Concrete Pump Blockage: Its Causes & Clearing Steps

Concrete pumping allows for effective concrete placement in tall structures as well as foundations, bridges, tunnels, and other construction projects. However, if the movement of concrete is interrupted during the pumping process, nothing can be accomplished.

Concrete Pump Blockage is not only a problem in terms of productivity; it also raises pump pressure, damages equipment, wastes concrete, and increases the risk of accidents. The major causes of the blockages can be eliminated by using the suitable type of concrete mixture, maintaining the pumping equipment properly, and observing the relevant operation norms.

What Causes Concrete Pump Blockage?

Concrete pump blockages generally come from three areas: the concrete mix, the pumping pipeline, and operator-related issues. Identifying the cause is important because simply forcing more pressure through the line may make the situation worse.

1. Problems with the Concrete Mix

The concrete needs to be balanced in terms of cement paste, water, fine aggregates, coarse aggregates, and additives.

Well-graded aggregates can create empty spaces inside the mixture, allowing separation of water and cement paste from each other. Bleeding can occur, leading to a lack of lubrication for coarse aggregates.

Poor mixing can also be a problem. When cement paste fails to cover aggregates properly, segregation is possible through the pipeline.

Also, fresh mixes can harden if left too long before being used. High temperatures result in faster setting of the mixture, so pumping pressure increases.

A good water reducer or superplasticizer should be used to reduce the necessity for water consumption in the mixture, but it must be compatible with the cement used and overall mix design.

2. Pipeline and Equipment Problems

Even with a good concrete mix, the pumping system may still fail if not maintained properly.

Before starting pumping, be sure to know the following:

• Pipeline diameter and configuration
• Pump power
• State of pipes and hoses
• Connections and gaskets
• Reducers
• Elbows and bends
• Leftover concrete in the pipeline

Old concrete in a dirty pipeline can harden and create problems for new concrete. Broken connections and gaskets can cause the cement mix to leak, which will leave heavy aggregates behind, resulting in possible stoppages.

Strong or excessive bends make the pumping harder. Sharp transitions in pipeline diameter can cause spots where aggregates get stuck.

One should pay attention to flexible discharge hoses. A kink makes the internal diameter of the hose decrease, which leads to stones in the hose itself.

3. Operator Error

Correct installation and skilled usage of equipment are crucial for blockage prevention.

If the pipeline has been properly designed and installed before the concrete pouring starts, it should be impossible to make unnecessary additions or modifications when pouring. Putting in a dry hose and the process with any other kind of mix can disrupt the lubricating layer.

Also, operators should keep track of the consistency of the concrete mixture during the process. If there are any changes in slump, segregation, excessive aggregate or something unusual coming from the mixer, there might be some problems arising.

How to Identify a Concrete Pump Blockage?

Identifying a blockage as soon as possible can help avoid complications. The sudden increase in pump pressure is among the most distinct signaling factors. Thus, continuous monitoring of the pressure gauge during the pumping process should be undertaken by an operator.

In addition, it is possible to guess the place of the blockage based on the pressure increase. Indeed, if the pressure reaches the maximum level quickly, it may be stated that the blockage is near the pump or reducer, whereas a slower pressure rise indicates that the blockage is farther along the pipeline.

Conducting an inspection of the pipeline is obligatory, especially when it comes to reducers, elbows, joints, and the discharge hose section.

Sounds can be useful as well. Thus, if a checked section produces less sound when compared to the uncovered section of the pipeline, it means that the blockage may be present there.

Clearing a Concrete Pump Blockage

Once a blockage is suspected, safety is paramount. Blocked pipelines may also have considerable built-up pressure, making loosening parts of the pipeline very dangerous.

Step 1: Stop Pumping

Cease all pumping activities and keep workers away from the working area of the blocked pipe.

Step 2: Release Pressure Safely

The pipeline must be confirmed as depressurized before any pipe part is removed or opened. Never loosen a coupling while the pipeline is pressurized.

Step 3: Identify the Location of the Blockage

Inspect the possible areas where the blockage could occur: reducers, elbows, fittings, and flexible pipes. This will help to find the best way to eliminate the blockage.

Step 4: Try Controlled Pump Reversal

If the blockage is small, some pumping systems allow the operator to reverse the pump for a short time and continue pumping forward. However, this has to be done according to the instructions of the equipment supplier and by trained staff.

Step 5: Open the Line Safely

If reversal does not clear the obstruction, the affected section should be isolated and opened only after pressure has been safely released. Personnel should remain clear of the opening because residual concrete can still move unexpectedly.

The blockage can then be removed using appropriate procedures and equipment.

Never Use Compressed Air to Clear a Blockage

A very important safety principle while pumping concrete is not to use compressed air to unblock the pipes. The use of compressed air can generate a dangerous amount of potential energy in the pipe. If something suddenly happens and the blockage is offset, there can be violence caused by a burst of concrete or aggregate coming out.

Compressed air can be used in a few specific situations for cleaning already unobstructed equipment, fair enough as long as the manufacturer’s guidelines are being followed.

How Can Concrete Pump Blockages Be Prevented?

It’s much more advantageous to prevent a blocked pipeline than to fix it during a crucial pouring event.

Before starting the pumping process, it is essential to ensure that the composition has the following features:

• Proper grading of constituents
• Sufficient amount of paste
• Required workability
• Required recipe of water-to-binder ratio
• Correct concentration of admixture
• Mixing

Another important aspect of the pipeline is to carry out its inspection and maintenance. It is recommended to avoid unnecessary curves, transitions, or damage to tubes.

When pumping over long distances or in hot weather, it is very important to keep the desired consistency of concrete.

The Role of Sakshi Chem Sciences

At Sakshi Chem Sciences Pvt. Ltd, we recognize that dependable performance in concrete is not contingent on just one product. We regard several factors in achieving a successful concrete pour, including proper mix design, compatibility of raw materials, the working conditions for application, and correct selection of the admixture.

Sakshi Chem Sciences specializes in manufacturing, supplying, and exporting various kinds of construction chemical solutions with 20 years in the industry.

Our advanced R&D facility is fully equipped, and modern manufacturing units provide advanced services for product development and quality control.

Our technical experts assist customers in finding appropriate admixture solutions that meet the requirements of concrete, weather conditions, and project functions.

Conclusion

Blocking of a concrete pump refers to the failure of a concrete mix, bad condition of the pipeline, insufficient handling, or incorrect working procedures. Some of the reasons such as differences in weight, moisture, and water in concrete, wrong grade of aggregates, solidified concrete remnants, bends in the pipe, and broken channels, can cause problems while pumping concrete.

Therefore, the best way is to avoid blocking of the concrete pump by using a right concrete mix, choosing appropriate additives, performing proper fixings, and employing trained operators. In case of blocking, pumping should be stopped, pressure should be let down, and the blocking should be dealt with using correct techniques.

Using correct preparations and reliable construction chemicals from Sakshi Chem Sciences, concrete manufacturers, and contractors can maintain consistent pumping, minimize inevitable downtime, and establish reliable concrete placement.