FI110494B - A method of making facade material - Google Patents

Description

, 110494

BACKGROUND OF THE INVENTION The present invention relates to a facade material intended for combined natural stone / concrete slab. Such consists of a facade layer of natural stone and a concrete layer abutting the natural stone layer.

In particular, the invention relates to a method according to the preamble of claim 1 for the production of combined natural stone / concrete slabs. According to the method, concrete pulp is cast on one side of the natural stone slab, which thereby constitutes the casting material of the concrete pulp, the concrete pulp 10 is, if desired, provided with reinforcement, and then the concrete pulp is solidified and hardened.

The following describes ways of making natural stone tiles, especially natural stone facade tiles, better water repellent.

15 So far, marble facades have used compact natural stone tiles. The disadvantage of such tiles is that within a relatively short period of time in outdoor conditions they bend and weather. It is also known to produce combined natural stone / concrete slabs, which contain a first, outer layer, which consists of natural stone, and a second, inner layer, which consists of concrete. As an example of the prior art, one can mention the two-layer plates ·. No. 4,242,026, CH 486,968, US 3,605,366, DE 4,141,414 and SE • 129141.

• · · · • · ·· • · ··· The lack of adhesion between the two layers, however, posed a major problem ····: for the known combination plates.

• · ·::: 25

The object of the invention is to remedy the disadvantages that relate to the prior art and to provide a combined natural stone / concrete slab of a completely new type, ··· $ · • · · * which can be used as facade material.

The invention is based on the idea that natural stone, e.g. marble, joined by a *: reinforced concrete slab to a facade element. According to the invention, it is thereby forbidden: - the natural stone plate, so that the surface on which the concrete mass of the concrete plate is cast becomes convex and has a bend of about 0.1 - 10 mm per meter. As the concrete mass shrinks as it solidifies and hardens, the natural stone plate is straightened by the concrete attached to the natural stone plate during the solidification and curing process. In order to obtain sufficient adhesion of the concrete to the natural stone, the surface of the natural stone before casting should be water-repellent, preferably by treatment with a polymeric resin. In addition, it is advantageous if the concrete mass contains a proportion of crushed natural stone, which increases the binding of water.

The use of crushed natural stone is known per se by "Rakentajain Kalenteri" 1987, p. 528, lines 24-26, and impregnation of natural stone layers with polymerized resin by DE 3 333 276. However, it is not known from before that in in this context, pre-cast the natural stone slab before casting the concrete pulp.

More specifically, the method according to the invention is characterized by what is stated in the characterizing part of claim 1.

By the invention there are considerable advantages. As mentioned above, the curved natural stone plate is straightened out of the concrete during the solidification and curing process, whereby the stress is absorbed by the reinforcements of the concrete. Continued (undesirable) bending of the natural stone plate is prevented both by the concrete and its reinforcement, thereby avoiding the bends in the natural stone, e.g. marmom, which otherwise leads to disintegration.

The life of marble facades can thus be significantly extended. Yid adhesion between. · 4 20 natural stone and concrete are excellent; tests have shown that the slab breaks in the concrete layer rather than in the interface between the natural slab and the concrete. The natural stone crusher in the ···· concrete mass acts as a water reservoir, which means that a controlled solidification of the concrete mass is achieved while the water is prevented from migrating out of the · · · ·: natural stone plate, which would impair the attachment.

In the following, the invention and its advantages will be examined in detail from the following: · Description of process and with reference to the accompanying drawings, wherein:

Ml • ·

Figure 1 shows in perspective view a composite natural stone / concrete slab according to the invention,: *. · Where the natural stone is made of marble, ··· Figure 2 shows the plate in front view,: *: *: Figure 3 shows the section 1-1,

Figure 4 shows the section 2-2,

Figure 5 shows the sections A-A and B-B, 110494 3 In the figures, the following reference numerals are used: 1 composite plate 2 marble layers 5 3 concrete layers 4 concrete projections 5 suspension rack 6 suspension bracket 7 reinforcing level 10 8 locking 9 in the locking recessed connecting rack 10 U-shaped connecting rail 11

The composite plate 1, shown in perspective view of Figure 1, figure of Figure 2 and sectional view of Figures 3 and 4, consists of a natural stone plate 2 and a concrete plate 3 with recessed suspension rods 5 recessed into the concrete on each edge of the plate. The concrete projections 4 cover connecting members 9,10 which reinforce the construction above the suspension points 5 and at the lower edge of the plate. The joints provide a mechanical attachment of the natural stone slab as a complement to the contact attachment between the concrete and the slab, which rises during casting.

Figure 5 shows in more detail the structure of the plate at the concrete projections 4 (section A-A) respectively.

*: 25 at the suspension rack 5 (section B-B). The reinforcement 7 is crossed in the middle of the concrete layer 3, so that a reinforcement net is obtained, which strengthens the tensile strength of the concrete layer in: · longitudinal and longitudinal joints. A suitable diameter of the reinforcing bar is 2 - 6 mm, e.g. about 4 mm, * · * 'for a slab with a 10 mm marble layer and a 30 mm concrete layer. As shown in figure 4, double reinforcement can be used to make the structure even stronger.

The natural stone plate 2 is provided with a longitudinal groove 8. At the edge, at the concrete projection 4, a U-shaped connecting sheath 9, which is embedded under the transverse reinforcing shaft. ·: · Is bent two gangs, so that it first runs over the longitudinal reinforcing shaft and then. 1. 'bends in with the bottom of the U engaging in the latch 8. A second, flat U-shaped bandage' '. The bonding iron is fitted into the concrete layer with the bottom of the U-molded into the concrete projection 4. The bonding iron is suitably made of spring racks.

• »i · • M * 110494 4

The section BB shows the attachment of a suspension number 5 in the concrete layer 3 between the reinforcing nets 7. The suspension frame consists of plate rods, whose end in profile is bent to a Z, so that it first abuts against the edge of the concrete plate and extends against the wall on which the plate should be suspended and thereafter form a fastening edge 5 'parallel to the wall (see Fig. 1). A helix 11 is formed at the fixed edge 5 '.

The plate 1 is suspended on suspension brackets 6 such as e.g. may be shaped as indicated in Figure 1.1 in this case, the plate has been suspended in place of a solid marble plate on its old bracket, of which some of an old stainless steel burst is left, which will abut against the back of the concrete layer. The suspension bracket has an upright edge, which grips the fixed edge of the suspension rack. The suspension frame is thereby inserted into a cut at the edge, so that the edge will abut close to the bracket. The fixed edge can be attached to the bracket with a screw.

In order to prepare a plate mentioned above, a natural stone plate consisting of a natural stone type suitable for use in facade material is used. Such natural stones are, for example. the oxide and hydroxide minerals and the carbonate minerals. Examples of suitable natural stones include marble and other calcium- and calcium-magnesium carbonate-based minerals (e.g., limestone) and granite, quartz, and quartzite. labradorite and other similar silicate-based minerals. Marble or granite is preferably used.

• «,» «· *«

According to the invention, the natural stone plate is subjected to a bend of about 1 - 4 mm / m. The bend is counted as the distance from a point in the center of the plate to an imaginary straight line joining the edges of the plate. Preferably, the desired bending is achieved by sandblasting the inside of the natural stone slab. When sandblasting, sand of type OK 50 - 90, preferably OK 70 containing nickel slag, is preferably used. The pressure generally rises to about 5-20 kg / cm 2, preferably about 10 -12 kg / cm 2. The plate can also be bent in other ways, e.g.

♦ ·; * * * mechanically by applying pressure to the center of the plate.

·: ··· 30 :. ·. As a result of the sand blasting, the plate bends, so that it bends out in the middle. At • · M · * ..... sandblasting a marble surface of the soft portions are removed, leaving a dimpled surface, 5 110 494 which provides a large vidfastningsarea for the concrete mass. The area of the marble tile usually increases by about 50 - 500%. Granite and quartz slabs also bend in similar ways and give a larger surface by sand blasting.

5 After sandblasting, the surface is polished free of abrasive flour. In order to obtain a good adhesion of the concrete mass, the plate is then treated, so that it does not substantially absorb water from the concrete mass. This can be achieved by saturating the plate with water, so that it does not absorb more water from the concrete mass, which would weaken the strength of the natural stone / concrete joint. However, in a particularly preferred embodiment, this is achieved by the application of a polymer which forms a water-repellent surface to the natural stone. The amount of the polymer is usually about 0.00001 -1%, preferably about 0.00005 - 0.1%, especially about 0.0001 -0.01% of the weight of the natural stone layer. Typically, 1 - 100 g, preferably about 5 - 50 g, of polymer per square meter of natural stone are applied. In connection with the coating, the polymer is also absorbed into the natural stone's pores and cracks and helps to make the stone's facade surface better water repellent. This way of improving natural stone water repellency can also be generally applied to those who raised natural stone applications, ie. by coating at least one side of a piece of natural stone with a solution of a polymer which is sucked up into the pores and cracks of the stone. If necessary, additional cracks or shrimp can be made in the sieve to make the suction more effective.

. Suitable polymers for the above purposes are synthetic resins which can be used e.g. in the form of latexes or other dispersions. After treatment, even • φ • * · is removed. ·. ·. total overflow amounts to prevent the formation of polymeric intermediate layers between the natural stone and the concrete, which would also substantially reduce the pour strength. Examples of suitable preparations include dispersions containing polymer and copolymers of the following substances: acrylic acid, acrylic acid esters, acrylonitrile, vinyl acetate, butadiene and: styrene. The dispersions can be used as such or in combination with suitable natural binders, such as modified starch and carboxymethyl cellulose. Products such as: “* are used as“ primers ”before coating, surface treatment, painting and construction · · ·: 30 work is suitable.

• When the convex surface is dry, concrete is poured onto it. The concrete mass, which, after solidifying, constitutes the second part of the composite element, contains a hydraulic binder (i.e., a binder which cures upon addition of water), fillers and suitable additives. The binder may e.g. consist of Portland, Rapid or slag cement, preferring to use cement with high hall strength, such as white cement. The fineness of the cement is preferably up to 100 - 800 m2 / g, preferably 200 - 600 m2 / g. The filler of the concrete pulp can be sand, polymeric material and fiber material. Preferably sand with grain sizes up to 3 mm is used. According to a preferred embodiment, sand is used by two different rough sizes. In addition to sand, the concrete mass can also contain fibrous fillers, such as natural and synthetic fibers. Examples include cellulose-based fibers, glass fibers, carbon fibers and plastic fibers.

In addition to the aforementioned conventional fillers, a component that binds water is also included in the concrete mass. This component is preferably constituted of crushed natural stone having a grain size of about 0.5-15 mm, preferably about 2-10 mm, in particular about 3-5 mm. The crusher 15 may be derived from some of the natural stone materials mentioned above. Commonly used marble, limestone, granite or quartz crusher. By saturating the crusher with water before or in connection with the casting of the pulp, a water reservoir is obtained in the solidifying pulp, which helps to increase the adhesion of the concrete.

Depending on the cement used and on the fillers, the concrete mass may contain known additives such as floatants, accelerators or decelerators, pore-forming agents for frost resistance and corrosion protection agents.

* 1 1

Starting from the above, the concrete layer generally contains from 0.1 to 25% by weight of hydraulic binder, from 0.1 to 25% by weight of filler and from 0.1 to 99.8% by weight of crushed natural stone.

In particular, the concrete mass used for casting the concrete layer consists of the following components: 1 - 5 parts by weight of cement · · 1 · 10 parts by weight of ordinary mineral filler containing:. · 1 -15 parts by weight of natural stone crusher t · # · · · 0.5 - 3 parts by weight of water 110494 7

The amount of water is usually about 0.5 - 0.55 times the amount of cement and the total amount of filler (including natural stone crushed) is up to 4-6 times the amount of cement.

In connection with the casting, the concrete layer is preferably provided with the aforementioned reinforcement, which absorbs the tensile stresses which are directed towards the plate, as well as with the above-mentioned connection and suspension figures.

After casting, the composite plate is allowed to dry and solidify. The bending of the natural stone layer then likes to go back as the concrete dries and thereby shrinks. The bending stress is transferred to the concrete layer and absorbed by the reinforcement.

Example 15 A composite facade element according to the invention was made of an approximately 10 mm thick marble plate, which had a polished and an unpolished surface. The unpolarized surface of the marble plate was sand blasted first, so that a bend of about 2 mm / µm of the plate occurred and the plate assumed a callous shape. The sandblasted surface was cleaned of dust and dust. was thinly coated with a synthetic polymer resin in the form of an aqueous solution (latex). The duct was approximately 1.5 dl of latex per square meter. In the example, an acrylic dispersion was used, such as ground ···· «. is under the name RESCON CP by Resco, Norway. The purpose of the treatment is to make the natural stone layer water repellent. The overflow primer solution was removed and • · «• · ·. ·. · Then the surface was allowed to dry.

• # 25 After coating with the polymer resin, the marble slab was immersed in a mold lined with a plastic film, the coated surface turned upside down and used as a casting base for a concrete pulp mixed according to the following recipe: ··· 9 · # * 9 • 9 1.2 kg white cement M · ί * ·· 30 1.8 kg of sand 1 0.85 kg of sand2 • M · •; * \ 3.3 kg of marble crusher, 110494 8 0.66 kg of water

The concrete mass was poured onto the marble slab so that it formed a layer of about 10 mm thick.

Thereafter, the reinforcing points and the joining sites were put in place and then an additional concrete mass was poured onto the reinforcement, whereby a total of about 30 mm thick concrete layer was obtained. The mass vibrated. The casting was then covered with plastic wrap and the concrete was kept moist for about 2 weeks. When the concrete had dried and shrunk, the bend of the Marmite plate had returned by over 50% and within about 3 months the surface was completely eating the pian.

The pour strength of composite marble / concrete tiles (25 x 35 cm) manufactured as above was tested at the VTT building engineering laboratory. The tiles contained granite, limestone and quartz crusher, respectively. In the tests, the frost resistance of the plates and the adhesion strength of the joint between the marble and concrete layers were determined.

The tensile strength of the plates after a freeze-thaw treatment (SFS 5447) was determined according to standard SFS 5445. An initial examination revealed that the treatment did not cause the plates any visual damage. The tensile strength of the tiles was at least 88% of the reference tiles, and amounted to 2.8 MPa for granite-crushed tiles, 2.5 * · * · · • · * · * MPa for limestone tiles and 2.9 MPa for quartz tiles . Since a facade construction is considered to be frost resistant when its strength after 100 cycles of freezing and, thawing has not been ill during 2/3 of the reference, it was noted that the plates according to ·· “*! invention very well meet the criteria of Her standards.

• S ·· · • · • ♦ • ·

• I

• · • · «* • · ·· ♦ ·· · · · · · · · · I · 9 9> M ·«

Claims (6)

110494 9 1. A method for producing a facade element consisting of a natural stone facade layer and a concrete core layer adjacent to the natural stone layer, according to which method 5. the concrete pulp is provided with pore-forming agents for frost resistance, concrete pulp is cast on one side of a natural stone plate, which thereby constitutes concrete. casting, the concrete pulp, if desired, is provided with reinforcement, and the concrete pulp is solidified, characterized by the natural stone surface being rendered water repellent by treatment with a polymeric resin, and the natural stone plate is bent for casting to the extent that the concrete pavement becomes convex, the natural stone plate is straightened by the concrete mass fixed to the natural stone plate as it hardens and shrinks. Method according to claim 1, characterized in that the natural stone slab is bent by sandblasting the side which forms the casting base of the concrete layer. • · • · • · · * 20 Method according to claim 1 or 2, characterized in that the natural stone plate is bent, so that a bend of 1 - 4 mm per meter is obtained. • · ·· · ····. . ·. Method according to any of the preceding claims, characterized in that: • · ·; * · '; the stone slab consists of marble or granite. 25 *: * 'i Process according to Claim 3 or 4, characterized in that a concrete • · · · ... is used: pulp containing a hydraulic binder, filler and crushed natural stone with a grain size of 1-10 mm. % • · · • · • · • · · 30 6. A method according to claim 5, characterized in that the crushed natural stone is saturated with water before or during the casting of the concrete mass. , 0 1 10494