System and method for determining a compaction of a flowable solidifiable building material

Abstract

The invention relates to a system for determining a compaction of a flowable, solidifiable building material, in particular concrete, during the production of a structural element with the building material, wherein the flowable building material is introduced into a formwork system (10), comprising: at least three sensors (S1, S2, S3) for determining an amplitude (AS1, AS2, AS3) of a vibration, which is introduced into the flowable building material by a vibration unit (VE), wherein the sensors (S1, S2, S3) are arranged on the formwork system (10), at least one computing unit which is configured to calculate, based on the amplitudes (AS1, AS2, AS3) determined by the at least three sensors (S1, S2, S3), possible positions (D1, D2, D3) of the vibration unit (VE) relative to the respective sensors (S1, S2, S3) and, on the basis thereof, to triangulate the current position of the vibration unit (VE) relative to the formwork system (10); a documentation unit for documenting the dwell time of the vibration unit (VE) in the respective current positions of the vibration unit (VE) relative to the formwork system (10), wherein the calculation unit determines a calculated compaction value in the respective current positions on the basis of the respective current positions of the vibration unit (VE) and the documented dwell time in the respective current positions.

Description

[0001] SYSTEM AND METHOD FOR DETERMINING THE COMPACTION OF A FLOWABLE RESOLVABLE BUILDING MATERIAL

[0002] The present application claims priority from German patent application No. 10 2024 121 270.5, the contents of which are incorporated herein in full by reference.

[0003] According to a first aspect, the invention relates to a system for determining the compaction of a flowable, solidifiable building material during the production of a structural element with the flowable building material according to the preamble of claim 1, and to a method for determining the compaction during the production of the structural element with the building material according to claim 10. Furthermore, the invention also relates to a method for compacting the building material according to claim 13 and a system for producing a structural element with a flowable, solidifiable building material according to claim 15.

[0004] Structural elements within the meaning of the present invention are, in particular, wall, floor, and / or ceiling elements or prefabricated components, which are especially manufactured as concrete components. For this purpose, formwork or frame formwork elements are generally used as parts of formwork systems for the production of the concrete components. The frame formwork elements are arranged such that they form a mold within the formwork system, into which a hardenable building material, i.e., a building material that is initially liquid or flowable and then hardens, usually concrete, is poured to produce a component, for example, a wall element. After the building material has hardened, the frame formwork elements are generally removed.

[0005] Insofar as reference is made to concrete or a concrete component within the scope of the present invention, it may also be another hardenable building material or a component made of another hardenable building material.

[0006] The frame formwork elements have a frame to which the formwork panel or formwork skin can be attached. The frame forms a supporting structure for the formwork panel, which itself can have one or more plate-shaped elements and / or layers. Hereinafter, the "front" refers to the side of the frame to which the formwork panel can be attached, i.e., the side of the frame formwork element facing the concrete element, and the "rear" refers to the side of the frame facing away from the concrete element. The frame formwork elements are placed on a base with one underside facing down, thus creating a formwork surface. This surface essentially corresponds to the area of ​​the formwork panel.The frame formwork element extends in a longitudinal direction, parallel to the edge of the frame resting on the substrate (horizontal extension) and in a direction perpendicular to it (vertical extension), whereby the longitudinal direction, for example in the case of a rectangular frame shape, also corresponds to the width of the formwork surface.

[0007] The typical process for manufacturing a structural element, such as a wall with a constant thickness, from a flowable building material, for example, concrete, comprises the following steps: first, the formwork system is erected, i.e., a so-called initial formwork in the form of a first frame formwork element is erected and secured; then, if necessary, reinforcement is mounted to the initial formwork; and in a further step, the so-called closing formwork in the form of a second frame formwork element is erected on the side opposite the reinforcement, parallel to the first frame formwork element, such that the reinforcement is positioned between the initial formwork and the closing formwork. Finally, the formwork is assembled, i.e., the erected components of the formwork system are secured in their relative positions to one another using, for example, formwork anchors or similar devices.Furthermore, necessary attachments and safety components, such as a concreting platform, counter railings and the like, are mounted to the formwork system on the construction site, which later enable construction site personnel to safely walk on the formwork system.

[0008] In a subsequent step, the concrete is poured; that is, flowable concrete is poured into the space between the formwork and the closing formwork and flows around the reinforcement. In practice, it has been shown that, due to the high viscosity of the flowable concrete poured into the formwork system from above, undesirable voids, so-called gas bubbles, or gravel nests can form on the outer surface of the component being produced, i.e., in the transition area to the formwork skin, or within the component itself. Therefore, vibration exciters or vibrators are often used to compact the concrete.

[0009] The poured concrete can be further compacted in an additional compaction process, whereby the pouring and compaction can be carried out layer by layer. A defined pouring height of 50 cm, 60 cm, 70 cm, or more or less has proven effective in practice as a so-called fill layer. This means that as soon as a new layer of concrete has been poured to the defined height, the compaction step takes place before another fill layer of concrete is added. Mixing the fill layers is also desirable.

[0010] Once the structural element to be produced has been cast and hardened, the formwork is removed, meaning the formwork system is dismantled. Only now can one determine, at least on the exposed concrete surface (the interfaces with the formwork system), whether the concrete was poured without visible voids or surface defects. Minor defects can be rectified by concrete finishing work such as filling holes, grinding down protrusions, and scraping off unwanted concrete edges. However, this finishing work is very time-consuming and should be minimized whenever possible.

[0011] Various compaction methods are known from the state of the art.

[0012] German patent application DE 10 2010 014 310 A1 describes how at least one, but usually several, vibration exciters in the form of so-called external vibrators are provided on at least one of the outer surfaces of the formwork. These vibrators are used to compact the concrete. The external vibrators are distributed at regular intervals along the respective outer surface of the formwork. An external vibrator typically has an electric motor that rotates at a predetermined speed. At least one, but usually two, unbalanced weights are mounted axially on the motor shaft. The electric motor can be positioned between the two unbalanced weights. When driven by the electric motor, the unbalanced weights generate a strong vibration that is transmitted through the formwork into the still-flowable concrete to be compacted. These vibrations help to release gas bubbles from the concrete and distribute any gravel pockets.This compacts the concrete and allows it to reach the intended strength.

[0013] Alternatively, it is also known from the prior art to embed or immerse so-called internal vibrators, also known as vibrating bottles, in the still flowable concrete to be solidified, which are moved inside the component to be manufactured and are intended to compact the concrete in this way.

[0014] One solution using such an internal vibrator is described, for example, in WO 2009 / 030 327 A1. The vibrations generated by the vibrator introduce energy into the concrete, resulting in deaeration and improved mixing of the components. The quality of the resulting concrete compaction and the associated structure and surface quality of the concrete element depend on numerous factors. For instance, an unsystematic approach can lead to situations where the internal vibrator is not immersed in certain areas of the concrete, preventing compaction in these areas. Similarly, problems can arise from improper compaction when multiple separating layers are present. Finally, over-compaction can also be detrimental.

[0015] It has proven difficult to measure the achieved compaction effect, which is why empirical methods are generally used. In particular, it is almost impossible to measure the compaction effect during the compaction process (in real time). In practice, the operator of the concreting system needs considerable experience and expertise to operate the vibrators to the extent required to achieve the necessary concrete strength or to comply with the relevant concrete compaction standards. There is a risk that, for example, if multiple vibrators are used, they will not be operated in a coordinated manner, causing their vibrations to overlap or cancel each other out. It is also possible that a vibrator may not operate at all or may malfunction, which the operator may not notice.Furthermore, the vibration duration may be too short or too long, or the overall vibration power may be too low or too high. This can result in the concrete not being compacted as required, potentially leading to a precast concrete element of inferior quality.

[0016] Since the quality of the concrete surface only becomes visible after the formwork is removed, the concreting process is highly dependent on the operator's experience. The composition of the formwork (the formwork system) and the duration of the compaction process have a significant impact on the quality. If the operator—for example, due to a lack of experience—positions external vibrators on the formwork or internal vibrators in the concrete improperly, or if the compaction process is carried out incorrectly, the compaction result may be insufficient, meaning that the concrete element, after removal from the formwork, will not meet the quality requirements and will have to be destroyed.

[0017] Based on these known problems, various solutions were developed to make a statement about the quality of the compaction during the compaction process and to carry out further compaction if necessary.

[0018] DE 10 2010 014 310 A1 describes a documentation device capable of recording the position of the vibration exciter or the various positions of multiple vibration exciters, as well as the operating state of each individual vibration exciter or the respective operating states of multiple vibration exciters. According to the invention, this makes it possible to document the concreting process in great detail and to monitor it during the concreting process. Based on the documentation of the operating states of the vibration exciters, along with knowledge of their respective positions, it is possible, for example, to determine the locally introduced vibration power acting on the concrete to be compacted. From this, conclusions can be drawn as to whether the vibration power is introduced uniformly – or, in the case of an uneven distribution, countermeasures can be taken. For example, if...If, during the pouring of fresh concrete into the formwork, it is determined that the vibration or compaction performance is insufficient, the pouring process can be slowed down or the vibration power of the relevant vibration exciters can be increased. Conversely, if it is determined that the vibration or compaction performance was already more than sufficient, vibration exciters can be selectively switched off to prevent harmful over-compaction and thus segregation of the fresh concrete.

[0019] This solution involves a camera pointed at the external vibrators mounted on the outside of the formwork system, documenting the introduced vibrations and the position of the vibrators. In practice, the method is comparatively complex and, for example, cannot be applied to systems with internal vibrators, or only with considerable inaccuracy.

[0020] WO 2009 / 030 327 A1 describes the use of an acoustic camera directed at the formwork to detect sound waves, determine their respective strengths in the form of sound levels, and / or identify the locations where the sound waves originate. Furthermore, a display device is provided to show the detected sound levels at the respective locations of origin. The underlying principle of this arrangement is to visualize the vibrations introduced into the concrete. It is assumed that the effective vibrations always also produce sound waves of comparable, and possibly even proportional, strength, so that the strength of the sound waves, i.e., the sound levels, is an indicator of the prevailing vibrations that compact the concrete. An acoustic camera – often referred to as an acoustic camera in contrast to an optical camera – is a known system used for the imaging localization and analysis of sound sources.By providing a clear, precise, and rapid real-time representation of sounds, such a sound camera enables the visualization of noise sources. The basic configuration of a sound camera consists of a microphone array, a data recorder, and a computer with appropriate software.

[0021] This solution also proved to be very complex in practice. Therefore, further solutions have been developed, which in particular include sensors that are integrated into the still-flowable concrete during the compaction process, as described, for example, in JP 2014218852 A, or inserted into the interior of the formwork, as described, for example, in JP 3897705 B2.

[0022] A disadvantage of such solutions is that the sensors are often designed for single use, meaning they cannot be reused after initial use due to the adhering concrete and may even remain embedded in the component (lost sensors), making the sensor system very expensive. Therefore, often only a single sensor is used, which then only provides a very localized vibration measurement. Furthermore, if the sensors are removed from the component being manufactured, unwanted measurement marks may remain in the concrete. To reduce these, the solution described in publication JP2021085238 A provides a particularly compact vibration-based measuring system that is immersed in the still-flowable concrete to detect vibrations during the compaction process and is then removed from the component after compaction.

[0023] However, a sensor system that can reliably assess the compaction process using sensor data from sensors that do not come into contact with the concrete is preferable to such a solution.

[0024] The publication JP 2014231691 A discloses a method for testing the compaction process using an accelerometer mounted on the outside of the formwork. The accelerations of the formwork skin, as determined by the accelerometer, are considered to be the accelerations of the concrete in contact with the formwork skin inside the formwork skin. Based on the measured vibrations and their duration, a connected computer calculates the cumulative vibration energy that has acted on the (contacting) concrete. In a further step, the cumulative vibration energy is compared with a compaction completion energy stored in the computer. If the cumulative vibration energy is greater than the compaction completion energy stored in the computer, the compaction process is considered complete.The compaction energy stored in the computer indicates the compaction or vibration energy required to achieve optimal compaction of a specific building material. Samples are used that are to be compacted to a defined theoretical density, and the compaction time, maximum acceleration, vibration frequency, and volumetric weight of the sample are measured to calculate and store the respective specific compaction or vibration energy.

[0025] One disadvantage of this well-known method is that various external factors, particularly external vibrations, can negatively affect the measurement results and thus the reliability of the system. One example of external vibrations is the influence of construction site personnel. For instance, during the concreting process, at least one worker is typically on the concreting platform, and their movements naturally transmit vibrations to the corresponding formwork element. Furthermore, the movement of the internal vibrator or vibrator head through the concrete being compacted, and the resulting changes in distance to the external sensor, can significantly distort the results.

[0026] Another similar solution is disclosed in publication JP 2023123831 A. In this solution, several acceleration sensors are mounted outside the formwork skin. In one embodiment, a method for placing concrete into a formwork is provided, the method comprising: subjecting the concrete in the formwork to vibrations by means of a vibrator inserted into the concrete, which is in contact with the concrete via another material, is vibrationally isolated from the formwork, and detects the vibrations caused by the vibrator using an acceleration sensor that can be attached to the formwork; and detecting the compaction state of the concrete near the formwork based on the kinetic energy of the concrete calculated by the method.Thus, the acceleration sensors measure the vibrations of the shell surface in order to draw conclusions about the compaction process in a similar way to the solution of printed document JP 2014231691 A.

[0027] This solution also has a disadvantage in that various external factors that can affect the membrane, especially external vibrations, can adversely affect the measurement results and thus the reliability of the system.

[0028] In contrast, one object of the present invention is to further develop the known solutions in order to make more reliable statements about the compaction process and thus reduce the required rework.

[0029] According to the invention, a system for determining the compaction of a flowable, hardenable building material, in particular concrete, during the production of a structural element with the building material is provided, wherein the flowable building material is introduced into a formwork system comprising at least three sensors for determining the amplitude of a vibration. The vibration is introduced into the flowable building material by a vibration unit, for example, an internal vibrator referred to as a vibrator bottle. The sensors are arranged on the formwork system, and according to a preferred embodiment, they can be arranged on an outside of the formwork system, making them particularly easily accessible, replaceable, and protected from contact with the building material. In particular, the sensors are advantageously reusable, which reduces costs.The sensors can be detachably or permanently attached to the formwork system. Detachable sensors can be used on different formwork systems, which reduces costs. Furthermore, the system includes at least one processing unit configured to calculate possible positions of the vibration unit relative to the respective sensors (distances or clearance spaces) based on the amplitudes determined by at least three sensors. Based on this calculation, the system triangulates the current position of the vibration unit relative to the formwork system. The triangulation step involves overlaying the calculated distances or clearance spaces, which represent possible positions of the vibration unit relative to the respective sensors, using trigonometric calculations to determine an intersection.This triangulated section provides a comparatively accurate indication of the current position (or a current position range) for the vibration unit. Furthermore, the system according to the invention comprises a documentation unit for recording the dwell time of the vibration unit in its respective current positions (or current position ranges) relative to the formwork system, wherein the computing unit determines a calculated compaction value in the respective current positions based on the respective current positions of the vibration unit and the documented dwell time in the respective current positions.

[0030] According to a further development of the invention, a feedback unit can be provided that gives the operator feedback on the compaction at the current position (or current position range) of the vibration unit. The calculated compaction value can thus be output to the operator via the feedback unit (for example, on a display unit of the feedback unit), and the operator can then decide whether the compaction is sufficient. Alternatively, several value ranges can be defined, such as a first range between a minimum and a maximum compaction value ("sufficient compaction"), a second range below the minimum compaction value ("insufficient compaction"), and a third range above the maximum compaction value ("compaction for too long").By assigning the calculated compaction value to a defined compaction value range, the operator can be given simplified feedback on the compaction quality via the feedback unit. Furthermore, according to a further development of the invention, a more differentiated evaluation and feedback of the calculated compaction value can also be carried out by comparison with reference values ​​or comparative values ​​(as will be explained in more detail later). Possible configurations of a feedback unit include, for example, acoustic, haptic, or visual feedback, and in particular a display unit, which can also be designed to indicate, across the entire formwork surface of the formwork system, those areas in which the compaction is classified as sufficient or in which the compaction is classified as insufficient.Furthermore, the feedback unit can be designed to provide feedback to the vibration unit, in particular an activation signal for manual or automatic change of the position of the vibration unit.

[0031] As a further development of the invention, the system can also include a comparison unit configured to receive the calculated compaction values ​​determined by the computing unit and compare them with comparative compaction values ​​from a system database. If the calculated compaction value is higher than a corresponding comparative compaction value, the compaction is then classified as sufficient. In this way, it is possible to determine optimal compaction values, i.e., optimal dwell times, for a desired compaction result in a test setup with known parameters such as specific material composition, type of vibration unit used, etc. These values ​​are then stored as comparative compaction values ​​in a database.By using such compaction comparison values, an even better compaction is achieved that takes into account parameters that can be changed in practice, such as the composition of the building material and the vibration unit used.

[0032] It is not uncommon for additional attachments and safety components required on the construction site, such as a concreting platform, guardrails, and the like, to be mounted on the formwork system. These components later enable construction personnel to safely access the formwork system. These additional attachments and safety components can introduce further vibrations into the formwork system, for example, from operators moving on them. To distinguish these external vibrations from those of the vibration unit, at least three sensors can be designed to determine the frequency of a vibration.In a further development of the invention, the system comprises a filter unit which is configured to compare the vibration frequencies determined by the at least three sensors with reference vibration frequencies of the vibration unit and to identify extraneous frequencies that do not originate from a vibration of the vibration unit in order to determine the vibration introduced into the flowable building material by a vibration unit for the purpose of determining the vibration amplitude.

[0033] The reference vibration frequencies can be defined within a specific frequency band. Alternatively, they can be stored in a system database and derived from comparative tests with at least two parameters, including the type of specific vibration unit used for compaction and the type of specific building material to be compacted. These reference vibration frequencies (like the compaction reference values) can thus be determined in a test setup with known parameters, such as the specific composition of the building material and the type of vibration unit used, and then stored as reference vibration frequencies in a database accessible to the system.

[0034] The filter unit can utilize the Fast Fourier Transform (a mathematical algorithm for the efficient calculation of the Discrete Fourier Transform (DFT)) to identify extraneous frequencies. The FFT transforms a discrete-time signal into its frequency components, allowing for analysis. It transforms a specific amount of time-domain data into the frequency domain by decomposing the signals into their harmonic components. Using a filter, the filter unit can then isolate specific frequencies (extraneous frequencies that deviate from the reference vibration frequencies) and transform the remaining frequencies back, for example, using the Inverse Fast Fourier Transform (IFFT), to provide the vibration amplitude.Finally, regarding the sensors, it should be mentioned that these can be arranged, for example, in mounting openings at predetermined sensor points on the formwork system, and / or that they can include an accelerometer, velocity sensor, position sensor, ultrasonic sensor, and / or a laser vibrometer. The sensors can be of the same or different types, and more than the three mentioned above may be used.

[0035] The present invention also relates to a method for determining a compaction according to claim 11, a method for compaction according to claim 14, and finally a system for producing a structural element according to claim 15.

[0036] It should also be noted that terms such as "comprehensive," "exhibiting," or "with" do not exclude other characteristics or steps. Furthermore, terms such as "a" or "the," which indicate a singular number of steps or characteristics, do not exclude a plurality of characteristics or steps—and vice versa.

[0037] Exemplary embodiments of the invention are described in more detail below with reference to the drawings. The figures show preferred embodiments in which individual features of the present invention are combined with one another. Features of an exemplary embodiment can also be implemented independently of the other features of the same exemplary embodiment and can therefore be readily combined by a person skilled in the art to form further meaningful combinations and subcombinations with features of other exemplary embodiments. In the figures, functionally identical elements are provided with the same reference numerals.

[0038] They show schematically:

[0039] Figure 1a shows a rear view of a formwork system with two frame formwork elements shown;

[0040] Figure 1b is a graphic representation of the rear view according to Figure 1a, in which areas where sufficient compaction has taken place using an internal vibrator are graphically highlighted; and

[0041] Figure 2 shows a rear view of a formwork system with a frame formwork element, which is equipped with sensors of the system according to the invention and with the vibration amplitudes determined for the sensors.

[0042] Figures 1a and 2 show a formwork system in a rear view, the formwork system being generally designated with the reference numeral 10.

[0043] The formwork system 10 comprises, as exemplified in Figures 1a and 1b, two adjacent frame formwork elements 12, which form a temporary formwork (and two frame formwork elements not shown, which accordingly form the closing formwork). A cavity is formed between the frame formwork elements of the temporary formwork and the frame formwork elements of the closing formwork, into which a flowable, hardenable building material, in particular concrete, can be poured to form a structural element, in particular a wall, when hardened. Additionally, one or more reinforcements can be accommodated in this cavity, which can provide improved stability to the structural element.

[0044] The frame formwork element 12 comprises a frame 14 and a formwork panel 16, the front of which faces the formed cavity and provides a formwork surface for the flowable, curable building material. For the assembly of the formwork and closing formwork, formwork anchor points 20 are indicated on the frame struts, through which formwork anchors are passed in a known manner. The adjacent frame formwork elements 12 (Figure 1a) can also be connected to one another in a known manner, or are connected to one another in the illustration shown.

[0045] Figure 1b shows, by way of example, a graphic representation of that formwork system, for example on a display of a display unit of a feedback unit of a system according to the invention for determining a compaction of a flowable solidifiable building material.

[0046] The sections labeled B denote the stacked layers of building material. The arrows labeled E indicate the immersion movement of a vibration unit VE designed as an internal vibrator, in this case an exemplary vibrating bottle. The black areas labeled V indicate the regions in which the compaction was assessed as sufficient by the system according to the invention for determining the compaction of a flowable, solidifiable building material.

[0047] With reference to Figure 2, the system according to the invention for determining the compaction of a flowable, solidifiable building material and a corresponding method will be briefly explained below.

[0048] The sensors Si, S2, and S3, designed as accelerometers, measure the vibrations on the outside of the frame formwork element 12. The magnitude of the amplitude of a measured vibration (shown as follows: Asi over time t for sensor S1, As2 over time t for sensor S2, and Ass over time t for sensor S3) indicates the distance of the vibration unit VE from the respective sensor Si, S2, or S3. Based on the calculated distances or distance spaces (labeled Di, D2, and D3 in the diagram), the exact position of the vibration unit VE relative to the frame formwork element 12 can be determined using the triangulation method.

[0049] Based on the precise position combined with the respective dwell time, a calculated compaction value can be determined for each current position. This calculated compaction value can be provided to the operator via a feedback unit. In principle, it is conceivable that this value could be displayed on a display unit similar to that shown in Figure 1b. Alternatively or additionally, an evaluation based on the calculated compaction values, for example by classifying them as sufficient or insufficient compaction, as shown in Figure 1b, can also be performed.Defined time intervals for dwell time in a position (in which the vibration unit VE is active and thus emits measurable vibrations) could indicate sufficient or insufficient compaction, allowing the operator to identify sufficiently or insufficiently compacted areas based on position and time. Excessive compaction can also be classified as "insufficiently compacted."

[0050] Alternatively, to assess whether compaction is sufficient, the calculated compaction values ​​can be compared with comparative compaction values ​​from a system database. A comparison unit can be configured to receive the calculated compaction values ​​determined by the computing unit, compare them with the comparative compaction values, and then, if the calculated compaction value is higher than a corresponding comparative compaction value, classify the compaction as sufficient. The comparative compaction values ​​can be determined, for example, in a test setup with known parameters such as a specific material composition, the type of vibration unit used, etc., as optimal compaction values, i.e., optimal dwell times, for a desired compaction result and stored in the comparison database.

[0051] The feedback unit provides real-time feedback to the operator, indicating areas where a desired compaction result has been achieved – haptically, audibly, or visually, for example, on a display. This allows the operator to react immediately and, if necessary, apply further compaction. Alternatively or additionally, the system's feedback unit can also transmit compaction feedback to the vibration unit (VE), for example, sending an activation or deactivation signal, or a signal to manually or automatically adjust the position of the vibration unit.

Claims

P a t e n t a n s p r ü c h e 1. System for determining the compaction of a flowable, hardenable building material, in particular concrete, during the production of a structural element with the building material, wherein the flowable building material is placed in a formwork system (10), comprising: at least three sensors (Si, S2, S3) for determining an amplitude (Asi, As2, Ass) of a vibration introduced into the flowable building material by a vibration unit (VE), wherein the sensors (Si, S2, S3) are arranged on the formwork system (10), at least one computing unit configured to calculate possible positions (Di, D2, D3) of the vibration unit (VE) relative to the respective sensors (Si, S2, S3) based on the amplitudes (Asi, As2, Ass) determined by the at least three sensors (Si, S2, S3) and, based thereon, to triangulate the current position of the vibration unit (VE) relative to the formwork system (10).a documentation unit for documenting the dwell time of the vibration unit (VE) in the respective current positions of the vibration unit (VE) relative to the formwork system (10), wherein the computing unit determines a calculated compaction value in the respective current positions based on the respective current positions of the vibration unit (VE) and the documented dwell time in the respective current positions.

2. System according to claim 1, wherein the system further comprises a comparison unit which is configured to receive the calculated compaction values ​​determined by the computing unit and to compare them with compaction comparison values ​​from a comparison database of the system and then, if the calculated calculated compaction value is higher than a corresponding compaction comparison value, to classify the compaction as sufficient.

3. System according to claim 1 or 2, wherein the at least three sensors (Si, S2, S3) are configured to determine a frequency of a vibration, and wherein the system comprises a filter unit configured to compare the vibration frequencies determined by the at least three sensors (Si, S2, S3) with reference vibration frequencies of the vibration unit and to identify extraneous frequencies that do not result from a vibration of the vibration unit (VE) in order to determine the vibration introduced into the flowable building material by a vibration unit (VE) for the purpose of determining the respective vibration amplitude.

4. System according to claim 3, wherein the comparison vibration frequencies are stored in a database of the system and are based on comparison tests with at least two test parameters, wherein the at least Two test parameters include the type of specific vibration unit used for compaction and the type of specific building material to be compacted.

5. System according to one of the preceding claims, wherein the at least three sensors (Si, S2, S3) are arranged on an outside of the formwork system (10).

6. System according to one of the preceding claims, wherein the at least three sensors (Si, S2, S3) are arranged at predetermined sensor points on the formwork system (10), in particular in receiving openings on a frame part of a frame formwork element (12) of the formwork system (10) and / or receiving openings on a formwork skin of a frame formwork element of the formwork system, wherein the receiving openings are closed on a side facing the building material, such that direct contact between the sensors (Si , S2, S3) received therein and the building material can be avoided.

7. System according to one of the preceding claims, wherein at least one of the at least three sensors (Si , S2, S3) is detachably attached to the formwork system (10), in particular being directly or indirectly connectable to it by means of a force-fit or form-fit connection.

8. System according to any of the preceding claims, wherein the at least three sensors (Si, S2, S3) comprise an accelerometer, velocity sensor, position sensor, ultrasonic sensor and / or a laser vibrometer.

9. System according to one of the preceding claims, further comprising a feedback unit configured to provide an operator with feedback on the compaction in the current position of the vibration unit (VE), wherein the feedback unit is particularly capable of providing acoustic, haptic or optical feedback when the compaction is classified as sufficient or when the compaction is classified as insufficient.

10. System according to claim 9, wherein the feedback unit comprises a display unit configured to indicate over an entire formwork surface of the formwork system (10) those areas in which the compaction is classified as sufficient or in which the compaction is classified as insufficient and / or wherein the feedback unit is configured to provide feedback to the vibration unit (VE), in particular an activation signal for manual or automatic change of the position of the vibration unit (VE).

11. Method for determining the compaction of a flowable solidifiable building material during the production of a structural element with the building material using a system according to one of the preceding claims, wherein the method comprises the steps: Attaching at least three sensors (Si, S2, S3) to a formwork system (10) intended to hold the building material in order to determine the vibration amplitudes (Asi, As2, Ass) and optionally vibration frequencies transmitted from the building material to the formwork system (10) of a vibration introduced into the flowable building material by a vibration unit (VE); Determine, using at least three sensors (Si , S2, S3), vibration amplitudes (Asi , AS2, Ass), and optionally vibration frequencies, and transmit the determined information to a computing unit; Calculate, using at least one computing unit, possible positions of the vibration unit (VE) relative to the respective sensors (Si, S2, S3) based on the amplitudes determined by the at least three sensors (Si , S2, S3); Triangulating, with the aid of at least one computing unit, the current position of the vibration unit relative to the formwork system based on the calculated possible positions of the vibration unit; and Document, using a documentation unit, the dwell time of the vibration unit in the respective current positions of the vibration unit relative to the formwork system (10).

12. The method of claim 1, wherein the method further comprises: Using a comparison unit, compare the calculated compaction values ​​determined by the computing unit with compaction comparison values ​​from a comparison database, and then, if the calculated compaction value is higher than a corresponding compaction comparison value, classify the compaction as sufficient.

13. The method of claim 1 or 12, wherein the method further comprises: Determination using at least three sensors (Si, S2, S3), a frequency of a vibration, and Identifying extraneous frequencies using a filter unit designed to compare the vibration frequencies determined by the at least three sensors (Si , S2, S3) with reference vibration frequencies of the vibration unit (VE) and to identify extraneous frequencies that do not result from a vibration of the vibration unit (VE) in order to determine the vibration introduced into the flowable building material by a vibration unit (VE) for the determination of the respective vibration amplitude, wherein the step of identifying extraneous frequencies includes in particular performing a frequency analysis using the Fast Fourier Transform.

14. Method for compacting a flowable solidifiable building material when producing a structural element with the building material using a system according to any one of the preceding claims 1 to 10, and using a vibration unit (VE) for compacting the flowable building material, wherein the method comprises the steps: Compacting the flowable building material placed in a formwork system (10) by means of a vibration unit; and the process steps according to one of claims 11 to 13, wherein, for example, the vibration unit (VE) comprises at least one internal vibrator, in particular a vibrating bottle, and wherein the compaction step comprises, for example, the following steps: Introducing at least one internal vibrator into the still flowable building material, in particular into the last layer of building material introduced; Activating at least one internal vibrator; Moving the at least one internal vibrator relative to the formwork system (10) within and / or outside the still flowable building material, in particular moving the internal vibrator along the longitudinal extent of a frame formwork element (12) of the formwork system (10) to achieve uniform compaction across the entire width of the formwork surface, and moving the internal vibrator in a direction parallel to gravity to achieve mixing of the individual layers of building material; and Removing the internal vibrator from the still flowable building material so that it can flow back into the receiving area of ​​the internal vibrator.

15. System for producing a structural element with a flowable, solidifiable building material, in particular with concrete, comprising: a formwork system (10) that forms a mold for the structural element to be produced, a device for supplying the flowable building material, wherein the flowable building material is introduced into the formwork system (10) for example by means of a movable funnel-shaped device, a vibration unit (VE) for compacting the flowable building material introduced into the formwork system; a system for determining the compaction of the flowable building material according to claims 1 to 10.

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