WO2014064635A1

WO2014064635A1 - Cementitious product for non-structural ornamental use

Info

Publication number: WO2014064635A1
Application number: PCT/IB2013/059610
Authority: WO
Inventors: Roberta Alfani; Giuseppe MANGANELLI; Flavio RAMPINELLI; Michele DE LONGIS
Original assignee: Italcementi SpA
Current assignee: Italcementi SpA
Priority date: 2012-10-25
Filing date: 2013-10-24
Publication date: 2014-05-01
Anticipated expiration: 2015-04-25
Also published as: EP2911847A1; ITMI20121818A1

Abstract

Object of the present invention is a cementitious product for ornamental, non- structural use, in particular for applications with aesthetic and decorative purposes in integrated architecture. It is produced by mould casting of a fluid composition comprising: I. a hydraulic binder II. one or more aggregates III. an anti-shrinkage agent IV. a superfluidifying agent V. water, wherein at least one insert in hydrophobic material previously fixed to the inside of the mould remains incorporated as visible marquetry in the product after extraction from the mould.

Description

CEMENTITIOUS PRODUCT FOR NON-STRUCTURAL ORNAMENTAL USE

Field of the invention

Object of the present invention is a cementitious product for ornamental, non- structural use, in particular for applications with aesthetic and decorative purposes in integrated architecture.

Background of the invention

Patent application PCT/EP2012/067762 by the same Applicant describes cementitious products having a thin thickness, particularly in plate form, with controlled surface curvature and roughness, produced by mould casting of a fluid composition comprising a hydraulic binder, one or more aggregates, an anti- shrinkage agent, a superfluidifying agent and water. The mould consists of two half-moulds which internal surface is at least partly or completely coated with a material selected from polyethylene terephthalate, polycarbonate, polyamide, polymethylmethacrylate, or other similar material capable of imparting low surface roughness to the cementitious product during the casting step.

Summary of the invention

By adopting the characteristics of this forming method, the present invention proposes a cementitious product for non-structural ornamental use, such as a plate or a panel, characterized in that it is produced by mould casting a fluid composition comprising:

I. a hydraulic binder

II. one or more aggregates

III. an anti-shrinkage agent

IV. a superfluidifying agent

V. water,

wherein at least one ornamental insert in hydrophobic material previously fixed to the mould remains incorporated as visible marquetry in the cementitious product after extraction from the mould.

Albeit embedded in the hardened mortar thus produced, following extraction from the mould, the face of the insert that was fixed against the mould to form a seal is thus free and visible, therefore appearing as a marquetry on the surface of the product. Since the insert can have a shape, design, colour of marked aesthetic effect that varies within an unlimited range, the cementitious product thus produced is indicated for decorative, even customisable architecture.

The material from which the inserts must be hydrophobic so as not to absorb the water present in the cement mix and can be selected from various non-absorbent plastic materials such as polymethylmethacrylate, fluorescent polymethylmethacrylate, or glass, metal, stone, minerals, cementitious products and/or derivatives thereof, or even materials that are as such hydrophilic, e.g. cardboard or wood, nevertheless treated in such a way as to make them completely water-repellent for the aims of the invention and provided with sufficient rigidity and non-deformability to be able to withstand the hydrostatic pressure of the fluid composition during the casting step.

In order to allow a conformation according to even complex drawings and decorative geometries, such inserts can be made by automatic computer aided cutting via laser, water-based tools, milling cutters and the like, with a view to obtaining greater cutting precision and to producing even elaborate ornamental motifs.

In a preferred embodiment of the invention a metal casting mould of the type that has horizontal walls for cementitious applications is used. In a different embodiment, a metal casting mould of the type that has vertical walls consisting of two die-halves is used.

In order to obtain a cementitious product according to the invention, the mould is previously prepared by fixing at least one ornamental insert in hydrophobic material, for example plastic, onto the internal wall of at least one of the two die- halves to form a seal by means of a secure but removable fixing system, so as to allow ease of removal, at the end, of the cementitious finished product that incorporates the insert. For this purpose, the fastening system is produced by magnetic coupling for example, or by means of a non-water absorbent adhesive film, or by surface tension by applying a suitable fluid to the insert-mould interface in question, such as for example a silicone oil, or other suitable systems.

So as to allow a view of the free surface, or face of the ornamental insert incorporated in the finished product with high decorative quality, this surface must be snug-sealed onto the internal wall of the mould onto which it is fixed so as not to allow the fluid composition to seep onto the surface during casting, thus covering and ruining the decorative effect sought. In the fixing operation of the insert to the mould it must also be ensured that the fixing agent (for example, a film of bi-adhesive material) of the insert to the mould does not protrude beyond the face or surface of the insert which should be visible, a circumstance that could cause points of discontinuity in the casting and therefore lack of adhesion of the insert-cementitious material interface in the finished product.

The insert having been thus fixed to the mould, there is casting of a fluid composition comprising a hydraulic binder, one or more aggregates, an anti- shrinkage agent, a superfluidifying agent and water, thus producing a mortar characterized by high fluidity, self-levelling properties, without segregation phenomena, minimal hygrometric shrinkage, reduced air content within the mixture. With these properties, the composition is capable of pouring and filling the mould in an ideal way, and of coupling with the insert embedded therein, incorporating it once hardened, giving a final product with controlled curvature and free of deformations, wherein at the end said insert is visible on the surface of the product as a ornamental marquetry.

In a preferred embodiment of the invention, a metal casting mould of the type that has horizontal or vertical walls for cementitious applications, is used. The mould consists of two half-moulds which internal surface is partly or completely coated with a material selected from polyethylene terephthalate, polycarbonate, polyamide, polymethylmethacrylate, or other similar material capable of imparting a high surface finish to the cementitious product during the casting step, in order to obtain a surface of the cementitious product that is characterized by a low surface roughness. No further finishing treatment such as sanding or polishing is thus required.

In a different form of the invention, wherein the surface or face of the product do not necessitate a special finish, a normal mould is used to form the cementitious products, without any special requirements in relation to surface roughness.

In yet another different form of the invention, the product is obtained by mould casting while applying a vibrating ancillary motion. Further variant embodiments, provide for the fixing of ornamental inserts in hydrophobic material to both the opposite internal walls of the mould to obtain a final cementitious product with visible insert on both faces of the plate or panel thus produced, or to fix several inserts onto the same face of the mould.

Detailed description of the invention

The said components from I to IV of the composition according to the present invention are now described in detail.

I. Hydraulic binder means a powdered material in the solid dry state which, when mixed with water, provides plastic mixtures that are capable of setting and hardening, even underwater, such as cement. A clinker usable for preparing a binder for the present invention is any common cement clinker, as defined according to UNI EN 197.1 standard, i.e. a hydraulic material with at least two- thirds in mass consisting of calcium silicates (3CaO*SiO₂) and (2CaO*Si0₂), the remaining part being AI2O3, Fe₂0₃ and other oxides; for example a Portland cement clinker.

The broad definition of hydraulic binder according to the present invention also comprises white, grey or pigmented cements defined according to the aforementioned UNI EN 197.1 standard, as well as the so-called cements for retention structures, cementitious agglomerates and hydraulic limes as defined in Italian law no. 595 of 26 May 1965 and inorganic silicates.

To form a product according to the present invention, calcium sulphoaluminate- based binders can be used, such as the compounds described in patents and/or patent applications WO2006/18569, EP-A-1306356 and EP-A-018 739, and those deriving from the calcium sulphoaluminate clinkers described in the "Green Chemistry for sustainable cement production and use" review by John W. Phair Green Chem., 2006, 8, 763-780, in particular in chapter 5.3 on page 776, as well as the calcium sulphoaluminate clinkers described in the article, "Calcium sulfoaluminates cements-low energy cements, special cements" J. H. Sharp et al., Advances in Cement Research, 1999, 1 , no. 1 , pp. 3-13. Alternatively aluminous, sulpho-ferroaluminous cements as described in Advances in Cement Research, 1999, 11 , No. 1 , Jan. 15-21 , can also be suitably used. According to the present invention, in the production of the products, including photocatalytic cements, i.e. binders having photocatalytic action obtained by adding to the composition a photocatalyst capable of oxidising the organic and inorganic pollutants present in the environment, in the presence of light, air and environmental humidity.

The photocatalyst can be selected from each compound capable of oxidising the pollutants that come into contact with the surface of the cementitious compositions in the hardened state, in the presence of light, oxygen and water. The preferred photocatalyst according to the present invention is titanium oxide or a precursor thereof, and more typically titanium oxide at least partially in the form of anatase. The expression "titanium oxide at least partially in the form of anatase" means that at least 5%, preferably 25%, more preferably at least 50%, still more preferably in at least 70% of the titanium oxide particles have an anatase structure, as percentages by weight on the total weight of the titanium oxide. Examples of photocatalytic cements are the products in the TX range (Italcementi), such as TX Area®, TX Air®.

A preferred form of the invention uses Italcementi sulpho-aluminous Alipre® Cement, Italcementi Portland Ultracem® 52.5R cement, Italcementi Italbianco® 52.5 cement and Italcementi cement TX Area® cement as binder.

The composition for producing a product according to the present invention can also optionally comprise anhydrite or gypsum.

The aggregates, also known as inert aggregates, according to the present invention can include:

- fine aggregates such as filler, powder and sand, defined in UNI EN 206. According to the present invention filler means a fraction of fine aggregate having maximum diameter d_max, equal to 40 microns;

- non-fine aggregates with diameter d_max greater than 40 microns.

The aggregates can be suitably selected from limestone, quartz or silico- calcareous aggregates in any form, or crushed, or spherical aggregates, for example marble powders, ceramic finish marble and even marble that has been lightened to reduce the final weight of the product.

The relative percentage amount of aggregates having different dimensions is optimised to give the mortar rheological characteristics suitable for mould casting, in particular high fluidity, prolonged machinability for the time necessary for casting, and absence of segregation phenomena prior to hardening, while safeguarding the final mechanical properties of the hardened product.

Some aggregates, as in the case of coloured marble powders, also have an aesthetic function; more specifically, the can confer special colour characteristics and nuances or veining. to the product by reproducing the appearance of natural stones.

The composition can also optionally contain one or more ancillary substances common in the field, such as mineral or pozzolanic fillers, organic and/or inorganic pigments or the like. Mineral or pozzolanic fillers means microsilica, silica fume, slag, fly ash, metakaolin, natural pozzolanas, natural limestones and precipitated calcium carbonate.

III. For the purposes of manufacturing the product according to the present invention, the starting cementitious composition must contain at least one agent or anti-shrinkage additive that is capable of reducing hygrometric shrinkage, in liquid or solid phase. These anti-shrinkage agents, also known as SRAs (shrinkage reducing agents), include a wide variety of glycols and polyols and are responsible for reducing shrinkage deformation throughout the working life of the hardened product. Lime, in the form of oxide, can be added in combination therewith.

In a preferred aspect of the invention, glycols, diols and polyols or mixtures thereof or glycol ethers, derivatives and mixtures thereof are used as anti-shrinkage additives III.

For example, the commercial products Espandex 2000 by Axis in aqueous solution, or Shape 920 by Elotex in solid form are used.

The commercial product, Cimparement, a liquid additive consisting of a mixture of synthetic polymers and ethers, albeit classified as an antifoam product has anti- shrinkage properties.

IV. According to the present invention, the cementitious starting composition must contain at least one superfluidifying agent or additive, preferably of the polycarboxylic type, added in either solid phase or in the form of an aqueous solution. In a preferred embodiment of the invention, polycarboxylic superfluidifying agents selected from the product Melflux 2641 F in solid form, or the product Glenium 71 SCC (modified polycarboxylate ether) or Driver 72 of Axim in liquid form are employed.

The combined use of the superfluidifying components IV and anti-shrinkage additive III allows optimisation of the desired rheological characteristics, with a low water-binder ratio, and significantly reduces hygrometric shrinkage measured up to 28 days. Water-binder ratio means the ratio of the total amount of water used in the composition's formulation to the amount of hydraulic binder I as previously defined.

So as to limit the absorption of water by capillary action on the part from the product, according to the present invention, the cementitious starting composition can contain a waterproofing or hydrophobicizing agent or additive. These agents include a wide variety of organic or organo-siliceous compounds. In a preferred aspect of the invention, Ligaphob N(T) 90 by Peter Greven or Seal 200 by Elotex, in solid form, is employed as waterproofing additive.

In addition to the above-mentioned components, the casting used to manufacture the product object of the present invention can contain various other additives so as to fine tune the characteristics of the mixture to the specific request. Examples of these additives can be setting regulators, rheology modifiers or modifiers of physical-mechanical properties, such as for example celluloses or latexes, expansive, air entraining agents, air-releasing agents and tackifiers. These additives are optional for the purposes of the invention.

The cementitious composition of the present invention can also include the addition of fibres of various nature, such as inorganic fibres like metal fibres or glass and wollastonite fibres, and organic fibres, such as polyvinyl alcohol- or polypropylene-based fibres or aramid fibres, selected on the basis of the final application. These fibres, even in the form of sheets or mesh networks, can be added to reduce the fragility of the cementitious product both during the casting step and when subsequently glued onto a surface of the product and are chosen according to the final characteristics of the product and its use.

With the aim of providing a better understanding of the features and advantages of the invention, a non-limiting method for preparing a cementitious product object of the invention, is described below.

A mould preferably having horizontal walls, of a shape such as to give the final product the desired final geometry, a plate shape for example, is thus prepared. The insert or inserts are arranged on the walls of the mould, preferably on the lower horizontal wall, by means of a secure but removable fixing system as previously described.

There follows an intimate mixing step of the said components from I to IV; water, component V, is then added, producing a fluid mortar; mixing is continued for a variable time variable depending on the mixer used. A planetary type mixer is fed: - a solid cementitious-based mixture comprising one or more components selected from cement, sand, aggregates, charges of mineral or pozzolanic origin, waterproofing and superfluidifying additives, if in solid form, rheology modifiers, fibres, pigments,

- water, stored in a liquid measuring device,

- any additives, in liquid form.

The solid-phase components are mixed in the planetary mixer for a period of time preferably between 30 seconds and 5 minutes, depending on the characteristics of the mixer and the external temperature, until a homogeneous mixture is obtained. The liquid components, including the water, are then added and the mixing is continued for a time between 30 seconds and 10 minutes, again depending on the characteristics of the mixer and the external temperature.

The fresh mortar thus obtained is poured into the mould. The high fluidity allows the homogeneous filling the mould even in the absence of vibration. There is preferably recourse to the use of metal moulds of the type used for cementitious applications, constituted by two matching halves, the internal surface of which can be coated with materials such as polyethylene terephthalate like Mylar® and the like, polycarbonate, polyamide, polymethylmethacrylate and the like, when there is a wish to impart high finish characteristic to the surface of the cementitious product from which the decorative insert emerges.

Cementitious products varying in shape and thickness, are thus manufactured depending on the final application. They can be very thin, inlaid on the surface with decorative inserts in different shapes and materials. Description of the drawings

Figures 1 and 2 of the accompanying drawings show a perspective view of the non-limiting examples of a cementitious product according to the invention.

In both of the embodiments shown, a cementitious, panel-shaped product 10 incorporates decorative inserts made of polymethylmethacrylate, thus with a coloured, transparency effect. These inserts are visible on the upper face 9 of the product 10.

In the case of Fig. 1 , there is a single insert 11 in fluorescent polymethylmethacrylate having a spiral or winding shape, while in the case of figure 2 there are three inserts 12, 13, 14 having a segment shape with trapezoidal cross section, arranged in parallel, each in a different colour of polymethylmethacrylate.

The following examples of the composition and preparation of a cementitious product according to the invention illustrate the invention without in any way limiting its scope.

Example 1 in particular describes the preparation of the product shown in Fig. 1. EXAMPLE 1

A decorative insert having a spiral or winding shape was prepared by automatic computer aided cutting via laser, produced in fluorescent polymethylmethacrylate. The insert, with 3 mm thickness, was positioned and fixed with silicone grease onto the lower surface of a metal mould with horizontal walls coated with polycarbonate.

The solid components listed in the following table 1 were mixed in an intensive Hobart mixer for 3 minutes.

Table 1

COMPONENTS Wt %

Italcementi Italbianco® cement 17.32

Omnyacarb 2 AV filler 18.11

Marble 0-0.2 mm 8.90

Marble 0.1-0.35 mm 10.01

Marble 0.3-0.7 mm 9.47 Marble 0.7 - 1.2 mm 19.86

Marble 1.2-1.8 mm 6.89

Driver 72 Axim Italy 0.39

Seal 200 Elotex 0.14

Espandex 2000 0.42

Clerol 0.0087

Water 8.49

The liquid components, including the water, were then added and mixing continued for a time equal to three minutes depending on the characteristics of the mixer and the external temperature.

The fresh mortar obtained was poured into the mould having internal surface with micrometric surface roughness. The fluidity allows homogeneous filling of the metal mould coated with polycarbonate without the application of vibrations to compact the cast mass.

After 24 hours, the hardened product can be removed from the mould to subject it to the seasoning step, which takes place by storing it in a vertical position in a conditioned chamber at 20°C and 55% relative humidity. A finished panel for ventilated facade having 60x60 cm dimensions and 15 mm thickness is thus obtained, with a decorative insert having a spiral or winding shape, that is visible on one face of the panel as shown in Fig. 1.

EXAMPLE 2

Proceeding substantially as described in example 1 but using the components described in the following Table 2, a product having the form of a plate was produced.

Table 2

COMPONENTS Wt%

Italcementi Ultracem® 52.5 R cement 39.4

Micronized quartz 5.8

Aggregate (0.1 -0.35mm) 43.8

Fibreglass (12 mm) 0.54

Melflux 2641 F 0.2

Cimparement 0.4

Water 9.9 The thickness of the plate, having a surface area equal to 40 x 40 cm ², was equal to 10 mm.

A decorative stainless steel insert was obtained by automatic computer aided cutting via laser. The insert, having a thickness of 2 mm, was positioned on the lower surface of the mould and fixed thereto using a vinyl-based adhesive.

EXAMPLE 3

Proceeding substantially as described in example 1 , an element for tables was obtained.

The thickness of the 60x60 cm panel was equal to 4 cm.

A decorative marble insert was obtained by computer aided water-jet cutting. The insert, having a thickness of 2 cm, was positioned on the lower surface of the mould and fixed thereto using an adhesive.

EXAMPLE 4

Proceeding substantially as described in example 1 , a plate for an advertising sign was obtained. With the aim of giving greater structural strength and increasing the shatterproof nature of the plate extracted from the mould, a reinforcing fibreglass mesh was glued onto the back thereof.

The thickness of this sheet is 10 mm, with dimensions of 60x60 cm.

A decorative insert in fluorescent polymethylmethacrylate having a thickness of 3 mm was positioned and fixed onto the bottom of the mould, followed by casting of the fluid composition. Having extracted the plate from the mould, in order to accentuate the luminous properties of the insert with advertising function, it was placed in contact with a light source.

Comparative EXAMPLE 5

Proceeding substantially as described in example 1 , a cardboard decoration, having a thickness of 2 mm, suitably fixed to the bottom, was used as insert. The cardboard, untreated for the purposes of the present invention, is therefore a hydrophilic material. It was consequently observed, during casting of the mortar, that the insert had begun to be impregnated with water. On release from the mould the insert presented as deformed as a result of water absorption, and with undefined contours as these were deformed due to inability to withstand the hydrostatic pressure of the cast fluid composition. The mortar thus being drawn between insert and mould, the aesthetic quality and coupling to cementitious material are unacceptable.

Generally, the quality of the finish of the concrete elements obtained after release from the mould according to the present invention is such that it does not require after-treatments such as sanding or polishing.

A product according to the present invention is generally suitable for a nonstructural use, principally as an architectural ornamental coating element and for design applications.

The prefabricated concrete products object of the present invention are intended for use in the construction industry for non-structural applications such as coating and covering elements of both the horizontal and vertical type, such as flat plates, ventilated facades, signs, infill panels and decorative elements or coatings for internal walls.

Claims

1 ) Cementitious product for non-structural ornamental use, characterized in that it is produced by mould casting of a fluid composition comprising:

I. a hydraulic binder

II. one or more aggregates

III. an anti-shrinkage agent

IV. a superfluidifying agent

V. water,

wherein at least one insert in hydrophobic material previously fixed to the inside of the mould remains incorporated as visible marquetry in the product after extraction from the mould.

2) Cementitious product according to claim 1 , characterized in that said insert in hydrophobic material is selected from non-water absorbent plastic materials such as polymethylmethacrylate, fluorescent polymethylmethacrylate, or glass, metal, stone, minerals, cementitious products and/or derivatives thereof, or materials that as such are hydrophilic, but treated in such a manner as to make them hydrophobic and provided with sufficient rigidity and non-deformability to be able to withstand the hydrostatic pressure exerted by the fluid composition during casting.

3) Cementitious product according to claim 1 , characterized in that said mould is of the type that has horizontal walls.

4) Cementitious product according to claim 1 , characterized in that said mould is of the type that has vertical walls.

5) Cementitious product according to claim 1 , characterized in that the internal surface of the mould is partly or completely coated with a material selected from polyethylene terephthalate, polycarbonate, polyamide, polymethylacrylate.

6) Cementitious product according to claim 1 , characterized in that an anti- shrinkage agent III is selected from glycols, diols, polyols, glycol ethers, derivatives or mixtures thereof.

7) Cementitious product according to claim 6, characterized in that

there is used as anti-shrinkage agent III Espandex 2000 by Axis in aqueous solution, or Shape 920 by Elotex in solid form. 8) Cementitious product according to claim 1 , characterized in that Cimparement, a liquid additive consisting of a mixture of synthetic polymers and ethers, is used as anti-shrinkage agent III.

9) Cementitious product according to claim 1 , characterized in that a superfluidifying agent IV is of the polycarboxylic type in solid phase or in the form of aqueous solution.

10) Cementitious product according to claim 9, characterized in that a superfluidifying agent IV is selected from Melflux-2641 F in solid form, Glenium 71 SCC or Driver 72 by Axim in liquid form.

11 ) Cementitious product according to claim 1 , characterized in that it comprises a waterproofing agent.

12) Cementitious product according to claim 1 , characterized in that it comprises, as waterproofing agent, Ligaphob N(T) 90 by Peter Greven (90% sodium oleate) or Seal 200 by Elotex (alkyloxysilane), in solid form.

13) Cementitious product according to claim 1 , characterized in that said hydraulic binder I is a photocatalytic cement.

14) Cementitious product according to claim 1 , characterized in that it is used as non-structural architectural coating and covering element, both of horizontal type and of vertical type, such as a flat plate, ventilated fagade, sign, infill panel, decorative element or coating for internal walls, design element.

15) Method of producing a cementitious product according to claim 1 , characterized in that at least one insert in hydrophobic material is arranged in a casting mould by means of a sealed and removable fixing system at least one internal wall of the mould, and in that said fluid composition is then cast.

16) ) Method according to claim 15, characterized in that said fixing system is obtained by magnetic coupling, or by means of a non-water absorbent adhesive film or by means of surface tension by applying a surfactant fluid such as a silicone oil to the interface between insert and mould.

17) Method according to claim 15, characterized in that several inserts are fixed on the same internal wall of the mould, or on both opposite internal walls of the mould.