If you have ever ordered ready-mix concrete and ended up paying for a full load when you only needed half of it, you already know the problem. Traditional concrete delivery works on a simple rule: you order a fixed amount, and you pay for that amount whether you use it or not.
Concrete mixed on site changes that completely. Using volumetric mixers, the concrete is made fresh at your location, and you only pay for what goes into the ground. This guide explains how the process works, why it saves money, and when it is the right choice for your project.
How On-Site Concrete Mixing Works
A volumetric mixer is a specially built truck that carries all the raw ingredients needed to make concrete: cement, sand, aggregates, and water. These materials are stored in separate compartments on the vehicle.
When the truck arrives at your site, the operator sets the mix to the correct grade and strength. The ingredients are then combined through an on-board mixing system and the fresh concrete is poured directly where you need it.
The whole process is controlled by a calibrated computer system on the truck. This means the mix ratios are precise and consistent from the first bucket to the last.
If you want to understand more about the technology behind this, our guide on what volumetric concrete is and how it works goes into more detail.
The Money-Saving Advantage
The biggest financial benefit of on-site mixing is simple: no waste. Here is how the costs compare for a typical domestic project.
| Scenario | Traditional Ready-Mix | Volumetric On-Site Mixing |
|---|---|---|
| Concrete needed | 2.5 cubic metres | 2.5 cubic metres |
| Minimum order | Often 3 or 4 cubic metres | No minimum; pay for what you use |
| What you pay for | The full minimum load (e.g. 4 m³) | Exactly 2.5 cubic metres |
| Leftover concrete | 1.5 m³ wasted and your problem to dispose of | None |
| Can you adjust mid-pour? | No, the mix is already set | Yes, strength and volume can change on the spot |
On a small domestic job, the savings from avoiding waste can easily cover the cost of the concrete itself. On larger projects with multiple pours, those savings multiply.
There is also a hidden cost with traditional delivery that many people overlook: disposal. If you end up with half a cubic metre of leftover concrete, you cannot just tip it in the garden. You need to let it set and then arrange for it to be taken away, which takes time and costs money.
The Time-Saving Advantage
On-site mixing also saves time in ways that are easy to overlook until you have experienced a delay.
With traditional delivery, you book a time slot and hope the truck turns up when expected. If it is late, your team is standing around waiting. If it arrives early and you are not ready, the concrete starts setting in the drum while you scramble to prepare.
Volumetric mixers give you much more control. The concrete is not mixed until the operator confirms you are ready. If there is a short delay on site, the raw materials are sitting safely in their compartments with no risk of setting. The pour starts when you say so, not when the clock says so.
This flexibility also means you can adjust mid-pour. If your builder decides the trench needs a bit more concrete than expected, the operator simply mixes more. If you need a different strength for a separate section, that can be done in the same visit. There is no need to book a second delivery.
When On-Site Mixing Is the Right Choice
On-site mixing works well for almost any project, but it is especially useful in certain situations.
When you are not 100% sure of the volume. If your measurements are estimates rather than exact figures, volumetric mixing removes the risk of over-ordering or under-ordering. When access is tricky. The mixer can pour in stages, so you do not need the entire area ready at once. When you need more than one grade. A single truck can mix different grades on the same visit, which is perfect for projects that need, say, C20 concrete for a garden path and C25 concrete for a garage base. When you want fresh concrete. Because it is mixed on arrival, the concrete is at peak workability when it goes into your formwork.
The Process from Arrival to Pour
Here is what to expect when a volumetric mixer arrives at your site.
The operator will check in with you and confirm the mix grade, the estimated volume, and where the concrete needs to go. They will position the truck as close to the pour area as possible. If the truck cannot reach the exact spot, you will need wheelbarrows or a concrete pump to move the mix from the discharge point to the formwork.
The operator then starts mixing. Concrete comes out of the truck through a chute, and you or your builder spread and level it as it arrives. The pace is steady and controllable, so you are not rushed.
Once you have enough concrete, the operator stops mixing. The meter on the truck shows exactly how much was used, and that is what you pay for. No arguments about minimum loads, no leftover material, and no waste disposal to worry about.
According to the Health and Safety Executive’s guidance on cement safety, anyone working with wet concrete should wear protective gloves and boots, and wash off any cement that contacts skin as soon as possible.
Is On-Site Mixing Right for Your Project?
If you are planning any concrete work in Cambridgeshire or the surrounding counties, on-site volumetric mixing is worth considering. It gives you better control over cost, timing, and quality than traditional drum delivery. For a quote or advice on the right mix for your job, get in touch with your local concrete delivery service and discuss your project details.
