Long-distance concrete pumping is not for the faint of heart. And when it comes to tunnel construction, it is more often than not the order of the day. In this particular post, we will look at the pressure component in long-distance concrete pumping. How does one go about calculating pressure for a specific job? And how exactly do you know whether your machine is up for the task at hand? Join us as we explore the wonderful world of pressure in long-distance concrete pumping.
Checklist: is your machine up for the job?
Three factors will determine whether your machine can get the job done:
- The machine’s available power.
- The maximum output you wish to reach.
- The pressure needed to carry out the job.
These three factors come together in the following formula:
Power [kW] = (Pressure [Bar] x Output [m3/h])/25
As such, when you calculate the required pressure, you will know whether your machine can carry out the job and at what output capacity.
The pressure is building or the art of estimating your project-specific requirements
Pressure is an important component when it comes to your machine’s capacity to perform a long-distance pump. And calculating it, albeit for estimate purposes, is not exactly a piece of cake – unless you have the right tools, that is. Just like any other calculation, the process involves filling in blanks before the final unveil (read: before the magic number is revealed). So without further ado, here’s a look at the variables you’ll need to shell out in order to get your hands on your pressure requirement estimate. Please keep in mind that you will later need to validate your results with on-site testing.
- Start-up pressure – as a rule, this element is standard across the board and consists of a recommendation of 20 bars.
- Height in metres – this variable takes into account variations in height from your point of pumping to the destination.
- Total length in metres – by this we mean actual length, not just flat length.
- Number of 90° elbows
- Number of 45° elbows
- Number of pipe couplings
- Number of end hoses (5m) – your ends hoses, which are generally of the 5-metre variety, will help to guide your concrete in the right direction.
- Safety factor in % – an error buffer.
Now this is where things get interesting for you. As we know that math isn’t everybody’s forte, we’ve put together a special calculator that will do the dirty work for you. So those variables listed above? Simply enter them into our tool, and you will be rewarded with a fresh estimate of your long-distance pumping pressure requirements. Not too shabby, eh? You can download it for free by clicking the button at the bottom of this page.
Did you know that. . .?
In order to be considered long distance, a concrete pumping effort must span a distance of at least 400 metres?
One more thing
Our formula was drawn up with a medium-grade concrete in mind. To determine the friction coefficient of your particular concrete and therefore obtain a more accurate value, you will need to conduct your own tests on site using a SLIPER rheometer.