Method for assessing the state of a reinforced-concrete-component reinforcement, and device therefor

Abstract

The present invention relates to a method for assessing the corrosive state of a reinforced-concrete component (1) comprising reinforcing steel (5), comprising the steps: providing a first conductor (LA) and establishing an electrical connection between the first conductor (LA) and a first section of the reinforcing steel (5) for the use thereof as an anode (100), and providing a second conductor (LK) and establishing an electrical connection between the second conductor (LK) and a second section, the second section being a section of the reinforcing steel (5) which is spatially separated from the first section, or a section of a steel element present outside the reinforced-concrete component (1), for the use thereof as a cathode (110); establishing a disconnectable electrical connection between the first conductor (LA) and the second conductor (LK) outside the reinforced-concrete component (1); determining the double-layer capacitance (CDL,A, CDL,K) of the anode (100) and of the cathode (110) and / or of the surface (AA, AK) of the anode (100) and of the cathode (110) on which the double-layer capacitance (CDL,A, CDL,K) is based; forming a mathematical relation of the double-layer capacitances (CDL,A, CDL,K) to one another or of the surfaces (AA, AK) to one another; and assessing the formed relation on the basis of exactly one or at least one predetermined criterion.

Description

[0001] NeoCorrTecs GmbH Description Method for Assessing the Condition of Reinforced Concrete Component Reinforcement and Device Therefore The present invention relates to a method for assessing the corrosion condition of a reinforced concrete component (or structure) according to claim 1 and a device for carrying out this method according to claim 13, a kit (alternatively "construction kit") according to claim 19 and a further method according to claim 21, or according to the respective preambles or generic terms of these claims. Corrosion of steel used as reinforcement in concrete has been a known problem in reinforced concrete construction for decades. The associated costs are estimated at single-digit percentages of the gross domestic product. Limiting this damage is therefore a central focus of structural maintenance and remains a motivation for research.The most prominent causes of reinforcement corrosion are the ingress of pollutants in the form of gaseous CO2 due to atmospheric contact, but above all, the ingress of dissolved chlorides through exposure to seawater or de-icing salt. Chloride-induced corrosion is the significantly more serious damage mechanism. In the common scenario of a cracked, de-icing salt-exposed concrete cover, the chlorides can very quickly penetrate the concrete cover along the cracks and lead to premature reinforcement corrosion at the surface of the reinforcing steel. The pitting corrosion typical of this manifests itself as localized scarring, which can lead to a significant loss of cross-sectional area in the reinforcement. With increasing cross-sectional loss, the reinforcement loses its structurally designed tensile strength, and the structural element can no longer guarantee its stability.To prevent unchecked cross-sectional loss, several repair principles have been developed. Each of these repair principles requires the integration of a monitoring system. By installing a three-electrode setup within the reinforced concrete structure, corrosion activity outside the component can be measured, and, where possible, the achievement of the repair objective can be tracked. The three-electrode setup includes instrumenting the anodically acting reinforcement (or reinforcing steel) as the anode, the cathodically acting reinforcement as the cathode, and the use of a reference electrode. This enables the calculation of the galvanic mass loss and the application of Ohm's law. Corrosion is an electrochemical process and is governed by the mechanisms of a galvanic cell. This cell is divided into an anodic and a cathodic half-cell.The corrosion current flows between these points and can be used as a measure of anodic iron dissolution with the aid of monitoring. A high corrosion current thus corresponds to rapidly progressing corrosion and, in the case of pitting corrosion, to a significant loss of cross-sectional area, and vice versa. NeoCorrTecs GmbH. One object of the present invention is to provide a further method for assessing the corrosion state of a reinforcing steel element of a reinforced concrete component. Furthermore, a device for carrying out this method, a kit, and a second method are to be provided.The problem according to the invention is solved by a method for assessing the corrosion state of a reinforcing steel in a reinforced concrete component, comprising the features of claim 1, and by a device for carrying out this method, comprising the features of claim 13, further by a kit comprising the features of claim 19, and by a method comprising the features of claim 21. The method according to the invention for assessing the corrosion state of a reinforced concrete component comprising reinforcing steel comprises the following steps (in the following or a different order): The method first comprises providing a first conductor and establishing an electrical connection between it and a first section of the reinforcing steel for use as an anode. It also comprises providing a second conductor and establishing an electrical connection between it and a second section of the reinforcing steel.The first and second sections of the reinforcing steel can be spatially separated. Instead of resting on the reinforcing steel, the second section can be a section of a steel element located outside or inside the NeoCorrTecs GmbH reinforced concrete component and / or separate from the reinforcing steel. The second section of the reinforcing steel, or the section of the steel element located outside the reinforced concrete component, can each be used as, or intended to be used as, the cathode. In an alternative configuration, the cathode is a metal—usually a more noble metal than the reinforcing steel—placed on the reinforced concrete component or positioned elsewhere outside the component under investigation, which can perform the partial cathodic reaction.The method further comprises establishing an interruptible electrical connection between the first conductor and the second conductor, wherein this electrical connection is optionally located outside or inside the reinforced concrete component. It can be implemented, for example, by means of a suitably connected electrical conductor, which preferably runs outside the reinforced concrete component but is not surrounded by its concrete. A switch or interrupter can be provided for interrupting the connection, for example, inserted into the electrical conductor. It is preferably provided that the anode and cathode are not two sections of a continuous steel element, such as a wire, in the sense that current could flow between them along the continuous steel element. Rather, the steel element is preferably interrupted in its continuity in a region located between the anode and cathode.Interruption, if not already accomplished, can be a further process step. The physical separation of the steel element between the anode and cathode can be achieved, or may have been achieved, by overdrilling or any other suitable method. Furthermore, the process includes determining the double-layer capacitance of both the anode and the cathode, and / or the active surface area of ​​both the anode and the cathode underlying the double-layer capacitance. An electrolytic double layer forms at the phase boundary between the electrode and the electrolyte. If the electrode is, for example, the cathode, i.e., negatively charged, the positively charged cations accumulate in front of it. The electrolytic double layer, i.e.,The negatively charged electrode and the positively charged surface layer of the electrolyte are comparable to a capacitor, because when the electrode potential is changed, a capacitive current flows, as when a capacitor is charged, and this current can be measured. The same applies to the anode. Using the determined double-layer capacitances, or starting from them, a mathematical relationship, in particular a ratio or quotient, between the double-layer capacitances or between the surfaces relevant to corrosion can be established, and this relationship can then be evaluated based on a predetermined criterion. This is also included as a step in the method. The present invention relates to a device or system for carrying out the method according to the invention or for its use therein.NeoCorrTecs GmbH The device comprises a first conductor for establishing an electrical connection between the first conductor and a first section of the reinforcing steel for use as an anode, and it comprises a second conductor for establishing an electrical connection between the second conductor and a second section for use as a cathode. The second section is again a section of the reinforcing steel that is spatially separate from or not connected to the first section, or a section of an element, in particular a steel element, located outside or inside the reinforced concrete component and / or separate from the reinforcing steel (5). The device further comprises a disconnect point, a switch, or an interrupter for interrupting the connection between the first conductor and the second conductor that runs outside the reinforced concrete component.The device further comprises a detection unit, a processing unit, and an evaluation unit. The detection unit serves to determine the double-layer capacitance of the anode and the cathode and / or the surface or active surface of the anode and the cathode underlying the double-layer capacitance, or the corresponding sections of the reinforcing steel or element(s). The processing unit is configured to generate a mathematical relationship, in particular a ratio or quotient, between the double-layer capacitances or the surface areas. The evaluation unit serves to evaluate this generated relationship based on a predetermined criterion. NeoCorrTecs GmbH. The present invention relates to a kit comprising or consisting of a plurality of devices or systems according to the invention.The method according to the invention serves to produce one or more reinforced concrete components containing reinforcing steel. It comprises inserting a device according to the invention, or sections thereof, into one or each reinforced concrete component containing reinforcing steel, preferably before its completion and / or commissioning. It optionally further comprises producing the reinforced concrete component, which may involve concreting, by inserting the reinforcing steel and the device, or at least a section thereof, e.g., the first housing, into the reinforced concrete component. The methods discussed herein are the subject of the present invention and are therefore in accordance with the invention. The device discussed herein is the subject of the present invention and is therefore in accordance with the invention. The kit discussed herein is the subject of the present invention and is therefore in accordance with the invention.Inventory embodiments may, based on any one of the independent claims, have one or more of the features mentioned above or below. The features mentioned herein may be the subject of any combination of inventive embodiments based on any one of the independent claims, provided that a person skilled in the art does not recognize a specific combination as technically impossible. NeoCorrTecs GmbH. In all the above and following descriptions, the use of the expressions "may be" or "may have," etc., is to be understood synonymously with "is preferably" or "has preferably," etc., and is intended to explain inventive embodiments. Whenever numerical terms are mentioned herein, a person skilled in the art understands them to indicate a lower numerical limit.Provided this does not lead to any contradiction recognizable to a person skilled in the art, a person skilled in the art will therefore always interpret the term "a" or "a" as meaning "at least one" or "at least one." This understanding is encompassed by the present invention, as is the interpretation that a numerical word such as "a" can alternatively be meant as "exactly one," wherever this is technically feasible to a person skilled in the art. Both are encompassed by the present invention and apply to all numerical words used herein. Whenever spatial references such as "above," "below," "left," or "right" are mentioned herein, a person skilled in the art understands this to mean the arrangement in the figures attached hereto and / or in the state of use. "Below" is closer to the Earth's center or the lower edge of the figure than "above." Advantageous further developments of the present invention are the subject of dependent claims and embodiments.Whenever an embodiment is mentioned herein, it refers to an exemplary embodiment according to the invention, based on one of the independent claims, and is not to be understood as limiting. If it is disclosed herein that the subject matter of the invention has one or more features in a particular embodiment, it is also disclosed herein that the subject matter of the invention expressly does not have precisely this or these features in other embodiments, which are also according to the invention, e.g., in the sense of a disclaimer. For each embodiment mentioned herein, the opposite embodiment, formulated, for example, as a negation, is therefore also disclosed. Embodiments as disclosed herein further develop the invention as defined by the independent claims.Where process steps are mentioned herein, the device according to the invention is configured in some embodiments to execute one, several, or all of these process steps, particularly if they are automatically executable steps, in any combination, or to control corresponding devices, which preferably bear a name derived from the designation of the respective process step (e.g., "Determining" as a process step and "Device for Determining" for the device, etc.) and which may also be part of the device(s) according to the invention or be connected to it by signal communication. NeoCorrTecs GmbH. Where the terms "programmed" or "configured" are used herein, these terms may be interchangeable in some embodiments. Where a signal or communication connection between two components is mentioned herein, this may refer to a connection already in use.This can also be understood to mean that preparation for such a signal connection (wired, wireless, or implemented in any other way) exists, for example, by coupling both components, such as through pairing, etc. Pairing is a process that occurs in connection with computer networks to establish an initial connection between computer units for the purpose of communication. The best-known example of this is establishing a Bluetooth connection, by means of which various devices (e.g., smartphone, headphones) are connected to each other. Pairing is sometimes also referred to as bonding. In some embodiments, a connection can be understood as, for example, a material-locked, force-locked, form-locked, and / or electrical (electrically conductive) connection. The device can initiate the execution of all or substantially all of the process steps.The method according to the invention can be carried out essentially or completely by the device according to the invention, but at least the steps of determining the double-layer capacity or the active surface area, forming the mathematical relationship, and outputting the result. NeoCorrTecs GmbH. It can be carried out partially by the device; in particular, those steps that do not require or involve human intervention and / or provision can be carried out by the device. Reinforcing steel in fresh concrete builds up a surrounding passive layer or protective layer through initial corrosion, which initially protects it from further corrosion. The size of the defect in the passive layer built up around the reinforcement, which is gradually caused by further corrosion, corresponds to the size of the corrosion-active surface of the reinforcement. This corrosion-active surface is synonymous with the term "anode" in this context.If two sections of the reinforcement are electrically contacted as anode and cathode, respectively, according to the invention, and if they are located at sections that have been exposed to different levels of corrosion (which is determined a priori and thus allows them to be defined accordingly), then, assuming that the size of the cathode changes only slightly over time, calculating the ratio between the cathode area and the anode area can provide very valuable information about the size of the anode, i.e., the corrosion-active surface connected to the first conductor. In this way, it is possible, for the first time according to the invention, to make further statements about the corrosion process non-destructively. In some embodiments, the reinforcing steel, or a first section thereof, itself serves as the anode, and a different section of the same reinforcing steel element, or of another reinforcing steel element of the same structure, serves as the cathode.NeoCorrTecs GmbH In other embodiments, the reinforcing steel itself serves as the anode or cathode, and a steel element not serving as a reinforcing steel element (alternatively a metal element), which is optionally not integrated into the structure, serves accordingly as the cathode or anode. The use of a steel element not integrated into the structure to be tested, or integrated but exposed to different conditions than those that led to the corrosion of the reinforcing steel due to other circumstances, can lead to an unadulterated evaluation by allowing a comparison, for example, with a copy of the reinforcing steel originally installed when the structure was built. The steel or metal element not exposed to corrosion, also referred to herein as the second section or test specimen, can be evaluated with respect to at least one characteristic, e.g.,the geometry, thickness, diameter, steel composition, bending state, manufacturing-related microstructural changes or states, and / or other characteristics must correspond to the reinforcing steel element to be tested for corrosion, e.g., its condition at the time of the concrete structure's manufacture. In some embodiments of the method, the anode and cathode are part of a three-electrode setup with the anode, the cathode, and a reference electrode. Since electrochemical investigations or syntheses are usually only of interest to the reaction at one electrode, this electrode is also referred to as the working or measuring electrode. With a two-electrode arrangement, cell voltage and current can be measured and / or adjusted, for example, using an ammeter or potentiometer. NeoCorrTecs GmbHSince the electrode potential of the working electrode determines the electrode reaction, it is advantageous to measure this in a three-electrode setup using a third, currentless electrode, the so-called reference electrode, and an additional ammeter, potentiometer, or potentiostat. In some embodiments, the anode and / or the cathode is designed as an anodic or cathodic half-cell, or has one, or is modeled on one in practice. Such a half-cell can, in some embodiments, be a Randles cell and / or a combination of, or including, a preceding ohmic resistor and a subsequent parallel circuit consisting of, or including, an ohmic resistor and a capacitor or an RC circuit. Components that are connected upstream or downstream of each other are, in some embodiments, connected in series.In some embodiments, the method includes determining a corrosion current between the anode and cathode along the interruptible electrical connection and / or determining a resting potential, e.g., using a potentiometer, and / or determining a time constant for reaching the resting potential after interrupting the corrosion current. NeoCorrTecs GmbH. In some embodiments, the criterion is a limit value, a limit value range, a lookup table (or specific values ​​therefrom), and / or a scale (or specific values ​​thereof), or includes such and / or the like.In some embodiments, the formation of the mathematical relation, in particular the ratio or quotient, provides information about a cross-sectional narrowing or reduction of at least the first or second section and / or a corrosion state assessment of the first or second section, or allows such a statement or corrosion state assessment, or is used for this purpose. In some embodiments, the first conductor and / or the second conductor are connected to the reinforcing steel installed in the structure by means of a reinforcement connection. In some embodiments, the method further includes outputting a statement, a representation, a numerical value, and / or an alarm, and evaluating the formed relation based on the criterion. The necessary devices and / or programming for this purpose may be provided and are also included in the present invention.In some embodiments, repair measures are initiated or arranged based on findings, particularly based on the evaluation according to the predetermined criterion, and / or repair proposals are submitted. NeoCorrTecs GmbH. In some embodiments, the method further includes introducing the second section into the reinforced concrete component, preferably after its completion and / or commissioning, i.e., e.g., subsequently, or in existing structures, e.g., into a borehole, or preferably before its completion and / or commissioning, i.e., e.g., during new construction or manufacturing, e.g., by embedding in concrete. In order for the anodic iron dissolution to proceed via the new cathode, it is advantageous in some embodiments if this cathode consists of a precious metal.In some embodiments, the method comprises that the second section is or comprises a first housing with an interior, wherein at least one element of a group of elements consisting of or comprising the second conductor, the disconnect point, the detection unit, the processing unit, and the evaluation unit is arranged, preferably completely, within the housing interior. In some embodiments, the method comprises transmitting values ​​relating to the double-layer capacitances (CDL,A, CDL,K) and / or the underlying surfaces (AA, AK) of the double-layer capacitance (CDL,A, CDL,K) to the processing unit and / or transmitting the mathematical relation formed by the processing unit to the evaluation unit and / or an evaluation generated by the evaluation unit to an output unit, and receiving from the output unit, preferably wired or wirelessly.NeoCorrTecs GmbH: In certain embodiments, the evaluation is carried out taking into account values ​​obtained from a kit comprising or consisting of a plurality of devices or systems by means of which the method is performed, with geometrically identical second sections. In some embodiments of the device or system, it comprises a first housing, which serves as the second section. In certain embodiments of the device or system, at least one element of a group of elements, consisting of or comprising the second conductor, the separation point, the detection unit, the processing unit, and the evaluation unit, is preferably arranged entirely within the interior of the first housing.In some embodiments of the device or system, it comprises a second housing which is connected to the second section by means of the second conductor, or into which the second conductor leads, or to whose interior the second conductor establishes a connection, wherein at least one element of the group of elements comprising or consisting of the separation point, the detection unit, the processing unit, and / or the evaluation unit is preferably arranged completely within the interior of the second housing. In some embodiments, the first and second housings are independent of each other; that is, a second housing and / or a first housing may be provided. It is not necessary for both to be provided.In some embodiments, the first housing is designed to be inserted into and remain within the reinforced concrete component, while the second housing may be designed to remain and be used outside the reinforced concrete component. In some embodiments, the first housing (in the simplest case, so to speak) is a microcontroller that is protected against weather or environmental influences such as pressure, etc., by a housing, referred to here as the first housing.In some embodiments, the device or system comprises at least one transmitter and at least one receiver, configured to send values ​​transmitted by the detection unit relating to the double-layer capacitances (CDL,A, CDL,K) and / or the underlying surfaces (AA, AK) of the double-layer capacitances (CDL,A, CDL,K) to the processing unit and / or the mathematical relation generated by the processing unit to the evaluation unit and / or an evaluation generated by the evaluation unit to an output unit, and to receive each of these, preferably wired or wirelessly. In some embodiments, the system comprises a reinforced concrete component containing reinforcing steel, wherein the reinforced concrete component has the first housing inside and / or wherein the second housing is arranged in an outer part of the reinforced concrete component.NeoCorrTecs GmbH: The reinforced concrete component has the first housing inside it, and / or the second housing is arranged in an outer end of the reinforced concrete component. In some embodiments of the kit, the respective second sections are geometrically identical. Some or all embodiments according to the invention can have one, several, or all of the advantages mentioned above and / or below. One advantage of the present invention can be the optimization of the monitoring of corrosion-active reinforced concrete components. While monitoring the corrosion current using methods known from the prior art could track the corrosion activity, it could not differentiate between pitting corrosion and surface erosion. This is advantageously possible with the present invention.This is possible, in particular, by calculating the quotient of the two double-layer capacitances and evaluating this quotient using tables, scales, minimum or maximum values, etc. Under the plausible assumption that the parameters ε, ε0, and d, as used herein, are constant for both electrodes (cathode and anode) or, if the anode and cathode are made of the same material, identical, the quotient exclusively reflects the area ratio of the two electrodes. Should there be deviations in at least one of the aforementioned quantities ε, ε0, and / or d between the two (model) half-cells or their double-layer capacitances, these can be taken into account by simple mathematical corrections and, if necessary, by re-creating tables of values, limit values, etc., or criteria related to NeoCorrTecs GmbH. This, too, is encompassed by the present invention.A further advantage of the present invention lies in its ability to differentiate between, for example, a single corrosion spot and multiple corrosion spots on an instrumented, anodically acting reinforcement section. A single corrosion spot with the same corrosion current intensity represents the worst-case scenario in terms of structural stability, potentially leading to catastrophic consequences. The present invention enables such differentiation between these cases. The significant improvement in the effectiveness monitoring of potential repair principles for reinforced concrete components, made possible by the insights gained from the present invention, represents a further advantage. This can significantly increase the structural stability of reinforced concrete components, thereby indirectly saving time and costs.A further advantage of the present invention lies in the ability to identify any outstanding repair needs of reinforced concrete components. In this way, the structural stability of reinforced concrete components can be significantly increased, and time and costs can be saved. Due to the widespread and ongoing use of energy-, resource-, and cost-intensive reinforced concrete construction in industry and infrastructure, the maintenance of these structures has the highest priority. With the present invention from NeoCorrTecs GmbH, corrosion monitoring of real reinforced concrete components can be quantitatively verified for the first time. This can represent a further advantage of the present invention. According to the invention, it may be possible for the first time to prove, at the time of measurement, i.e., at each scheduled corrosion monitoring appointment, whether severe corrosion or – measured against a predetermined criterion – cross-sectional narrowing corrosion is currently present or not.To measure or determine the current surface conditions, the widely installed three-electrode setup of existing reinforced concrete structures can be used without the need for additional sensors. With the countless corrosion sensors already available for conventional monitoring in real reinforced concrete structures, the present invention can be advantageously and easily implemented in industrial applications. A further advantage is that, apart from the reference electrode and the measuring technology, no additional sensors need to be installed. The naturally occurring corrosion system consisting of the reinforcement anode and the reinforcement cathode is therefore only minimally affected and can continue to function as such.A further advantage is that, according to the invention, to provide anodic and cathodic areas, it is not necessary to electrically separate sections of the reinforcing steel from one another, as the electrical connection inherent in the metallic structure of reinforcing steel does not need to be interrupted for measurement. According to the invention, it is not necessary to drill a hole in the reinforcing bar or element under investigation, which then remains in the component as a sample without a static function. This opens up new, innovative possibilities according to the invention. For example, in the case of advanced component age, the corrosion point can be detected using conventional methods. At this point, an additional cathode, e.g., in the form of a sheet, is then installed, perhaps as a housing, e.g., inserted into a borehole, and connected to the anodically acting area of ​​the reinforcement for measurement purposes.Because the area of ​​the retrofitted cathode is known and identical in all applications, it is possible to unambiguously classify the size of the anodically acting reinforcement surface and thus accurately assess the condition of the component. Furthermore, this method has the significant advantage that the existing reinforcement only needs to be electrically contacted and does not need to be cut. It therefore retains its full structural function and simultaneously serves as a representative sample of the component under investigation. This fundamentally expands the scope of this monitoring method, as it allows for the non-destructive testing of structurally relevant reinforcement elements. Moreover, this form of corrosion monitoring can be easily installed on the reinforcement before concreting. It is therefore suitable for both new construction and existing structures.It is advantageous if the calculation method described above can be performed locally by a microcontroller, i.e., integrated into the component, especially if the microcontroller housing is used as the cathode plate. The measurement and numerical evaluation thus take place inside the installed plate. Assuming that several such measuring cells are installed in a component on the same reinforcement system, a monitoring network is created, with the measurement data being transmitted externally via cables. Outside the component, the collected measurements can then be stored and retrieved remotely. The integrated product preferably and advantageously handles the measurement, numerical evaluation, digitization, and / or transmission of the data. This product package, consisting of an integrated measuring device, digitization, and remotely controllable readout, can be marketed as a compact product.The uniform data thus obtained can, if desired, generate a steadily growing database in the long term, continuously increasing the reliability of the individual measured values. Here, the advantage is again that the calculation is always performed against the same cathode area, thus enabling a global classification of the monitoring measurements. All advantages achievable with the method according to the invention can also be achieved without impairment in certain embodiments of the invention with the device according to the invention, and vice versa. The present invention is described below by way of example only, with reference to the accompanying figures. In these figures, the same reference numerals denote the same or similar components. The following applies: Fig. 1 shows a simplified schematic of the structure of an electrochemical cell; NeoCorrTecs GmbH. Fig. 2 shows a simplified schematic of the process of the method according to the invention in an exemplary embodiment; Fig.Figure 3 shows a schematically simplified exemplary arrangement for carrying out the inventive method for corrosion in steel in one embodiment; Figure 4 shows a schematically simplified device according to the invention in one exemplary embodiment; Figure 5 shows a schematic device according to the invention in a further embodiment; and Figure 6 shows a schematically simplified device according to the invention in yet another embodiment. Figure 1 shows a schematically simplified structure of an electrochemical cell, here in a three-electrode configuration, as is relevant below. An electrochemical cell consists of a voltage source 170 and at least two electrodes, anode 100 and cathode 110. The anode 100 and cathode 110 are arranged in a compound which, in the dissolved, liquid or solid state, dissociates ions, the so-called electrolyte 160; for example, they are immersed in it.The mobile ions are responsible for charge transport within the cell. In the electrolyte 160, negatively charged anions migrate in the electric field to the anode 100, which is also referred to as the positive pole by NeoCorrTecs GmbH, while positively charged cations migrate to the cathode 110, which is also referred to as the negative pole. Since electrochemical investigations or syntheses are usually only of interest to the reaction at one electrode, this electrode is also called the working or measuring electrode. In the example shown in Fig. 2, the anode 100 is the working electrode. With a two-electrode arrangement, cell voltage and current can be measured and / or adjusted, for example, using the ammeter or potentiometer 180. However, since the electrode potential of the working electrode, here the anode 100, determines the electrode reaction, it is also necessary to measure this potential.This is achieved in a three-electrode setup using a third, normally unpowered electrode, the so-called reference electrode 150, and another ammeter or potentiometer 190. The reference electrode 160 is positioned as close as possible to the working electrode, here the anode 100, in order to minimize the ohmic voltage drop between the anode 100 and the reference electrode 160. Since the voltage drop is directly measurable in some embodiments due to the often high measurement frequency (100 Hz), the distance is less relevant. Electrodes of a different type are usually used as reference electrodes, characterized by a simple design and a rapidly established, constant, and easily reproducible equilibrium potential, for example, those in which the cations of the electrode metal form a sparingly soluble compound with the anions of the electrolyte. Fig.Figure 2 schematically illustrates a simplified sequence of the inventive method in an exemplary embodiment. For its subsequent discussion, reference is made to the discussion of Figure 1, as well as to the explanations and reference numerals of the following figures, in order to avoid repetition. The present method serves to assess the corrosion state of a reinforced concrete component 1 or of a reinforcing steel 5 or element encompassed by it (see Figure 2). Fig. 3). In one embodiment, the method may comprise the steps described below. Method step M1 represents the selection or use of an anode 100 and a cathode 110, as simplified for clarity shown in Fig. 1, where, by way of example, both the anode and the cathode are part of the reinforcing steel 5, which is interrupted in its continuity. They are or are electrically connected to a first and second conductor L, respectively. A , L K, for example, by means of a reinforcement connection 10, 50. The reinforcing steel 5 itself can be the anode 100 or the cathode 110. Establishing an electrical connection between the anode 100 and the cathode 110, or using the anode 100 electrically connected to the cathode 110, leads to a corrosion current IMAKRO and is represented by process step M2. The resulting driving voltage ΔE between anode 100 and cathode 110 (the difference between these two potentials (E)) 0,K -E 0,AThe process begins to develop from the moment the electrical connection between the anode and cathode is interrupted. Process step M3 represents the interruption of the electrical connection, for example by means of switch 39. This development is numerically monitored, and the double-layer capacitance CDL,A, CDL,K of the anode 100 and the cathode 110 can be derived from the rate of this development (M4). Determining a time constant for reaching the respective rest potential E0,A, E0,K after interrupting the corrosion current IMAKRO (M4a) can be a further step of the process. Determining the double-layer capacitance CDL,A, CDL,K of the anode 100 and the cathode 110 and / or the surface or active surfaces AA of the anode 100 or AK of the cathode 110 underlying the double-layer capacitance (CDL,A, CDL,K) is represented by process step M5.In process step M4a, a mathematical relation is formed from the double-layer capacitances CDL,A, CDL,K of the anode 100 and the cathode 110, in particular a ratio or a quotient to each other (e.g. C). DL,A / C DL,Kor vice versa) or, for this NeoCorrTecs GmbH relation, the surfaces AA and AK are related to each other, for example again as a quotient (e.g., AA / AK or vice versa) (M6). A mathematically common variation of this relation(s) by additionally introducing constants, multipliers, and / or further variables is also encompassed by the present invention. Evaluating the relation thus formed based on a predetermined criterion is described by method step M7. The criterion is optionally a limit value, a limit value range, a value from a reference table, and / or a value from a scale, or may include the same. The criterion may be determined such that, for example, if it is exceeded, there is a need to take anti-corrosion measures, otherwise not. Specifying a measure of the progress of corrosion by evaluation based on at least one criterion is also possible and is likewise included as an option.The calculation of the mathematical relationship, in particular the ratio or quotient, optionally allows for a statement about the cross-sectional narrowing of the anodically acting reinforcement section. The optional procedure step M8 includes the output of a statement, a representation, a numerical value, an alarm, and / or the like, which is based on the evaluation of the calculated relationship. An optional procedure step M9 concerns the initiation or commissioning of repair measures for the reinforced concrete component examined by NeoCorrTecs GmbH, based on findings from the present procedure, in particular based on the evaluation according to the predetermined criterion. The sequence described herein is not to be understood as restrictive. Optionally, the steps described above are carried out in the order mentioned above, overlapping in time, or simultaneously.The steps shown can be carried out in any technically feasible sequence and time series for a person skilled in the art. Fig. 3 shows a schematically simplified example of an arrangement for carrying out the inventive method for determining corrosion of reinforcing steel in one embodiment. The reinforced concrete component 1 to be measured or tested protrudes above optional contact openings 4, into which the first or second conductor L is optionally inserted. A and L KThe reinforcing steel components 10 and 50, which are connected to the respective associated reinforcement connection, are connected to the device 1000 according to the invention. The optional contact openings 4 allow contact with the reinforcing steel 5 through the outer concrete layer 3 at the passive layer 4. As shown, the conductor LA is optionally connected to a first section of the reinforcing steel, while the second conductor LK is connected to a second section of the reinforcing steel. The first and second sections can be either not connected to each other or spatially separated from each other. This is already shown by way of example in Fig. 3 by the interruption of the reinforcing steel in the middle. However, the present invention is not limited to such an embodiment. The second section can also be located outside the reinforced concrete component.To better understand and model corrosion, an equivalent electrical circuit diagram for the aforementioned galvanic cell is frequently used. Since the two half-cells 20, 40 are physically and therefore galvanically separable, this is referred to as macrocell corrosion. The core of the model is the so-called "Randles cell," a combination of a series resistor 21, 41 and a parallel circuit consisting of a resistor 23, 43 and a capacitor 25, 45, i.e., an RC circuit. Both the anodic half-cell 20 and the cathodic half-cell 40 can each be considered a "Randles cell". With switch 39 closed (in Fig. 3 this switch is open), current flows and the two potentials EA and EK measured by potentiometers 27, 47 correspond to the corrosion potential of the entire reinforcement. However, if switch 39 is opened for, for example, a certain period of time, such as...After a few hours, the current flow is interrupted and both half-cells 20, 40 depolarize to their respective resting potentials E0,A, E0,K. This depolarization can be recorded simultaneously for both half-cells 20, 40 using potentiometers 27, 47, if desired. The figure also shows an optional additional current meter 37. NeoCorrTecs GmbH. The recorded curve can be numerically modeled, e.g., using transient analysis. The curvature of the measured curves corresponds to the time constant of the RC circuit under investigation and can therefore be recorded at each measurement point without significantly influencing the corrosion system. Considering the time constant within the framework of corrosion monitoring, which can also be carried out in ways other than those disclosed here, provides valuable information about the parameter of the double-layer capacitance (CDL).The following formulas show the physical relationship based on the modeling of the potential profile in an open short circuit, i.e., the potential profile after opening switch 39:^^. ^ E^,^ = E^ ∙ e^ ^ + E^,^ ^^ ^ E^,^ = E^ ∙ (1 − e^^ ) + E^,^RC = R^ ∙ C^^ where E t the free corrosion potential of the respective electrode at time t in the unit [V]E0,A the open-circuit potential of the anode in the unit [V]E0,K the open-circuit potential of the cathode in the unit [V]RCA the time constant of the anode in the unit [s]RCK the time constant of the anode in the unit [s]t the time in the unit [s]NeoCorrTecs GmbHR P Polarization resistance of the respective electrode in the E inheit [Ω] C DL Double layer capacitance of the respective electrode in the E inheit [F]ε the electric field constant -120 e 8.8542 ‧ 10 F / mε the material-specific permittivity (dimensionless)d the thickness of the double layer in units [m]A the active surface area in units [m²]. In corrosion monitoring, knowledge of the active surface area is of paramount importance. According to the invention, this value relating to the surface area need not necessarily be determined as an absolute value; a ratio or quotient is advantageously sufficient, as the inventor of the present invention was able to surprisingly discover. Based on our own experiments, it can be stated here that the calculation of the quotients of the plausible double-layer capacitances is capable of making a decisive contribution to the condition assessment of corrosion-active components. In particular, the determination of the area ratios represents a paradigm shift in corrosion research on steel in concrete.This allows the damage pattern resulting from corrosion to be determined non-destructively, and the embedded reinforcement to be further investigated without destruction, more so than was previously possible. For the first time, it becomes possible to draw conclusions about the actual cross-sectional loss. The difference between surface erosion and a correspondingly less statically relevant cross-sectional loss, as well as corrosion scars, which are deeper and thus relevant to structural stability, can be determined using the criterion(s).For the practical, industrial application of this invention in construction, the first-ever information on the area ratio of the steel electrodes represents a significant economic advantage. This new design method according to the invention makes it possible, among other things, to demonstrate why the effectiveness of the repair principle applied here—coating the reinforced concrete surface after short-term exposure to de-icing salts—cannot be implemented without doubt. Advantageously, this method succeeds for the first time in demonstrating a direct correlation between corrosion monitoring and actual cross-sectional loss. While the pitting patterns and the associated area ratios are typical of chloride-induced macrocellular corrosion, they are clearly not necessarily present and, until now, could not be monitored non-destructively, let alone verified.The present invention enables the measurement of which type of damage is to be expected in a given, corrosion-active, real reinforced concrete component. Since the instrumentation is based entirely on conventional corrosion monitoring, the inventive method can be readily integrated into existing corrosion monitoring systems for real reinforced concrete components. This allows, for the first time, a deterministic assessment of the effectiveness of repairs to corrosion-active, real reinforced concrete components. NeoCorrTecs GmbH. Due to the numerous existing corrosion sensors for conventional monitoring in real reinforced concrete structures, the inventive method is advantageously very easy to implement in industrial applications. Fig. 4 shows a simplified schematic representation of an inventive device 1000 in an exemplary embodiment. Reference is made to the reference numerals and description in Fig.Reference is made to Figure 3 to avoid repetition. Therefore, only the differences from Figure 3 will be referred to below. The device 1000 in the example of Figure 4 generates a driving voltage ΔE between the anode 100 and the cathode 110 without any external intervention. Both of these lie, but at different locations, on the reinforcing steel 5, which is interrupted between them. Furthermore, a determination unit 200 is provided for determining the double-layer capacitance CDL,A, CDL,K of the two half-cells 27, 47 and / or the active surface AA, AK of the anode 100 and the cathode 110 underlying the double-layer capacitance CDL,A, CDL,K. A calculation unit 210, configured to form a mathematical relation, in particular a ratio or a quotient, of the double-layer capacitances CDL,A, CDL,K to each other or of the surfaces AA, AK to each other, is also shown in Figure 4. The device shown in the example in Fig.Figure 4 further comprises an evaluation unit 220, which is intended and / or suitable for evaluating the formed NeoCorrTecs GmbH relation based on a predetermined criterion. A result of this evaluation can be output at an optional output unit 230 of the device, for example in the form of a statement, a representation, a numerical value, an alarm, and / or the like. The representation of the half-cells 20, 30 serves for illustration. The device 1000 may have differently configured measuring electronics, as long as the corresponding steps of the method to be carried out with the device 1000 are executable. Figure 5 schematically shows a device according to the invention in a further embodiment. On the left in Figure 5, a reinforced concrete part 1 is indicated in a frontal section; on the right in Figure 5 is the position of the section shown on the left in a larger section of the same reinforced concrete part 1.Figure 5 shows a borehole 8 in the concrete of the reinforced concrete component 1 with a borehole opening 8a. The borehole opening 8a represents the dividing line between an inner I of the reinforced concrete component 1 and its outer Ä. A corrosion point Korr, which will hereinafter be referred to as the anode, is visible on a section of the reinforcing steel 5. A measurable corrosion signal Korr_S emanating from the corrosion point Kor is indicated. NeoCorrTecs GmbH. A first housing 53 is inserted into the borehole 51. The housing 53 serves as the cathode and optionally includes a microcontroller 55, a potentiometer 47, and is electrically connected to the reinforcing steel 5 and to a reference electrode 150. A measurement data line 57, or alternatively a wireless transmission, from the inner I to the outer Ä is indicated by a dotted line.The first conductor LA is connected to the reinforcing steel 5, the second conductor LK is designed as the first housing 53 or lies inside the housing of the first housing 53 and connects its electronics to the housing 53. The first housing 53 and that of the first conductor 53 are not electrically connected to each other. Fig. 6 schematically shows a device according to the invention in a further embodiment. On the left in Fig. 6, a reinforced concrete part 1 is indicated in a frontal section, on the right in Fig. 6 is the position of the section shown on the left in a larger section of the same reinforced concrete part 1. In the following, only the differences from Fig. 5 are described; for all other aspects, reference is made to the discussion of Fig. 5. The first conductor LA is connected to the reinforcing steel 5 as in Fig. 5, the second conductor LK is connected as in Fig. 5 is designed as the first housing 53 or is located inside the housing of the first housing 53. Unlike in Fig. 5, the electronics, e.g.For example, the microcontroller 55, the potentiometer 47, the NeoCorrTecs GmbH evaluation unit, etc., are not housed in the first housing 53, but in a second housing 59. Unlike the first housing 53, the second housing 59 is not located inside the reinforced concrete component 1. Evaluation can therefore take place outside the reinforced concrete component 1. The necessary data transmission can be wired between the first housing 53 and the second housing 59, as indicated in Fig. 6, or wirelessly, e.g., by a transmitter and receiver (not shown). The present invention is not limited to the embodiments described above. These serve only for illustration.

[0002] NeoCorrTecs GmbH Reference List 1 Reinforced concrete component 3 Outer concrete layer 4 Contact opening 5 Reinforcing steel 7 Passive layer 10 Reinforcement connection 20 Anodic half-cell ("Randles cell") 21 Resistor 23 Resistor 25 Capacitor 27 Ammeter; Potentiometer (electrode potential anode) 37 Ammeter (corrosion current) 39 Switch 40 Cathodic half-cell ("Randles cell") 41 Resistor 43 Resistor 45 Capacitor 47 Ammeter; Potentiometer (electrode potential cathode) 50 Reinforcement connection 51 Borehole 51a Borehole opening 53 First housing 57 Measurement data, measurement data line 59 Second housing 100 Anode 110 Cathode 150 Reference electrode; NeoCorrTecs GmbH 160 Electrolyte 170 Voltage source 180 Ammeter 190 Ammeter; Potentiometer (electrode potential) 200 Determination unit 210 Calculation unit 220 Evaluation unit 1000 Device Corr Corrosion point Corr_S Corrosion signal L A first leader L K second conductor

Claims

NeoCorrTecs GmbH Claims 1. Method for assessing the corrosion state of a reinforced concrete component (1) comprising reinforcing steel (5), comprising the steps of: - providing a first conductor (LA) and establishing an electrical connection between the first conductor (LA) and a first section of the reinforcing steel (5) for use as the anode (100), and providing a second conductor (LK) and establishing an electrical connection between the second conductor (LK) and a second section, wherein the second section is a section of the reinforcing steel (5) spatially separated from or not connected to the first section, or a section of a steel element located outside or inside the reinforced concrete component (1) and / or separate from the reinforcing steel (5), in each case for use as the cathode (110); - establishing an interruptible electrical connection between the first conductor (LA) and the second conductor (LK).preferably outside or inside the reinforced concrete component (1), preferably providing a switch or interrupter for interrupting the connection; NeoCorrTecs GmbH - Determining the double-layer capacitance (CDL,A, CDL,K) of the anode (100) and the cathode (110) and / or the surface area (AA, AK) of the anode (100) and the cathode (110) underlying the double-layer capacitance (CDL,A, CDL,K); comprising the steps of - forming a mathematical relation, in particular a ratio or a quotient, of the double-layer capacitances (CDL,A, CDL,K) to each other or of the surface area (AA, AK) to each other; and - evaluating the relation formed based on exactly one or at least one predetermined criterion.

2.

3. Method according to claim 1, wherein the anode (100) and the cathode (110) are part of a three-electrode setup comprising the anode (100), the cathode (110) and a reference electrode (150).

3. Method according to any one of the preceding claims,wherein the anode (100) and / or the cathode (110) is configured as an anodic half-cell (20) or cathodic half-cell (40), respectively, wherein such a half-cell (20, 40) is a Randles cell and / or is a combination of or comprising a preceding ohmic resistor (21, 41) and a subsequent parallel circuit comprising or comprising an ohmic resistor (23, 43) and a capacitor (25, 45).

4. Method according to any one of the preceding claims, wherein the method further comprises: NeoCorrTecs GmbH - Determining a corrosion current (IMAKRO) between the anode (100) and the cathode (110); and / or - Determining a resting potential (E0,A, E0,K); and / or - determining a time constant (t) to reach the resting potential (E0,A, E0,K) after an interrupting corrosion current (IMAKRO).

5. Method according to any of the preceding claims, wherein the criterion is or comprises: - a limit value; - a limit value range; - a reference table,or predetermined values ​​thereof; and / or a scale, or predetermined scale values ​​thereof.

6. Method according to any of the preceding claims, wherein the formation of the mathematical relation, in particular the ratio or quotient, is a statement about a cross-sectional reduction of at least the first or the second section; and / or is a corrosion condition assessment of at least the first or the second section, or is permitted or used for this purpose.

7. Method according to any of the preceding claims, wherein NeoCorrTecs GmbH connects the first conductor (LA) and / or the second conductor (LA) to the reinforcing steel (5) by means of a reinforcement connection (10, 50).

8. Method according to any of the preceding claims, further comprising: outputting a statement, a representation, a numerical value and / or an alarm relating to the evaluation of the formed relation.

9. Method according to any of the preceding claims,10. Method according to the preceding claim, wherein the second section is or comprises a first housing (53) with a housing interior, wherein at least one element of a group of elements consisting of or comprising the second conductor (LK), the separation point, the determination unit (200), the processing unit (210), and the evaluation unit (220) is arranged in the housing interior.

11. Method according to any of the preceding claims, further comprising: - Sending the values ​​transmitted by the determination unit (200) to the double-layer capacitances NeoCorrTecs GmbH (CDL,A, CDL,K) and / or the surfaces (AA, ) underlying the double-layer capacitance (CDL,A, CDL,K).AK) relating to the computing unit (210) and / or the mathematical relation formed by the computing unit (210) to the evaluation unit (220) and / or an evaluation generated by the evaluation unit (220) to an output unit (220), preferably wired or wireless.

12. Method according to any one of the preceding claims, wherein the evaluation is carried out taking into account values ​​obtained from a kit comprising or consisting of a plurality of devices or systems by means of which the method is carried out, with geometrically identical second sections.

13. Device (1000) or system for carrying out the method, or for its use therein, according to any one of the preceding claims,with: - a first conductor (LA) for establishing an electrical connection between the first conductor (LA) and a first section of the reinforcing steel (5) for use as an anode (100); - a second conductor (LK) for establishing an electrical connection between the second conductor (LK) and a second section, wherein the second section is a section of the reinforcing steel (5) spatially separated from the first section or a section of an element, in particular a steel element, located outside or inside the NeoCorrTecs GmbH reinforced concrete component (1) and / or separately from the reinforcing steel (5), in each case for use as a cathode (110); - a disconnect point, switch or interrupter for interrupting the connection between the first conductor (LA) and the second conductor (LK) outside the reinforced concrete component (1); - a detection unit (200) for determining the double-layer capacitance (CDL,A, CDL,K) of the anode (100) and the cathode (110) and / or the,14. Device (1000) or system according to claim 13, comprising: - a first housing (53), which serves as the second section.

15. Device (1000) or system according to claim 13 or 14, wherein at least one element of a group of elements, NeoCorrTecs GmbH which consists of or comprises the second conductor (LK), the separation point, the detection unit (200), the computing unit (210) and the evaluation unit (220),16. Device (1000) or system according to one of claims 13 to 15, comprising: - a second housing (59) which is connected to the second section by means of the second conductor (LK) or into which the second conductor (LK) leads or to whose housing interior the second conductor (LK) establishes a connection; wherein at least one element of the group of elements comprising or consisting of the separation point, the determination unit (200), the computation unit (210) and / or the evaluation unit (220) is arranged in the housing interior of the second housing (59).

17. Device (1000) or system according to one of claims 13 to 16, comprising: at least one transmitter and at least one receiver, configured to receive values ​​transmitted by the detection unit (200) from the double-layer capacitances (CDL,A,CDL,K) and / or the surfaces (AA, underlying the double-layer capacitances (CDL,A,CDL,K) (AA,AK) relating to the computing unit (210) and / or the mathematical relation formed by the computing unit (210) to NeoCorrTecs GmbH, the evaluation unit (220) and / or an evaluation created by the evaluation unit (220) to an output unit (220), preferably wired or wirelessly.

18. Device (1000) or system according to one of claims 13 to 17, comprising: - a reinforced concrete component (1) having a reinforcing steel (5), wherein the reinforced concrete component (1) has the first housing (53) inside it and / or wherein the second housing (59) is arranged in an outer (Ä) of the reinforced concrete component (1).

19. Kit comprising or consisting of a plurality of devices or systems according to one of claims 13 to 18.

20. Kit according to claim 18, wherein the respective second sections (53) are geometrically identical.

21. Method for producing one or more reinforced concrete components (1) comprising reinforcing steel (5).comprising: -Introducing a device (1000) according to one of claims 13 to 18, or sections thereof, into a, or any, reinforced concrete component (1) having a reinforcing steel (5), preferably before its completion and / or commissioning; and NeoCorrTecs GmbH - Manufacturing, optionally concreting, the, or any, reinforced concrete component (1) by incorporating the reinforcing steel (5) and the device (1000) or at least a section thereof into the reinforced concrete component (1).

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