How is pumped concrete constructed?

Can pumps also transport concrete? What kind of pump is it?

Concrete with the mixture can be transported through pipes using a concrete pump. 　　It is required to have good fluidity; the particle size of the aggregates should generally not exceed one-quarter of the pipe diameter. Pumping agents must be added to prevent the concrete mixture from separating and clogging within the pumping pipes, as well as admixtures that enable the concrete mixture to flow smoothly under pump pressure. Water reducers, plasticizers, aerators, and thickeners can all be used as pumping agents. Adding an appropriate amount of mixed materials (such as fly ash) can prevent stratification and segregation of the mixture, bleeding, and blockage of delivery pipes during concrete construction.

Construction method for pumped concrete 1. Pumping process: (1) Before pumping the concrete, pump out the water in the storage hopper through the pipes to moisten and clean them; thereafter, add cement mortar (or 1:2 cement mortar) with the same ratio as that of the concrete into the hopper. Once the pipes are lubricated, concrete pumping can begin. (2) When starting pumping, the pumping speed should be reduced, and the oil pressure changes should remain within the allowable range; only once pumping proceeds smoothly should the normal pumping speed be used. (3) During pumping, the amount of concrete in the hopper should be maintained at a level between 10 mm above the cylinder opening and 150 mm below the hopper opening. The efficiency of preventing inhalation is low; air can easily be drawn in, causing blockages in the tube. If too much air is drawn in, it will overflow during backflow and increase the load on the stirring shaft. (4) Concrete pumping should be carried out continuously; when the concrete supply is delayed, the pumping speed must be reduced. If pumping is temporarily interrupted, mixing should not cease. When the blade gets stuck, it is necessary to reverse the rotation direction, then rotate forward and backward for a certain period of time; only after forward rotation proceeds smoothly can pumping continue. (5) If the pumping is interrupted for more than 20 minutes and the pipeline is long, the pump should be started every 5 minutes to pump a small amount of concrete. When the pipeline is short, the pump can be rotated forward and backward 2–3 times every 5 minutes to move the concrete within the pipeline and prevent water separation. Prolonged shutdowns (over 45 minutes), especially in high temperatures when the concrete’s slump is low, may cause blockages in the pipeline; in such cases, it is advisable to remove the concrete from the pump and delivery pipes. (6) Pump from far to near, and gradually remove the pipes during pouring. (7) When pumping during the hot season, it is advisable to cover the pipes with warm straw bags to cool them down and reduce the temperature of the material entering the mold. (8) The total horizontal equivalent distance of the pumping pipes should be less than the maximum pumping distance of the equipment. 2. Cleanup work after pumping is completed: (1) Near the end of pumping, it is necessary to estimate the amount of concrete stored in the concrete pipes and hoppers, as well as the amount of concrete still needed at the pouring site (1.75 m3 per 100 units for pipes with a diameter of Φ150mm), in order to determine the amount of concrete that needs to be mixed. (2) When cleaning the pipeline after pumping is complete, an air compressor is used to push the cleaning balls. First, prepare the dedicated cleaning water, then start the air compressor and gradually increase the pressure. During the cleaning process, the conveyor pipe should be tapped from time to time to determine whether the concrete is nearing completion of evacuation. When there is still about 10 meters of concrete in the conveying pipe, the compressor should be slowly depressurized to prevent large explosions and injuries. (3) After pumping is completed, the concrete pump, distributor, and pipes should be cleaned immediately; once the pipes are removed, they should be stored separately according to their different specifications.

The original poster can also take a look at this post; I hope it will be helpful to you. A brief analysis of pumped concrete construction technology: http://bbs.hcbbs.com/thread-435936-1-1.html

High-quality material; highly recommended for learning*. It is sourced from the internet and intended solely for educational purposes. A concrete pump is an effective tool for transporting and pouring concrete. Powered by a pump, it delivers concrete through pipes, enabling both horizontal and vertical transportation in a single operation, thus delivering concrete directly to the place where it is to be poured – making it an efficient method for concrete transport. It can be applied in road construction, bridge construction, underground works, as well as in the construction of industrial and residential buildings. It is being vigorously promoted in our country; in Shanghai, over 90% of ready-mixed concrete is delivered by pumping, and good results have been achieved. http://www.scutde.net/t14courses/1412-efmdljiaif/hunningtu/3.3/IMAGE/3-38.GIF Figure 3-38 Concrete mixer truck 1—Water tank ； 2—Admixture tank ； 3—Stirring cylinder ； 4—Feeding hopper ； 5—Fixed discharge chute ； 6—Moving discharge chute: In China, piston pumps are primarily used at present. These pumps are usually driven by hydraulics and consist mainly of a hopper, hydraulic cylinders and pistons, a concrete cylinder, a distribution valve, Y-shaped conveyance pipes, flushing equipment, a hydraulic system, and a power system (Figure 3-39). When the piston pump is in operation, the concrete discharged from the mixer or from the concrete mixing transport vehicle is poured into hopper 4. The distribution valve 5 opens while valve 6 closes; under hydraulic pressure, the piston rod drives the piston 2 to move backward, and the concrete in the hopper enters the concrete cylinder 1 due to gravity and suction. Then, the direction of flow of the pressure oil in the hydraulic system reverses; piston 2 pushes forward, while distribution valve 5 closes and distribution valve 6 opens. The concrete mixture in the concrete cylinder is then forced into the delivery pipe through the “Y”-shaped conduit. With two cylinder blocks feeding and discharging alternately, continuous and stable discharge is possible. Different models of concrete pumps have varying discharge capacities, as well as different horizontal and vertical transport ranges. For commonly used models, the concrete discharge capacity is between 30 and 90 m3/h, the horizontal transport range is 200 to 900 meters, and the vertical transport range is 50 to 300 meters. At present, our country is able to deliver vertically to a depth of 400 meters in one go. If pumping is difficult at once, sequential pumping can be used. The concrete delivery pipes commonly used in fixed concrete pumps are steel pipes, as well as rubber and plastic hoses. With a diameter of 75–200 mm and a length of about 3 m per section, it is also equipped with elbows at 45°, 90°, etc., as well as tapered pipes. By mounting a concrete pump on a vehicle, a concrete pump truck is created (Figure 3-40). The vehicle is also equipped with a telescopic or foldable \"delivery arm\" whose end is fitted with a hose, allowing concrete to be delivered directly to the place of pouring, which makes it very convenient to use. The pumping concrete process imposes requirements on the concrete mix ratio: the ratio of the maximum particle size of the aggregate to the inner diameter of the delivery pipe should generally not be greater than 1:3, while for pebbles this ratio can be 1:2.5 ； When the pumping height is between 50 and 100 meters, a ratio of 1:3 to 1:4 is advisable; when the pumping height exceeds 100 meters, a ratio of 1:4 to 1:5 is recommended to prevent blockages. If lightweight aggregates are used, those with a low water absorption rate are preferred, and they should be pre-wetted with water to prevent excessive water absorption under pressure, which could reduce the slump and cause blockages in the pipes. Medium-grained sand is suitable; the proportion of sand that passes through a 0.315 mm sieve should be no less than 15%. The sand ratio should be controlled between 38% and 45%; it can be increased slightly if the coarse aggregate is lightweight aggregate. The amount of cement used should not be too low, otherwise the pumping resistance increases; the minimum amount of cement required is 300 kg/m3. The water-cement ratio should be 0.4~0.6. The slump of pumped concrete can be selected with reference to Table 3-12 according to different pumping heights. Concrete pumps should be used in conjunction with concrete mixer trucks, and the supply capacity of the concrete mixing plant as well as the transportation capacity of the concrete mixer trucks must be greater than the pumping capacity of the concrete pump, in order to ensure that the concrete pump can operate continuously without getting clogged. When arranging the delivery pipelines, they should be as straight as possible; turns should be gentle, pipe joints must be secure, and conical pipes should be used sparingly to reduce pressure losses. If the delivery pipe is inclined downward, it is necessary to prevent the concrete inside the pipe from being interrupted due to gravity-induced flow, as well as the inclusion of air, which could cause segregation of the concrete and lead to blockages. To reduce pumping resistance, an appropriate amount of water and cement slurry or cement mortar is pumped in first to lubricate the inner wall of the delivery pipe, after which normal pumping can proceed. During pumping, the pump’s intake hopper should be filled with concrete to prevent air from being drawn in and causing blockages. Concrete pumps have a high discharge capacity; when pouring concrete over large areas, it is best to use a concrete distributor for spreading the concrete. After pumping is complete, the pump body and pipes should be cleaned promptly. http://www.scutde.net/t14courses/1412-efmdljiaif/hunningtu/3.3/PIC/3.3.3.jpg Vehicle-type concrete pump, Concrete transport vehicle
http://www.scutde.net/t14courses/1412-efmdljiaif/hunningtu/3.3/PIC/3.3.5.JPG Dump truck
http://www.scutde.net/t14courses/1412-efmdljiaif/hunningtu/3.3/PIC/BALL1.GIF (Please click on the image below to view the animation showing the working principle of the hydraulic piston concrete pump.)
http://www.scutde.net/t14courses/1412-efmdljiaif/hunningtu/3.3/IMAGE/3-39.GIF Figure 3-39: Schematic diagram of the working principle of the hydraulic piston concrete pump; 1 – Concrete cylinder ； 2—Piston ； 3—Hydraulic cylinder ； 4—Hopper ； 5—Control valve for the horizontal distribution of intake air ； 6—Vertical distribution valve for controlling discharge ； 7—Y-shaped delivery pipe ； 8—Flushing system: http://www.scutde.net/t14courses/1412-efmdljiaif/hunningtu/3.3/IMAGE/3-40.GIF. Figure 3-40: Concrete pump truck with a fabric rod. Table 3-12: Recommended values for concrete slump at different pumping heights. Pumping height (m): Below 30, 30–60, 60–100, Over 100. Slump (mm): 100–140, 140–160, 160–180, 180–200