The present invention relates to a cement-based material comprising ordi- nary and/or high strength concrete materials, and it further relates to a method of applying this material to a surface.

BACKGROUND OF THE INVENTION PCT/DK2009/050090 INSULATING HIGH STRENGTH CONCRETE MATERIAL discloses a high strength concrete with supplementary bodies such as nanocomposite insulation glass spheres or other ceramic spheres, glass bubbles or Leca™ as well as polymeric materials giving low thermal conductivity and low density. However, the invention does not disclose the most efficient combination of sufficiently low thermal conductivity, strength and density (weight) for insulation of pipelines in general.

Aspen Aerogels, Inc. discloses in a brochure on the web-side a nano aerogel blanket material (Spaceloft™ 6250) which has a very low thermal conductivity. The blankets are used for insulating various industrial equipment such as hot or cold pipelines, towers and tanks. When insulating pipelines, the blankets are wrapped around the pipes by mechanical means followed by coverage of a steel casing, due to lack of bonding capability for the aerogel blankets. This pipe design category is called pipe in pipe and suffers from substantial assembly cost.

Three insulation concepts are typically used for the present offshore pipelines: 1) For more than 200 meters water depth:

a. Pipe in pipe b. Syntactic foam, solid PUR and other high strength insulation materials

2) Single pipe for laying at depths greater than 200 meters

3) Single pipe for laying at depths less than 200 meters

Single pipes are described as pre-insulated pipes for district heating, comprising a medium conveying pipe, an insulating material surrounding at least a part of the length of the medium conveying pipe and a jacket pipe at least partly surrounding the insulating material. In the alternative, the single pipe may be provided with an insulating material surrounding at least a part of the length of the medium conveying pipe, but without a jacket pipe surrounding the insulating material.

Such pre-insulated pipes are mostly used for any media at a temperature between -200 °C and +315 °C in order to provide insulation of different media when applied on-shore. However, e.g. for single-user offshore pipelines, in order to ensure flow assurance, the media temperature is usually restricted to an application temperature between -48 °C and +160 °C depending on the water depth and the required insulation thickness .

During the years much effort has been invested in designing new pre-insulated pipes having increased initial as well as long term insulation properties at higher temperatures, and at the same time keeping the production, laying and material costs at a low level in order to provide the lowest possi- ble operating costs for the owner of the flow line system.

SUMMARY OF THE INVENTION

The object of this invention is to overcome the drawbacks discussed above. This is achieved by providing a cement-based material comprising an ordinary and/or a high strength concrete material said cement-based material further comprising a nano-aerogel insulating tape material. This blend of 2 different materials, of which one (called component I) is an ordinary and/or a high strength concrete material such as the materials manufactured by the company Densit ApS of Denmark, and the other material (called component II) is a nano-aerogel insulation tape which is applied in such a way, that it is embedded into the first material (I), forms an insu- lating ordinary and/or a high strength concrete material with very low thermal conductivity.

In this respect, the concrete formulation (component I) may be described as a cement-based material comprising a coherent matrix, the matrix com- prising

A) homogeneously arranged inorganic solid particles of a size of from about 50 A to about 0.5 μ, or a coherent structure formed from such homogeneously arranged particles, and

B) densely packed solid particles having a size of the order of 0.5 - 100 μ and being at least one order of magnitude larger than the respective particles stated under A), or a coherent structure formed from such densely packed particles, the particles A or the coherent structure formed therefrom being homogeneously distributed in the void volume between the particles B, and optionally

C) additional bodies of a size which is at least one order of magnitude larger than the particles A in respect to at least one dimension of the additional bodies.

In cases where concrete of low strength is sufficient, high strength concrete materials are not necessary, and ordinary concrete materials may be used. The typical ordinary and/or high strength concrete materials may be formulated with a number of different additives in order to achieve significant strength improvements over traditional concrete formulations. By adding supplementary nanocomposite insulating materials to ordinary and/or high strength concrete materials, significant insulating properties may be achieved, while still achieving mechanical properties similar to typical concrete formulations, however with significant insulating properties as well as weight and price reductions. High strength concrete materials such as Densit™ ultra high strength concrete materials are mostly used for applications related to floor, pavement as well as offshore applications, where extreme strength and mechanical properties out-perform the usual concrete formulations. Due to these properties, materials such as Densit™ ultra high strength concrete materials have gained a significant marketplace within its typical field of applications.

However, in cases where further low thermal conductivity properties are needed, other materials have to be added to the insulating ordinary and/or high strength concrete material in order to reduce the thermal conductivity as well as to maintain density and strength. Nano-aerogel insulation tape is such a material.

Nano-aerogel insulation tape (component II) is a material which could be produced from the Aspen Aerogel™ product portfolio. The aerogel material is among the insulation materials that have the lowest possible thermal conductivity of all materials. The thermal conductivity is less than 20 mW/mK (-200 to +600 °C) and lesser than lOmW/mK (-200 to +50 °C).

However, the aerogel material has reduced compression strength related to its tape thickness, and the material has a crushing strength of minimum 0.03 MPa. at 10% or less compression. The nano-aerogel insulating tape material has a poor ability to bond to other materials. According to the invention, ordinary and/or high strength insulation concrete material may be blended along with the nano-insulation aerogel applied as a tape and applied in different configurations. This opens a whole new range of products and applications. Applying nano-aerogel insulation tape with the ordinary and/or high strength nano composite concrete composi- tion causes significant changes of the concrete properties, where the new nano composite-concrete composition has very low thermal conductivity at a high overall system density, however still having a strength that is comparable to traditional concrete. The material according to the invention combines the super insulation properties of the nano-aerogel insulation material embedded into the ordinary and/or high strength concrete material which has been, or could be premixed with other nanocomposite insulating materials. The material according to the invention has several fields of application where significant achievements may be reached. The achievements are all related to the combination of insulation performance along with structural and physical strength of the material. The following platforms are: 1. Insulation of LNG lines above ground (LNG - lines for liquid natural gas -163 °C)

2. Insulation of offshore LNG pipelines

3. Insulation of offshore pipelines in order to ensure flow assurance

4. Insulation of onshore pipelines e.g. in order to ensure terrorism protection

5. Insulation of pipes in general 6. High strength lightweight structural elements

7. Fire protection

The basis of all the applications is the formulation of ordinary and/or high strength concrete such as the materials provided by the company Densit ApS of Denmark, and blended further with a supplementary insulating material such as glass spheres. The significance of this insulating material is the size and insulation capability, namely various types of microspheres, described as nano glass bubbles that interact with the composition of the ordinary and/or high strength concrete material, and such that theses microspheres are imbedded into the concrete material. The more of the insulating microsphere material, the less weight and the greater the overall insulation capability of the total matrix is; the physical properties, especially the strength, are moreover reduced but still comparable to concrete formu- lations. Another important feature is the possibility of exactly adjusting the density of the ordinary and/or high strength concrete with insulating material to other desired properties.

Concrete matrices with added insulating materials are not typically used in the market due to the lack of comparable performance related to other insulation concepts, like foamed polyurethane (PUR) for district heating pipes, mineral wool for building applications and other industrial insulation concepts. The major advantage of the present invention is the fact that two different types of bonding, determined by the nature of the insulating material, are clearly effective between the added insulating materials and the ordinary and/or high strength concrete materials. The effect of this is an insulating material made from materials comparable to concrete (like minerals) and insulating materials made from polymeric materials as a group, which ensures the major advantage that the concrete material acts like a reinforced jacket.

Insulating materials comparable to concrete and high strength concrete materials will have the ability to interface on molecular basis. Therefore the insulating materials make a contribution to the strength of the concrete matrix that outperforms typical concrete blends and further has substantially improved insulating properties. Other materials than glass spheres, Leca™, nano-tubes and other inorganic materials can be identified.

The significance of the bonding of the other "type" of insulating materials, if these are based on polymeric materials, is more related to the encapsulation of the insulating particles into the ordinary and/or high strength concrete material, where the insulating material itself does not make a contri- bution to strength, however, when blended with the right particle size and volume, the ordinary and/or high strength concrete materials may be produced and tailored to the specific application mentioned earlier. Typical insulating polymeric materials could be EPS, PUR, foamed PP or other foamed insulating material.

However, specifically the use of glass spheres of nano size improves the processing performance, as the high strength concrete material blended with the insulating nano glass spheres in the right ratio makes the blend sprayable and later on applicable in a hardened state. When applied in a spray formulation, allowing this blend (component I) to be sprayed on to the pipe, it is possible simultaneously to apply the nano-aerogel insulation tape (component II) in different compositions. In this way, a sufficient amount of the nano-aerogel tape is encapsulated until the final layer of nano-compos- ite high strength materials has been applied. The finished insulation system will then constitute a complete system of insulating high strength nano- composite concrete material. When the component I is applied as a solid material, the different layers of the tape (component II) and the component I, respectively, will have to be applied in each of these production stages. However, with the right production equipment, these production stages may be combined to one automated continuous production.

A major advantage is also present for the composition according to the invention, when applied to onshore as well as sub-sea-level pipelines. Insulation of pipelines may be provided for one or more different reasons: 1) Insulation of offshore pipelines in order to ensure a certain flow rate

2) Insulation of onshore pipelines e.g. in order to ensure terrorism protection

3) Insulation of pipelines in general, e.g. for ensuring a certain temperature, be it cooling, hot medias as well as cryogenic conditions

The significance of offshore pipelines is the nature of the fluid flowing inside the pipeline. Waxes and other fluid components need to remain above a certain temperature throughout the length of the pipeline to reduce the fric- tional behaviour of the pipe wall as well as to avoid clogging of the pipeline. The essential parameters for offshore pipelines are governed by the needed insulation in order to assure that the fluid, being carried, maintains its properties until further processing is possible. At the same time, the size of the pipe diameter and the water depth determine the weight of the coating necessary in order to maintain the balance between the necessary buoyancy and weight that will keep the pipeline in position on the bottom of the sea.

Other parameters are the method of laying the pipes, which is determined by the total weight, the outer diameter of the pipeline, as well as the type of insulation method used for the pipeline. Usually, the deeper the pipeline is to be laid, the higher the hydrostatic pressure and several other parameters like insulation requirement and density which have to be incorporated into the total evaluation of the best fit for the complete installation of the pipeline. The feasibility study, including price issues, depends greatly on the laying method. Four typical laying methods are identified as:

1) J-lay

The principle of the laying method applies to deep sea pipelines laid on water depths deeper than typically 500-1500 meters with a laying speed of 1 to 3 km/day

2) S-lay

The principle of the laying method typically applies to pipelines laid down to 0-1500 meter with a laying speed between 5 and 7 km/day depending on which of the 3 known insulation concepts is being used

3) Reeling

The principle of the laying method applies to pipelines laid on all water depths, however not all types of insulation concepts are well suited for this method, as the strength of the insulation layer determines the suitability

4) Towing

The principle of the laying method is applied after the pipeline has been welded and joined on-shore, the pipeline is towed to the site and lowered to its potion on the sea bed.

Alternatively, pipes manufactured of a cement-based material according to the invention may be used for district heating systems.

Therefore an object of the present invention may also be to provide a pre- insulated pipe of the kind mentioned above, simplified by having sufficient insulation properties and at the same time having the sufficient weight to perform as a weight coating.

With the present invention, a one layer solution with the embedded nano- aerogel insulation tape not only provides an impermeable insulation coating, it also provides simplified joint solutions as well as improved insulation properties independent of the water depth, as the impact from the outer pressure is related to the strength of the concrete material and not the polymeric matrix, which is usually the designing parameter for pre-insulated pipes according to the described single pipe system. As no temperature dependant shrinkage occurs in connection with the insulation concept according to the invention, long term insulation properties are thereby maintained, as no creep and hysteresis phenomenon occur in the different concrete blend formulations.

Applying the present invention to a pre-insulated pipe, where the pipe is characterized in that it comprises a layer of high strength concrete material (component I) blended with polymeric materials in which component II is embedded, at least partly surrounding the flow line being impermeable to water and/or water vapour, results in significantly improved barrier properties than traditional jacket materials like PE, e.g. for resistance against cell gas diffusion of oxygen, nitrogen and carbon dioxide.

When producing traditional district heating pipes, it is very common to use foaming agents such as cyclopentane for producing polymeric foam from e.g. polyurethane and styrene foam. In the finished foam, the cell gas composition will contain a significant amount of carbon dioxide and pentane, where the carbon dioxide is primarily generated during the foaming reaction process. By the present invention it is ensured that water vapour is not allowed to penetrate into any of the polymeric insulating materials, and that the high strength concrete material will prevent any other cell gas compositions from being exchanged with the ambient oxygen or nitrogen and from being built up inside the insulating materials.

The effect of the present invention will be significantly advantageous as the layer(s) of nano-aerogel insulation tape material has/have a resistance against diffusion of oxygen and carbon dioxide, as these nanocells are closed as well as show outstanding water vapour resistance measured according to any accepted test methods such as ASTM F-1249-90: 38°C, 90%RF, ASTM D-3985-81 , 23°C, 0%RF and DIN 53380 part 1 1982, 23°C, 0%RF. As aerogels cannot be produced completely pure, some insignificant moisture may penetrate into the nano-meter scale voids, which are incorporated in an amorphous silica aerogel or in a structure of reinforced fibres with a hydrophobic nature that carries the silica aerogel. With the present invention, a multi-layer solution with mineral materials embedded in the different types of concrete and layers of nano-aerogel tape insulation not only provides an impermeable insulation coating. It also provides simplified joint solutions as well as insulation properties independent of the water depth, as the impact from the hydrogenic pressure is related to the strength of the concrete material. The nature of the mineral materials such as ceramic spheres, glass bubbles, Leca™ or other spheres, improves the mechanical stability and strength of the concrete material.

The crushing strength of high strength concrete blends easily reaches a level of 5 to 50 MPa depending on the blend, which enhances the application parameters for deep-sea pipe laying. The tailored insulation blend of the two components I and II is the designing parameter for the strength, the weight (density) and/or the insulating properties e.g. of the pipes. Such application parameters are just as valid as for blends not only to achieve the required insulation, but also to provide the right density to accommodate necessary weight coating.

These features are obtained by the pre-insulated pipe according to the invention, where the pipe is characterized as a layer of material according to claim 1 at least partly surrounding the coating of the flow-line, having the suitable bonding strength to the typical FBE (Fusion Bonded Epoxy) or other coating material enabling the complete insulation structure to be integrated with the pipeline material. Further, the insulating material according to the invention provides a layer of material which is impermeable to water and/or water vapour and has significantly improved barrier properties com- pared to PE, with regard to resistance against diffusion of oxygen and carbon dioxide.

Another major advantage is incombustible properties of the blend of component I and component II, ensuring application of the material in very fire sensitive areas. The insulating material does neither produce any toxic gases nor any sulphurous or other acid like material when exposed to fires of all sorts, inclusive of jet fires, enabling the invention to be applied in areas where most other insulating concepts are not appropriate. Further, an enhanced processing performance may be achieved, producing different types of insulation layers, specifically obtained when using glass- spheres as blended with the high strength concrete in the right ratio; this makes the blend sprayable and allows the blend to be combined with the nano-aerogel tape in different compositions. The nano-aerogel insulation tape material (component II) may have a varying width, typically 10 to 150 mm, and a varying thickness, typically from 0.8 to 10 mm thick. According to the invention, nano-aerogel insulation tape material is applied on the basis of different criteria. These criteria would or could be:

1. Insulation capability related to needed strength

2. Needed insulation related to the needed weight

3. Needed strength related to applicable water depth

4. Needed flexibility during pipe laying related to the above parameters

All the above criteria may, but need not, also be related to price.

Another effect of the invention is that the sensitivity to cracks is very low in the outer insulation layer during bending of the flow line e.g. during pipe laying, and does not cause any hazard to the insulation, as the insulating material is embedded in the concrete material and is thereby unaffected by the water filled environment created during the cracking condition. When the pipe is straightening out on the bottom of the sea, the magnitude of the cracks is insignificant as the cracks are expected to close when the pipeline is straightened out.

Reeling is a laying method which applies to pipelines laid on all water depths, however not all types of insulation concepts are well suited for this method, as the strength of the insulation layer determines the suitability. To improve the flexibility of the pipe and to avoid destruction of the insulating layer, the insulation layer may be cut in a pitching manner as the pipe is rotated. To cover the insulating material, flexible polymeric materials or rubber materials may be winded around the pipe and vulcanized. Despite the fact that nano-aerogel tape insulation material absorbs water and has some compressibility, it does not change the insulating performance, as the water absorption and compressibility apply only to the casing material that encapsulates the nano particles. When nano-aerogel tape in- sulation is applied in very thin layers with concrete compositions in between, the compression strength is usually increased.

One way of applying the invention is related to a multilayered structure, where the concrete (component I) with or without supplementary insulating bodies, according to the invention, is sprayed in a layer as thin as possible on to the surface to be coated. Then a layer of the insulating nano-aerogel tape (component II) is applied, and the concrete component I is then sprayed on to the insulating nano-aerogel tape material. In this way the concrete material serves the purpose of bonding the tape layers to the sur- face and to each other. The bonding effect may be improved by applying an insulating nano-aerogel perforated tape material which joins the layers of concrete on both sides of the tape. The finishing and last layer of concrete may be made from a kind of concrete that is suitable for adjusting either the weight, or is a protective layer of either ordinary, high strength or insulating type concrete. The nano-aerogel tape insulation material is configured in width and thickness suitable for the production of different products. When applying the nano-aerogel tape insulation material, said material may be slanted over each other as the tape is progressively applied to the surface. The slanted angle is determined by the tape configuration. The bonding effect may be further improved by leaving concrete in the overlapping area of the slanted nano-aerogel tape material.

Another way of applying the invention is related to a multilayered structure, where each layer is a straight layer of material, of concrete materials and nano-aerogel tape material, respectively. The concrete material may be ordinary and/or high strength concrete blended with insulating materials. The nano-earogel tape insulation material may be made from different types of aerogel tape, e.g. a perforated tape material, and applied in different thickness and number of layers on top of each other. However, the terminating layer is always a layer of concrete, as mentioned in the preceding paragraph.

A third way of applying the invention is a combination of the other two ways, where the layers of nano-aerogel tape insulating materials may be applied in a slanted manner and in a straight manner, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross-sectional view of a piece of a pipe, which has been provided with insulating tape material in a slanted way in a multistructure layer of the cement-based material according to the invention.

Fig. 2 is a cross-sectional view similar to fig. 1 , but with insulating tape material applied in a straight layer. Fig. 1 shows a pipe 1 provided with a multistructure layer. The layer 2 is a concrete layer which has been sprayed on to the surface of the pipe. The layer has been made sprayable e.g. by adding nano glass-spheres to the concrete. The layer 3 is a layer of nano-aerogel insulating tape material, which is applied in a slanted way, overlapping the neighbouring tape. The slanted angel is determined by the tape configuration. The layer 4 is a concrete layer similar to the layer 2. The layer 5 is a layer of nano-aerogel insulating tape applied in a way similar to layer 3. The layer 6 is a concrete layer similar to layer 2. The insulating tape material may be with or without perforations. Fig. 2 shows a pipe 1 provided with a multistructure layer similar to the one applied to the pipe in fig. 1. The layers 3 and 5 of nano-aerogel insulating tape are applied in a straight layer, where the neighbouring tape materials are placed side by side. The insulating tape materials may be with or with- out perforations.