plant due to the hydration window.
Volumetric: no distance limitation. A volumetric truck can service remote locations hours from the nearest batch plant.

Who Uses Volumetric Concrete

Volumetric concrete is particularly well-suited to operations where flexibility, precision, or remote access are priorities:

Small and specialty pours — Repair work, curb and gutter, small slabs, post holes, and utility work where exact quantities matter and waste is costly.

Remote or rural jobsites — Projects far from a central batch plant where a ready-mix truck couldn't deliver within the hydration window.

Multiple mix designs — Projects requiring different strengths or specifications in a single day — a single volumetric truck replaces multiple ready-mix deliveries.

High-volume operations — Large producers who run volumetric alongside ready-mix and aggregate fleets to cover the full spectrum of customer needs from a single dispatch platform.

DOT and infrastructure work — Road repair, bridge work, and government infrastructure projects that require certified mix designs with precise documentation and GPS-validated delivery records.

Volumetric Concrete Dispatch: What's Different

Dispatching a volumetric fleet has its own set of operational considerations that differ meaningfully from ready-mix dispatch.

No load sequencing pressure — Because there is no hydration clock, dispatchers don't need to space loads in tight intervals the way ready-mix dispatch requires. A volumetric truck can wait on-site without consequence.

Longer on-site time — Volumetric trucks typically spend more time at each jobsite than a ready-mix truck, which discharges and leaves. Dispatchers need to account for extended site time when planning daily schedules.

Mix design management — Dispatch software needs to capture and transmit the correct mix design to the driver's tablet for each job. A mismatch between the ordered and batched mix design is a compliance and quality issue.

Exact yardage tracking — Because volumetric trucks batch on demand, the actual quantity delivered may differ slightly from the ordered quantity. eTicketing systems must capture the exact batched yardage at the time of delivery, not just the ordered amount.

DOT compliance documentation — Like all commercial vehicles, volumetric mixer trucks are subject to federal DOT regulations including hours-of-service requirements and weight limits. Digital ticketing provides the GPS-validated timestamps required for compliance documentation.

Multi-vertical fleet management — Many volumetric producers also operate ready-mix, aggregate, or asphalt & paving fleets. Managing all fleet types from a unified dispatch platform gives operations managers complete visibility without switching between systems.

Technology Stack for Volumetric Operations

Modern volumetric dispatch operations rely on the same core technology platform as ready-mix and aggregate fleets:

Near real-time GPS tracking — 5-second location updates give dispatchers live visibility into every truck's position, ETA, and status regardless of how remote the jobsite is.

eTicketing and digital proof of delivery — The driver's tablet receives the job manifest before departure. At the pour site, the customer signs to confirm delivery and the system generates a digital ticket with GPS-validated arrival and departure timestamps.

Drum sensor equivalent — Some volumetric trucks are equipped with sensors that monitor metering system activity to automatically detect batching, pausing, and completion — transmitting status updates to the dispatch platform without manual driver input.

Push-to-Talk communication — Dedicated LTE radio hardware gives dispatchers and remote drivers reliable voice communication in areas where cell coverage is limited — common in the rural and remote locations that volumetric trucks frequently serve.

Customer portal — Contractors can submit order requests, track their truck's location, and view past digital tickets online — reducing inbound calls to dispatch on active jobsites.

What is the difference between volumetric concrete and ready-mix?

Ready-mix is batched at a central plant and arrives pre-mixed with a 60–90 minute delivery window before it begins to set. Volumetric concrete is batched on demand at the jobsite by a mobile mixer truck, eliminating the time constraint entirely and allowing multiple mix designs from a single load.

Can a volumetric truck produce any mix design?

Yes — within the material inventory loaded on the truck. The operator programs the mix design at the point of pour. Most volumetric trucks carry sufficient material for multiple mix designs in a single load, making them highly flexible for projects with varying concrete specifications.

Is volumetric concrete as strong as ready-mix?

Yes, when properly batched. Volumetric concrete meets the same ASTM standards as plant-batched ready-mix. The key is accurate metering and calibration of the truck's batching system, which should be regularly certified and tested.

How is volumetric concrete ticketed for DOT compliance?

The driver receives the job manifest on their tablet before departure. At the jobsite, the customer signs the tablet to confirm the pour. The dispatch platform generates a digital ticket capturing the exact batched yardage, mix design, and GPS-validated arrival and departure timestamps — providing a complete, unalterable compliance record.

How far can a volumetric truck travel to a jobsite?

Unlike ready-mix, there is no distance limitation for volumetric trucks because the concrete isn't mixed until arrival. The practical limits are driver hours-of-service regulations and the truck's material capacity for the day's jobs.

Can volumetric trucks be dispatched alongside ready-mix trucks?

Yes. Many producers run mixed fleets that include both volumetric and ready-mix trucks. A unified dispatch platform manages both fleet types from a single map and order management interface, with eTicketing and GPS tracking operating identically across all vehicle types.