DE3122347A1 - MECHANICAL PROTECTIVE COATING FOR A COATED TUBE - Google Patents

Description

description

The invention relates to a protective layer for a corrosion protection layer on a metal support to protect the latter from mechanical damage and harmful To protect the environment. The invention will be described primarily in connection with piping, but it can be apply to other cases as well.

- | 0 Pipelines are generally used to conduct Water, gas, oil and other substances. They are often laid under water, embedded in the earth or freely laid without protection, with the pipelines in most cases showing considerable corrosion subject. To counteract these difficulties, a thin anti-corrosion layer is generally used applied to the pipelines, usually an epoxy or polyethylene coating. Difficulties arise with such coatings because they are Storage, preparation, conveyance and installation are often damaged. A rough handling with normal Transport facilities and pipes knocking against each other often damage these coatings.

In addition, there is a risk of damage to overland pipelines while they are in rough terrain

130067/0874

- rr-40

Trenches are sunk and when the trenches are again filled with coarse rock. Even during storage the coatings often deteriorate just because they have an ubiquitous ultraviolet Exposed to radiation. Further damage to the coatings occurs when pipelines are underwater be weighted, usually concrete, to put them under To hold water. These loads are often applied to the pipeline with such little protection that that their aggregates shatter the thin anti-corrosion layer.

It is therefore the object of the invention to provide an improved. Protective layer for those provided with anti-corrosion layers To create pipelines or metal elements.

The measures specified in the characterizing part of the main claim serve to solve this problem. According to the invention a thin protective layer of cement-like material is thus applied over the anti-corrosion layer. The cement-like coating surprisingly adheres to the anti-corrosion layer. It has furthermore Surprisingly found that some cementitious coatings were removed when the pipeline was lowered can compress or stretch so that they are together with

130067/0874

the pipe can be bent without detaching from the pipe. In doing so, they retain the protective effect for the Corrosion protection layer upright.

According to the invention, a combination of a metal pipe with a corrosion protection layer is therefore provided, whereby a thin cement-like coating serves to protect the anti-corrosion layer and which is marked is by a cementitious material with a fine filler in an amount of 0 to 3.5 Parts by weight per part of the cementitious material, with a polymeric material in an amount of 0.05 to 0.55 parts by weight of the polymeric solids per part of the cementitious material, and by cut fibers or flakes in an amount of from 0 to 0.2 parts by weight per part of the cementitious material, the Thickness of the cementitious coating is between 0.5 and 5 mm and the coating is on the anti-corrosion layer adheres.

Since some tubes are provided with cathodic protection and thereby have to allow a current flow through their outer surface, the coating according to the invention has in a preferred embodiment has sufficient electrical conductivity.

130067/0874

Further advantages of the invention are based on the subclaims as well as the following description of the figures.

The invention is explained in more detail below with reference to figures; show it:

Figure 1 shows a section through a pipe with the invention Coating; and

FIG. 2 shows a schematic representation of a system for applying the coating according to the invention. 10

The invention relates to steel pipes, iron pipes or other pipes that have a thin anti-corrosion layer exhibit. Such a layer is generally an epoxy layer, but it is also polyethylene, Coal tar, polyurethane or other commonly used thin protective layer are suitable. It will be common in a thickness of about. 0.25 to 3 mm applied. Although the anti-corrosion layer is usually adheres to the pipe, it can also be wrapped tightly around the pipe as a bushing, for example as a Polyethylene bushing, or shrink-on. Typical epoxy coatings are sold by MobilOil as No. 1004 and 1003-R and by 3M under No.

206N.
25th

1 30067 / 087A

/ 3

The mechanical protective layer according to the invention has a cementitious material. "Cement-like material" refers to durable substances based on inorganic Calcium oxide cement understood, for example Portland cement, slag cement or calcium aluminate cements.

Preferably, but not necessarily, fibers are added to the cementitious material in order to

- | 0 to improve the availability and to increase the shock resistance. The fibers are, for example, mineral fibers such as asbestos, glass or stone, or synthetic fibers such as nylon, Polypropylene, rayon, polyester, polyacrylic, polyethylene or polyurethane. Natural fibers such as CeI-

-J5 lulose, cotton, silk, wool, hemp, sisal, or jute Flax can be used. Small flakes such as mica flakes can also be used. The length of the fibers is not particularly critical as the fibers are allowed to decompose after the pipe is installed. The fibers are very small, usually between about 6 and 12.5 mm long and about 0.06mm as larger pieces are less suitable for a thin cementitious coating.

The coating according to the invention also comprises a po-

130067/0874

lymeres material that strengthens the coating serves and is intended to improve its adhesion to the smooth corrosion protection layer. Suitable polymeric substances for The use as coatings according to the invention are those that are compatible with cementitious substances. These include vinyl acetate polymers and copolymers, styrene polymers and copolymers, vinyl chloride polymers and copolymers, butadiene polymers and copolymers, and acrylic polymers and copolymers. The polymer solids are

.JQ usually provided as an aqueous solution. the preferred polymeric materials are acrylic polymers, especially acrylic polymers with some or only Methacrylate, acrylate and acrylic acid groups, styrene / butadiene polymers and polyvinyl chloride. It will care

-I5 pointed out that some polymers for the respective Purpose are better suited than others. When the coating is exposed to ultraviolet radiation acrylic polymers are particularly well suited.

The cementitious coating according to the invention has also fillers such as silica sand, sieve rock (trap rock screenings), slag from iron ore or steel production, Iron ore, roasted bauxite, mika, barite or nephylensynite. It should be noted that

130067/0874

the fillers used for cement production on j

J. All over the world are different. Your particle i

size distribution, its particle shape and the porosity J the cement and water requirements, the workable

the speed and durability of the coating.

sen. '

The coating according to the invention also has white Other additives such as air binders, foam inhibitors, j 1Q dyes and other chemical additives based on that improve the properties of the coating.

The thickness of the cementitious coating applied is between 0.5 mm and 5 mm, preferably between 1 and 3 mm. Coatings of less than 1 mm will be used normally used for UV protection layers, while thicker layers are mainly used for mechanical protection to serve.

The quantity of filler used varies according to Invention from 0 to 3.5 parts by weight per part of the cementitious material, and is preferred between 1.0 and 3.0 parts by weight per part of cementitious material. The filler is a fine material, for example sand, as opposed to coarse aggregate

130067/0874

materials for concrete, such as stones or gravel, so that you Impingement on the protective layers during the application of the coating does not damage the already causes corrosion protection layer applied to the pipe.

The amount of polymeric solids used will vary from 0.05 to 0.55 parts by weight per part of the cementitious material, preferably from 0.1 to 0.3 parts by weight cement-like material per part. Preferred polymers for use in the deeper areas are Acrylic polymers, while styrene / butadiene polymers above of 0.15 parts are preferably used.

- | 5 The amount of fibers or flakes used varies from 0 to 0.20 parts by weight per part of cementitious material, preferably from 0.01 to 0.10 parts by weight per part of the cementitious material.

In the preparation of the cementitious according to the invention Coating, the selected substances are mixed together, generally with water, like this is set out in the following examples. The material obtained after mixing is thick Mixture, which is then applied to the corrosion protection

1 30067/0874

layer is applied to the pipe. The mixture is applied in that it is for example by means of a screw conveyor between two counter-rotating Brushes which fling the mixture onto the pipe. The tube is rotated in front of the brushes and the mixture is applied over its entire length by either moving the tube past the brushes or by moving the brushes along the pipe.

The coatings according to the invention can be used with Temperatures between 5 C and a sufficiently below the solidification temperature (false or flash setting temperature) of the mixture. A preferred temperature is about 16 ° C. The lower temperatures are used when the pipe is at a higher temperature. However, it is clear to the person skilled in the art that applying a coating at 5 ° C to a cold pipe does not give a good coating.

The invention is illustrated below by means of examples explained in more detail. In the examples below, ratios are expressed as parts by weight.

130067/0874

example 1

A mortar made from 100 parts of Portland cement, 31 parts of Rhoplex MC-76 from Rohm & Haas Co. (a dispersion of 47 parts of acrylic polymer and 53 parts of water) and 18 parts of water. The mortar received was spray applied to an epoxy coated pipe to give a coating to a thickness of 0.5 mm to form. Since there were no fibers, •} 0 this resulted in an extremely thin coating that was a Protection against penetration by ultraviolet radiation formed.

Example 2

A mortar was made from 100 parts of Portland cement, 115 parts of Rhoplex MC-76 and 11 parts of an additive manufactured under the number FRCA501 by FRC Composites Limited of Don Mills, Ontario, Canada, is distributed. The additive contained the water necessary for the mortar and acted as a thickener to bring about an even distribution of the material. The mortar was then epoxy coated on Pipe applied by spraying to form a coating 0.5mm thick. That

130067/0874

m »ι ·>

The result was similar to Example 1.

Example 3

A mortar made of 100 parts of Portland cement, 31 parts of Rhoplex E-330 (a dispersion of 47 parts Acrylic polymer and 53 parts of water), 250 parts of silica sand, 2.5 parts of glass fibers and 22 parts of water. The fibers were 6 mm long. The mortar was "with the help of rotating brushes on an epoxy-coated Pipe applied in a layer thickness of 2.5 mm.

It has been shown that this coating has excellent impact resistance, high adhesion and despite its large size Thickness had sufficient flexibility so that the pipe worked and something during the laying itself could be bent without the coating falling off.

Example 4

Example 3 was repeated with the exception that a dispersion of 48 parts of butadiene / styrene rubber in 52 parts of water (Dow 460 ² ^ from Dow Chemical Company) was used instead of Rhoplex E-330. The results were similar to Example 3.

13 0067/0874

Example 5

Example 3 was repeated with the modification that

instead of Rhoplex E-330 a styrene / butadiene rubber 5

in the form of a dispersion of about 48 parts of rubber in 52 parts of water (Dylex-1186 from Atlantic Richfield Company) was used. Results similar to those of Example 3 were obtained.

Example 6

Example 3 was repeated, but instead of Rhoplex E-330 a dispersion of about 48

Parts of styrene / butadiene rubber in 52 parts of water 15

(97-314 Tylac from Reichhold Chemicals Inc.) was used wound. Results similar to those of Example 3 were obtained.

Example 7

Example 3 was repeated with the modification that instead of Rhoplex E-330 a dispersion of 55 parts Polyvinyl acetate in 45 parts of water (40-155 plyamul

Reichhold Chemicals Inc.) was used. Man 25

obtained similar results as in Example 3.

130067/0874

Example 8

A mortar with 100 parts Portland cement, 31 Parts of Rhoplex MC-76, 150 parts of Silkasand, 1.5 parts of short, finely chopped glass fibers and 10 parts of water. The mortar was applied to an epoxy coated pipe with the help of counter-rotating brushes in a cementitious manner Layer thickness of 4 mm applied. It has been shown that due to the thickness a very high There was shock resistance and great mechanical strength, with a certain flexibility also being present which, however, was somewhat smaller than in example 3 due to the greater layer thickness.

Example 9

Example 8 was repeated with the modification that Dow-460 was used in place of Rhoplex MC-76. Man

obtained similar results as in Example 8.
20th

Example 10

Example 8 was repeated with the modification that Dylex-1186 was used in place of Rhoplex MC-76.

Similar results as in Example 8 were obtained.

130067/0874

Example 11

Example 8 was repeated with the modification that 97-314 Tylac used instead of Rhoplex MC-76

became. The results were similar to those of Example 8 5

achieved.

Example 12

Example 8 was repeated with the modification that

40-155 Plyamul used instead of Rhoplex MC-76 10

became. Results similar to those of Example 8 were obtained.

Example 13

A mortar was made with 100 parts of Portland cement, 11 parts of Rhoplex MC-76, 350 parts of silica sand and 44 parts Share water made. The mortar was coated onto an epoxy with the help of counter-rotating brushes

Tube for forming a coating 4 mm thick 20

upset.

The coating thus formed had a high impact resistance, which, however, was somewhat lower than in Example 8 because no fibers were used. Also was 25

the flexibility somewhat less than in example 8, because

130067/0874

a little less polymer was used.

The pipes coated with the cementitious material according to the preceding examples could be opened after 10 Min. Handle to some extent and could be rolled over each other after 30 min. After being at room temperatures had tied. The setting speed naturally increases with higher temperatures and decreases with lower temperatures.

It has been shown that the inventive cementitious Coating on most epoxy and coal tar corrosion layers without any special surface treatment of the Ex'poxids adhere sufficiently. It is single

lent a corresponding cleaning of the epoxy layer to make. However, if the corrosion layer is very smooth or greasy, as is the case with most polyethylenes is the case, then it is expediently either

mechanically roughening or before applying the ze-20

chemical pretreatment. this improves the adhesion of the cementitious coating.

A main area of application for the invention is the coating of pipes for pipelines. Those in pipelines 25th

130067/0 8 74

- it -

Pipe sections used are often very long, for example 12 m or more, which must also be laid uphill, downhill and around bends. Such Pipe sections are necessarily bent to some extent. It has been found that the invention cement-like coating even under these circumstances on the smooth corrosion layer of the pipe can stick. It should be noted, however, that the cementitious coating increases with increasing

JQ thick and easily peeled off with decreasing polymer content. Thicker coatings of 3 to 4 mm with a low polymer content, for example according to Example 13 and in particular according to example 13 therefore allow only very little curvature without a certain flaking

ever done. A coating produced according to Example 3 however, allows a much greater bend without peeling off the layer.

If a suitable cementitious coating is applied, it will break if carefully bent 20th

of the pipe, but will not normally fall off the pipe in pieces. Even when broken the cement-like coating provides essential protection for the anti-corrosion layer from mechanical Damage to machines or around 25

Particles thrown down the pipe. It is important to

13 0067/0874

15th

indicated that the impact of particles or aggregates can be very violent. In the case of weights for underwater pipelines, for example, large Stones are used to create the densest possible heavy

layer to create and the impact of these stones on the pipe is carried out at speeds of more than 130 km / h.

As mentioned earlier, most piping comes with it

provided with a cathodic protection. Although the anti-corrosion layer naturally provides protection against corrosion cathodic protection is also necessary if the corrosion protection layer is damaged. Cathodic protection can be achieved by initiating a

Current that is directed opposite to the current generated by corrosion and this countercurrent must flow through the cementitious coating. This must therefore have a sufficiently small resistance so that

a sufficient protective current can flow.
20th

A very small thickness of the cementitious layer reduces its resistance, since the resistance is linear Function of thickness is. Since, in addition, in certain coatings according to the invention, the cement content

is relatively low, this increases the porosity and

130067/0874

thus the water absorption of the coating what the electrical conductivity of the cementitious coating increases. The resistance of the cementitious coating was measured as follows:

A cement-like coating according to Example 3 with a thickness of 2.5 mm was applied over an epoxy coating applied which adhered to a large diameter steel pipe. It got a hole with a Diameter of 3 mm through the cement-like coating and the epoxy coating drilled to the steel pipe and filled to the top with mercury. The mercury acted as a conductor between the wall of the hole in the cementitious coating and the pipe. The top of the hole was then made with a circular sealed with a plug made of silicone rubber, which had a diameter of 25 mm and above the bore was centered. The plug extended beyond the edge of the hole. One end of a plexiglass tube of about 90 mm in diameter, which was open at both ends, was then connected to the surface of the cement-like Coating sealed in such a way that the hole containing the mercury was in its center.

The Plexiglas tube was then filled to a height of 150 mm with a solution of 5 % NaCl in water.

A platinum anode was used to a depth of 75 mm in

130067/0874

312 2 3 A

dipped the solution. The steel pipe acted as a cathode. There was a DC voltage of 5 volts was applied and the current flowing was measured with a digitally readable mini _ kilometer meter measured.

The current measured initially was very low, but it was when the cementitious coating had absorbed the NaCl solution due to its porosity, the current ceased ._ to. After 24 hours the current had stabilized at 5.5 mA and then remained at this value.

The resistance of the cementitious material was calculated as follows:

.,. It was assumed that the conductivities of the NaCl solution and the steel pipe were very high against the cementitious coating and that the epoxy coating acted as insulation. The current thus flowed through the steel pipe into which the 3 mm diameter mercury hole

2Q tion, through the coating under the silicone rubber stopper, into the solution at the perimeter of the plug and to the anode. The specific resistance calculated from this as:

130067/0874

Resistance times the cross section through which the current flows divided by the length of the current path.

This gave a resistance of 5: 0.0055 = 909 ohms. Of the The way through the cementitious coating began on the wall of the 3 mm hole and ended at the edge of the 25 mm 0 Plug and was 1.11 cm long.

The cross section through which the current flows was not

evenly. On the wall of the hole the transverse was 10

cut pi χ 0.3 cm 0.25 cm (the coating thickness)

or 0.253 cm total. Around the circumference of the 2.5 cm stopper the cross section was pi 2.5 cm 0.25 cm or 2.03

2
cm. The cross-section was then taken as the mean

these two values respectively chosen as 1.14 cm.
15th

The specific resistance was thus calculated as (909 x 1.14): 1.11 = 934 ohm cm.

The resistivity was small enough to carry a sufficient amount of current for cathodic protection in the Let the pipeline flow. The resistivity is believed to be up to about 3500 ohm cm can be and still allows sufficient current to flow so that a reasonable cathodic protection of the

130067/0874

Pipeline is guaranteed.

Figure 1 shows an important application example of the Invention, namely in an underwater pipeline. In Figure 1, the thickness is for the sake of clarity shown enlarged. One recognizes in Figure 1 a steel pipe 2, which in the illustrated embodiment the sea bed 4 lies. In another embodiment, it can be washed into it. The tube 2 is with a Provided epoxy protective layer 6, which in turn is provided with a thin, cement-like coating 8 according to the invention is covered. A cement weighting 10 is applied over it and prevents floating of the empty one Rohres, whereby it also forms protection from ships or other objects. The heavy layer 10 is generally 5 to 15 cm thick. The thin cementitious coating 8 protects the epoxy layer 6 from Impact of aggregates in the heavy layer as well as damage during handling prior to application the heavy shift. Because the aggregates in the thin cementitious layer are fine and fed under controlled conditions, they damage the Epoxy layer or any other anti-corrosive layer is not.

130067/0874

Although the invention has been described in connection with metal tubing, it is applicable to any other metal substrate applicable, which has a corrosion protection layer to be protected. For example, the Invention for oil rigs, offshore platforms, components or other steel parts, bridges or refineries. The thickness of the coating can also be larger than described; for example, the cementitious coating can be in a thickness of up to Apply about 12 mm, although thinner coatings because of their lower weight and because of their reduced tendency to break as well as flake from the substrate to which they are applied will. If cathodic protection is necessary through the coating, increased conductivity can be achieved by using more conductive additives such as iron in the coating.

Although the thin coating has been described as cementitious, it is also possible to use coatings in which the aggregates are held together by polymers rather than cement. Such Coatings are necessarily plastic coatings with aggregates and / or embedded Fibers that provide protection for the corrosion protection

130067/0874

form a layer. However, cementitious coatings are preferred because such coatings are relative are easy to manufacture and because they behave well.

Figure 2 shows a system in a schematic representation, with which a continuous mixture to achieve a uniform cementitious coating a corrosion protection layer 6 of a pipe 2

-) 0 ^dar is. The system shown in FIG. 2 has feed funnels 12, 14 and 16 through which the dry substances, namely cement, aggregates and fibers, are poured into a common feed funnel 18. The feed hopper 18 directs these materials into a preparation chamber 20. A shaft 22 extends through the chamber 20 and also through a narrowed channel 24 and through a wet mixing chamber 26. The shaft 22 is driven by a motor 28.

In the preparation chamber 20 arms are connected to the shaft 22, the premixing of the dry substances cause. These mixed substances are fed by a metering screw which is also attached to the shaft 22 32 conveyed into the wet mixing chamber 26.

13006770874

The liquids used in the process, namely water and polymer suspension, are each of Sources 34 and 36 fed into the wet mixing chamber 26. The supply of water takes place via a line 38

upstream of a line 40 through which the Zu-5

was carried out by polymer suspension. That near the The water sprayed in at the exit of the narrowed channel 24 serves to remove the polymer, which otherwise acts like an adhesive away from the outlet of the channel 24 so as to prevent its clogging. This will also the entry into the mixing chamber 26 is not blocked.

In the mixing chamber 26, the substances are mixed by paddles 42 attached to the shaft 22 and by a

slight angular position of the paddles 42 also through the 15

Chamber 26 conveyed »The mixed substances leave the mixing chamber 26 at an outlet opening 44 and fall into a receiving funnel 46, which supplies the usual, counter-rotating brushes 48, 50, but which have fine bristles _ "Ben. The brushes 48 and bO spray the mixed ones Substances on the anti-corrosion layer 6 of the pipe 2.

The method described allows a continuous supply of the components of the thin cementitious Coating and its continuous application to a pipe. A batch mix is not required.

130067 / 087A

The continuity of the process supports a more uniform coating that is thinner for the application Coatings are of great benefit. In contrast, the thickness of the mixture fluctuates in batch processes over time and also from batch to batch, creating difficulties for achieving a uniform coating means.

hu / do
10

130067/0874

Blank page

Claims (27)

Claims %} Mechanical protective coating for a pipe coated with corrosion protection, with a thin cement-like layer applied to protect the corrosion protection layer, characterized by a cement-like material, by a fine filler in an amount of 0 to 3.5 parts by weight per part of the cement-like material, by a polymeric material in an amount of 0.05 to 0.55 parts by weight of polymeric solids per part by weight of the cementitious material; and by chopped fibers or flakes in an amount of 0 to 0.2 parts by weight per part of the cementitious 130087/0874 Material, being the thickness of the cementitious coating is between 0.5 and 5.0 mm and the cementitious coating adheres to the anti-corrosion layer. 2. Combination according to claim 1, characterized in that the amount of the filler in the range of 1.0 and 3.0 parts by weight per part of the cementitious material and the amount of the polymeric solids in the range of 0.1 to 0.3 parts by weight per part of the cementitious material, and that the amount of the fibers or flakes is in the range of 0.01 to 0.1 parts by weight per part of the cementitious material. 3. Combination according to claim 2, characterized in that the coating has a thickness of 1 to 3 mm Has. 4. Combination according to one of claims 1 to 3, characterized in that a polymeric material Acrylic polymer is. 5. Combination according to one of claims 1 to 3, characterized in that the polymeric material is a Butadiene / styrene copolymer. 130067/0874 6. Combination according to one of claims 1 to 3, characterized in that the polymeric material is a Vinyl acetate is polymeric. 7. Combination according to one of claims 1 to 3, characterized characterized in that the protective layer is an epoxy layer. H. Koinbihdl ion after rinom clnr · Λκ * ■ (> ru < In 1 hi, i, <i.i characterized in that the fibers are glass fibers. 9. Combination according to claim 1, characterized in that the filler is sand in an amount of substantially 350 parts by weight per part of the cementitious material, that the fibers are present as glass fibers in an amount of substantially 2.5 parts by weight per part of the cementitious material that the polymeric material is an acrylic polymer in the form of a latex dispersion in an amount of essentially 31 parts by weight per part of the cementitious material, the dispersion being essentially 53 % water and the remainder acrylic polymer, the cementitious material being portland cement. 130067/0874 10. Combination according to claim 9, characterized in that the thickness of the cementitious coating between 1.5 and 3 mm, the corrosion protection layer being an epoxy layer. 11. Combination according to one of claims 1 to 3, characterized characterized in that the coating has a substantial electrical conductivity when saturated with water having. 12. Metal element with an applied anti-corrosion layer and one on top of the anti-corrosion layer adhesive thin coating, which serves to protect the corrosion protection layer, thereby characterized in that the thin layer has a thickness of less than about 12 mm. 13. Combination according to claim 12, characterized in that the thickness of the thin coating is between 0.5 and 5 mm. 14. Combination according to claim 12 or 13, characterized in that the metal element is a tube. 15. Combination according to claim 12 or 13, characterized in that the metal element is a component. 130067/0874 16. Combination according to claim 12 or 13, characterized in that that the thin coating comprises: a cementitious material, a filler in an amount of from 0 to 3.5 parts by weight per part of the cementitious material, a polymeric material in an amount of from 0.05 to 0.55 parts by weight of the polymeric solids per part of the cementitious Material and chopped fibers or flakes in an amount of 0 to 0.2 parts by weight per part of the cementitious material. 17. Underwater pipeline, characterized by: a metal pipe with an applied anti-corrosion layer, with a thin coating adhering to the anti-corrosion layer for mechanical protection of the anti-corrosion layer, and by one adhering to the thin cementitious coating
Heavy layer to prevent swimming when the tube is filled with air. 18. Pipeline according to claim 17, characterized in that the thickness of the thin coating is between 0.5 and 5 mm. 19. Pipeline according to claim 17 or 18, characterized in that that the coating has a cementitious 130067/0874 term material, a fine filler in an amount of 0 to 3.5 parts by weight per part of the cementitious material and a polymeric material in an amount of 0.05 to 0.55 parts by weight of the polymer solids per part of the cementitious material as well as cut fibers or flakes in in an amount of from 0 to 0.2 parts by weight per part of the cementitious material. 20. A method for applying a heavy layer with large inclusions on a pipe provided with a corrosion protection layer, characterized in that, that a thin coating for mechanical protection of the anti-corrosion layer is applied to the anti-corrosion layer and that subsequently a heavy layer is applied over the thin coating, whereby the thin coating becomes Protection of the corrosion layer against the impact of heavy substances in the heavy layer as a buffer works. 21. The method according to claim 20, characterized in that that the thin coating is applied in a thickness of 0.5 to 5 mm. 22. The method according to claim 21, characterized in that the coating is a cementitious material, 130067/0874 a fine filler in an amount of 0 to 3.5 parts by weight per part of the cementitious material, a polymeric material in an amount from 0.05 to 0.55 parts by weight of the polymeric solids each Part of cementitious material and cut fibers or flakes in an amount from 0 to 0.2 Parts by weight per part of the cementitious material are applied. 23. A method for protecting a metal element provided with an applied anti-corrosive layer, characterized in that a thin coating is sprayed onto the metal element and this thin coating is glued to the anti-corrosion layer, the thin coating has a thickness of less than 12 mm and forms a protection for the anti-corrosion layer. 24. The method according to claim 23, characterized in that the thin coating in a thickness of 0.5 up to 5 mm is applied. 25. The method according to claim 24, characterized in that the thin coating is a cement-like material with a fine filler in an amount of 0 to 3.5 parts by weight per part of the cementitious Materials, with a polymeric material in one 130067/0874 Amount from 0.05 to 0.55 parts by weight of the polymer Solids per part of the cementitious material and with cut fibers or flakes in one Amount of 0 to 0.2 parts by weight per part of the cementitious material is applied. 26. The method according to claim 23, characterized in that the components of the thin coating are continuous fed into a mixer and mixed therein, and then the mixed Components are fed into a spray device. 27. The method according to claim 26, characterized in that the spray device has a pair of counter-rotating brushes having. 130067/0874