Concrete is usually a mix of water, cement and aggregate, which are heavy, high-volume materials. How do concrete services companies manage to pump it up tall buildings and get it to arrive where it’s needed at just the right consistency?
The answer lies in using a pump that has enough power to pump the concrete and enough resilience to cope with the water and aggregate particles that it encounters. There are two kind of pumps that can do this.
Peristalsis or pistons?
The first type of pump uses a peristalsis movement. That’s what our intestines do when they’re digesting our lunch – in effect, squeezing the tube behind the load to move it forward.
The second uses a piston action with rotary valves that are able to cope with the aggregate present in the mixture. The pump chamber is emptied by a number of pulses, but the pipe delivering the concrete is constantly full. Incredibly, 130 cubic metres can be shifted in one hour using this method.
The peristaltic version isn’t quite as powerful as the piston version. It has a set of rollers that power the pipes moving the concrete, and they can move 20 cubic metres an hour. While the piston method uses a 20cm pipe, the peristaltic method uses an 8cm one.
Each time the pump fires, it has to move everything that’s in the chamber; otherwise, what’s left there will start to harden. The pressure has to be kept low or the mixture gets compacted, affecting its quality. It’s clear that if you need concrete pumping services http://www.monstermixconcrete.co.uk/concrete-services.php, you need to use a firm of experts who have plenty of experience.
What’s the highest that concrete has been pumped?
There are lots of contenders for the title, but Construction Week gives the world record for vertical concrete pumping to the Burj Khalifa in Dubai.
The actual building is 828m tall, but the pumping record stands at 601m. Reaching these dizzying heights took the concrete 40 minutes from leaving the hopper to being discharged at the delivery point. This was delivered by a piston pump, and after every stroke, 26 tonnes were carried by the pump.
If you think that sounds like a lot, you’re right; it’s the equivalent of five large elephants!