Oct 03

Pumping Concrete Troubleshooting: How to avoid Blockages

 

Troubleshooting Concrete Pumping ProblemsAnyone who has ever pumped concrete will have encountered, at some point, problems with pump line blockages. They are a part and parcel of the job, especially in the beginning when operators are learning the ropes. So learning what cause them is a first order on the agenda for any operator. The good news is that most blockages can all be traced back to 3 main causes:

1. Problem with the mix (think batter recipe)
2. Problem with the pipe line (think capacity & maintenance)
3. Operator error (think proper handling)

1)   MIXING ISSUES:

Problem: Insufficient mixing
Insufficient mixing of the concrete can result in segregation or separation of heavier particles moving to the bottom of the concrete.
Solution: Ensure proper coating of cement grout and lubrication of the mix. Also avoid overworking cement that is prone to bleeding.

Problem: Concrete Bleeding
Concrete can sometimes bleed, meaning that the aggregates  (solid components) do not evenly retain the mixing water. This could come from the sand not being well graded and the water flowing through the tiny channels or floats to the surface of fresh material (since water is the lightest of all the mix constituents).

Solution: Use a different sand, more cement, entrained air or fly ash to reduce bleeding. Avoid remix the bleed water during the finishing of the surface. Instead wait until it has evaporated. Make sure that the evaporation is not faster than the rate of bleed, otherwise plastic shrinkage cracking could happen.

Problem: Premature setting
If, for some reason, the temperature on the site is high on that day or the pumping is delayed due to site issues or traffic, your concrete can set too quickly. This means that the mix could become too thick to pump, not fill the chambers and as a result put undue pressure on the equipment.
Solution: Plan ahead. Check the weather for the week, make sure everything is ready on the site to avoid delays, use the proper mix for the job and if all else fails, use ad mixers (for cold or hot weather).

2)   PROBLEM WITH THE PIPE LINE 

Sizing the system for the job is essential to avoid common problems. Here are some common pitfalls:

  • You have insufficient pump capacity and motor horsepower to push the concrete through the entire pipeline.
  • The aggregate you use is too large for your line so you will need to switch to a larger diameter to solve the problem.
  • Did you forget to properly clean your pipes on your last job?
    This will most likely result in blockages where the old concrete hardened, not to mention causing segregation and bleeding. Don’t cut corners, even if it means working overtime!
  • Are your couplings, gaskets and weld collars are in working conditions? If not, you risk grout loss. Not good!
  • How many short and sharp bends do you have in your pipeline? Do you have reductions in your pipeline’s diameter? Bends, on the one end, increase the pressure while reductions, on the other, slow the flow. But both increase the risk of blockages wherever they occur. So now you know: check and recheck your line.

3)  OPERATOR ERROR

Novice concrete pump operators may not know that hoses and pipes should only be removed and not added once the pour is in progress. Adding a new hose with dry internal walls could cause a blockage.

Then, there is poor handling of flexible hoses that can result in kinking and rock jam where the kink occurred. This is a double whammy, because not only will you halt or delay the job trying to clear the jam but the constricted aggregate in the line will contribute to wear and tear of the hose leading to an eventual hose rupture.

So make sure you have the right equipment for the job and that it is in good working condition. Using more cement or a larger diameter pipe will increase the cost of the job. So plan your work and work your plan. It will save you money on manpower and equipment cost over time.

For more information on concrete pumping and equipment sizing, give us a call at (503) 283-2105. If you have an older concrete pump that needs some TLC, we have a complete repair shop. Need new couplings, gaskets? We have it all. Check us online at UnitedEquipmentSales.com.

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Aug 16

5 TIPS TO SAVE MONEY ON CONCRETE PUMPS

Putzmeister-TK303 concrete line pump

In difficult economic times, we all need to learn to do more with less. This often means extending the life of our equipment by treating it with a little extra TLC. Prevention is the key.

Here are a few tips everyone should follow to do just that with concrete pumps:

 1.      Grease your machine

Main parts: lubrication of pump’s pivot points
Frequency: approximately every 2 hours of use

Note: Failure to grease your pump could result in potential failure of bearings and bushings, breaking down of equipment on the job, loss of productivity, costly repairs…

2.      Check fluid levels

Minimum: hydraulic oil, engine oil & slosh box
Frequency: Daily before starting the job.
Since it only takes a minute, don’t skip this step. Start making it part of your job routine.

3. Clean the pump

Areas: Pump water through the pump and the hose simultaneously.
Frequency: End of job/daily

Note: This isn’t something you can postpone, depending on the temperatures, concrete can harden in the pump and hoses anywhere from 0-2hrs!

4. Hire an experienced operator

There are many advantages to have an experienced operator.
Here are a just a few:

a. Safety on the job:  Knowing how to quickly react to pumping problems is paramount. It can save lives.

b. Proper hose connection (many deadly accidents have happened because of this).

c. Overall inspection of pump and hoses prior to starting the job.

5. Follow the manual’s procedure

Take a moment to scan through the manual that came with your pump. Only dealers will provide you with a manual when purchasing a used pump (brokers don’t always do) so if you are serious about your work, contact a dealer first. They will stand by their products and will help you make a more educated decision.

For product or brand specific information on used concrete pumps (Putzmeister, Mayco, Schwing, Olin and Reed ) or to find a great deal, visit: http://unitedequipmentsales.com/UsedConcreteLinePumps.php