BG99487A - Flexible protection cover, in particular for hydroinsulation and protection of reinforced concrete structures and steel tubes and pipes - Google Patents

Abstract

The cover includes elastic polymer foil of well-expressed texture surface on both its sides forming internally connected cavities open to the atmosphere which can be impregnated by cement binding material. In the preffered applications each of the texture surfaces is a fibrous layer and at least one of the fibrous layers is reimpregnated with cement binding material based on Portlandor other hydraulic cement which by nature is in non-hydrated condition.

Description

FLEXIBLE PROTECTION COATING SPECIFICALLY SPECIAL TO. WATERPROOFING AND PROTECTION OF REINFORCED CONCRETE BODIES AND MEGALTUBES

The present invention relates to protective coatings for providing protection against corrosion and / or water ingress. The protective coating according to the present invention is capable of being bonded to a cement mortar or concrete that is compacted and solidified in contact with it. Therefore, it is particularly suitable for such protection of buildings and concrete structures and also of metal pipes, therefore the following applies to these applications, but the invention could be suitably used for another purpose, such as for protection purposes. of sheet metal structures.

The main reason for the destruction of reinforced concrete structures is the corrosion of steel reinforcement. Initially, the steel is protected against corrosion by the passivation effect of the high alkalinity of the concrete. But over time, the penetration of carbon dioxide from the air into the concrete causes the highly alkaline calcium hydroxide, which is a constituent of the concrete, to be converted to non-alkaline calcium carbonate, which reduces the alkalinity of the concrete and the said passive effect. In addition, penetration into concrete of chlorides dissolved in water also reduces the passivating effect. With the reduction and / or disappearance of the passivating effect, oxygen, in the presence of moisture in the air, causes corrosion of the steel reinforcement to a degree dependent on the degree of oxygen access.

Steel pipes are usually protected against corrosion by wrapping the pipe with polyethylene or other polymeric tape or by forming a layer of cement mortar around the pipe. However, the protection of steel tubes with a polymer strip does not provide the above-described passivation effect against the tube for corrosion inhibition; moreover, possible defects in the polymer strip, which may initially be present or occur during operation, expose the pipe to corrosion at the site of the defects. Although a layer of cement mortar deposited around the pipe provides a passivating effect on the surface of the pipe, this effect diminishes over time as the cement layer is not protected and subjected to carbonation; in addition, the penetration of salts in dissolved form through unprotected concrete also reduces this effect.

Another method of protecting steel tubes is to apply a concrete layer around the pipe and at the same time wrap around a concrete layer of polymer tape. In this case, however, the concrete does not adhere well or all over the polymer surface and therefore the effectiveness of the polymer shell in preventing the carbonation and penetration of moisture and salts is limited.

Coatings of bituminous materials or polymer resins are also often used to protect against moisture from concrete structures and steel pipes and to protect against corrosion. However, the application of such materials on the cement surface does not allow the application of an additional layer of concrete or concrete paste on this coating after curing, since the hydrated products in the cement mortar do not generally bond well with these coatings.

Currently widely used in construction are textile fibrous pre-impregnated cementitious bandages. The impregnated shroud is a carrier of a dry concealed cement binder. When wet, the dry cement paste has a paste-like consistency and enables the bandage to bond with the hydrated products of the cement materials. If the mortar is poured onto the impregnated shroud, it hardens with the shroud upon curing and the shroud forms a surface layer on the cement layer. If the grout is poured below and above the impregnated shroud, a solid multilayer solid with a continuous intermediate layer is obtained upon curing. The bandage is used for waterproofing and repairs.

It is an object of the present invention to provide a flexible protective coating, especially for waterproofing buildings, reinforced concrete structures, metal pipes, sheet metal structures and the like, as well as for providing them against corrosion.

According to the present invention, there is provided a flexible protective coating comprising a soft polymer film with a pronounced textured surface on at least one of the two opposite sides, defining interconnected open cavities open to the atmosphere and which can be impregnated with a cementitious binder.

-3B The flexible protective coating is provided as a means of bonding the polymer film to other surfaces using a cementitious material that serves as a bonding agent. The coating provides the way in which the polymer film is bonded to the surface of the construction equipment with a layer of cement mortar or to the mass of concrete or cement mortar directly poured onto it. The new protective coating utilizes the excellent properties of the polymer film to serve as a protective and waterproofing layer and the application of cementitious material as a universal binder and bonding material in construction.

Building a multi-layer system is a well-known method in construction technology. Portland cement cement products are used primarily as a cementing agent, both in the manufacture of building components and in situ for the production of building materials. A polymeric film that adheres to the hydrated products of the cement mortar poured onto it may thus be incorporated into the conventional structure of the building blocks. A continuous intermediate layer will be created and moisture, vapor and gases from the atmosphere into the concrete mass will be largely prevented, and a foil that binds to the cement mortar will allow two overlapping sections of it to be bonded by applying cement mortar. on the overlap.

According to another feature of a preferred embodiment of the invention described below, the textured surfaces are preferably fibrous layers bonded to both sides of the polymer film. The fiber layers may be of natural or synthetic fibers, such as polyester textile fibers, polypropylene fibers and the like. Each fiber layer may be woven, non-woven, knitted, knotted, mesh, etc., such that it forms interconnected voids and which can be impregnated with a cementitious binder by means of which forms a continuous phase wholly incorporating the fibrous material and bonding it. It is also contemplated that the polymer film itself may be formed with a pronounced textured surface that defines interconnected voids open to the atmosphere, unable to be impregnated with a cementitious binder.

-4When textured surfaces are formed of fibrous layers, the same fibrous layers can be bonded to the polymer film by commercially available polymeric bonding agents known in the field of polymer film production. Another method that can be used is to impregnate the fibrous layer with a liquid polymer and, while the polymer is liquid, to bond non-impregnated fibrous layers on its opposite sides. Another possible method involves coating and partially impregnating the fibrous layer on one side with a liquid polymeric material and then bonding another fibrous layer to the liquid polymeric material. Another method that can be used is to cover and partially impregnate each of the two fibrous layers with liquid polymer material on one side and then bond the two layers to the polymer coated sides.

The polymer layer formed after solidification of the liquid polymer material creates a coating that is watertight. Materials suitable for polymer layers are any polymeric materials that form a flexible and robust polymer layer having a watertight property and to which fibrous layers can be bonded. Examples of materials suitable for the polymer layer are: polyvinyl chloride (PVC), polyethylene elastomeric materials such as polyurethane, etc.

According to other features of the described preferred embodiments of the invention, at least one, but preferably two, of the fibrous surface layers may be pre-impregnated with a cementitious binder that remains substantially unhydrated until the coating is applied. This can be accomplished by applying a slurry containing non-hydrated cement grains in a liquid medium to the fibrous textured surfaces of the polymer sheet. As a result of pre-impregnation, the impregnating material will solidify to a quasi-solid state, while the cement powder inside will remain substantially unhydrated. If fully hydrated, the degree of hydration of the cement powder will not noticeably interfere with the subsequent hydration and resultant hardening of the binder material, which is wetted again by contact with the concrete or cement binder applied in place. The degree of hydration of the pre-impregnation does not adversely affect the performance of the coating.

-5 For example, if the liquid phase of the slurry with cement grains is aqueous, the water in the slurry should be quickly released before the hydration of the cement grains in the impregnating agent can be substantially hydrated and a number of retardants can be used, such as gluconates to reduce hydration. The liquid phase in such a suspension may be non-aqueous, such as alcohol.

The fibrous surface layers serve to bond the binder material impregnated therein with the polymer coating and to regulate the distribution of the binder material on the surface of the polymer layer. They also serve as a storage site for the binder under protection conditions during use and form connected internal voids open to the external environment so that impregnation of these surface fibrous layers with a cement binder will result in the formation of a continuous phase completely closed on all sides and incorporating fibers.

One way to bond the fibrous surface layers to the polymer film in the manufacturing process is, as is usually done, by applying on one side of the polymer film a thin layer of suitable polymer adhesive that adheres well to the film, and then pressing the fiber layer to the adhesive. so that the fibrous layer partially penetrates the adhesive layer and thus forms a fibrous surface layer. In doing so, it is necessary to provide a sufficient portion of the fibrous surface layer which is free of adhesive so that it can absorb the impregnating material. Bonding the fibers to the polymer coating thus results in the formation of a thin layer of adhesive that separates the polymer film from the fibrous surface layer and the impregnating material.

The role of the impregnating / binder material in the coating is to provide the coating with a surface to which the hydrated products of the cement mortar / concrete poured on it can adhere. This material thus provides the connection and the presence of a continuous intermediate layer between the polymer layer and the outer layers of the cement mortar / concrete that hardens while in contact with the coating.

One effective way to achieve a good bond between two cement layers is to pour the two layers on top of each other while both are wet so that they solidify after a tight wet contact. Okay

A -6 bond with a similar effect can be achieved by pouring wet concrete, which is cured by hydration, onto a suitable polymeric resin in a liquid state that hardens upon polymerization. A good bond can also be achieved between wet cement material poured onto the coating impregnated with a binder material still in the wet state, both in the case where the impregnating material is cemented and hardened by hydration and in the case where the impregnating agent the material is resin and hardens upon polymerization.

The coating may be pre-impregnated with impregnating material during or after application. A suitable pre-impregnated coating binder causes the intermediate state of the impregnated binder to form after impregnation and before use. In this intermediate state, the binder material is not sufficiently hardened, but has reached a quasi-solid state, which remains until the time of actual use. The impregnating material in the intermediate state must have sufficient strength and chemical stability to ensure that, together with the fibrous structure of the fibrous surface layers, it remains mechanically sound until the coating is applied; however, the coating should not be too rigid so that its performance is not too limited. In this case, the surface layer is such that when wet it becomes self-adhesive and can bond to an external surface.

As an alternative to the formation of a bonding material having an intermediate state as described above, it can be used to pre-impregnate an impregnating material that will fully cure after impregnation without an intermediate state to the subsequent curing which the material provides surface coverage, to which the hydrated products of the cement layer poured onto the coating can be adhered to and further providing the coating in its solid state, the bonding layer does not compromise the flexibility of the coating and its operation its quality.

The impregnation may also be carried out on site or during or immediately prior to the application of the coating. Suitable impregnating materials for this purpose are materials similar to those used for pre-impregnation as well as others such as water-dispersible polymeric resins such as water-soluble epoxide and water-soluble polyurethane. The impregnating material suitable for in situ impregnation will harden to a degree depending on the time and in accordance with the operations required for the specific application.

Impregnating materials, both pre-impregnating and in-situ impregnating materials, should be, in their initial state, sufficiently flowing and fine-grained, if they contain solids, to penetrate the voids of the fibrous surface layers and fully absorb and cover the fibers. The two types of impregnating materials must be such that, after coating, the material hardens to a stable, solid state, forming a bonding layer that can adhere the hydrated products of the cementitious materials formed while in contact with them. In both categories of impregnating materials, the curing must be the result of a physical / chemical process that is not dependent on the loss of water from the system in the environment, and which may therefore take place indoors.

The textured surface of the fibrous surface layers may first be pre-impregnated with a water-dispersible polymer resin to serve as a primer for the cement slurry. Examples of such a primer include a two-component water-dispersible epoxy resin and a water-dispersible polyurethane resin. The pre-impregnation of the fibrous surface layers with non-hydrated cement powders may also be carried out by a dry process in which the cement powder, preferably mixed with a powder organic binder and, optionally, other additives, is applied as a powder to the fibrous surface layer of the polymer foil and ram into it by applying pressure and vibration at a moderately high temperature so that the powdery mass is compacted and stabilized in the fibrous surface layer.

The pre-impregnating material, which is applied either as a slurry or as a dry powder, may also contain one or more of the following additives: mineral fillers such as fine quartz sand, microsilicon powder, clay, etc., to enhance the strength of the mixture and its wettability; additives such as sulfonated melamine formaldehyde to increase the workability of the suspension; supplements such as calcium formate or sodium gluconate to slow or accelerate hydration; organic adhesives or polymer additives such as water-soluble cellulose ethers, water-dispersible polymer powders, polymeric emulsions or resins for increasing the initial strength in the quasi-solid state or for regulating rheological parameters, improving the elasticity and increasing the bond strength of the bonding layer.

-8The pre-impregnating material may also consist of or include non-cementitious materials compatible with cementitious materials. Examples of such non-cement materials are fine quartz sand, microsilicon powder and clay. These materials can be applied in the same way as cement pre-impregnating materials.

Examples of protective coatings constructed according to the invention:

Polyvinyl chloride film, 1 mm thick, is coated on both sides with a thin layer of thermoplastic polymer adhesive, commonly used for bonding textiles to PVC, and a 15-day polyester textile fiber adhesive is required on the adhesive layers so that the fibers partially break through. in the adhesive layer. The coating is then heated and the adhesive polymerized and solidified.

The fibrous layers thus obtained, on both sides of the polymer film, were impregnated with a suspension of the following composition in weight ratios of the components:

ordinary Portland cement 1000 fine quartz powder500 microsilicon powder80 (water soluble cellulose ether) hydroxyethyl cellulose tylose Η 20P-5 sulfonated melamine formaldehyde20 sodium gluconate2 water400

The suspension thus applied is dried with hot air at a temperature of up to about 140 C for a time sufficient to evaporate the water. After drying, the impregnated surface of the fibrous layer is preferably brushed mechanically to remove excess impregnating material and to improve the wettability and surface bonding ability.

The protective coating may be impregnated with a suspension of a composition as described above, except that the liquid phase of the suspension is ethyl alcohol, preferred to water.

-9The coating may be impregnated with an aqueous suspension as described above, except that prior to application of the cement slurry to the fibrous layers, the fibrous layers are pre-impregnated with a primer based on a water-dispersible polyurethane resin.

Figures 1 to 10 illustrate various applications of this protective coating. FIG. 1 shows a protective coating 10 covering the face surface 11 of a reinforced concrete structure 12 that is reinforced with steel bars 13. The protective coating 10 includes a polymeric film 14 having fibrous surface layers 15,16 on the two opposite surfaces, each forming a textured textured surface. interconnected voids open to the atmosphere which can be impregnated with a binder.

As described above, the two fibrous surface layers 15,16 are pre-impregnated with a cementitious binder material which is substantially unhydrated or with a cementitious material compatible with the cementitious material. The fibrous surface layer 15 is bonded to the surface of the cement mortar17 layer of the reinforced concrete structure 12, which can be modified with polymer additives to improve adhesion and bonding properties. The water from the fresh mortar moistens the pre-impregnating cement binder, thus causing the hydration of the cement in it and creating a strong bond with the concrete body.

In another embodiment of FIG. 1, the fibrous surface layer 15 is not pre-impregnated and impregnated immediately prior to application of a water-soluble polymer resin, such as a water-soluble epoxide, and then bonded via the cement binder 17 to the concrete body 12.

In another embodiment, according to FIG. 1, the fibrous surface layer 15 is impregnated in place immediately prior to the construction of the coating in two steps. In the first step, the fibrous surface layer is partially impregnated with a water-dispersible polymeric resin such as a water-dispersible epoxide and then in the second stage the impregnation is completed with a cement slurry and then bonded to the concrete body 12 by means of a layer of cement 17.

In another embodiment of FIG. 1, the coating having a fibrous surface layer 15 impregnated by any of the methods described above is constructed while in the wet state and the fibrous surface layer 15 is applied directly in the wet state to the surface of the concrete. body 11. In this case, a layer of cement mortar is missing.

In another embodiment, according to FIG. 1, the middle polymer layer 14 is made of polyurethane resin and the fibrous surface layers 15,16 are made of polypropylene fibers.

Figure 2 shows a coating marked with 20 applied to a steel tube 21. In this case, the coating 20 is in the form of a strip, wound in a spiral way around the tube 21 to form multiple layers, with each layer partially overlapping the lower layer. The strip 20 includes a polymer layer 24 and fibrous surface layers 25 and 26 on its two sides. The coating is bonded to the pipe through a cement layer 27. If the pre-impregnation is with a cement impregnating agent, the water from the cement mortar layer will wet the cement grains of the impregnating layer, thereby hydrating the cement therein and creating a strong bond with the surface of the pipe.

In another embodiment, according to FIG. 2, a coating is constructed in which the fibrous surface layers are not pre-impregnated. In this case, the fibrous surface layer 25 can be impregnated in place with a cement slurry and then bonded to the surface of the pipe by a layer of cement mortar 27.

In another embodiment of FIG. 2, the fibrous surface layer 25 can be impregnated in two steps. In the first step, the fibrous surface layer is partially impregnated with a polymer resin as a primer. In the second step, the impregnation of the fibrous surface layer is completed with a cement slurry and then connected to the pipe through a layer of cement mortar 27.

In another embodiment, according to FIG. 2, the fibrous surface layer 25 is impregnated with a water-dispersible polymer resin such as a water-dispersible epoxy resin and then the impregnated coating is bonded to the pipe surface by a layer of cement mortar 27.

In each of the above-described embodiments, the bonding layer 27 may be formed of an impregnating material.

-11 FIG. 3 illustrates coating 30, also comprising polymer film 31 and fibrous surface layers 32,33, pre-impregnated with cement binder material on both sides, as described above with respect to FIGS. 1 and 2. The coating 30 shown in Fig. 3 also includes a flexible metal mesh layer 34 deposited on the fibrous surface layer 32 or inside the fibrous layer 32 when the coating is used to prevent corrosion in the cathodic protection of the equipment. In one configuration according to FIG. 3, the fibrous surface layer 32 contains a conductive filler, for example carbon black. In another configuration according to FIG. 3, the fibrous surface layer comprises a conductive filler and does not include a metal mesh.

FIG. 4 illustrates a protective coating 40 used for waterproofing on the outside of a concrete element 45 poured onto a primer 48 and consisting of a slab and a wall. The coating contains fibrous surface layers 41,42, pre-impregnated with cement binder material and is constructed on a primer behind the formwork 44, with the desired configuration and concrete is poured directly on it.

In this application, the surface layers 42,43 of the coating 40 are preferably impregnated with a cement impregnating material. When the wet concrete is poured onto the coating, the water from the concrete mix soaks the impregnating binder material in the surface layer 42 and causes the cement grains to hydrate therein. The concrete mass is then hydrated and solidified spontaneously and in contact with the cement grains in the surface layer 42, forming a solid bond and a continuous intermediate layer.

Figure 5 shows another application wherein the coating 50 is applied along the outlines of the inner surface of the formwork 54 so as to cover and connect to all surfaces of the concrete block 55 poured in into the formwork.

Figure 6 shows the overlapping portions of the coating 60. The two overlapping portions of the coating can be connected to form a wider portion of the coating. The connection is recognized by applying a cement binder layer 67 at the overlap site, and it connects the fibrous surface layer 63 of the lower coating to the fibrous surface layer 62 of the upper coating. If the two parts of the coating are pre-impregnated with cement binder, the overlapping bond may be due to the wetting of the overlying layers in the overlapping area and no separate bonding of layer 67 is required

-12Fig. 7 shows the above-described coating, generally referred to as 70, used as a building joint sealing plate between two concrete bodies 75,76, connected by means of a bonding layer 77 having fibrous surface layers impregnated with cement binder.

8 shows a coating 80 used as a barrier against water for the gap between concrete slabs 86,87.

Said coating is used as a water barrier for waterproofing the separation gap between the upper layer 86 and the lower layer 87 of a concrete element, which is poured in two steps and the coating is constructed as a vertical lateral lining on the inside of the formwork 84 before being poured and bonded to the vertical sides of the cast layers so that after hardening the coating connects to the vertical surfaces of the two parts of the composite structure 88 and connects the upper and lower cast layers.

Fig. 9 shows a coating 90 that can be used as a waterproofing and exterior lining 95 of an apparatus, and comprises a polymer film 91 with fibrous surface layers 92.93 on both sides. In the example shown in FIG. 9, one surface layer 92 of the coating 90 is bonded to a plurality of mosaic parts in the manner described above by means of a suitable bonding layer 97. The other fibrous surface layer 93 is pre-impregnated with cementitious binder material. which connects to the surface of the facility and connects the lining layer to the cementitious binder.

FIG. 10 shows the construction of a cylindrical body from the coating by winding a strip 100 helically around and in the direction of the axis with overlapping sections 108 and connecting the overlapping parts with a connecting layer 107.

Claims (12)

Patent Claims 1 A flexible protective and waterproofing coating comprising a flexible polymer film having a pronounced textured surface on each side forming interconnected voids open to the atmosphere and which can be impregnated with a cementitious binder The flexible protective and waterproofing coating according to claim 1, wherein each of said textured surfaces is a fibrous layer A flexible protective and waterproofing coating according to claim 2, wherein at least one of said fibrous layers is pre-impregnated with a cementitious binder based on Portland or other hydraulic cement that is substantially unhydrated. A flexible protective and waterproofing coating according to claim 2, wherein at least one of said fibrous layers is pre-impregnated with a material consisting of or containing a non-cementitious material having the ability to bind to Portland cement mortar or concrete which binds and hardens while in contact with it. A flexible protective and waterproofing coating according to any one of claims 2 to 4, further comprising at least one or two electrically conductive fillers, such as carbon blacks, in the cement impregnating material and in an electrically conductive metal grid or mesh or on the fibrous layers , pre-impregnated with cement-based impregnating material, enabling the application of cathodic reinforcement to a concrete body or sheet metal structure to which the coating is bonded by a Portland cement-based bonding layer 6 A combination of a protective and waterproofing coating according to any one of claims 1 to 5, and a concrete, metal or other body connected to this coating by a Portland cement-based bonding layer and also bonded by fiber-impregnated bonding materials, lying on the surface of the body and binders containing at least one of the materials - cement and polymer resin The combination of claim 6, wherein said body is a body of concrete poured from a concrete mixture on the expressed textured surface of the coating so that the cement material of the concrete mixture will wet the binder material impregnated in the fibrous layer or in the absence of impregnating material into the fibrous layer, to penetrate into the empty spaces inside the fibrous layers The combination of claim 6, wherein said protective and waterproofing coating is applied as a watertight joint of joints between two concrete bodies and the coating is bonded directly to said bodies by cement material pre-impregnated in the coating, filling the interconnected interstices of textures surface, The combination of claim 6, wherein the protective and waterproofing coating is applied as a sealing bond between building concrete panels to which the coating is bonded via a cement bonding layer. The combination of claim 6, wherein the protective and waterproofing coating includes a pronounced textured surface on both sides, one side being bonded to the lining material through the cementitious material filling the interconnected voids of the textured surface of said side, the other side being joined to the concrete structure by means of a cement material filling the interconnected voids of the textured surface of said second side. Combination according to claims 1 to 5, in which two or more parts of the coating are joined together, forming a wider area of the coating, by overlapping sections in the desired configuration and linking those sections with a mixture based on Portland-cement mineral fillers and polymer additives. Combination according to claims 1 to 5, in which a three-dimensional body is constructed, using one or more pieces of coating by arranging the pieces with overlapping parts in the desired configuration and joining the overlapping sections of the coating by a suitable binding material The combination of claims 1 to 5, wherein said body is a metal tube, said coating piece is wound around the metal tube with said overlap, and wherein said coating is connected to the surface of the tube by binders impregnated in the fibrous layers immediately covering the pipe surface and the impregnating binder materials contain at least one of the materials - cement slurry and polymer resin