Patent Description:
Constructing a stone wall on location is costly, time consuming and leaves the site cluttered with piles of stone and other masonry construction materials and debris. It is also subject to weather conditions, which are unpredictable.

In order to avoid the above-mentioned problems, numerous methods for preparing prefabricated construction elements have been developed. For example, <CIT> and <CIT> disclose methods for producing reinforced construction elements, wherein natural stones are loaded on a bottom of a mould. Slits between the natural stones are filled with sand prior to installing reinforcing structures and to pouring concrete to the mould. <CIT> discloses an alternative method for producing construction elements comprising mounting an arrangement comprising stone-based coating material pre-assembled on reinforcement means onto uncured self-compacting concrete.

<CIT> discloses a mould wherein natural unworked stones are pushed into a pliable foam rubber layer on the insides of the mould.

One challenge of the methods cited above is how to avoid leaking of wet concrete on the outermost surface of the construction element. This is a particular challenge when self-compacting concrete is used. Furthermore, the methods are suitable for producing construction elements wherein only one of their outermost surfaces is coated with natural stones. For making a two-sided stone wall by using construction elements produced by the methods described above, two construction elements has to be placed back to back.

<CIT> discloses a method of making building panels adapted to form exterior enclosure of prefabricated homes. The building panels are a sandwich composed of masonry elements such as bricks, synthetic polyester mortar, reinforced wire mesh, a polymer foam, and a suitable inner facing layer, all held together by the mortar and foam.

<CIT> discloses a method for producing a concrete product with surface decorations produced by affixing a concrete non-cure material the surface of the decorative material.

<CIT> discloses a method for producing patterned paving slabs with many ornamentations and divisions wherein the top layer of the slab is made up from a group of stones, or tiles. It discloses a method for producing a construction element, the method comprising steps of.

<CIT> discloses a method of producing outer layers in the surface of concrete bodies, wherein the method comprises releasably securing particles to a flexible carrier by partially embedding the particles in a synthetic resin material while it is in a soft or liquid state.

Thus, there is still need for further methods for producing construction elements.

The following presents a simplified summary in order to provide a basic understanding of some aspects of various embodiments of the invention.

In accordance with the invention, there is provided a new method for producing a construction element as disclosed in claim <NUM>.

A number of exemplifying and non-limiting embodiments of the invention are described in accompanied dependent claims.

Various exemplifying and non-limiting embodiments of the invention and to methods of operation, together with additional objects and advantages thereof, are best understood from the following description of specific exemplifying embodiments when read in connection with the accompanying figures.

The verbs "to comprise" and "to include" are used in this document as open limitations that neither exclude nor require the existence of also unrecited features.

The exemplifying and non-limiting embodiments of the invention and their advantages are explained in greater detail below with reference to the accompanying figures, in which.

The present invention relates to a method for producing a construction element which outermost surfaces comprise coating elements such as stones. The method comprises the following steps.

For illustrative purposes the method has been divided in different stages shown in the figures.

The first stage of the method comprising steps a) - c) is shown in <FIG> as non-limiting exemplary embodiments. Accordingly, an admixture comprising self-compacting concrete is poured to the mould <NUM> to produce a concrete layer <NUM>. The admixture may consist of self-compacting concrete, or it can comprise a mixture of self-compacting concrete and one or more basic concretes. Self-compacting concrete is liquid, cohesive concrete with the ability to condense without gravity and without traditional concrete vibration (The European Guidelines for Self-Compacting Concrete. Specification, Production and Use; http://www. org/pdf/SCCGuidelinesMay2005. A particular self-compacting concrete comprises aluminate cement. The self-compacting concrete forms also a surface suitable for forming the first outermost surface of the construction element.

The concrete layer may comprise two or more concrete sublayers, but the uppermost sublayer in the mould comprises self-compacting concrete.

According to a particular embodiment the method comprises pouring to the mould prior to step c) an admixture comprising basic concrete. A basic concrete comprises general purpose cement, such as general-purpose Portland cement or general-purpose blended cement. General-purpose blended cements contain typically Portland cement and more than <NUM>% of either fly ash, ground slag, amorphous silica or a combination of these. Other components of the basic concrete are water and aggregates such as sand and crushed rocks.

According to this embodiment for producing the concrete layer <NUM> the method comprises.

Thus, the concrete layer <NUM> consists of two concrete sublayers 101a and 101b comprising basic concrete and self-compacting concrete, respectively. The use of a layer of basic concrete below a layer of self-compacting concrete is preferable when the second outermost surface of the construction element is not modified.

According to a particular embodiment recycled material is admixed the concrete of step b) and/or c). Exemplary recycled material include crushed rubber, crushed plastics, crushed burned clinker, crushed asphalt, crushed concrete and crushed bricks. Also, various crushed polymers, preferably crushed recycled polymers can be admixed to the concrete.

According to another embodiment, the concrete layer <NUM> comprises two concrete sublayers 102a, 102b, and a heat insulating means <NUM> therebetween. The concrete layers are engaged to each other with plurality of shafts, one of which is presented in <FIG> with reference number <NUM>. According to this embodiment the method comprises for producing the concrete layer <NUM>.

The first concrete layer and the second concrete layer can be made of same or different type of concrete. At least the second concrete sublayer 102b comprises self-compacting concrete.

The first outermost surface of the construction element comprises coating elements such as stones, preferably natural stones. Accordingly, slits between the coating elements cannot be avoided.

<FIG> shows an arrangement <NUM> comprising coating elements <NUM> such as stones layered on reinforcement means <NUM> and an elastic member <NUM> arranged on the layered coating elements and protruded to slits between the coating elements. In order to protrude to the slits between the coating elements, the elastic member is pressed between the layered coating elements and a non-elastic member <NUM>.

The arrangement is preferably provided in the aid of a lifting means <NUM> comprising the non-elastic member and plurality of rods adapted to be engaged to the reinforcement means. One of the rods is marked in <FIG> with reference number <NUM>. The rods can be engaged to the reinforcement means mechanically or magnetically. When magnetism is used, the lifting means includes preferably an electromagnet, and the rods and the reinforcement means are made of ferromagnetic material such as steel or iron. According to another embodiment, the magnet is a permanent magnet such as neodymium magnet.

According to an exemplary embodiment the providing of the arrangement <NUM> comprises the following steps:.

The pulling direction is shown in <FIG> also with an arrow.

According to a preferable embodiment the lifting means comprises an electromagnet and the plurality of rods and the reinforcement means are made of ferromagnetic material such as iron or steel. Accordingly, the engaging and releasing the plurality of rods from the reinforcement means is performed by switching on and off the electromagnet, respectively.

The coating elements are preferably stones, more preferably natural stones. Exemplary natural stones are marble, granite, diabase, feldspar, flintstone and basalt. A preferable natural stone is slate. Also, artificial stones made from recycled materials such as recycled glass, crushed bricks and crushed concrete can be used as coating elements.

The reinforcement means is preferably made of ferromagnetic material such as iron or steel. An exemplary reinforcement means is a typical reinforcement mesh. Another exemplary reinforcement means is a fiber, preferably steel fiber or plastic fiber.

The elastic member may be made of any elastic material such as foam plastic, silicone and Styrofoam. A particular elastic material is foam plastic.

The non-elastic member may be made of any material which is less elastic than the elastic material. Preferable non-elastic materials are steel, aluminum and iron. Further exemplary non-elastic members are plates made of plastic and plywood. According to a particular embodiment the non-elastic member is part of the lifting means. According to another particular embodiment also the elastic member is part of the lifting means.

The next stage, shown in <FIG>, comprises mounting the arrangement <NUM> on the concrete layer <NUM> using the lifting means <NUM>. The mounting is performed before the concrete has cured. The arrangement is submerged to predetermined depth d to the concrete layer by moving the lifting means in (-)-y-direction of the coordinate system <NUM>. Since the elastic member fills any slits between the layered coating elements, the uncured concrete does not leak to the first outermost surface of the construction element.

The next stage, shown in <FIG>, comprises moving the lifting means <NUM> in y-direction of the coordinate system <NUM>, releasing the rods <NUM> from the reinforcement means, and removing the elastic member from the first outermost surface. Final steps of the method include removing the construction element from the mould and cleaning the construction element e.g. by brushing and/or washing. An exemplary finishing by washing is shown in <FIG>.

The method of the present invention is applicable also for producing construction elements wherein the second outermost surface is modified. Modification of the second outermost surface, i.e. the surface which is towards the bottom of the mould can be done by one of more methods known in the art.

According to one embodiment, the concrete is poured into a mould comprising 3D patterns. When the concrete has cured and the construction element has been removed from the mould, the 3D patterns of the mould are reproduced to the second outermost surface of the construction element.

According to another embodiment a membrane, such as a raster fabric comprising the desired pattern or image and a surface retarder is placed in the mould followed by pouring of the admixture comprising self-compacting concrete. The surface retarder is a material adapted to retard hydradation reaction of the concrete. According to one embodiment an area of the membrane comprising the pattern or image comprises the surface retarder. According to another embodiment the area of the membrane not comprising the pattern or image comprises the surface retarder. After the concrete has cured and the construction element is removed from the mould, the membrane is washed away, revealing a pattern or image that results from the contrast between the smooth cement surface and the exposed aggregate surface as depressions or humps in the second outermost surface of the construction element. Color pigments or aggregates of different colors can also be used in the concrete to further enhance a pattern or design.

According to still another embodiment stones, recycled materials such as crushed glass or pigments such as iron oxide is layered to the mould prior to step a). After the concrete is cured and the construction element has been removed from the mould, the material layered on the bottom of the mould is exposed.

The final steps of the method comprise typically removing the construction element from the mould, transferring to vertical arrangement and washing the outermost surfaces with water. The washing shown in <FIG> removes any filler materials or membranes or the like from the outermost surfaces. The washing can be done e.g. by using high pressure cleaners.

The mould does not need to be straight as in the embodiments disclosed above, but also non-straight moulds such as curved, concave and convex moulds can be used. When a non-straight mould is used in the method, all materials e.g. the coating elements, non-elastic members, elastic members, admixtures comprising self-compacting concrete and the reinforcement means disclosed above can be applied. The use of non-straight mould in the method has been demonstrated by exemplary non-limiting embodiments shown in <FIG>.

<FIG> shows an embodiment wherein an admixture comprising self-compacting concrete <NUM> has been poured into a curved mould <NUM>. According to this embodiment, the mould has been covered by a curved lid <NUM>, and the admixture has been poured to the mould through ends of the mould. The pouring direction is shown in <FIG> with arrows.

After the lid <NUM> has been removed, the first outermost surface is mounted on the concrete layer.

<FIG> shows an exemplary curved arrangement <NUM> comprising coating elements <NUM> such as stones layered on reinforcement means <NUM> and an elastic member <NUM> is arranged on the layered first coating elements and protruded to the slits between the coating elements. The elastic member has been pressed between the layered coating elements and a non-elastic member <NUM>. The figure shows also the mounting of the arrangement <NUM> on the curved concrete layer <NUM> using the lifting means <NUM>. The mounting is performed before the concrete has cured. The arrangement is submerged to predetermined depth to the concrete layer by moving the lifting means in (-)-y-direction of the coordinate arrangement <NUM>. Since the elastic member fills any slits between the layered coating elements, the uncured concrete does not leak to the first outermost surface of the construction element.

<FIG> shows another curved arrangement <NUM> comprising the coating elements <NUM> such as stones layered on reinforcement means <NUM> and an elastic member <NUM> arranged on the layered coating elements and protruded to the slits between the coating elements. The elastic member has been pressed between the layered coating elements and a non-elastic member <NUM>, and the arrangement has been mounted on a curved concrete layer <NUM>.

According to a non-claimed embodiment the present disclosure concerns an arrangement <NUM> comprising.

The coating elements of the arrangement are preferably stones, more preferably natural stones. Exemplary natural stones are marble, granite, diabase, feldspar, flintstone and basalt. A preferable natural stone is slate. Also, artificial stones made from recycled materials such as recycled glass, crushed bricks and crushed concrete can be used as coating elements.

The reinforcement means of the arrangement is preferably made of ferromagnetic material such as iron or steel. An exemplary reinforcement means is a typical reinforcement mesh. Another exemplary reinforcement means is a fiber, preferably steel fiber or plastic fiber.

The elastic member of the arrangement may be made of any elastic material such as foam plastic, silicone and Styrofoam. A particular elastic material is foam plastic. The arrangement can be straight such as <NUM>, or non-straight such as <NUM> or <NUM>. The use of an arrangement in the method has advantages. The elastic member of the arrangement prevents the self-compacting concrete from leaking to the outermost surface of the construction element during assembly. Furthermore, it prevents the coating elements from moving on the reinstatement means during transportation, mounting, vibrating and the like. This is important in particular when producing non-straight, such as curved, concave and convex construction elements. Still another advantage of the use of the arrangements is that they do not need to be assembled in the same site as the entire construction element. According to an exemplary embodiment plurality of arrangements are prepared on a quarry, stacked on each other, bundled, and transported to the final production site, where the bundles are removed, and the arrangements are used one by one in the method for producing construction elements as described above.

According to still another non-claimed embodiment the present disclosure concerns a lifting means suitable for use in the method. An exemplary lifting means is shown in <FIG>, and its exemplary encaging means are shown in <FIG>.

The lifting means <NUM> comprises plurality of rods, two of them are marked with reference numbers 911a and 911b. The rods are adapted to be engaged to the reinforcement means as described above. The lifting means comprises typically also means adapted to move the rods in ± y-direction of the coordinate system <NUM>. The movement can be performed e.g. by threads 913a or by means 913b adapted to operate with pressurized gas or hydraulics.

According to a preferable embodiment the rods 1011a and the reinforcement means <NUM> is made of ferromagnetic material such as steel or metal, and the lifting means comprises an electromagnet. The electromagnet is not shown in the figure. Thus, the engaging and releasing is performed by switching on and off the electromagnet. An exemplary engaging means of this type is shown in figure 10A. Another exemplary magnet is a neodymium magnet.

According to another embodiment the rods 1011b, 1011c are engaged to the reinforcement means <NUM> mechanically. An exemplary mechanical engaging means is shown in figure 10B.

According to a preferable non-claimed embodiment the lifting means comprises means for adjusting how deeply the arrangement is submerged to the concrete layer. The means is exemplified in <FIG> by the numbered markings in the rod 1011a.

The finished construction elements can be used not only as vertical structures as walls pillars and fences but also in various horizontal structures such as stairs, walkways and driveways.

Claim 1:
A method for producing a construction element, the method comprising the steps of
a) providing a mould (<NUM>, <NUM>, <NUM>),
b) optionally pouring to the mould an admixture comprising basic concrete,
c) pouring to the mould an admixture comprising self-compacting concrete to produce a concrete layer (<NUM>, <NUM>, <NUM>, <NUM>) wherein
d) for forming a first outermost surface of the construction element
∘ providing an arrangement (<NUM>, <NUM>, <NUM>) comprising
• coating elements (<NUM>, <NUM>, <NUM>) such as stones layered on reinforcement means (<NUM>, <NUM>, <NUM>),
• an elastic member (<NUM>, <NUM>, <NUM>) arranged on the layered coating elements and protruded into slits between the coating elements,
∘ mounting the arrangement on the concrete layer, and
∘ removing the elastic member.