Investors who plan to produce box culverts usually ask the same three questions first: which sizes will I make, which machine do I need, and how many pieces will it produce a day? This guide explains how box culverts are made by machine, which size is produced on which İbar Makina concrete pipe machine, and the difference that really decides output. For what box culverts are and where they are used, see our guide to box culverts.
How are box culverts made by machine?
In machine production a box culvert is cast vertically and compacted by vibration, on the same principle as a concrete pipe. The machine uses a box culvert mould instead of a pipe mould, so the same machine can make both concrete pipes and box culverts after a mould change.
- Preparing the mould: the inner and outer moulds are set in the machine on a bottom pallet.
- Filling: earth-moist concrete is fed evenly into the mould from the hopper and distributor belt.
- Vibration: powerful vibration motors compact the concrete across the whole mould, so walls and corners come out free of voids.
- Finishing the top: the top of the unit is trimmed and the dimensions and joint surface are completed.
- Demoulding and curing: the fresh unit is released from the mould and taken to the curing yard. How this step is done directly decides the output, as explained below.
Which size is made on which machine?
The largest box culverts that can be produced on İbar Makina's concrete pipe machines are:
| Machine | Concrete pipe diameter | Largest box culvert | Demoulding |
|---|---|---|---|
| CPM 1400 PRO | 300–1400 mm | 1200 × 1200 mm | In the machine, no crane |
| CPM 1600 PRO | 300–1600 mm | 1500 × 1500 mm | In the machine, no crane |
| CPM 2400 | 300–2400 mm | 2000 × 2000 mm | By crane, in the yard |
| CPM 3600 | 600–3600 mm | 3000 × 3000 mm | By crane, in the yard |
These are upper limits; each machine also makes smaller box culverts with the right mould. Each size needs its own box culvert mould.
The difference that decides output: is the mould moved by crane?
What affects daily output most in box culvert and pipe production is how the product is released from the mould.
Crane system (CPM 2400, CPM 3600)
For large sizes the product is carried to the curing yard together with its mould by crane. The mould is opened in the yard, the product is left there, and the empty mould is brought back to the machine by crane. While the mould travels out and back, the machine waits for the next cycle.
Crane-free PRO system (CPM 1400 PRO, CPM 1600 PRO)
On PRO machines the product is released from the mould right in the machine. A forklift takes the fresh unit on its bottom pallet to the curing yard while the machine starts the next one without waiting. Because the trip of the mould to the yard and back is gone, PRO machines produce about twice as fast. For a plant making box culverts up to 1500 × 1500 mm, that means twice the output in the same shift.
How many box culverts a day?
Daily output depends on the size, the number of moulds and the demoulding system; the smaller the size, the more pieces. Two examples:
- 3000 × 2000 mm box culvert: about 15–20 pieces a day by machine.
- Concrete pipes, CPM 1400 PRO: with enough bottom pallets, 150–200 Ø600 pipes or 80–100 Ø1000 pipes a day.
For smaller box culvert sizes daily output is clearly higher; the exact figure is calculated at the quotation stage for your sizes and number of moulds.
What does a box culvert plant need?
- Concrete preparation: a batching plant or a mixer of sufficient capacity for consistent, homogeneous concrete.
- Handling: a forklift for PRO machines; a crane system working with the machine for large sizes.
- Moulds and bottom pallets: a mould for each size you will make and enough bottom pallets for the daily output.
- Curing yard: space where fresh units are protected from sun and fast drying in the first days, with room for the forklift or crane to work.
- Foundation: a level concrete base with enough bearing capacity for the machine.
Examples from the field
The 3000 × 2000 mm box culvert production plant we set up in Türkiye is an example of serial machine production at this size. For the crane-free PRO system, see the CPM 1400 PRO we shipped to Costa Rica, which makes box culverts up to 1200 × 1200 mm alongside concrete pipes.
Frequently asked questions
Can the same machine make both concrete pipes and box culverts?
Yes. Our concrete pipe machines make both after a mould change; each size needs its own mould.
Which machine is needed for box culverts larger than 2000 × 2000 mm?
Sizes above 2000 × 2000 mm, up to 3000 × 3000 mm, are made on the CPM 3600.
Why is a PRO machine faster?
The product is demoulded in the machine, so there is no waiting for the mould to be craned to the yard and back; the machine keeps producing. That is why output is about twice as high.
Which machine should I start with?
The box culvert sizes most in demand in your market decide it. For sizes up to 1500 × 1500 mm, the fast crane-free PRO machines are the right choice; for larger sizes, the CPM 2400 or CPM 3600. See all models on our concrete pipe machines page.
Tell us the box culvert and pipe sizes you want to make — message us on WhatsApp and we will send you the right machine, mould list and price. Installation and operator training are included in the price, and our machines carry a 2-year warranty.
