EP3640407A1 - Impregnated fabric with additives - Google Patents

Abstract

The invention specifies a method for producing a textile reinforcement from a scrim, an impregnation being applied to a thread of the scrim or to the scrim, the textile reinforcement allowing mechanical reinforcement for freely weathered and used structures and being easy to install. For this purpose, the impregnation comprises a base material to which at least one additive is added.

Description

The invention relates to a method for producing textile reinforcement from a scrim, an impregnation being applied to a thread or a strand of the scrim or to the scrim. Furthermore, the invention relates to such textile reinforcement.

Reinforced concrete structures are an integral part of the infrastructure in almost every country in the world. In addition to residential and work buildings, many busy structures are also made of reinforced concrete, e.g. Parking garages, garages, highways, bridges, tunnels etc. A large number of these structures are used for 50 to 100 years (and sometimes even longer). However, in addition to mechanical stress, above all de-icing salts add to the reinforced concrete structures. The de-icing salts are usually chloride-containing. In connection with water, solutions are created that trigger corrosion in the buildings. In many buildings, therefore, substantial, cost-intensive repair work must be carried out on the reinforcement after just 20-25 years.

For this purpose, the contaminated covering concrete is usually removed, the reinforcing steel cleaned and provided with new corrosion protection (e.g. on a polymer or cement basis). However, the repaired area often only lasts for a few years (due to mechanical, thermal and / or hygric incompatibilities), so that timely further repairs are required, especially when the covering concrete is heavily used. This causes high costs, represents a significant intervention in the structure and, last but not least, leads to restrictions on use during the repair.

One possibility to suppress corrosion and ideally to prevent it is the cathodic corrosion protection (KKS) of buildings. As a largely non-destructive repair method, cathodic corrosion protection wins is becoming increasingly important as an economical repair process for components that are at risk or corroded.

Especially with reinforced concrete structures used, but in addition to corrosion protection and due to a steadily increasing volume of traffic and increasingly heavy vehicles (trucks, SUVs), many structures used (bridges, parking structures) have to be reinforced subsequently. There are a variety of processes here, such as: B. Prestressing with external tendons, shear force reinforcement with tendons or steel drawers, concreting with dowels, cross-sectional additions with shotcrete with additional reinforcing steel reinforcement and (slotted) glued CFRP (steel) slats.

So far, however, no method is known that protects freely weathered and used reinforced concrete structures in the long term against steel corrosion and at the same time represents a mechanical reinforcement for the structure. Although composite materials made of carbon concrete or other textile concretes made of basalt or AR glass fiber, which are soaked in an epoxy resin or styrene-butadiene rubber, are increasingly being used, these have so far been limited in their possible uses, since they are only used, for example, in interior structures which weather-related influences hardly occur, are suitable or lack the often necessary freedom of form.

Previous carbon fiber reinforcements only fulfill the function of building reinforcement or corrosion protection. However, there are already attempts to soak the carbon fibers in epoxy resin or styrene-butadiene rubber in order to obtain a stable clutch. Scrims with epoxy resin impregnation have a high bond strength. On the other hand, scrims with styrene-butadiene rubber are characterized in particular by their good processability, formability and in particular adequate polarization properties. However, there is currently no impregnation which has a pronounced mechanical bond and at the same time good processability / formability and advantageous polarization properties.

Previously impregnated textile reinforcements also have in common that laying around corners and edges, or at acute angles and tight radii of curvature (e.g. transition from floor to column) is very difficult. The poor flexibility of the textile reinforcement or the creation of defects due to narrow radii of curvature means that the reinforcement and corrosion protection effects are not achieved as required.

The invention is therefore based on the object of specifying a method for producing a textile reinforcement and a textile reinforcement which enables mechanical reinforcement for freely weathered and used structures and is easy to install.

The textile reinforcement can also include glass, for example. If cathodic corrosion protection is also made possible as part of the mechanical reinforcement, it is advisable to use a carbon fabric or a fabric which is at least partially formed from carbon fibers.

In the context of this application, scrims are understood to mean a flat structure which consists of several layers of stretched threads which run essentially parallel. The individual layers are placed on top of each other and fixed together at the crossing points. If the threads of different layers are oriented in two different directions, one speaks of a biaxial fabric, if several layers with multiple orientations are provided, one speaks of a multiaxial fabric. In the context of this application, the term scrim is also to be understood to mean a grid which likewise has a corresponding structure.

A single stretched strand is understood as the thread of a scrim. This thread can consist of a number of carbon multifilaments, which together form a thread or strand.

This object is achieved according to the invention in that the impregnation comprises a base material to which an additive is added.

The invention is based on the consideration that the provision of sufficient mechanical reinforcement and possibly a sufficiently high conductivity for cathodic corrosion protection can be achieved by suitable selection of an impregnation medium. It has been shown here that the scrim of the textile reinforcement can be particularly easily adapted to the specific requirements at the place of use if the impregnation and there the base medium used for the impregnation is modified by adding additives to increase the electrical, mechanical and thermal properties. It is possible, for example, to increase the electrical properties, in particular the conductivity, by adding carbon nanotubes, metal particles, salts (or ionic compounds) or graphite, while the thermal properties are increased by adding metals, carbon and Graphite particles can be influenced. To improve the mechanical properties, in particular also the bond with the solid mortar, it is possible to add hard materials, for example in the form of silicon carbide, quartz and ceramics.

Furthermore, by adding the additives, it is possible to modify the process parameters and possible processability of the scrim, in particular a carbon scrim. It is conceivable to use plasticizers, retarders or swelling agents to influence the properties of the fresh and solid mortar.

In particular, the addition of additives can ensure that the strength of the mortar in the area of the scrim is particularly high, while it is comparatively low on the surface. This strength gradient, which drops away from the scrim, enables the scrim to be used particularly flexibly.

For a particularly flexible and varied possibility of modification, the base material is preferably made by radical polymerization synthesized a monomer and a starter. It is now possible to add the additive to the monomer and / or the starter before the synthesis. This enables the impregnation to be modified even before the base material is synthesized. Additionally or alternatively, it is also possible to add the additive to the already synthesized base material before, as part of the impregnation and / or after the impregnation in the form of a sprinkling on the impregnated scrim.

In a special form of impregnation or as part of the subsequent coating, the starter is applied to the scrim in a first process and only then is the monomer applied, so that the base material is synthesized directly on the scrim.

The use of a polymethyl methacrylate as the base material for the impregnation has proven particularly advantageous. Since this base material can be introduced particularly well into the interstices of the scrim but also into the interstices of the fiber strands due to the low density. In addition to the use of polymethyl methacrylates as the base material, the epoxy resins, styrene-butadiene rubbers and acrylates or polyurethanes mentioned above are also quite conceivable.

In order to produce a firm bond between the impregnated textile reinforcement and the surrounding concrete, in a preferred embodiment the surface of the impregnated scrim is roughened and thus enlarged. For this purpose, additives, for example in the form of particles, are added to the coating medium, which bring about such an increase in surface area. In particular, granite, quartz powder, cement stone or conductive particles can be used. The enlarged surface leads to a non-positive and positive connection (reinforcing effect). By adding conductive particles, the charge transfer can be optimized to improve the cathodic protection against corrosion. As an alternative or in addition, it is also possible to use ionic compounds, concrete admixtures, mixtures of salts and microsilica (as a suspension or in solid form) or pozzolana reactives. These can be the hardening reaction kinetics influence, for example when using salts on the one hand to increase the conductivity in the border area and on the other hand to increase the mortar strength in the tissue environment.

In addition to or in addition to enlarging the surface of the scrim by adding particles, in an advantageous embodiment a coating can also be applied to the already impregnated scrim so that, like the particles, the surface is enlarged or the additives are better integrated. This coating can then either be the carrier medium for the particles or itself provide a higher bond. In a preferred embodiment, additives are also added to this coating medium to improve the electrical, thermal or mechanical properties before, during or after application to the impregnated scrim.

The impregnation or coating can be applied in particular in the immersion bath process, an emulation process, a spray process or else coated or rolled.

The advantages achieved by the invention are, in particular, that, by using an impregnation of the scrim tailored to the respective area of application and modified by an additive, in the case of a carbon scrim especially the carbon fibers, carbon threads or the entire carbon-containing scrim, the properties of the reinforcement the mortar in the immediate vicinity of the reinforcement can also be influenced. In addition to flat surfaces, curved, freely weathered and used structures can be permanently protected from steel corrosion and mechanically reinforced at the same time. A particular advantage is that, with a suitable modification of the mechanical properties, it can be achieved that the carbon fabric used here as a thin-layer textile concrete can provide sufficient load-bearing capacity or an increased load capacity even without the combination with cathodic corrosion protection. Here, it is also possible to remove thin old coverings that are no longer necessary for load-bearing capacity (such as screed, Asphalt or low-strength concrete) lead to a reduction in the load, increased payload and higher clearance heights in parking garages.

Increasing the strength near the fibers leads to an improvement in performance without causing excessive shrinkage cracks. Furthermore, the addition of flow agents to the fiber can improve the penetration into the fabric.

In detail, the main advantages of the coating medium used are the improvement of the electrical, chemical and mechanical properties of the entire system, in particular the high mechanical strength and load absorption of the materials used (e.g. static and dynamic tensile, adhesive and Shear loads), long-term resistance to environmental influences, d. H. chemical inertness and temperature resistance in a temperature range from -20 ° C to 80 ° C. The load capacity behavior can be improved in the larger temperature range. Furthermore, the advantages lie in the flexible processability and deformability (drapability) with sufficient rigidity for laying the textile reinforcement. Connections across corners and edges can be made non-positively and electrically conductive. The rigidity also enables easy application during installation. Further advantages are the high bond strength between concrete and textile reinforcement (if necessary through the additional use of a coating) and the optimized conductivity in the "metallic" conductor (carbon, 1st order conductor) and good charge transfer to the ionic conductor (cement block; conductor 2 . Order).

A fabric produced according to the above method is explained in more detail in an embodiment of the invention in a drawing.

• Fig. 1 ein Querschnitt durch einen Faden des Geleges
• Fig. 2 ein Gelege mit einer eingenähten Primäranode

It shows:

• Fig. 1 a cross section through a thread of the scrim
• Fig. 2 a clutch with a sewn-in primary anode

In Fig. 1 a thread 2 of a scrim is shown in cross section. The thread 2 comprises a large number of individual carbon multifilaments 12, each of which has between several 1,000 and up to 100,000 individual filaments. The thread 2 is in the embodiment Fig. 1 provided with an impregnation 10, to which one or more additives 14 were added in the impregnation process in order to improve the electrical, mechanical or also thermal properties. In a downstream production step, the thread 2 has been coated with a coating medium 16. In the present case, sanding occurred, so that the coating 16 serves as a carrier medium for the particles 18. The sanding increases the surface of the thread 2, which results in better bonding properties with the mortar.

The clutch 1 after Fig. 2 comprises a plurality of threads 2 or strands, which are arranged in two planes. Each level comprises a number of threads 2 which are spaced apart and essentially parallel to one another. Each of these threads 2 comprises a number of carbon multifilaments, which in the present exemplary embodiment have been glued to form an elongated strand. However, it is also conceivable that these carbon multifilaments are sewn into a strand or connected in some other way. The threads 2 of two planes are essentially orthogonal to one another, which is why a lattice structure with square spaces is formed. The threads 2 are fixed at the crossing points 4 with a continuous sewing thread 6, but can also be glued or connected to one another in another way.

It goes without saying that the planes of the scrim 1 do not necessarily have to be arranged orthogonally to one another, but, depending on the intended use, can also be arranged offset at a different angle. It is also conceivable that more than two levels can be provided.

In the embodiment according to the Fig. 2 a ribbon-shaped primary anode 8 is sewn along the entire length on a thread 2, whereby the anode system can be supplied with current over the entire length in contrast to contacting in a single point. In addition to sewing on the primary anode 8 on a thread 2, it is also conceivable that the primary anode 8 is sewn into a thread 2 and is therefore essentially completely surrounded by carbon multifilaments.

In order to increase the mechanical, electrical and thermal properties, in particular to improve the ability to lay and activate the mechanical properties of the scrim 1 and also the anode system embedded in the mortar, an impregnation 10 and then a coating according to the above statements are applied to the scrim 1. In this case, by means of a suitable choice of the impregnation and coating formulation and by the addition of appropriate additives, a scrim 1 for an anode system can be provided which has optimal mechanical, electrical and thermal properties for the respective application and place of use.

Reference list

1

Clutch

2nd

thread

4th

Crossing point

6

Sewing thread

8th

Primary anode

10th

impregnation

12th

Carbon multifilaments

14

Additive

16

Coating

18th

particle

Claims (7)

Method for producing a textile reinforcement from a scrim, an impregnation being applied to a thread of the scrim or to the scrim, characterized in that the impregnation comprises a base material to which at least one additive is added. A method for producing a textile reinforcement according to claim 1, characterized in that the base material is synthesized by radical polymerization from a monomer and a starter and the additive is added to the monomer, the starter and / or the synthesized base material. A process for producing a textile reinforcement according to claim 1 or 2, characterized in that a polymethyl methacrylate is used as the base material. Method for producing a textile reinforcement according to one of claims 1 to 3, characterized in that at least one coating is subsequently applied. A method for producing a textile reinforcement according to claim 4, characterized in that an additive is added to the coating medium before, during or after the coating of the scrim. A process for producing a textile reinforcement according to one of claims 1 to 5, characterized in that the impregnation is applied in an immersion bath process, an emulation process or a spray process. Textile reinforcement produced by a method according to claims 1 to 6.

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