DE102014200792B4 - Structural textile, process for its preparation and use - Google Patents

Abstract

Structural textile (2), comprising a textile carrier material (6), wherein at least two electrical conductors (3) arranged parallel to each other in the carrier material (6) and led out for electrical contacting of the carrier material (6), characterized in that the carrier material (6 ) -either as a knitted spacer structure by means of right / right warp knitting technology is formed three-dimensionally, or- that the carrier material (6) is strand-shaped, wherein the carrier material (6) comprises a core material of absorbent or swellable fiber or nonwoven fabrics to the in a spatial arrangement the or the sensors forming electrical conductors (3) are arranged.

Description

The invention relates to a building fabric, a method for its production and a use of the building fabric.

In areas of wood and concrete construction, moisture measurements are required for quality assurance measures in the manufacturing process, to ensure functionality, reliability and safety in the use of the building, as well as quality assessment of repair work. This concerns a significant proportion of the infrastructure, such as B. structures made of wood or concrete, timber structures of the object, but also engineering timber structures, highways (road surface), structures made of waterproof concrete and foundations.

To control the moisture state, it is known to use moisture probes, which are installed point by point in the component / structure to be controlled. Often done for introducing the probes bores.

One differentiates between relative and absolute measured values. There are a number of selective measuring methods and measuring instruments available for this purpose.

Moisture measurement according to the known dielectric measuring method allows the non-destructive, orienting performance of moisture measurements. Due to the immediate display of the measured value, moisture profiles can be displayed. No probes need to be inserted, you just sweep the component with the measuring head.

In moisture measurement according to the known electrical resistance measuring method, in contrast to the dielectric measuring method, moisture-sensitive measured values can also be measured in larger component depths via depth measuring electrodes introduced into boreholes. Resistance measuring instruments generate an electrical measuring current, which is conducted with electrodes through the building material to be measured. The electrodes may be embodied as knock-in, piercing, or through-hole electrodes connected to the meter by a cable. Measuring electrodes for greater depths require two side-by-side, approx. 8 mm drill holes, through which the depth measuring electrodes are inserted into the component. Usually, these holes are created in a so-called measuring axis at different heights in order to obtain an accurate picture of the course of moisture. The procedure is indirect. The prerequisite for the determination of material moisture content with the help of the resistance measurement method is the knowledge of substance-specific resistance-humidity characteristics.

Furthermore, a moisture measurement by means of neutron probe (Troxlersonde) is known. For the detection of moisture concentrations, the principle of neutron moderation is used in this measuring device. Neutron moderation describes the fact that the fast neutrons emitted by the radiation source present in the measuring instrument are decelerated by hydrogen atoms to "thermal" speed. Statistically, nineteen collisions with hydrogen atoms are needed until the neutron is decelerated to a thermal energy level. For other atoms, a multiple of collisions is necessary. Hydrogen atoms are therefore mainly responsible for the presence of decelerated neutrons. The number of decelerated neutrons that can be measured in a material exposed to a fast neutron source is in a linear relationship to the water content of the material. For measuring the probe is placed on the material to be measured, so this must be accessible for the purpose of measurement. Since the activity of the radiation source is known as the number of fast neutrons per second, this can be compared with the number of counts in the detector. From the difference one can conclude on the number of hydrogen atoms, which is linearly correlated with the moisture content in the material. Even with dry materials, the meter indicates a basic value, which is due to the chemical hardening in the material, which, however, does not contribute to the humidity.

The determination of moisture in a material sample by the well-known Darr measurement principle (of drying) is based on the comparison of the sample weight in different water saturation states. With the Darr moisture data are determined in percent by weight. The determined value is given in mass percent. In this measurement method z. B. taken by core drilling material sample packed airtight and then weighed at a suitable location. Then it is dried in a drying oven at 105 ° C until no mass loss occurs. Thus, the matrix of the dry sample is present. The water content can be determined by calculation.

When determining the moisture content in a material sample using the known CM method (calcium carbide method), a material sample is also taken, for example by means of core drilling, as in the Darr method, and then examined for its moisture content. A building material sample is taken, crushed and the amount of sample weighed (for example 10 g). The sample is filled with a calcium carbide ampule and steel balls put a pressure bottle, which is closed and shaken. After the lapse of a period of, for example, 10 minutes, the pressure in the pressure bottle is determined.

In another known method are used for moisture monitoring multi-ring electrodes for determining the moisture distribution in the concrete edge zone in water-stressed components z. B. used under bridge caps or in joint areas. The multi-ring electrode consists of eight stainless steel rings, which are arranged with a center distance of 5 mm, and a temperature sensor. Between each two stainless steel rings a PE insulating ring is installed. By measuring the AC resistance between two adjacent rings, a resistance profile can be recorded over the installation depth of the sensor, which can be converted into a moisture profile using calibration curves.

In another known method for moisture monitoring stray field capacitance sensors are used to determine the relative humidity on a capacitive path. The basic idea of the measuring principle is to arrange sensor elements along the path, which the moisture flow in a component takes, in order to be able to register the "moisture wave" through the test body. For this purpose, a separate volume element free of the material to be monitored of the test specimen is required for each element. In practical terms, this is achieved by integrating the miniaturized humidity sensors into a tube (with a diameter of, for example, 5 mm). The installation of partitions between the individual sensors and the insertion of lateral slots in the pipe material, create separate, consecutively located measuring chambers with a defined volume of air. Corresponding to the material moisture in the vicinity of the measuring chamber, a certain relative humidity occurs in the measuring chamber volume. Capacitive measurement of relative air lights in the individual measuring chambers indirectly determines material moisture profiles and their temporal evolution.

Furthermore, a moisture monitoring by means of a textile measuring system on an optical basis is known. The measuring system consists of an optical fiber network, a light source and a microspectrometer. The fiber end of the plastic fiber optic cable is equipped with a special swellable polymer matrix. The water content of the polymer matrix is determined using a solvatochromic pyridinium-N-phenolate betaine as an indicator dye. For the measurement, the indicator dye is dissolved in the relatively non-polar solvent acetonitrile. When the proportion of water in the solution is increased, a hypsochromic shift of the absorption spectrum is observed. Different water concentrations show defined spectra, so that from the wavelength of maximum absorption on the water content can be concluded. It is a punctual measuring method.

The DE 10 2011 056 548 A1 discloses a measuring device and a method for determining the moisture content of a material to be examined. The measuring device has at least one moisture sensor with at least two electrically conductive electrodes fixed at a distance from one another in or on a moisture-permeable base material. The at least one moisture sensor is a capacitive sensor, which is introduced for determining the moisture content in the material to be examined.

The DE 10 2008 035 658 A1 discloses a device for capacitive moisture measurement of a composite of several layers of a preferably hygroscopic material composite structure, which are interconnected by at least one, preferably hygroscopic, adhesive layer, wherein a sensor having a first sensor element and a second sensor element, of which at least one sensor element the adhesive layer is in contact, is provided. The measuring method relates to measuring the dielectric constant of the adhesive layer and / or a material of the composite structure with a sensor element in contact with the adhesive layer. In this way, it is easy to determine the moisture which has penetrated into the adhesive layer and which may result in a reduction in the strength of the adhesive layer and thus of the entire composite structure by means of a capacitive measuring method.

The DE 198 06 340 A1 discloses a mineral seal consisting of at least one laterally in a sealing plane extending layer of a water-impermeable mineral building material. There is a humidifying aggregate system extending parallel to the sealing plane. Furthermore, at least one sensor element extending parallel to the sealing plane is arranged for measuring the degree of moisture. The humidifying assembly system is above, within or immediately below the seal and the sensor element is disposed within the seal. The humidification unit system can be controlled and / or regulated in accordance with a comparison of actual values of the degree of humidity measured by means of the sensor element with predetermined desired values of the degree of humidity.

The DE 197 55 052 A1 discloses a method for determining the volumetric liquid water fraction and the density of snow and an apparatus for carrying out the method. This is achieved by installing a probe, which consists of at least three mutually parallel electrical conductors with different distances from each other, before snowfall or introduction of the probe in the already fallen snow and applying two of the conductors with a two-frequency electromagnetic signal in which the dielectric coefficients of water and ice are known and Determining the Dieleketrizitätskoeffizienten the snow with an unavoidable air gap around the probe from the transmission behavior of the electromagnetic signal.

The DE 102 45 411 B3 discloses a humidity sensor consisting of a multi-core measuring line and a phase / amplitude measuring device or a time-domain measuring device. The humidity sensor comprises a plurality of multi-wire sections forming the measuring line, shielded bypass lines running parallel to the measuring line sections, switches between the individual measuring line sections and the parallel bypass lines for selecting individual measuring line sections, with the corresponding measuring line sections instead of the non-selected measuring line sections Bypass lines are activated and means for driving the circuit.

The DE 10 2008 052 807 B3 discloses a lamella made of high-performance fibers, their production and use in particular for the reinforcement and monitoring of concrete or wooden structures, which also allows monitoring (monitoring) in addition to the classic roof trolleys. The arrangement of the optical fiber on the lamella is such that the beginning and end of free guidance to the load-oriented arrangement of the optical fiber are fixed on the surface directly next to each other. The optical fiber is embroidered on the lamella for this purpose. Due to the type of plug positioning, measuring signals can be obtained via one intact connection piece with one and the same measuring device, even in the case of fiber breakage.

The invention is based on the object to provide an improved means for monitoring a component of a building, an improved method for producing this agent and a use of the agent.

With respect to the agent, the object is achieved by a building fabric with the features of claim 1. Regarding the method for producing the agent, the object is achieved by a method having the features of claim 3. Regarding the use of the object is achieved by a Use with the features of claim 7.

Advantageous embodiments of the invention are the subject of the dependent claims.

An inventive construction textile comprises a carrier material, in particular made of fibers, for example a knitted fabric, wherein at least two electrical conductors, in particular at least three electrical conductors are arranged parallel to one another in the carrier material and led out for electrical contacting of the carrier material.

The building fabric can be used for monitoring a component of a building, wherein the building fabric is arranged in or on the component during the manufacture or renovation of the component, wherein the electrical conductors of the building fabric are led out of the component and connected to a measuring device. Dielectric properties of the material surrounding the electrical conductor of the component textile of the component are determined with the measuring device.

The determined dielectric properties allow the determination of a state of the component, for example moisture and / or pest infestation, for example fungal infestation, in particular infestation by real dry rot or massive changes in the geometry of the component.

Unlike in methods for determining the moisture, in which bores are introduced into the component and are consequently local, temporary and non-destructive, the inventive use of the building fabric allows a non-destructive, large-scale, spatially resolved monitoring of the component, which is limited in time, can be periodic or continuous.

Unlike the dielectric measuring method, in which the component must be accessible for the measurement, wherein the maximum penetration depth of the electric stray field is about 3 cm and thus no depth measurements are possible, the use of the invention also allows the monitoring of inaccessible after their preparation components, provided that its connection points are connected to the meter. If the building fabric is used as a reinforcement, it is often arranged at a certain depth of the finished component, so that depth measurements are possible.

In one embodiment of the use, the dielectric properties are determined by the measuring device by means of time domain reflectometry (TDR). In this case, an electrical signal, such as a voltage jump is applied to the electrical conductor of the building fabric, which propagates along the electrical conductor at the speed of light. The dielectric properties of the material of the component differ along the electrical conductor, for example due to local moisture, so varies accordingly locally the characteristic impedance of the sensor formed by the electrical conductors. As a result, there are different partial reflections of the electrical signal. Accordingly, a step response to the electrical signal is received in the measuring device, from which the propagation velocity of the electromagnetic waves along the sensor can be determined spatially resolved by analysis in the time domain. An equivalent circuit diagram can be used to draw conclusions about the relative permittivity of the material and the averaged moisture content. Alternatively or additionally, the signals obtained can also be analyzed in the frequency domain in order to improve the accuracy of the measurement.

In addition to monitoring the component, the structural textile can additionally be used for at least one of the purposes of reinforcement, insulation and sealing of the component or a part of the component. The multiple function of the building fabric can save costs for separate monitoring sensors.

In particular, the monitored or monitored component is a wooden component or a concrete component. Based on the determined dielectric properties, moisture and / or (at least in the case of the wood component) pest infestation, for example fungal infestation, in particular infestation by real dry rot of the component can be determined, since the moisture is the basis for destructive organisms. Since not only changes due to moisture, but in principle structural changes can be determined, a higher building security can be achieved, especially in the wood construction sector.

The support material may be formed, for example, lattice-like, strand-shaped, band-shaped or as a three-dimensional spacer structure. In the case of the three-dimensional embodiment, the electrical conductors can also be arranged three-dimensionally relative to one another, so that an improved, depth-resolved determination of the dielectric properties of the material to be monitored is possible.

In a method according to the invention for producing a building fabric, a carrier material is formed from a textile structure, wherein at least two electrical conductors are incorporated parallel to one another on or into the carrier material and led out of the carrier material for galvanic contacting.

For example, the electrical conductors are applied in a production direction or transversely to the production direction or incorporated into the carrier material.

The carrier material can be formed, for example, by load-absorbing fibers, threads or yarns comprising at least one of polyester, polyethylene, polypropylene, glass, carbon, aramid, high-tensile plastic fibers and basalt.

The electrical conductors can be incorporated by means of the Soutage embroidery method in or on the substrate. The Soutagesticktechnik deals with the application of thread-like structures directly on a carrier fabric. Typically, thread-like materials are used whose cross section is so large that they can not be passed through the needle eye of the embroidery needle. This thread-like material is positioned defined with a machine element belonging to the embroidery machine the so-called "casual" on the carrier fabric. The fixation of the thread-like materials is done with two other thread systems (upper and lower thread) by overstitching or piercing the same.

The electrical conductors can be integrated as wire-shaped sensors in the carrier material in one operation. Since the sensors are inexpensive conductive wire materials, the textile surface sensor formed by the construction textile can be brought directly to the position to be monitored when the component of the building is erected and remain there as a stationary sensor until a structural analysis of the structure is required.

The electrical conductors are after insertion or application in or on the carrier material slightly longer than the textile structure, that is, they have a reserve of material, which can be used to connect a connection cable and measuring device.

Due to the multifunctional building fabric according to the invention, a serious increase in building safety is achieved in new construction or renovation. The building fabric can be used for a desired upgrade of the component and is also suitable for detecting the different moisture conditions of the building.

In addition, damage locations can be displayed continuously in the event of water ingress into the component. In the normal load condition, a periodically activatable online monitoring is possible. The measured data can be recorded and registered in measuring stations.

By integrating the electrical conductors in the building fabric can be measured over the entire length of the building fabric and thus a large-scale monitoring of the changes, for example the moisture can be achieved. The possible sensitive length of the building fabric depends on the surrounding material to be monitored and can be up to several tens of meters.

Due to the possibility of monitoring at arbitrary times, periodically or continuously, early detection of danger and defense can take place by automatic weak point analysis and detection of an increase in damage. Likewise, an automated collection of area-wide information of the condition of the monitored component or all of the building fabric-equipped components of the structure, that is a damage mapping done.

Due to the possibility of automated, if necessary, permanent monitoring of critical, especially difficult to access building areas, a required for monitoring personnel costs is reduced.

Embodiments of the invention are explained in more detail below with reference to drawings.

• 1A eine schematische Ansicht einer Anordnung umfassend ein Bauteil mit einem erfindungsgemäßen Bautextil mit einem durch elektrische Leiter gebildeten Sensor sowie ein an die elektrischen Leiter angeschlossenes Messgerät,
• 1B ein beispielhaftes Diagramm eines mit dem Messgerät in der Anordnung aus 1 ermittelten, im Sensor reflektierten Signals,
• 1C ein beispielhaftes Diagramm einer aus dem im Sensor reflektierten Signal ermittelten relativen Feuchteverteilung im Bauteil,
• 2 eine schematische Ansicht eines dreidimensionalen Bautextils,
• 3 eine schematische Ansicht einer weiteren Ausführungsform eines dreidimensionalen Bautextils in geschlossener Konstruktion,
• 4 eine schematische Ansicht einer weiteren Ausführungsform eines zweidimensionalen Bautextils in offener Konstruktion,
• 5 eine schematische Ansicht einer weiteren Ausführungsform eines zweidimensionalen Bautextils in geschlossener Konstruktion, und
• 6 eine schematische Ansicht einer weiteren Ausführungsform eines dreidimensionalen Bautextils in offener Konstruktion.

Show:

• 1A a schematic view of an arrangement comprising a component with a building fabric according to the invention with a sensor formed by electrical conductors and a device connected to the electrical conductor measuring device,
• 1B an exemplary diagram of one with the meter in the arrangement 1 determined, reflected in the sensor signal,
• 1C an exemplary diagram of a relative humidity distribution in the component determined from the signal reflected in the sensor,
• 2 a schematic view of a three-dimensional building fabric,
• 3 a schematic view of another embodiment of a three-dimensional building fabric in a closed construction,
• 4 a schematic view of another embodiment of a two-dimensional building fabric in an open design,
• 5 a schematic view of another embodiment of a two-dimensional building fabric in a closed design, and
• 6 a schematic view of another embodiment of a three-dimensional building fabric in an open design.

Corresponding parts are provided in all figures with the same reference numerals.

1A shows a schematic view of an arrangement comprising a component 1 with a building fabric according to the invention 2 with an electrical conductor 3 formed sensor and one to the electrical conductors 3 connected measuring device 4 , The component 1 is for example a concrete component or a wooden component or masonry. The building fabric 2 can be used as reinforcement on the component 1 be applied and serves, for example, the stabilization of a on the component 1 applied plaster layer.

The building fabric 2 comprises a carrier material of a textile structure, wherein at least two electrical conductors 3 arranged parallel to each other in the carrier material and led out for galvanic contacting of the carrier material. The electrical conductors 3 are in 1 simplified as a cable. The carrier material may be latticed, strand-shaped, band-shaped or formed as a spacer structure. In one area 5 of the component 1 a moisture ingress is shown. The component 1 , in particular the material of the component 1 into which the building fabric 2 is embedded, so points in the area 5 higher humidity than outside this range. Through the meter 4 becomes an electrical signal, for example a voltage pulse on the electrical conductors 3 given, extending along the electrical conductor 3 propagates at the speed of light. The dielectric properties of the material of the component 1 along the electrical conductor 3 are within the range due to the higher humidity 5 unlike outside. As a result, locally varies the characteristic impedance of the electrical conductors by the local 3 formed sensor. As a result, there are different partial reflections of the electrical signal. In the meter 4 Accordingly, a step response to the electrical signal is received, from which the propagation velocity of the electromagnetic waves along the sensor can be determined spatially resolved by analysis in the time domain. 1B shows an exemplary diagram of a relative intensity I one with the meter 4 detected in the electrical conductors 3 reflected signal over the term t the signal.

An equivalent circuit diagram can be used to draw conclusions about the relative permittivity of the material and the averaged moisture content.

1C shows an exemplary diagram of a in the electrical conductor 3 reflected signal determined relative humidity distribution F in the component 1 above that by the building fabric 2 monitored length L of the component 1 ,

Alternatively or additionally, the signals obtained can also be analyzed in the frequency domain in order to improve the accuracy of the measurement.

The carrier material of the building fabric 2 can have different basic structures.

2 shows a schematic view of an embodiment of a three-dimensional building fabric 2 made with a stranding technology. In this case, the carrier material comprises 6 a material core of absorbent or swellable fiber or nonwoven fabrics, around the spatial arrangement of the or the sensors forming electrical conductors 3 are arranged. The fixation of the electrical conductors 3 on the carrier material 6 is about four threads, for example 7 realized via a 4-gripper system on the circumference of the rope-shaped component textile 2 be meshed. In this embodiment, for example, strand-shaped building textiles 2 be realized with diameters of 5 mm to 50 mm, for example, a sealing function in the component 1 able to fulfill. Due to the spatial arrangement of the electrical conductors 3 Depth profiles of the dielectric properties can be detected.

3 shows a schematic view of another embodiment of a three-dimensional building fabric 2 in a closed construction, with a three-dimensional carrier material produced in right / right warp knitting technology. These are surfaces of the building fabric 2 with different opening width, for example, the in 3 shown full area or in 4 illustrated grid feasible. Due to the knitted spacer structure are the electrical conductors 3 spatially arranged so that depth profiles of the dielectric properties can be detected. The in the 3 and 4 illustrated construction textiles 2 can also fulfill a reinforcement function and / or a drying function, for example via an air flow through the carrier fabric. For this purpose, optionally hydrophilic or load-absorbing materials are to be arranged in the component-contacting layers.

5 shows a schematic view of another embodiment of a three-dimensional building fabric 2 in closed construction and 6 in open construction. The building fabric 2 is produced in a composite knitting process on a nonwoven raschel machine. In this technology, both closed fabrics, consisting of a closed nonwoven web, which are connected in the composite knitting process with orthogonal threads produced, which consist of nonwoven fabrics in combination with thread materials and sensor fibers as well as open mesh structures, consisting of orthogonally arranged threads and functional materials without nonwoven fabric ,

The electrical conductors 3 can each transverse or parallel to the direction of preparation of the carrier material 6 to be ordered.

The electrical conductors 3 can by means of the so-called Soutagestickverfahrens with any support material 6 get connected. This embroidery technology allows individual positioning of the electrical conductors 3 on any textile carrier surface. In this case, the parallel guidance of the electrical conductors takes place 3 completely free in the surface, whereby the beginning and the end are fixed directly next to each other. In order to keep dimensionally stable non-displaced binding variants, a finishing process can take place after the textile surface formation. Immediately after the surface preparation, a stabilizer, for example a co-polymer is applied and cured at about 100 ° C and dried.

LIST OF REFERENCE NUMBERS

1

component

2

Bautextil

3

electrical conductor

4

gauge

5

Area

6

support material

7

threads

F

moisture distribution

I

relative intensity

L

length

t

running time

Claims (7)

Structural textile (2), comprising a textile carrier material (6), wherein at least two electrical conductors (3) arranged parallel to each other in the carrier material (6) and led out for electrical contacting of the carrier material (6), characterized in that the carrier material (6 ) - either as a knitted spacer structure by means of right / right warp knitting technology is formed three-dimensional, or - that the carrier material (6) is formed strand-shaped, wherein the carrier material (6) comprises a core of absorbent or swellable fiber or nonwoven fabric to the material in a spatial arrangement the or the sensors forming electrical conductors (3) are arranged. A method for producing a building fabric (2), wherein a textile support material (6) is formed, wherein at least two electrical conductors (3) are incorporated parallel to each other on or in the carrier material (6) and led out for electrical contacting of the carrier material (6) , where either - the carrier material (6) is formed as a knitted spacer structure by means of right / right warp knitting technology in three dimensions, or - wherein the carrier material (6) comprising a material core of absorbent or swellable fiber or nonwoven webs is formed strand-shaped by means of a stranding technology, wherein the material core is arranged in a spatial arrangement the or the sensors forming electrical conductors (3) are arranged. Method according to Claim 2 , characterized in that the electrical conductors (3) in a manufacturing direction or transversely to the manufacturing direction in the carrier material (6) are incorporated. Method according to one of Claims 2 or 3 , characterized in that the carrier material (6) by load-absorbing fibers comprising at least one of polyester, polyethylene, polypropylene, glass, carbon, aramid, high tensile plastic fibers and basalt is formed. Use of a building textile (2), comprising a textile carrier material (6), wherein at least two electrical conductors (3) arranged parallel to each other in the carrier material (6) and led out for electrical contacting of the carrier material (6), prepared by means of a method at wherein a textile carrier material (6) is formed, wherein at least two electrical conductors (3) are incorporated parallel to each other on or in the carrier material (6) and led out for electrical contacting of the carrier material (6), for monitoring a component (1) of a Building, wherein the building fabric (2) during manufacture of the component (1) in or on the component (1) is arranged, wherein the electrical conductors (3) of the building fabric (2) with the finished component (1) arranged arranged connection points be electrically connected, wherein a measuring device (4) is connected to the connection points, by means of which dielectric properties of the elec the conductor material (3) of the component (2) surrounding material of the component (1) are determined, wherein the dielectric properties are determined by the measuring device (4) by means of time domain reflectometry. Use after Claim 5 , characterized in that the building fabric (2) is additionally used for at least one of the purposes of reinforcement, insulation and sealing of the component (1) or a part thereof. Use according to one of Claims 5 or 6 , characterized in that the component (1) is a wooden component or a concrete component, wherein based on the determined dielectric properties moisture and / or pest infestation of the component (1) are determined.

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