Choosing a concrete mixer for small jobs: matching discharge to the pour

Size the machine on the concrete that has to arrive at one point in one go, not on the word small. A strip footing, a bay of village road, a drainage channel, a slab repair in an old district a truck mixer cannot turn in — each is a job of a few cubic metres at a time. The number that decides the machine is therefore a discharge volume per load, and the number that decides whether it reaches the pour at all is a width. Of the sixteen self-loading mixers in our product record, fourteen carry a discharge figure stated by the plant, and those fourteen run from 1.0 to 4.5 cubic metres a load. Two carry no discharge figure at all, and they are not sized on this page or anywhere else on this site.

These are the jobs a ready-mix supplier serves badly or not at all, and the reason is delivery rather than price. A truck mixer has to reach the pour, turn, and discharge inside the time the load allows, and a job that is small, remote, or reached down a lane defeats at least one of those three conditions. The same holds where there is no batching plant within reach: a rural self-build, or a road job that moves along its own alignment all day. The question to settle before buying anything is therefore not whether ready-mix is cheaper, but whether it will turn up at the pour you actually have. We hold no sourced figure for minimum load charges or delivery radii in any market, so none appears here. What we can state is what leaves the drum, because the plants state it.

Read the number in a model name as a discharge figure rather than a drum volume, because on this site the designation is taken from the top of the discharge range the plant states, not from the litres the drum holds. On the SLM-18 the plant states 1.6 to 1.8 cubic metres a load, and the drum's geometric volume is 2,900 litres, a separate and much larger number. A drum is never filled to its geometric volume and a mix is not water, so a litre figure on a nameplate is not concrete you can place. The fourteen stated discharges, in order, are 1.0, 1.3, 1.5, 1.6–1.8, 1.8, 2.0, 2.4, 2.4, 2.5, 3.0, 3.0, 3.5, 3.8–4.0 and 4.0–4.5 cubic metres — twelve distinct values across fourteen machines, because 2.4 and 3.0 each appear twice on different machines.

Three of those fourteen are ranges rather than single figures, and a range is a range for a reason: plan the job on the bottom of it. A machine stated at 1.6 to 1.8 cubic metres is a two-load answer to a 2.0 cubic metre footing, and the batch joint that produces is a decision for your engineer rather than for a specification table. The two figures that repeat, 2.4 and 3.0 cubic metres, sit on four different machines, one of which carries no overall dimensions at all, which is why the load and the access are treated here as two separate questions rather than one. Only one model on this site, the SLM-18 at 1.6 to 1.8 cubic metres, has enough of its specification confirmed in writing for a figure to be published against its model number. The rest of the ladder is given here as a range, and that is deliberate.

A larger discharge does not reliably mean a wider machine, so check the width itself rather than infer it from the load. Ten of the sixteen self-loading mixers carry a set of overall dimensions. Across those ten the widths are 1.60, 1.65, 1.80, 1.85, 1.95, 2.10, 2.15, 2.15, 2.21 and 2.30 metres, and the lengths run from 4.35 to 7.06 metres. The narrowest of the ten is 1.60 metres across and 4.35 metres long, which is the machine to ask about first if the site is reached down a lane. But the ladder breaks in the middle: the SLM-18, at 1.6 to 1.8 cubic metres, is 2.21 metres wide and 7.06 metres long — wider, and 1.76 metres longer, than a 3.0 cubic metre machine in the same record that measures 2.15 metres across.

One qualification belongs with those ten sets, and it is not small. Nine of them come from a table of overall dimensions supplied by the plant that gives a single set of figures without saying whether the machine was standing in travelling posture or with its bucket raised. Width barely changes between the two postures, so the widths above stand. Height changes a great deal. The one machine measured from a dimensioned drawing, the SLM-18, stands 2.58 metres over the body in travelling posture and 3.45 metres with the bucket up — a difference of 870 millimetres. So this page publishes no travelling height for the other nine, and no height should be planned against a gateway, a canopy or a container door until the plant confirms which posture its table records. The same dimensions decide how a machine ships, which the container guide on this site works through.

A day of one pour and a day of six small pours in six places ask different things of the machine, and only the second explains why a self-loader exists. The cycle is the argument: the machine fills its own bucket from the aggregate pile, mixes while it drives, and discharges through its chute at the pour point, so nothing in that sequence needs a batching plant or a second vehicle. Five of the sixteen mixers carry a plant-stated travel speed — four at 0 to 36 km/h, and one, the SLM-18, at 0 to 23 km/h with full-time four-wheel drive. Fifteen of the sixteen carry water on the machine in the configuration list supplied with it: seven with a self-draw controller and an external suction pump, eight with a large tank and a draw system.

No plant has given us a loads-per-day count, an output per hour or a cycle time for any of the sixteen, so none appears here. That arithmetic is yours to do, against your own haul distance, your own stockpile and your own crew, and it will be better than any average we could print. What the record does support is the shape of the day: one machine, moving under its own power between pour points, carrying its own mixing water, with no second vehicle in the sequence and nothing to wait for between placements. Whether that is worth more than a drum mixer on your sites depends on how far apart your pours are and how often the front moves, which is a question about your work rather than about the machine.

A drum mixer stops being enough when the pour front moves. The difference between the two machines is where the concrete is made and who moves it afterwards. A drum mixer makes concrete where it stands and someone then has to carry the mix to the work, so the barrow run sets the pace of the pour and fixes how far the mixer can usefully sit from it. A self-loading machine loads itself, mixes while it drives and discharges at the pour point, so that distance is driven rather than walked and the work is allowed to move during the day. That is the whole of the structural case for the larger machine, and it has to be made in cubic metres placed on your own sites. No market volume or import count appears here, because the figures we hold are filed by customs heading, and a heading does not tell you which machine was in the box.

The photographs published on this site show the jobs this page is about, and four are worth naming here: a strip pour being screeded beside a paddy field with a three-wheeler bringing the aggregate, a footing filling with mountains behind it, tied reinforcement in timber formwork with an excavator and a tipper working the same footing, and a machine discharging onto a village road with its drum crusted in cured concrete. They are photographs of working sites, not renderings and not stock images. What they cannot tell you is where they were taken or which model is in them. No location is verifiable, so no country is attached to any of them, and none identifies a model — so no photograph here is used to show what a given discharge size looks like on the ground.

The omissions here are deliberate, and naming them is the reason to trust the figures that are present. Not one of the sixteen mixers in our record carries an output per hour, a loads-per-day count, a cycle time or a fuel consumption, so no productivity claim appears on this site and none will until a plant puts a figure in writing. Two of the sixteen carry no discharge figure, and they are sized nowhere on this site. Six of the sixteen carry no overall dimensions at all, so for those we cannot tell you whether the machine passes a gateway, and we will not estimate it from a machine of similar load. There is no price on this page, and this site quotes no price for any machine we sell. Each of those gaps is on the list of questions put to the plants, and this page changes when an answer arrives in writing.

What is useful to send instead is four things: the volume you place at one pour point, the narrowest gap the machine has to pass, whether the pour front moves during the day, and the destination country and port. The first two choose the machine, the second two decide how it ships and what it must be certified against, and none of the four commits you to anything. A model number is welcome but not needed; those four answers are enough to narrow the range. Send them through the quotation form on this site and the answer comes back as the models whose figures we hold, with the unconfirmed fields named as unconfirmed rather than filled in with something plausible. The range as a whole, gaps visible, is set out on the self-loading mixer page.