A collapse protection device and collapse protection process for extending concrete transportation time

Abstract

The present invention belongs to the technical field of concrete collapse prevention, and specifically relates to a collapse prevention device and a collapse prevention process for extending the transportation time of concrete, comprising a concrete transport vehicle, a display screen, a water tank, a control box, an L-shaped rectangular tube, a cleaning tube and a dripping tube, wherein the L-shaped rectangular tube comprises an inner tube and an outer tube, a card plate at the feed port of the transport vehicle is clamped on the outer tube bolt, and the inner tube extends into a mixing barrel; a camera is fixed at the center of the inner tube port, spotlights are fixed on both sides of the camera, a cleaning tube extends from a pipe outlet on one side, and a dripping tube extends from a pipe outlet on the other side, there are two water tanks in the water tank, and the cleaning tube outside the pipe inlet is divided into a water pipe and an air pipe, which are respectively connected to a water pump and an air pump, and the dripping tube is connected to a water reservoir on the other side of the water tank through a peristaltic pump, and the display screen, the water tank and the control box are arranged in a cab. The device and process solve the problem of large collapse of concrete over time caused by long-term transportation of concrete, and can be widely used in long-distance transport vehicles of various types of concrete.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete collapse prevention, and in particular relates to a collapse prevention device and a collapse prevention process for prolonging the transportation time of concrete. Background Art

[0002] With the rapid development of society and the standardization of environmental protection requirements by the state, concrete mixing stations have gradually moved from urban areas to suburbs, and the transportation distance has gradually increased. In addition, the increased traffic pressure has led to a gradual increase in transportation time, which has had a great impact on project quality and construction progress. Since concrete materials cannot be stored for a long time after mixing, a long period of time will cause the slump of concrete to decrease, reduce the workability of concrete, and increase the difficulty of construction. According to GB / T14902-2012 "Ready-mixed Concrete" 7.5.3, after the concrete arrives at the construction site, it is allowed to adjust the slump twice through additives, but the adjusted concrete collapses very quickly over time. If it is not well controlled, it is very easy to block the pipe, cupping, and the concrete is scrapped. In addition, the construction personnel have low quality and often use water to increase its workability, which brings great safety and quality risks to the project. If it is returned, it is easy to cause waste. Therefore, appropriate measures must be taken to strengthen the management of transported concrete.

[0003] At present, there is no specific equipment that can realize real-time monitoring of the condition of concrete inside the tank truck, so that there is a means of management during the transportation of concrete, which can ensure the quality of concrete, reduce the unqualified rate of engineering structures and the scrap rate of concrete, and extend the transportation time of concrete to at least 6 hours through appropriate dripping. As time goes by, the strength will not only not decrease, but will increase by 3MPa to 8MPa, and the final setting time will be normal.

[0004] Therefore, it is necessary to make improvements to the above problems. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the present invention provides a collapse prevention device and a collapse prevention process for extending the transportation time of concrete. The invention can solve the problem of large collapse of concrete over time caused by long-term transportation of concrete.

[0006] The technical solution adopted by the present invention is: a collapse protection device for extending the transportation time of concrete, comprising a concrete transport vehicle, a display screen, a water tank, a control box, an L-shaped rectangular tube, a cleaning tube and a dripping tube, wherein the transport vehicle is fixed with two vertical clamping plates on the side wall of the feed port near the feed hopper, the L-shaped rectangular tube comprises an inner tube and an outer tube, a pipe inlet is reserved on the side of the outer tube, fixing bolts are symmetrically welded on both sides of the outer tube, nuts are screwed on the bolts, the clamping plates at the feed port of the transport vehicle are clamped on the outer tube bolts, and the inner tube extends into the mixing barrel; the port of the inner tube is an inclined port with a longer upper edge, an irregular rectangular glass plate is sealed in the inclined port by glass glue, pipe outlets are reserved at the upper left and upper right corners of the glass plate, and the inner tube is provided with a plurality of screws, wherein the inner tube is provided with a plurality of screws ... A camera is fixed at the center of the port behind the plate, and spotlights are fixed on both sides of the camera respectively; the cleaning pipe is L-shaped, one side of the cleaning pipe extends from the pipe outlet on one side of the glass plate, and is horizontally fixed on the outside of the glass plate in parallel with the glass plate, and the dripping pipe extends from the pipe outlet on the other side of the glass plate and is fixed, there are two water storage tanks in the water tank, the cleaning pipe outside the pipe inlet is divided into a water pipe and an air pipe, the water pipe is connected to the water storage tank on one side of the water tank through a water pump, the air pipe is connected to the air pump, the dripping pipe outside the pipe inlet is connected to the water storage tank on the other side of the water tank through a peristaltic pump, the water pump, air pump and peristaltic pump are connected to the control box through lines, the display screen is connected to the camera through lines, and the display screen, water tank and control box are arranged in the cab.

[0007] The inner tube and outer tube of the L-shaped rectangular tube are rectangular tubes, the inner tube and the outer tube are welded, the angle between the inner tube and the outer tube is 95° to 110°, the cross-section of the rectangular tube is 50×100mm, the thickness is 3mm, the length of the inner tube is 300mm, the upper edge of the inclined port of the inner tube is at least 30mm longer than the lower edge, the length of the drip tube extending out of the glass plate is 30mm, and the port of the outer tube is sealed.

[0008] One end of the cleaning pipe located outside the pipe inlet is connected to the air pipe and the water pipe respectively through a three-way connecting pipe. A one-way check valve and an electromagnetic control valve are installed at the connection between the cleaning pipe and the three-way connecting pipe. The electromagnetic control valve is connected to the controller through a line; one side of the cleaning pipe located outside the glass plate is provided with a row of multiple flushing holes facing the glass plate, and the cleaning pipe port outside the glass plate is closed.

[0009] The water tank is installed under the seat in the cab, one side of the water tank stores flushing water, and the other side of the water tank stores additives; the control box is installed next to the center console in the cab, and the control box is provided with control buttons.

[0010] The length and width of the glass plate are respectively adapted to the cross-sectional size of the inner tube, and the glass plate is aligned with the lower edge of the inclined port of the inner tube and fixed vertically; the spotlights on both sides of the camera are respectively inclined 30° toward the camera.

[0011] The L-shaped rectangular tube is an aluminum tube; the drip tube is a polytetrafluoroethylene tube; the glass plate is ultra-white glass; the spotlight is an LED white light lamp; the camera is a 170° wide-angle, 4k high-definition small explosion-proof camera; the line specification is a vehicle-mounted line.

[0012] A collapse protection device and collapse protection process for extending the transportation time of concrete, comprising the following steps: S1, pouring concrete into a mixing barrel of a transport vehicle and starting the collapse protection device; S2, the transport vehicle starts to transport concrete, and the condition of the concrete in the mixing barrel is observed through a display screen in a cab of the transport vehicle; S3, when the display screen in the cab shows that the glass plate in front of the camera is contaminated, the contaminants in front of the camera are cleaned and blown dry through a control box; S4, when it is observed that the slump of the concrete in the mixing barrel is about 200±20mm, a peristaltic pump and an electromagnetic control valve are controlled accordingly in the cab to continuously drip additives; S5, the condition of the concrete in the mixing barrel is continued to be observed, and the dripping amount of the additive is controlled through the control box according to the condition of the concrete; S6, the additive is continuously dripped, and when it is observed that the slump of the concrete in the mixing barrel meets the technical requirements, the additive is continued to be added until it is transported to a construction site for construction, and the dripping of the additive is stopped through the control box.

[0013] After the control box is controlled in step S3, the cleaning and drying is an automatic control process, which is to first turn on the water pump and turn off the air pump, and at the same time, the solenoid valve opens the water pipe and closes the air pipe. After the delayed cleaning, the water pump is automatically turned off and the air pump is turned on, and at the same time, the solenoid valve opens the air pipe and closes the water pipe.

[0014] The additive in step S4 is a polycarboxylate water-reducing agent.

[0015] The amount of the additive added in step S5 is in the range of 1‰ / h of the amount of the admixture per cubic meter of concrete.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adds a time control axis during transportation and drips a collapse-preventing agent at a corresponding rate into the mixing tank, thereby preventing the concrete from collapsing too much over time due to long-term transportation during transportation, thereby affecting the workability of the concrete and eliminating the problem of uncontrollable quality due to prolonged time.

[0017] 2. The present invention adds a camera in the mixing tank and a display screen in the cab, so as to realize real-time monitoring of the concrete in the mixing tank and take targeted measures.

[0018] 3. The present invention arranges the collapse protection device on the upper wall of the tank inlet, selects materials with good thermal conductivity for the entire device, and adopts a setting that does not affect lighting at the camera, thereby ensuring that the device is not affected by concrete.

[0019] 4. The present invention provides a multi-purpose flushing device above the camera, which can flush the glass plate and dry it by air flushing at any time, thus ensuring the observation quality of the concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a structural schematic diagram of the L-shaped rectangular tube part of the present invention; Figure 3 This is a schematic diagram of the installation position structure of the L-shaped rectangular tube of the present invention; Figure 4 It is a structural schematic diagram of the inner tube part of the present invention; wherein: 1 is a transport vehicle, 2 is a display screen, 3 is a water tank, 4 is a control box, 5 is an L-shaped rectangular tube, 6 is a cleaning tube, 7 is a drip tube, 8 is a pallet, 9 is a glass plate, 10 is a camera, 11 is a spotlight, 12 is a water pump, 13 is an air pump, 14 is a peristaltic pump, 51 is an inner tube, 52 is an outer tube, 53 is a pipe inlet, 61 is a water pipe, 62 is an air pipe, 63 is a one-way check valve, and 91 is a pipe outlet. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] like Figures 1 to 4As shown, a collapse protection device for extending the transportation time of concrete comprises a concrete transport vehicle 1, a display screen 2, a water tank 3, a control box 4, an L-shaped rectangular tube 5, a cleaning tube 6 and a dripping tube 7. The side wall of the feed port of the transport vehicle 1 near the feed hopper is fixed with two vertical clamping plates 8. The L-shaped rectangular tube 5 comprises an inner tube 51 and an outer tube 52. A pipe inlet 53 is reserved on the side of the outer tube 52. The line, the cleaning tube 6 and the dripping tube 7 are all inserted from the pipe inlet 53. Fixing bolts are symmetrically welded on both sides of the outer tube 52. Nuts are screwed on the bolts. The clamping plate 8 at the feeding port of the transport vehicle is clamped on the bolts of the outer tube 52, and the L-shaped rectangular tube 5 is fixed at the feeding port of the mixing barrel, and the inner tube 51 extends into the mixing barrel; the port of the inner tube 51 is an inclined port with a longer upper edge, and the inclined port can be used for a camera 10 to resist the collapse of concrete, so as to achieve high efficiency of the device. An irregular rectangular glass plate 9 is sealed in the inclined port by glass glue, and a pipe outlet 91 is left at the upper left corner and the upper right corner of the glass plate 9. A camera 10 is fixed at the center of the port behind the glass plate 9. The camera 10 Spotlights 11 are fixed on both sides of the cleaning pipe 6; the cleaning pipe 6 is L-shaped, one side of the cleaning pipe extends from the outlet 91 on one side of the glass plate 9, and is horizontally fixed to the outside of the glass plate 9 in parallel with the glass plate 9, and the dripping pipe 7 extends and is fixed from the outlet 91 on the other side of the glass plate 9; there are two water storage tanks in the water tank 3, which can store two kinds of liquids. The cleaning pipe 6 outside the pipe inlet 53 is divided into a water pipe 61 and an air pipe 62, which is a multi-purpose pipe, simplifies the structure, and can make the function better. The water pipe 61 is connected to the storage tank on one side of the water tank 3 through the water pump 12. The air pipe 62 is connected to the air pump 13, the dripping tube 7 outside the pipe inlet 53 is connected to the water reservoir on the other side of the water tank 3 through the peristaltic pump 14, the peristaltic pump 14 can realize the dripping function, the water pump 12, the air pump 13 and the peristaltic pump 14 are connected to the control box 4 through the line, the display screen 2 is connected to the camera 10 through the line, the display screen 2, the water tank 3 and the control box 4 are arranged in the cab, the water tank 3 is placed in the cab to meet the modification requirements of the mixer truck 1, and finally the whole device is controlled by the control box 4 in the cab.

[0023] The inner tube 51 and the outer tube 52 of the L-shaped rectangular tube 5 are rectangular tubes, and the inner tube 51 and the outer tube 52 are welded. The angle formed by the inner tube 51 and the outer tube 52 is in the range of 95° to 110°, so as to ensure that the display screen 2 can clearly see the situation in the center of the mixing barrel. The cross-section of the rectangular tube is 50×100mm and the thickness is 3mm. The length of the inner tube 51 is 300mm, and the length of the outer tube is determined according to the vehicle model. The upper edge of the inclined port of the inner tube 51 is at least 30mm longer than the lower edge. The length of the drip tube 7 extending out of the glass plate 9 is 30mm, which is just within the upper edge and will not be affected by the concrete. The port of the outer tube 52 is sealed.

[0024] One end of the cleaning pipe 6 located outside the pipe inlet 53 is connected to the air pipe 62 and the water pipe 61 respectively through a three-way connecting pipe. A one-way check valve and an electromagnetic control valve are installed at the connection between the cleaning pipe 6 and the three-way connecting pipe to prevent water backflow and ensure that water is not released while blowing, and air is not blown while releasing water. The electromagnetic control valve is connected to the controller 4 through a line; one side of the cleaning pipe 6 located outside the glass plate 9 is provided with a row of flushing holes facing the glass plate 9, so that the camera 10 can be sprayed and blown dry from the upper end of the camera 10, and the port of the cleaning pipe 6 outside the glass plate 9 is closed, and water and air are only sprayed out from the flushing holes.

[0025] The water tank 3 is installed under the seat in the cab. One side of the water tank 3 stores flushing water, and the other side stores additives. One tank has multiple uses. The control box 4 is installed next to the center console in the cab to facilitate the driver to control. The control box 4 is provided with control buttons, including a switch button, a drip speed adjustment button, a cleaning button, etc.

[0026] The length and width of the glass plate 9 are respectively adapted to the cross-sectional size of the inner tube 51; the glass plate 9 is aligned with the lower edge of the inclined port of the inner tube 51 and fixed vertically; the glass plate 9 is sealed and black glass glue is used to ensure that the device in the L-shaped rectangular tube 5 is not affected by the environment in the mixing barrel, and the camera 10 is not prone to fogging, condensation, etc.; the spotlights 11 on both sides of the camera 10 are respectively tilted 30° toward the camera 10 to ensure that the camera 1 collects the clearest light but is not exposed.

[0027] The L-shaped rectangular tube 5 is an aluminum tube with good thermal conductivity; the drip tube 6 is a polytetrafluoroethylene tube that does not stick to concrete; the glass plate 9 is ultra-white glass that does not affect refraction; the spotlight 11 is an LED white light lamp with a required voltage of 24 volts; the camera 10 is a 170° wide-angle, 4k high-definition small explosion-proof camera to ensure clear images; the line specification is a vehicle-mounted line and is corrosion-resistant.

[0028] A collapse protection device and collapse protection process for extending the transportation time of concrete, comprising the following steps: S1, pouring concrete into a mixing barrel of a transport vehicle, and turning on the collapse protection device; S2, the transport vehicle starts to transport concrete, observing the condition of the concrete in the mixing barrel through a display screen 2 in a cab of the transport vehicle, and starting to drip additives; S3, when the display screen 2 in the cab shows that the glass plate 9 in front of the camera 10 is contaminated, the control box 4 is used to clean and dry the contaminants in front of the camera 10, first rinsing, then drying to ensure that the picture is clear and not affected; S4, observing that the concrete in the mixing barrel is contaminated, and then drying. When the soil slump is about 200±20mm, the peristaltic pump 14 and the electromagnetic control valve are controlled accordingly in the cab through the control box 4 to continuously add additives; S5, continue to observe the condition of the concrete in the mixing barrel, and control the amount of additives added through the control box 4 according to the condition of the concrete; S6, continue to add additives, and observe that the slump of the concrete in the mixing barrel meets the technical requirements. Continue to add until it is transported to the construction site for construction, and stop adding additives through the control box 4. As the addition time increases, the concrete strength will gradually increase by 3 to 8 MPa.

[0029] After the control box 4 is controlled in step S3, the cleaning and drying is an automatic control process. The process is to first turn on the water pump 12 and turn off the air pump 13, and at the same time, the electromagnetic control valve opens the water pipe 61 and closes the air pipe 62. After the delayed cleaning, the water pump 12 is automatically turned off and the air pump 13 is turned on, and at the same time, the electromagnetic control valve opens the air pipe 61 and closes the water pipe 62.

[0030] The additive in step S4 is a polycarboxylate water-reducing agent.

[0031] The additive amount in step S5 is in the range of 1‰ / h of the admixture dosage per cubic meter of concrete, that is, if the standard dosage of concrete is 2.5%, then 0.1% is continuously added to each cubic meter of concrete per hour, that is, about 500g~800g / cubic hour, and the higher the strength, the more the amount added.

[0032] The present invention applies the display screen 2 and the camera 10 in the mixing tank and the cab to realize the state monitoring of the concrete, and arranges the L-shaped rectangular tube 5 at the feed port to be connected with the water tank 3, etc., so as to realize the dripping of additives to the concrete while monitoring the state of the concrete, thereby solving the problem of the unavoidable deterioration of the quality of the concrete due to the long time in long-distance transportation, and also saves the driver from frequently getting off the vehicle to check and adding additives outside the vehicle, thus ensuring the quality of the concrete to the greatest extent, improving the transportation efficiency, and greatly reducing the problem of damage to the mixing barrel caused by condensation in the concrete tank, which will save costs. The whole device can ensure that the concrete does not change for 6 to 8 hours during the long-term transportation process, and the concrete has the same condensation time as normal concrete from the stop of dripping to the condensation, and the performance state is relatively stable.

[0033] Only the preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the protection scope of the present invention.

Claims

1. A collapse protection device for extending the transportation time of concrete, characterized in that: The invention comprises a concrete transport vehicle (1), a display screen (2), a water tank (3), a control box (4), an L-shaped rectangular tube (5), a cleaning tube (6) and a dripping tube (7), wherein two vertical clamping plates (8) are fixed to the side wall of the feed port of the transport vehicle (1) near the feed hopper, the L-shaped rectangular tube (5) comprises an inner tube (51) and an outer tube (52), a tube inlet (53) is left on the side of the outer tube (52), fixing bolts are symmetrically welded on both sides of the outer tube (52), nuts are screwed on the bolts, the clamping plate (8) at the feed port of the transport vehicle is clamped on the bolts of the outer tube (52), and the inner tube (51) extends into the mixing barrel; The port of the inner tube (51) is an inclined port with a longer upper edge, an irregular rectangular glass plate (9) is sealed in the inclined port by glass glue, pipe outlets (91) are left at the upper left corner and the upper right corner of the glass plate (9), a camera (10) is fixed at the center of the port behind the glass plate (9), and spotlights (11) are respectively fixed on both sides of the camera (10); the cleaning pipe (6) is L-shaped, one side of the cleaning pipe extends from the pipe outlet (91) on one side of the glass plate (9), and is horizontally fixed to the outside of the glass plate (9) in parallel with the glass plate (9), and the dripping pipe (7) extends from the pipe outlet (91) on the other side of the glass plate (9) and is fixed; The water tank (3) has two water storage tanks in it. The cleaning pipe (6) outside the pipe inlet (53) is divided into a water pipe (61) and an air pipe (62). The water pipe (61) is connected to the water storage tank on one side of the water tank (3) through a one-way check valve (63) and a water pump (12). The air pipe (62) is connected to the air pump (13) through a one-way check valve (63). The dripping pipe (7) outside the pipe inlet (53) is connected to the water storage tank on the other side of the water tank (3) through a peristaltic pump (14). The water pump (12), the air pump (13) and the peristaltic pump (14) are connected to the control box (4) through a line. The display screen (2) is connected to the camera (10) through a line. The display screen (2), the water tank (3) and the control box (4) are arranged in the cab. One end of the cleaning pipe (6) located outside the pipe inlet (53) is connected to the air pipe (62) and the water pipe (61) respectively through a three-way connecting pipe, and a one-way check valve and an electromagnetic control valve are installed at the connection between the cleaning pipe (6) and the three-way connecting pipe, and the electromagnetic control valve is connected to the control box (4) through a line; one side of the cleaning pipe (6) located outside the glass plate (9) is provided with a row of a plurality of flushing holes facing the glass plate (9), and the end of the cleaning pipe (6) outside the glass plate (9) is closed; The water tank (3) is installed under the seat in the cab, one side of the water tank (3) stores flushing water, and the other side of the water tank stores additives; the control box (4) is installed next to the center console in the cab, and the control box (4) is provided with control buttons.

2. A collapse protection device for extending the concrete transportation time according to claim 1, characterized in that: The inner tube (51) and the outer tube (52) of the L-shaped rectangular tube (5) are rectangular tubes. The inner tube (51) and the outer tube (52) are welded. The angle formed by the inner tube (51) and the outer tube (52) is in the range of 95°-110°. The cross section of the rectangular tube is 50×100 mm and the thickness is 3 mm. The inner tube (51) is 300 mm long. The upper edge of the inclined port of the inner tube (51) is at least 30 mm longer than the lower edge. The length of the drip tube (7) extending out of the glass plate (9) is 30 mm. The port of the outer tube (52) is sealed.

3. A collapse protection device for extending the concrete transportation time according to claim 1, characterized in that: The length and width of the glass plate (9) are respectively adapted to the cross-sectional size of the inner tube (51); the glass plate (9) is aligned with the lower edge of the inclined port of the inner tube (51) and is vertically fixed; the spotlights (11) on both sides of the camera (10) are respectively inclined 30 degrees in the direction of the camera (10).

4. A collapse protection device for extending the concrete transportation time according to claim 1, characterized in that: The L-shaped rectangular tube (5) is a steel tube; the drip tube (7) is a polytetrafluoroethylene tube; the glass plate (9) is ultra-white glass; the spotlight (11) is an LED white light lamp; the camera (10) is a 170° wide-angle, 4K high-definition small starlight-level explosion-proof camera; and the line specification is a vehicle-mounted line.

5. A collapse protection process for extending the concrete transportation time adopted by the collapse protection device according to claim 1, characterized in that: The following steps are involved: S1. Pour concrete into the mixing barrel of the transport vehicle and turn on the collapse protection device; S2, the transport truck starts transporting concrete, and the condition of the concrete in the mixing barrel is observed through the display screen (2) in the cab of the transport truck; S3, when the display screen (2) in the cab shows that the glass plate (9) in front of the camera (10) is contaminated, the contaminants in front of the camera (10) are cleaned and dried through the control box (4); S4. When the slump of the concrete in the mixing barrel is observed to be 200±20 mm, the peristaltic pump (14) and the electromagnetic control valve are controlled accordingly in the cab through the control box (4) to continuously drip the additive; S5. Continue to observe the condition of the concrete in the mixing barrel, and control the amount of additive added through the control box (4) according to the condition of the concrete; S6. Continue to drip additives until the concrete slump in the mixing drum meets the technical requirements. Continue to add additives until the concrete is transported to the construction site for construction. Then, stop dripping additives through the control box (4).

6. A collapse-preserving process for extending the concrete transportation time according to claim 5, characterized in that: After the control box (4) is controlled in step S3, the cleaning and drying is an automatic control process, wherein the water pump (12) is first turned on and the air pump (13) is turned off, and at the same time, the electromagnetic control valve turns on the water pipe (61) and turns off the air pipe (62); after the delayed cleaning, the water pump (12) is automatically turned off and the air pump (13) is turned on, and at the same time, the electromagnetic control valve turns on the air pipe (62) and turns off the water pipe (61).

7. A collapse-preserving process for extending the concrete transportation time according to claim 5, characterized in that: The additive in step S4 is a polycarboxylate water-reducing agent.

8. The collapse-preserving process for extending the concrete transportation time according to claim 5, characterized in that: The amount of the additive added in step S5 is in the range of 1‰ / h per cubic meter of concrete admixture.

Images