Transcrete recommends that all operators attend a recognised training course. For course information contact the C.I.T.B.

Planning
Pre - Delivery
Pre - Pumping
Pumping
Trouble shooting
Clearing the line

Planning

What is the concrete pump output?
What distance will it pump?
Will it pump your mix aggregate?
Can you handle the delivery pipeline?
Is your access good for the concrete trucks?
Are you able to control concrete deliveries?
Do you have washout facilities to hand?
Is your workforce trained to pump concrete?
Is your pump driver in contact with the placer?
Then ask what is your fall back position?
Can you stop concrete deliveries fast?
Do you have an alternative concrete supplier?
Do you have standby pumping available?
Can you reduce the intended pour?
Do you have spare pipeline on site?
Is your team aware what to do if the pipe blocks?
Have you any space for waste concrete?

Predelivery

Ask if they really want a trailer pump
Ask what they intend to do with the pump
Do they have an experienced pump operator?
Should you provide an operator?
How are they moving the pump around site?
Are they able to clean the pump adequately?
Then make sure you are covered
Confirm delivery/hire arrangements
Give the pump a full pre-delivery service
Have you enough backup for a breakdown?
Never send a pump that is inadequate
Tell your delivery driver what to expect
If the site has no water available, Say no!
Better to lose a hire than a concrete pump

Pre Pumping

Let's check out a few things first.

1 Team talk, does everybody know what we are doing and what their role is?
2 Check out the pumping line, are the clamp pins in?
3 Make sure the line is secure and not bridging gaps that will sag when its full of concrete.
4 Have you got a good communication link?
5 Are you able to contact the concrete plant, do you have a contact number to hand?
6 What delay is there between wagons? How quickly can you alter this arrangement?
7 Do you have grout mixing facilities and an adequate supply of cement? Water should be on hand, if not, you must not start
8 Who is testing the slump of the concrete, the pump operator may not have time
9 Last check with the pumping team, is everyone in place
10 When the first wagon arrives and has been checked, the line can then be groute

Pumping

A wide range of mixes can be pumped successfully, slump in itself is not the limiting factor.
The slump is to the specification set by the contract planners, you are ready to tip the concrete
into the hopper.
Pump as much grout as possible from the hopper before tipping concrete in, then fill the hopper to just below the grille before starting to pump the concrete.
Many modern concrete pumps have variable output Controls, set this control low. Set the engine speed at the working level indicated by the pump supplier. The concrete should soon reach the outlet.

Troubleshooting

Mix Design

Concrete is placed under pressure when pumped, this pressure increases the further the concrete is pushed along the pipe.

Some mix designs are inadequate for pumping under pressure, concrete that may pump quite well through a boom pump may not pump at all through a fixed line. This is because most boom pumps have a relatively short 125 mm dia. pipeline, the pump can develop a high output with very little line pressure.

If the pressure needed to get the concrete through the line is the same for a trailer pump using a fixed line, this too will succeed. If however, the fixed line is a smaller dia. or as is often the case, l-o-n-g-er, a higher pressure is needed to push the concrete through the line. If the concrete mix design is at its limit, the extra pressure needed to pump the concrete, will force the fine content of the mix through the larger aggregate, this separation of the mix causes a blockage. It is simply a poor mix design, not a pumping failure.

Concrete blocks in the line

Reverse the pump, count three strokes of the piston. Attempt to pump forward slowly. If the line blocks again. Reverse the pump again for three strokes.

Locate the blockage, working from the pump, walk along the length of the pipeline lightly tapping the pipe with a steel bar or small hammer, the sound will change significantly in the section of pipe where the concrete has not reached.

Break the coupling on either side of the blockage and check the content of the pipe. The section near the placing end should be wet with grout, if not there has been insufficient grout in the line and you will have to remove the block and re-grout the line in front of the concrete.

If there is a significant amount of wet concrete and grout ahead of the block and a solid section of packed concrete behind this, (nearer to the pump) assuming you pumped slowly when starting. The mix has separated, put a hold on deliveries.

Take off the blocked pipes and empty by hand, avoid hitting the pipes with a hammer, this will dent them and have an adverse effect on later pumping operations.

Clearing the line

Is a technique used by boom pump operators that is often not that successful on fixed lines.

By opening the hopper trap door allowing the concrete to fall from the hopper. Placing a sponge ball in the end of the outlet hose, then pumping in reverse produces a negative pressure in the concrete line, (suction) In theory the concrete is drawn back to the pump aided by atmospheric pressure in the end of the pump line.

A boom pump line will empty simply by the concrete falling out of the drop pipe and the boom remaining pipes will empty as the concrete is drawn towards the pump aided as much by gravity as by suction.

Fixed lines are often longer than boom pump lines and almost without fail will be laid level. This rules out any help from gravity. The pipeline clamps must also be as near to air tight as possible, in short, this is a great idea that doesn't work as well as we would like it to.

So trailer pumpers have to do it the hard way. If you plan ahead, it can be a doddle. Just make sure you have everything ready, you should have started to clear the line within four or five minutes of finishing pumping.

With training and teamwork you can do it.