Pumped Concrete is the concrete which is transported to higher levels through pumping with concrete pumps. Pumped concrete is employed when an enormous amount of concrete is required at a higher elevation in situations where different methods of transportation aren’t feasible.
Concrete pumping has been in use for over 50 years. In the present scenario massive amounts of concrete are transported via pipelines for long distances, frequently to construction sites which may not be accessible via other methods of delivery.
The process of pumping concrete is based on an hopper through which concrete is pumped out of the mixer. The mixer is then fed back to the concrete pump and then the pipelines for delivery through which concrete is transported.
Concrete Pumps , Pumping Capacity and the Pumping Mechanism
In general concrete pumps are placed on a truck or on trailers. The pumps can be electrically or diesel-powered. Concrete is pumped through the pipe with a diameter ranging from 100mm and 180mm. The most well-known and ideal diameter for pumping normal is 125mm.
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The latest portable concrete pumps made in other countries are currently in their fifth generation, with a huge power, high capacity and a highly solid hydraulic system. Pumps can move concrete up to the height of almost 500m or reach horizontal distances that can reach 2000 meters. They are equipped with hydraulic systems that can manage create concrete pressures as high as 200 bar. The output of the pump ranges from 19m3 to 150m3 each hour. Different companies have come up with various types of valves or systems. A rock valve the ‘C valve system flat gate valve and the ‘S’ trunk systems are all commonly used, based on the preference of the buyer and preference, or the company’s patent-pending method.
But, it should be mentioned it is believed that the valve has its origins in Germany. The German language, the word rock refers to the skirt of a woman and because the valve shares similar shapes and movements, it is referred to as that.
Concrete pumps are typically built with enough protection to withstand negative usage. They are not sensitive to harsh treatment and operate on construction sites. They are constructed with solid construction and are easy to maintain.
The gate valve is able to cut through concrete, and is fully lined with extremely wear-resistant steel and is easily replaced when it wears out. Rams are made from special vulcanized rubber that is coated with steel core and they are simple to replace since they feature quick-release connectors. The core of the metal is completely enclosed to prevent cement adhesion.
Control systems in every concrete pump are compact, hydraulic and dirt-sensitive. This pump’s hydraulic settings are output controlled which means it optimizes motor power use at the optimal speed and pressure. Its instrument panel nicely organized and displays the pressure of the system. It also has operating controls.
The outlet of the pump consists of a taper as well as an attachment device that clamps to pipeline. It’s simple and quick to clean and features an easy side swing. The agitator keeps that concrete’s agitated shape with two different batches that are fed to the bin. The high-torque drive makes sure that the concrete remains in continuous rotation, even in rough and stiff mixes.
The concrete pump conveying device is set up on the chassis of a truck. The hydraulic drive of the pump is directly driven by the engine of the truck. A water pump that is hydraulically driven is connected to the tank. It is employed to evacuate conveying pipelines using pressured water as well as to clean and cleaning the concrete pump. The swivel-pipe system developed by Rock Chieber is typically mounted at the top of the truck mounted pump instead of the gate valve system.
The main feature of this swivel pipe is the absolute and perfect movement balancing in any conditions. This ensures that the bearing and shaft unaffected from wear. Swivel pipe systems improve the pumping capability even over larger distances and more vertical reaches since they are more expensive than flat gate valves on building sites with high rises. However, flat valves can be used for poor, hard aggregate concrete is oversized or to be pumping.
Concrete pump manufacturers typically have the maximum theoretical output, or pumping capacities in cubic meters/hour. This is based on the distance over the pump it is able to pump, the size of the line and the maximum pressure for the line.
The output of the pump for pumped Concrete
The output of the concrete pump is contingent on a variety of factors, including:
The length of horizontal pipe.
Longness of vertical pipe.
Many bends, particularly designed bends.
Diameter of delivery pipeline.
Length of flexible hose.
Variations in the diameter of lines or reducers.
The concrete’s working capacity is determined by the slump.
The concrete’s cohesiveness.
The type of aggregate that are used in concrete.
The figure below shows the line pressure and pumping rate in relation to the diameter of the line as well as pumping distance and the slump. When the desired rate of pumping is determined, the line’s diameter can be determined together with the pumping distance as well as slump, and then the expected line pressure can easily determined. For instance, if the desired rate of pumping is 25m3/hr then the line diameter, the pumping distance and the slump are determined as 125mm 300m and 80mm, respectively. So, the pressure of the line will be 36.40 bars.
Concrete pump performance estimator
In reality, the pump is unlikely to remain in operation for a long time.
It is to be noted that the maximum pressures listed in the manuals and leaflets cannot be utilised since the safety valves are pre-controlled and begin to open at 90 percent of the set pressure.
For all pumps driven by hydrostatic force, it is mandatory that the working pressure do not exceed 90 percent of the pressure stated by the manufacturer, i.e. the set pressure. In addition to the previous details, the dimensions of the line, layout of the job concrete properties and the output of the pump calculated from estimates of downtime are also considered when determining the required pumping pressure.
The combination of output and the pressures required for pumping is a good way to select the most suitable pump for the task.
It is important to keep of the fact that, unless the location is equipped with the right infrastructure to make concrete that is consistent and of good quality and speed, no attempts should be made to perform the pumping because it could result in devastating outcomes.
Concrete production and the transportation for the pump plays an essential part in the pumping process. If a boom to place it on isn’t readily available, the managing flexible hoses and other pipelines may cause a major issue when calculating downtime.
Concrete compacting should be able to handle the placement rate. Formwork designs require careful analysis because the hydrostatic pressure resulting from the rapid growth of concrete within the formwork is much higher than that of manual placement of concrete.
The reinforcement layout needs to be altered to permit the lower of the flexible hose closet down to the point of placement. For the beginning, 30m3/hr to 40m3/hr is sufficient in the event that the points above are taken care of. Besides the selection of concrete pump and pipeline, equipment such as truck/mounted mixer, automatic/manually-controlled batching plant, and placing boom plays a very important role in successful concrete pumping operation.
Concrete is usually fed into the concrete pump hopper by an on-truck mixer. It should be noted that the correct selection of the mix of different equipment could greatly affect concrete’s quality and speed and cost of concrete.
Benefits of Pumped Concrete
One of the biggest benefits of pumped concrete is the fact that concrete can be moved vertically and horizontally in one move. The output of the pump typically ranges between 30m3 and 150m3 of concrete per hour.
The concrete pump can be among of the most effective tools for quality control. This is the only technique that any change in the consistency of the mix or its performance can be readily identified at the point of pumping by watching the pressures of the pumping. It is a an inconspicuous quality control device and will not handle any concrete that is excessively hard, unmixed or non-cohesive. It also refuses to handle concrete that is inconsistently incorrect.
In the UK the situation is not difficult to form large gangs of laborers regularly for concrete pours and, consequently for concrete pours that are large, it is beneficial to utilize concrete pumps for concrete at a more rapid speed.
Pumped concrete generally has high cohesion, high workability and therefore, offers a more attractive appearance and durability for concrete constructions. Concrete can be used in areas that are difficult to access. Mass concrete can be completed in a short amount of duration and at a high speed with no cold joints.
Concrete pumps can assist in accelerate the completion of contracts and, in turn, contribute to an increase in cash flow, decrease in overheads on site, and better use of resources.
Pipeline that is used to deliver the concrete takes up very little area and is easily extended or taken down.
Concrete delivery is continuous streams. If the pump’s mobile boom is employed it is possible to use both horizontal and vertical motions for putting concrete in the ground can be made, cutting out the need for elephant trunks and drop chutes. Concrete is best placed closer to the final position, which it is less dragged and shoveled, thus making sure that concrete is not separated from the mix.
Benefits and disadvantages of pumping Concrete
The capacity to convey concrete pumps is limited, which means that the distance of conveying and the height of concrete is limited. Concrete that is pumping is not ideal for situations where it is too long and the vertical height too high.
Pumped concrete must have the ability to pump of the concrete that is moved, which can increase the water-to-cement ratio of the concrete. This concrete is susceptible to shrinkage and cracks.
The concrete slump utilized for the purpose of making concrete used for the pumping of concrete is large and the pouring rate is extremely quick. Pumping concrete makes the measurement of the concrete’s pressure to grow, and the usage of pumped concrete is more structurally demanding to formwork.
Pipeline to pump Concrete
The pipeline that supplies concrete is constructed of seamless pipes made of premium precision steel. It is made up of bends and straight section, which are connected with disconnectable couplings. The inner diameter of pipelines commonly used ranges between 80mm and 180mm, as well as length ranges from 0.5m to 3 meters. Apart from 90o bends 15 30, 30o, 45o and 60o bends also are available. The pipe’s diameter is contingent on the following elements.
Dimension and kind of the concrete pump.
The required horizontal and vertical spacing distances.
The quality of the concrete that is to be pumped in relation to its consistency.
The maximum size of aggregates.
The cumulative impact on bends, rises vertically and flexible hoses on laid pipe is calculated as a percentage of the length of the horizontal pipe. The correlation for more than 100mm internal diameter pipe is as is as follows:
1.m vertical rise equals 2m up to 3m horizontal length
One 90o bend equals 3m of horizontal length
One 45o bend equals 2m of horizontal length
One bend of 30o = 1m of horizontal length
1m rubber pipe = 2m steel pipe
For UK conditions the 125mm diameter pipe is the most appropriate. However, a diameter of more than 150mm pipe is not recommended in any way. Pipes with various sizes are available in thicknesses that range from 4- 7 millimeters. For demanding pumping tasks such as buildings with high rises 7mm thick pipes are suggested, while for regular pumping jobs that do that do not require enormous vertical lifts or hard concrete, 5mm pipes are appropriate.
Normally, at the conclusion of each delivery line the hose can be kept flexible to facilitate the placement and handling. However, more than 5m of flexible hose isn’t recommended. Flexible hoses with two to four layers of high-tensile steel cable reinforcement are readily available and are able to handle pressures up to 50 bar. Its tube rubber is soft and resilient to abrasion.