Method for influencing frictional resistance between electrically conductive member and building material, method for removing electrically conductive member, and device

Abstract

A method for influencing the frictional resistance between an electrically conductive component (12) and an at least partially cured, water-containing building material (14) is described, wherein the component (12) is at least partially surrounded by the building material (14). An electrode (18) is provided, which is separate from the electrically conductive component (12). Furthermore, a voltage is applied between the electrode (18) and the component (12) so that an electric field is generated and a boundary layer (22) between the component (12) and the building material (14) lies within the electric field. A method for removing an electrically conductive component (12) is also presented. Finally, a device is presented which is configured to carry out the method for influencing the frictional resistance.

Description

[0001] The invention relates to a method for influencing a frictional resistance between an electrically conductive component and an at least partially hardened, water-containing building material.

[0002] Furthermore, the invention relates to a method for removing an electrically conductive component from a water-containing building material that is at least partially hardened.

[0003] Furthermore, the invention relates to a device which is set up to carry out the above-mentioned method for influencing frictional resistance.

[0004] In civil engineering projects, such as the construction of basements, underground parking garages, tunnels, and other structures below ground level, various excavation support techniques are used to create and secure excavation pits, stabilize changes in elevation, or prevent water flow. These techniques involve constructing walls and slabs below ground level, such as bored pile walls, soil-concrete walls, or base slabs. These walls are typically made of concrete or comparable self-hardening materials. Depending on the structural requirements, these walls are often reinforced with metal reinforcement elements. These reinforcement elements are typically in the form of steel components, such as steel profiles.

[0005] These walls and panels often do not become part of the actual building under construction, but rather serve only to secure the excavation or the change in elevation during the building process. Consequently, they are only useful during construction. For this reason, such walls for securing the excavation or the change in elevation are economically disadvantageous, as they require a significant amount of material without contributing to the construction of the actual building. Furthermore, the high material consumption also results in additional CO2 emissions.

[0006] The object of the present invention is therefore to provide a method and a device that reduce the costs and emissions for the production of walls for excavation support or for securing a drop in terrain.

[0007] The problem is solved by a method for influencing the frictional resistance between an electrically conductive component and an at least partially cured, water-containing building material, wherein the component is at least partially surrounded by the building material. The method comprises: Providing an electrode that is separate from the electrically conductive component, and applying a voltage between the electrode and the component, so that an electric field is generated and a boundary layer between the component and the building material lies within the electric field.

[0008] The basic idea of ​​the invention is to influence the frictional resistance between the electrically conductive component and the building material. This is achieved by utilizing the effect of electroosmosis and inducing an electrolysis process. Both the electroosmosis effect and the electrolysis process can be triggered by an applied voltage. In electroosmosis, water migrates from an anode to a cathode due to the applied voltage. Therefore, depending on the electrical configuration, electroosmosis can create a fluid film on the surface of the electrically conductive component or on the surface of the electrode. For example, by applying the appropriate polarity, a fluid film in the form of a water film can be created on the surface of the electrically conductive component.More precisely, this water film forms in the boundary layer between the component and the substrate, thereby reducing friction between the component and the substrate. Alternatively, the water film can also form on the surface of the electrode. This can further reduce friction between the electrode and the surrounding material. During the electrolysis process, oxygen is produced at the anode, while hydrogen is simultaneously produced at the cathode. This generates a gas at both the surface of the electrically conductive component and the surface of the electrode, creating a gas pressure. Here, too, the polarity determines whether oxygen or hydrogen is produced at the electrically conductive component and, consequently, the opposite gas at the electrode.By superimposing the effect of electroosmosis with an electrolysis process, a water film can be generated at the cathode, and simultaneously, a gas pressure can be generated by hydrogen, while a gas pressure can be generated by oxygen at the anode. Consequently, a gas pressure and a water film can be generated on the surface of the electrically conductive component or electrode. The superposition of a gas-generated gas pressure and a water film on the surface results in a particularly significant reduction in frictional resistance.

[0009] The influence on frictional resistance is understood to mean an influence on adhesion resistance and / or sliding resistance.

[0010] Accordingly, for example, the friction between the electrically conductive component and the building material can be reduced.

[0011] Reducing the friction between the component and the building material also reduces the force required to move the electrically conductive component relative to the building material. This allows the electrically conductive component to be removed from the building material and reused. This saves costs and avoids emissions that would otherwise be generated by manufacturing a new electrically conductive component.

[0012] In this process, the stress is only applied when the building material is already in at least a partially cured state. Specifically, the process is only carried out once the building material has cured. A partially cured state of the building material is understood to be one in which the material has reached at least 70% of its nominal strength, and in particular, at least 90% of its nominal strength.

[0013] To apply the voltage, a voltage source can be provided, which is connected to the electrode and to the component.

[0014] The term "building material" can refer to materials including concrete, bentonite, soil concrete, binder-stabilized soil, cement, and / or mortar. Furthermore, building materials may also include clay powders, rock powders, and / or metal oxides.

[0015] By combining the materials listed above, the effect of electroosmosis and the electrolysis process can be specifically influenced and consequently improved.

[0016] The term "electrically conductive component" can refer to a component that includes, for example, a rod element, a tube element, and / or a profile element, particularly a metal profile. The rod element can have a circular or polygonal cross-section. The tube element can also have a circular or polygonal cross-section. The profile element can, for example, be an I-profile, a T-profile, a U-profile, or an L-profile.

[0017] Preferably, the electrically conductive component is a reinforcement element for stabilizing the building material, which at least partially surrounds the electrically conductive component.

[0018] The term "boundary layer" can refer in particular to a contact area between the building material and the building element, or to an area where the surface of the building element is in close proximity to the building material.

[0019] The electrode can already be integrated into or attached to the building material. This is particularly advantageous when using a semi-finished component that can be filled with the self-curing, water-based building material. This eliminates the need for actively inserting the electrode to later establish an electric field between the electrode and the component.

[0020] Preferably, the electrode is a reinforcement element for stabilizing the building material, which at least partially surrounds the electrode.

[0021] Alternatively, the process can involve bringing the electrode into contact with the building material and / or with a surface that is in contact with the building material. This allows the distance between the electrode and the building component to be individually determined.

[0022] The method can further include orienting the electrode along the main direction of extension of the component. Alternatively, it can include providing the electrode in a state oriented along the main direction of extension of the component. In both cases, this ensures that a nearly homogeneous electric field can be generated between the component and the electrode by applying a voltage. This has the advantage that the effect of electroosmosis and any electrolysis process act as uniformly as possible along the surface of the component and the electrode. Consequently, the frictional resistance between the component and the substrate is also affected uniformly. The term "along the main direction of extension of the component" can refer in particular to the direction of extension of the component.essentially parallel to the main extension direction of the component, the term "essentially parallel to the main extension direction of the component" includes a deviation of up to + / - 45° from a parallel orientation, in particular + / - 10° from a parallel orientation.

[0023] The method can further include arranging the electrode in such a way that the electrode at least partially surrounds the component. This also has a beneficial effect on the uniformity of the effects described above caused by electroosmosis and electrolysis.

[0024] The distance between the component and the electrode can range from 5 cm to 5 m. Preferably, the distance between the component and the electrode can range from 10 cm to 2 m. These distances have proven particularly advantageous in practice for influencing the frictional resistance between the component and the building material.

[0025] The electrode can comprise or be a braided element, a grid element, a perforated sheet, a tube element, a rod element, and / or a wire element. These elements simplify the formation of a homogeneous electric field between the electrode and the component and / or allow the electrode to be positioned and removed from the component particularly easily. If the electrode comprises or is a braided element, a grid element, a perforated sheet, a tube element, and / or a wire element, it is conceivable that the electrode at least partially surrounds the component, as explained above. Furthermore, these elements also allow for a design in which the component is completely surrounded by the electrode.In particular, in an embodiment where the electrode comprises or is a tubular element, the tubular element can be arranged such that it extends circumferentially around the component, while the component itself, or at least a section of the component, is located within the tubular element. If the electrode additionally or alternatively comprises or is a rod element, this simplifies the provision and arrangement of the electrode relative to the component. For example, the rod element can be positioned in particularly hard or tough soil relative to the component and subsequently removed.

[0026] The applied voltage can be direct current (DC) and / or alternating current (AC). Using a DC voltage allows for particularly precise control of the electroosmosis effect and the electrolysis process through appropriate polarity adjustment. Furthermore, a DC voltage can effectively and relatively strongly induce the formation of a water film and / or gas pressure due to gas production. The DC voltage can be applied intermittently, meaning with time intervals during which no voltage is applied. If the DC voltage is pulsed, the pulses can have a period ranging from 1 second to 10 hours. Additionally or alternatively, the DC voltage can exhibit a waveform, a rectangular waveform, a square-wave pulse, a needle-wave pulse, and / or a sawtooth waveform.

[0027] When using alternating current (AC), it can be pulsed; in other words, it can be applied discontinuously—that is, with time interruptions during which no voltage is applied. If the AC is pulsed, the pulses can have a period of 1 second to 10 hours. Additionally or alternatively, the AC can have a waveform, a rectangular waveform, a square-wave pulse, a needle-wave pulse, and / or a sawtooth waveform.

[0028] Furthermore, the alternating voltage itself can have a relatively long period. The period of the alternating voltage can range from 1 second to 10 hours. The alternating voltage can cause a water film and gas pressure to form on both the component and the electrode through gas generation. It is also conceivable that the applied voltage alternates between a direct current (DC) and an alternating current (AC) voltage over time, or that an applied voltage is a DC voltage that is reversed at time intervals.

[0029] The voltage can be applied for a predefined duration. Furthermore, a voltage parameter, a field strength parameter, and / or a power parameter of the voltage source can be selected as a function of this duration. Alternatively, the duration can be selected as a function of a voltage parameter, a field strength parameter, and / or a power parameter of the voltage source. The voltage parameter can specify the magnitude of the applied voltage. This can be the effective and / or the maximum voltage. Additionally or alternatively, the voltage parameter can specify a voltage waveform. The power parameter can specify the magnitude of the electrical power supplied by the voltage source and / or a power waveform. The field strength parameter can specify the magnitude of the electric field between the component and the electrode and / or a field strength waveform.A "predefined time period" refers to the duration within which a desired effect on the frictional resistance between the component and the material has occurred. Accordingly, the parameters of the applied voltage can be adjusted to achieve the desired effect on the frictional resistance within a predefined time period. Conversely, it is also conceivable that the parameters of the applied voltage are already predetermined, and a time period can be derived from these parameters, indicating when the desired effect on the frictional resistance occurs. In this way, the frictional resistance can be influenced to a desired extent.

[0030] The applied voltage can be equal to or greater than the decomposition voltage of water. The decomposition voltage of water is 1.23 V. In practice, however, hydrogen and oxygen often only form at a higher voltage. This higher voltage is also referred to as overvoltage. The magnitude of the overvoltage depends, among other things, on the material of the electrode and the component, their surface properties, their distance, the conductivity of the building material, the conductivity of the ground, the electric field strength, and the current density.

[0031] Furthermore, the maximum applied voltage must not exceed 400 V, and in particular, it must not exceed 75 V. Additionally or alternatively, the RMS value of the maximum applied voltage must not exceed 120 V, and in particular, it must not exceed 50 V. The requirement that the RMS value of the maximum applied voltage must not exceed 120 V applies specifically to DC voltages. Furthermore, the requirement that the RMS value of the maximum applied voltage must not exceed 50 V applies specifically to AC voltages. This ensures the safe operation of the process.

[0032] Furthermore, the electric field strength is between 10 V / m and 2000 V / m, specifically between 20 V / m and 1000 V / m. Alternatively, it is also conceivable that the electric field strength is between 10 V / m and 100 V / m. This also ensures a safe and effective implementation of the process.

[0033] When voltage is applied between the electrode and the component, the electrode can be connected as the anode and the component as the cathode. Alternatively, the component can be connected as the anode and the electrode as the cathode. If the electrode is connected as the anode and the component as the cathode, oxygen can form on the electrode surface due to electrolysis, as previously described. Furthermore, hydrogen can form on the surface of the component connected as the cathode due to electrolysis. Additionally, a film of water can form on the component surface due to electroosmosis and the associated migration of water from the anode to the cathode.Since a gas pressure can be generated at the cathode by the hydrogen, and a water film can form, it is advantageous to connect the component as the cathode, as this allows for particularly effective control of the frictional resistance between the component and the substrate. The above explanations can be applied analogously in reverse if the component is connected as the anode and the electrode as the cathode.

[0034] The process can further include applying a voltage between the electrode and the component before the material has hardened. This can generate gas pressure and a water film on the surface of the electrode and / or component through water migration while the material is still hardening. Applying a voltage both before and after the material has hardened allows for greater control over the frictional resistance than applying the voltage only after the material has hardened. Consequently, this can further reduce the frictional resistance between the material and the component.

[0035] Furthermore, multiple electrodes can be provided, and a voltage can be applied between each of these electrodes and the component. This allows for the generation of several individual electric fields, which in turn can be used to create a relatively uniform gas pressure by generating gas and / or a water film by water migration on the surface of the component or electrode.

[0036] Furthermore, the problem is solved by a method for removing an electrically conductive component from an at least partially hardened, water-containing building material, wherein the component is at least partially surrounded by the building material. The method comprises: Influencing, in particular reducing, the frictional resistance by means of the inventive method for influencing a frictional resistance between an electrically conductive component and an at least partially hardened, water-containing building material, and at least partially removing the component from the building material.

[0037] Such a method allows for at least partial, and in particular complete, removal of the component from the building material, especially non-destructive removal. If the component is completely removed from the building material, it can be reused. This saves costs and reduces emissions. When the component is removed from the building material, the area of ​​the building material surrounding the component is in a hardened state.

[0038] To remove the component from the building material, it can be subjected to a tensile force, for example. Alternatively or additionally, it can also be subjected to a compressive force and / or a cyclical alternating force and / or vibrations. A construction machine, such as a crane, can be used for this purpose. The component can then be pulled out of the building material.

[0039] Furthermore, the problem is solved by a device configured to carry out a method for influencing the frictional resistance between an electrically conductive component and an at least partially cured, water-containing component according to one of the embodiments described above. The device comprises a voltage source and an electrode. Such a device makes it possible, for example, to reduce the frictional resistance between the electrically conductive component and the building material. This, in turn, simplifies the removal of the component from the building material. As a result, the electrically conductive component can be recovered and reused with relatively little effort. This saves costs and reduces emissions.

[0040] The additional effects and advantages resulting from this can be found in the paragraphs above.

[0041] The invention is explained below with reference to an exemplary embodiment shown in the accompanying drawings. These show: Figure 1 shows a schematic representation of a device according to the invention, by means of which a method according to the invention for influencing a frictional resistance between an electrically conductive component and an at least partially hardened, water-containing building material is carried out, Figure 2 shows a schematic representation of a device according to a second variant, and Figure 3 shows a diagram in which a normalized tensile force acting on a component is plotted over a distance of the component relative to the building material.

[0042] Figure 1 shows a device 10, an electrically conductive component 12 and a water-containing building material 14 that is at least partially hardened.

[0043] The device 10 comprises a voltage source 16 and an electrode 18.

[0044] The voltage source 16 can be a DC voltage source. Alternatively, the voltage source 16 can be an AC voltage source. It is also conceivable that the voltage source 16 is a voltage source that can switch between DC and AC voltage.

[0045] The voltage source 16 can be electrically coupled to the electrode 18. In the operating state of the device 10, which is in Figure 1 As shown, the electrode 18 is electrically coupled to the voltage source 16.

[0046] The electrode 18 is provided separately from the electrically conductive component 12. The electrode 18 can comprise a braided element. Alternatively or additionally, the electrode 18 can comprise a grid element, a perforated sheet, a tube element, a rod element, and / or a wire element. Figure 1Only a single electrode 18 is shown. However, it is also conceivable that the device 10 comprises a plurality of electrodes 18 (see Figure 2 ).

[0047] This is the in Figure 1 The electrode 18 shown is arranged by way of example in a base 20 that contacts the building material 14. However, this is not necessarily the case, and alternative variants will be discussed in more detail later.

[0048] The electrically conductive component 12 is at least partially surrounded by the building material 14. A boundary layer 22 exists between the electrically conductive component 12 and the building material 14.

[0049] In the embodiment from Figure 1 The electrically conductive component 12 is designed as reinforcement for the building material 14.

[0050] The electrically conductive component 12 can be electrically coupled to the voltage source 16 of the device 10. In the operating state of the device 10, which is described in Figure 1 As shown, the electrically conductive component 12 is electrically coupled to the voltage source 16.

[0051] The electrically conductive component 12 can comprise a rod element, a tube element, and / or a profile element, in particular a metal profile. The rod element can have a circular or polygonal cross-section. The tube element can also have a circular or polygonal cross-section. The profile element can, for example, have an I-profile, a T-profile, a U-profile, or an L-profile.

[0052] The building material 14 comprises concrete, bentonite, soil concrete, binder-stabilized soil, cement and / or mortar. A partially cured state of the building material 14 is understood to be a state in which the building material 14 has reached at least 70% of its nominal strength, and in particular at least 90% of its nominal strength.

[0053] Furthermore, it shows Figure 1 A pulling device 24, which is mechanically connected to the component 12. A tensile force F can be applied to the component 12 by means of the pulling device 24, which is in the Figure 1 The embodiment shown acts along the upward-pointing arrow.

[0054] Figure 2Figure 10 shows a device according to a second embodiment of the invention. Similar components are identified by identical reference numerals. For the sake of brevity, they are not described again, but reference is made to the corresponding description above. The following description focuses on the changes that have been made in the embodiment of Figure 2 were introduced. Compared to the in Figure 1In the embodiment shown, the device 10 depicted here comprises a further electrode 18 (right). While the first electrode 18 (left) is arranged in the soil 20 adjacent to the building material 14, the further electrode 18 (right) is arranged in the building material 14 and is thus in direct contact with it. The further electrode 18 (right) can, for example, be arranged within a (drilled) channel that was introduced into the building material 14 before the further electrode 18 (right) was placed there. Alternatively, the further electrode 18 (right) can also be provided directly in the building material 14, for example by placing it in the building material 14 while it is still in an uncured state. The further electrode 18 (right) can be electrically coupled to the voltage source 16. In the operating state of the device 10, which is shown in Figure 2As shown, the additional electrode 18 (right) is electrically coupled to the voltage source 16. This results in the generation of a further electric field between the additional electrode 18 (right) and the component 12, in addition to the electric field that is formed by applying a voltage between the additional electrode 18 (left) and the component 12, as soon as a voltage is applied between the additional electrode 18 (right) and the component 12.

[0055] How Figure 2 As can be seen, the electrode 18 (left) is arranged at a first distance A (left) from the component 12, and the other electrode 18 (right) is arranged at a second distance A (right) from the component 12, which differs from the first distance A (left). In an alternative embodiment, not shown here, the first distance A can essentially correspond to the second distance A. It is also obvious to a person skilled in the art to use only one electrode 18 instead of two (as in Figure 2 shown), to provide three, four, five, six or more than six electrodes 18 which are electrically coupled to the voltage source 16 in the operating state of the device 10.

[0056] The device 10 according to the in Figure 1 or Figure 2 The embodiment shown is designed to carry out a method for influencing a frictional resistance between the electrically conductive component 12 and the at least partially hardened, water-containing building material 14.

[0057] This procedure will be described below with reference to the Figure 1 and 2 explained. This shows Figure 3 Furthermore, a schematic diagram is shown in which a normalized tensile force acting on a component 12 is plotted over a distance of the component 12 relative to the building material 14.

[0058] In a first step S1, an electrode 18 is provided.

[0059] The electrode 18 can be positioned in the ground 20 as described above, with the ground 20 contacting the building material 14. Alternatively or additionally, the electrode 18 can also be brought into contact with the ground 20 in another way. This can be done, for example, by placing the electrode 18 on the ground 20. Alternatively or additionally, it is also conceivable that the electrode 18 is brought into direct contact with the building material 14 (see Figure 2 , right electrode 18). Furthermore, it is also possible that the electrode 18 is already provided in the building material 14, so that it does not require an additional work step in the immediate

[0060] Contact must be made with the building material 14 and / or with the soil 20 that is in contact with the building material 14.

[0061] Furthermore, as explained above, it is also conceivable that several electrodes 18 are provided (see Figure 2This can involve two, three, four, five, six, or more than six electrodes. Each electrode 18 of a plurality of electrodes can be provided independently of the other electrodes 18 according to the above descriptions and arranged relative to the component 12.

[0062] In a further step S2, the electrode 18 can be oriented along a principal extension direction R of the component 12. Alternatively, the electrode 18 can be provided in a state oriented along the principal extension direction R of the component 12. Additionally or alternatively, the electrode 18 can be arranged such that it at least partially surrounds the component 12, particularly circumferentially.

[0063] The distance A between the component 12 and the electrode 18 can be 5 cm to 5 m. Preferably, the distance A between the component 12 and the electrode 18 can be 10 cm to 2 m.

[0064] In a third step S3, a voltage is applied between electrode 18 and component 12, thus generating an electric field. For this purpose, the voltage source 16 is electrically coupled to electrode 18 and component 12. The interface 22 between component 12 and build material 14 lies within the electric field. When the voltage is applied, the build material 14 is already in a hardened state. In addition to applying the voltage when the build material 14 is already in a hardened state, it is also conceivable to apply a voltage between electrode 18 and component 12 before the build material 14 is in a hardened state.

[0065] Due to the applied voltage, the effect of electroosmosis and an electrolysis process can be induced. In electroosmosis, water migrates from an anode to a cathode due to the applied voltage. With the appropriate polarity, electroosmosis can therefore cause a film of water to form on the surface of the electrically conductive component 12 or on the surface of the electrode 18.

[0066] During the electrolysis process, oxygen is formed at the anode, while hydrogen is simultaneously formed at the cathode. This allows a gas to be generated at the surface of the electrically conductive component 12 and at the electrode 18, each generating a gas pressure. Here, too, the polarity determines whether oxygen or hydrogen is formed at the electrically conductive component 12 and, consequently, the other gas at the electrode 18.

[0067] This has the effect of influencing, or more precisely, reducing, the frictional resistance between the component 12 and the material 14. The frictional resistance between the component 12 and the material 14 is reduced more significantly when both a water film and a gas pressure due to hydrogen form on the surface of the material 12 and thus in the boundary layer 22, than when only oxygen forms on the surface of the material 12.

[0068] The applied voltage can be a direct current (DC) voltage. With DC voltage, it is conceivable that the polarity remains the same after the voltage is applied, or that it reverses at predefined time intervals.

[0069] Consequently, when a voltage is applied, electrode 18 can be connected as the anode and component 12 as the cathode. This allows a water film to form on the surface of the electrically conductive component 12. More precisely, this water film forms in the interface 22 between component 12 and the material 14, thereby reducing the friction between the component 12 and the material 14. Additionally, hydrogen is produced on the surface of component 12 due to electrolysis, creating a gas pressure in the interface 22. Simultaneously, oxygen is produced on the surface of electrode 18.

[0070] Alternatively, it is also conceivable that component 12 is connected as the anode and electrode 18 as the cathode. In this case, hydrogen and a water film form on the surface of electrode 18. Oxygen also forms on the surface of component 12, thereby generating gas pressure in the boundary layer 22.

[0071] Additionally or alternatively, it is conceivable to apply an alternating voltage. This alternating voltage could, for example, be a pulsed alternating voltage with a relatively large period.

[0072] The applied voltage is preferably greater than the decomposition voltage of water. The decomposition voltage of water is 1.23 V. In practice, however, hydrogen and oxygen are often only produced at a higher voltage. This higher voltage is also referred to as overvoltage. The magnitude of the overvoltage depends, among other things, on the material of the electrode 18 and the component 12, their surface properties, their distance, the conductivity of the building material 14, the conductivity of the soil, the electric field strength, and the current density. Consequently, in practice, the applied voltage is preferably greater than the decomposition voltage of water.

[0073] For direct current (DC) voltage, the magnitude of the maximum applied voltage does not exceed 400 V, in particular 75 V. For alternating current (AC) voltage, the magnitude of the RMS value of the maximum applied voltage does not exceed 120 V, in particular 50 V.

[0074] Furthermore, the electric field strength is between 10 V / m and 2000 V / m, specifically between 20 V / m and 1000 V / m. Alternatively, it is also conceivable that the electric field strength is between 10 V / m and 100 V / m.

[0075] If a plurality of electrodes 18 are provided, a voltage is applied between each of the plurality of electrodes 18 and the component 12. The preceding statements regarding the applied voltage apply to each individual electrode 18 of the plurality of electrodes.

[0076] The voltage can be applied for a predefined period of time. The "predefined period of time" refers to the time within which the desired effect on the friction between the component 12 and the building material 14 has occurred.

[0077] In this process, a voltage parameter, a field strength parameter and / or a power parameter of the voltage source is selected depending on the duration of time.

[0078] The voltage parameter can include the magnitude of the applied voltage. This can be the effective and / or the maximum voltage. Additionally or alternatively, the voltage parameter can include a voltage waveform. The power parameter can include the magnitude of electrical power supplied by the voltage source and / or an electrical power waveform. The field strength parameter can include the magnitude of the field strength present between component 12 and electrode 18 and / or a field strength waveform.

[0079] Alternatively, it is also conceivable that the duration is chosen depending on a voltage parameter, a field strength parameter and / or a power parameter.

[0080] To illustrate the influence on frictional resistance, in Figure 3 A schematic diagram of a tensile test of a component 12 made of a hardened building material 14 is shown. In this diagram, a normalized tensile force F acting on a component is plotted over a distance of the component 12 relative to the building material 14.

[0081] The diagram shows two measurement curves 26 and 28. Measurement curve 26 represents a first tensile test in which a component 12 was pulled from a building material 14 without prior execution of the inventive method for influencing the frictional resistance. The highest measured tensile force F is defined as 1 or 100%. This tensile force F serves as the basis for normalization.

[0082] The measurement curve 28 represents a second tensile test in which the inventive method for influencing the frictional resistance was carried out beforehand, and subsequently a component 12 was pulled from a building material 14. This shows that the maximum required tensile force F of the second tensile test corresponds to only about 20% of the maximum required tensile force F of the first tensile test.

[0083] Furthermore, a method for removing the electrical component 12 from the at least partially hardened, water-containing building material 14, by which the component 12 is at least partially surrounded, will be explained below.

[0084] In a fourth step S4, the frictional resistance is influenced, in particular reduced, by means of a method for influencing a frictional resistance between the electrically conductive component 12 and an at least partially cured, water-containing building material 14 according to one of the embodiments described above.

[0085] According to the above explanations, it is advantageous to connect the component 12 as the cathode and thus to reduce the frictional resistance particularly strongly.

[0086] In a fifth step S5, the component 12 is at least partially removed from the building material 14. This step can be performed non-destructively, particularly with regard to the building material 14. Furthermore, the fifth step S5 takes place when the building material 14 is in a hardened state. The at least partial removal of the component 12 can be carried out, for example, using the pulling device 24.

[0087] Preferably, the component 12 is completely removed from the building material 14. Reference symbol list

[0088] 10 Device 12 Component 14 Material 16 Voltage source 18 Electrode 20 Soil 22 Boundary layer 24 Pulling device 26 Measuring curve 28 Measuring curve Distance, tractive force, main direction of extension S1 first step S2 second step S3 third step S4 fourth step S5 fifth step

Claims

1. Method for influencing a frictional resistance between an electrically conductive component (12) and an at least partially cured, water-containing building material (14), wherein the component (12) is at least partially surrounded by the building material (14), comprising: - providing an electrode (18) which is separate from the electrically conductive component (12) (S1), and - applying a voltage between the electrode (18) and the component (12) such that an electric field is generated and a boundary layer (22) between the component (12) and the building material (14) lies within the electric field (S3).

2. Method according to claim 1, further comprising bringing the electrode (18) into contact with the building material (14) and / or with a ground (20) contacting the building material (14).

3. Method according to claim 1 or 2, further comprising orienting the electrode (18) along the main extension direction (R) of the component (12) or providing the electrode (18) in a state (S2) oriented along the main extension direction (R) of the component (12).

4. Method according to one of the preceding claims, wherein the distance (A) between the component (12) and the electrode (18) is 5 cm to 5 m, preferably 10 cm to 2 m.

5. Method according to any of the preceding claims, wherein the electrode (18) comprises or is a braid element, a grid element, a perforated sheet, a tube element, a rod element and / or a wire element.

6. Method according to any of the preceding claims, wherein the applied voltage comprises or is a direct current voltage and / or an alternating current voltage.

7. Method according to one of the preceding claims, wherein the voltage is applied for a predefined time period, and wherein a voltage parameter, a field strength parameter and / or a power parameter of a voltage source is selected depending on the time period, or wherein the time period is selected depending on a voltage parameter, a field strength parameter and / or a power parameter of a voltage source.

8. Method according to any of the preceding claims, wherein the amount of the applied voltage corresponds to or is greater than the decomposition voltage of water.

9. Method according to one of the preceding claims, wherein the magnitude of the maximum applied voltage does not exceed 400 V, in particular does not exceed 75 V and / or the magnitude of the RMS value of the maximum applied voltage does not exceed 120 V, in particular does not exceed 50 V.

10. Method according to one of the preceding claims, wherein the electric field strength of the electric field is 10 V / m to 2000 V / m, in particular 20 V / m to 1000 V / m.

11. Method according to one of the preceding claims, wherein when the voltage is applied between the electrode (18) and the component (12) the electrode (18) is connected as the anode and the component (12) is connected as the cathode, or wherein when the voltage is applied between the electrode (18) and the component (12) the component (12) is connected as the anode and the electrode (18) is connected as the cathode.

12. Method according to one of the preceding claims, further comprising applying a voltage between the electrode (18) and the component (12) before the component material (14) is in a hardened state.

13. Method according to one of the preceding claims, wherein a plurality of electrodes (18) is provided and a voltage is applied between each of the plurality of electrodes (18) and the component (12).

14. Method for removing an electrically conductive component (12) from an at least partially cured, water-containing building material (14), wherein the component (12) is at least partially surrounded by the building material (14), comprising: - influencing, in particular reducing, the frictional resistance by means of a method according to one of the preceding claims (S4), and - at least partially removing the component (12) from the building material (14) (S5).

15. Device (10) configured to carry out a method according to any one of claims 1 to 13, comprising a voltage source (16) and an electrode (18).

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