HIGH-FLUIDITY CEMENTITIOUS COMPOSITION SUITABLE TO BE MOULDED, IN PARTICULAR INJECTION-MOULDED, TO MAKE A MANUFACTURED PRODUCT HAVING GOOD APPEARANCE

Abstract

The invention relates to a cementitious composition suitable to be moulded, in particular injection-moulded, to make a manufactured product with arithmetic average surface roughness Ra not higher than 500 nm and flexural tensile strength not lower than 5 MPa, measured after 28 days of curing, the fluidity of the composition, measured according to the method of standard UNI 7044, being not lower than 185 mm, characterised in that it comprises at least: I. a hydraulic binder II. one or more aggregates III. an anti-shrinkage agent IV. a superplasticiser agent V. fibres VI. water, wherein said fibres are made of an amorphous metal material consisting of an alloy with composition (Fe, Cr).sub.80 (P, C, Si).sub.20 in form of flexible lamellae of length equal to at least 10 mm and elastic modulus equal to at least 80000 MPa, present in the composition in amounts by weight of less than 4% with respect to the weight of the composition.

Claims

1. A cementitious composition suitable to be moulded by injection, to produce a manufactured product with arithmetic average surface roughness Ra not higher than 500 nm and flexural tensile strength not lower than 5 MPa, measured after 28 days of curing, the fluidity of the composition being not lower than 185 mm, wherein it comprises at least: I. a hydraulic binder II. one or more aggregates III. an anti-shrinkage agent IV. a superplasticiser agent V. fibres VI. water, wherein said fibres are made of an amorphous metal material consisting of a alloy with the composition (Fe, Cr).sub.80 (P, C, Si).sub.20 in the form of flexible lamellae of a length equal to at least 10 mm and elastic modulus equal to at least 80000 MPa, present in the composition in amounts by weight of less than 4% with respect to the weight of the composition.

2. The composition according to claim 1, wherein said fibres are present in the composition in an amount comprised between 1% and 2% with respect to the weight of the composition.

3. The composition according to claim 1, wherein said fibres are present in the composition in an amount comprised between 1.3% and 1.4% with respect to the weight of the composition.

4. The composition according to claim 1, wherein the number of fibres per cubic metre is at least 1.15e+07.

5. The composition according to claim 1, wherein said fibres have the following properties: TABLE-US-00007 Fibre Elastic Fibre Length Density no of Aspect surface modulus Trade name structure (mm) (Kg/m.sup.3) fibres/Kg ratio (mm.sup.2) (MPa) Fibraflex FF Amorphous 15 7200 385000 85.8 31 130000 15 E0Fibres metal Fibraflex FF Amorphous 20 7200 275000 114.4 41 130000 20 E0Fibres metal Fibraflex FF Amorphous 20 7200 150000 82.3 65 130000 20 L6Fibres metal

6. The composition according to claim 5, wherein it comprises said fibres according to the following properties: TABLE-US-00008 Total surface % weight/ fibres/ weight n.sup.o fibres/ mortar of the m.sup.3 of Surface of volume Trade name composition mortar single fibre (m.sup.2) (m.sup.2/m.sup.3) Fibraflex FF 15 1.3 1.15e+07 31 10.sup.6 356.50 E0Fibres Fibraflex FF 20 1.3 8.25e+06 41 10.sup.6 338.25 E0Fibres Fibraflex FF 20 1.3 4.5e+06 65 10.sup.6 292.5 L6Fibres

7. The composition according to claim 1, wherein it comprises as anti-shrinkage agent III. at least one compound selected from glycols, polyols, a mixture of synthetic polymers and ethers.

8. The composition according to claim 7, wherein it comprises in combination with said anti-shrinkage agent III. lime in the form of oxide.

9. The composition according to claim 1, wherein it comprises as superplasticiser agent IV. a compound selected from polycarboxylic ester and polystearic ester.

10. A method for the preparation of a cementitious composition comprising at least one hydraulic binder, one or more aggregates, an anti-shrinkage agent, a superplasticiser agent, fibres and water, suitable to be moulded by injection to produce a manufactured product with arithmetic average surface roughness Ra not higher than 500 nm and flexural tensile strength not lower than 5 MPa, measured after 28 days of curing, the fluidity of the composition being not lower than 185 mm, wherein said fibres are made of an amorphous metal material consisting of an alloy with the composition (Fe, Cr).sub.80 (P, C, Si).sub.20 in the form of flexible lamellae of a length equal to at least 10 mm and elastic modulus equal to at least 80000 MPa, present in the composition in amounts by weight of less than 4% with respect to the weight of the composition.

11. A method for forming a manufactured product with arithmetic average surface roughness Ra not higher than 500 nm and flexural tensile strength not lower than 5 MPa, measured after 28 days of curing, characterised by subjecting to injection under pressure in a range between 0.1 and 50 bar a cementitious composition comprising at least: I. a hydraulic binder II. one or more aggregates III. an anti-shrinkage agent IV. a superplasticiser agent V. fibres VI. water, wherein said fibres are made of an amorphous metal material consisting of an alloy with the composition (Fe, Cr).sub.80 (P, C, Si).sub.20 in the form of flexible lamellae of a length equal to at least 10 mm and elastic modulus equal to at least 80000 MPa, present in the composition in amounts by weight of less than 4% with respect to the weight of the composition, the fluidity of the composition being not lower than 185 mm.

Description

DESCRIPTION OF THE FIGURES

[0061] FIG. 1 shows a complex shaped, injection-moulded product having appearance properties according to the present invention.

[0062] FIG. 2 shows the situation described in Example 5 below according to the present invention.

[0063] FIG. 3 shows the situation described in comparison Example 6 below.

[0064] FIG. 4 shows the situation described in comparison Example 4, also with reference to the aforesaid method devised by the Applicant for measuring fluidity according to standard UNI 7044.

EXAMPLES

[0065] Specific reference will be made in the following examples to fibres according to the invention and to comparison (cfr) fibres not included within the scope invention which have the properties summarised in the following tables:

TABLE-US-00003 Fibre Elastic Fibre Length Density No. of Aspect surface modulus Trade name structure (mm) (kg/m.sup.3) fibres/kg ratio (mm.sup.2) (MPa) Fibraflex FF Amorphous 15 7200 385000 85.8 31 130000 15 E0 fibres metal Fibraflex FF Amorphous 20 7200 275000 114.4 41 130000 20 E0 fibres metal Fibraflex FF Amorphous 20 7200 150000 82.3 65 130000 20 L6 fibres metal Kuraray. PVA (cfr) 8 1300 7.65 10.sup.7 200 1.00 41000 Kuralon RECS15

TABLE-US-00004 Total surface % weight/ fibres/ weight No. of Surface vol. of of the fibres/m.sup.3 of of single mortar Trade name composition mortar fibre (m.sup.2) (m.sup.2/m.sup.3) Fibraflex FF 15 1.3 1.15e+07 31 10.sup.6 356.50 E0 fibres Fibraflex FF 20 1.3 8.25e+06 41 10.sup.6 338.25 E0 fibres Fibraflex FF 20 1.3 4.5e+06 65 10.sup.6 292.5 L6 fibres Kuraray Kuralon 0.24 4.22e+08 1 10.sup.6 422 RECS15

Example 1

Injection Moulding

[0066] The following solid components were mixed in an intensive Hobart type mixer for three minutes:

TABLE-US-00005 % amount COMPONENTS by weight Binder I: cement (i.active ultra 52,5R Italcementi) 17.1 Aggregate II: lime filler (dmax up to 50 pm) 17.9 Aggregate II: lime aggregate (dmax >50 m) 54.5 Superplasticiser agent IV: polycarboxylic (Melflux 2641 0.2 F-BASF) Hydrophobising agent: alkoxysilane (Seal 200 Elotex) 0.3 Anti-shrinkage agent III: glycol(SRA 04 - Neuvendis) 0.5 De-aerating agent: polyglycol (Agitan P845 - Munzing 0.1 Chemie) Water 9.4

[0067] After adding water, the mixture thus obtained was mixed for four minutes (as a function of the features of the mixer and of the external temperature). After this time, the fluidity of the mixture was measured as described above, and found to be equal to 319 mm.

[0068] At this point, amorphous metal fibres (Saint Gobain Fibraflex FF 20 E0) were added in percentage by volume equal to 0.42% with respect to the volume of the mixture, corresponding to a percentage by weight of 1.4%, and the mixing was protracted for other two minutes at slow speed. After this time, the fluidity of the mixture with the fibres was measured as described above, and found to be equal to 301 mm.

[0069] So, 4416 specimens were prepared according to EN 196-1, Methods of testing cementDetermination of strength, and then subjected to flexural test according to standard ASTM C1018-97 modified as described above.

[0070] The data obtained from the flexural tensile strength test were processed to obtain the total tensile strength energy. The obtained tensile strength energy was equal to 2.59 J (N.Math.m), with respect to 0.30 J of a comparison specimen obtained from the same mixture but without the addition of fibres.

[0071] The fresh mortar with fibres as obtained above was injected by means of Duplex Bredel model SPX80D peristaltic pump into rectangular section moulds having a void degree (void volume/total volume) equal to 50%, size 4 m4.20 m and thickness 16 cm. The high fluidity made it possible to obtain the homogenous filling of the mould obtaining a fault-free product. The surface roughness measurement, expressed as Ra according to standard ISO 4287, was equal to 120 nm.

Example 2

Injection Moulding

[0072] The solid components of example 1 were mixed in an intensive Hobart type mixer for three minutes. After adding water, the mixture thus obtained was mixed for four minutes (as a function of the features of the mixer and of the external temperature). After this time, the fluidity of the mixture was measured as described above, and found to be equal to 309 mm.

[0073] At this point, amorphous metal fibres (Saint Gobain Fibraflex FF 20 L6) were added in percentage by volume equal to 0.42% with respect to the volume of the mixture, corresponding to a percentage by weight of 1.4%, and the mixing was protracted for other two minutes at slow speed.

[0074] After this time, the fluidity of the mixture with the fibres was measured as described above, and found to be equal to 299 mm.

[0075] So, 4416 specimens were prepared according to EN 196-1, Methods of testing cementDetermination of strength, and then subjected to flexural test according to standard ASTM C1018-97 modified as described above.

[0076] The data obtained from the flexural tensile strength test were processed to obtain the total tensile strength energy.

[0077] The obtained tensile strength energy was equal to 1.39 J (N.Math.m), with respect to 0.30 J of a comparison specimen obtained from the same mixture but without the addition of fibres.

[0078] The fresh mortar with fibres as obtained above was injected by means of Duplex Bredel model SPX80D peristaltic pump into curvilinear section moulds having a void degree (void volume/total volume) equal to 40%, size 3 m2.20 m and thickness 8 cm. The high fluidity makes it possible to obtain the homogenous filling of the mould obtaining a fault-free product. The surface roughness measurement, expressed as Ra according to standard ISO 4287, is equal to 125 nm.

Example 3

Comparison

[0079] The solid components of example 1 were mixed in an intensive Hobart type mixer for three minutes.

[0080] After adding water, the mixture thus obtained is mixed for four minutes (as a function of the features of the mixer and of the external temperature). After this time, the fluidity of the mixture was measured as described above, and found to be equal to 307 mm.

[0081] At this point, the comparison fibres were added, made of PVA (Kuraray Kuralon RECS15), in percentage by volume equal to 0.42% with respect to the volume of the mortar and mixing was protracted for other two minutes at slow speed.

[0082] After this time, the fluidity of the mixture with the PVA fibres was measured as described above, and found to be equal to 181 mm.

[0083] So, 4416 specimens were prepared according to EN 196-1, Methods of testing cementDetermination of strength, and then subjected to flexural test according to standard ASTM C1018-97 modified as described.

[0084] The data obtained from the flexural tensile strength test were processed to obtain the total tensile strength energy. The obtained tensile strength energy was equal to 0.6 J (N.Math.m), with respect to 0.30 J of a comparison specimen obtained from the same mixture but without the addition of fibres.

[0085] The fresh mortar with PVA fibres thus obtained could not be worked by means of the Duplex Bredel model SPX80D peristaltic pump. The poor fluidity did not allow the uniform filling of the mould.

Example 4

Comparison

[0086] Example 1 was repeated with the difference that the same amorphous metal fibres (Saint Gobain Fibraflex FF 20 E0) were added in percentage by weight of 4% with respect to the weight of the mixture.

[0087] The corresponding fluidity measurements of the cementitious mixture were 310 mm in case of mortar free from fibres and 135 mm after the addition of fibres, as shown in FIG. 4.

[0088] Specimens made with such a mixture with fibres in percentage by weight with 4% demonstrated the infeasibility of injection moulding, visible separation of the fibres themselves from the cementitious matrix, as shown again in FIG. 4, and loss of all limits of roughness and of the respective appearance result.

Example 5

Casting Moulding

[0089] The following solid components were mixed in an intensive Hobart type mixer for three minutes:

TABLE-US-00006 % by COMPONENTS weight Binder I: cement (i.active ultra 52,5R Italcementi) 17.0 Aggregate II: lime filler (dmax up to 50 m) 17.9 Aggregate II: lime aggregate (dmax >50 m) 54.5 Superplasticiser agent IV: polycarboxylic (Melflux 2641 0.2 F-BASF) Hydrophobising agent: alkoxysilane (Seal 200 Elotex) 0.3 Anti-shrinkage agent III: glycol(SRA 04 - Neuvendis) 0.5 De-aerating agent: polyglycol (Agitan P845 - Munzing Chemie) 0.1 Water 9.4

[0090] After adding water, the mixture thus obtained was mixed for four minutes (as a function of the features of the mixer and of the external temperature). After this time, the fluidity of the mixture was measured as described above, and found to be equal to 318 mm.

[0091] At this point, amorphous metal fibres (Saint Gobain Fibraflex FF 15 E0) were added in percentage by volume equal to 0.42% with respect to the volume of the mixture, corresponding to a percentage by weight of 1.3%, and the mixing was protracted for other two minutes at slow speed. After this time, the fluidity of the mixture with the fibres was measured as described above, and found to be equal to 285 mm.

[0092] So, 4416 specimens were prepared according to UNI EN 196-1, Methods of testing cementDetermination of strength, and then subjected to flexural test according to standard ASTM C1018-97 modified as described.

[0093] The data obtained from the flexural tensile strength test were processed to obtain the total tensile strength energy. The obtained tensile strength energy was equal to 1.2 J (N.Math.m), with respect to 0.30 J of a comparison specimen obtained from the same mixture but without the addition of fibres.

[0094] The surface roughness measurement, expressed as Ra according to standard ISO 4287, was equal to 150 nm.

[0095] The fresh mortar with fibres as obtained above was cast into a rectangular section mould having a void degree (void volume/total volume) equal to 50%, size 4 m4 m and thickness 16 cm. After having caused the flexural failure of the product thus moulded, a homogenous dispersion of the amorphous metal fibres, satisfactory for the purposes of the invention, could be observed in section, shown in FIG. 2.

Example 6

Comparison

[0096] The solid components of example 5 were mixed in an intensive Hobart type mixer for three minutes.

[0097] After adding water, the mixture thus obtained was mixed for four minutes (as a function of the features of the mixer and of the external temperature). After this time, the fluidity of the mixture was measured as described above, and found to be equal to 305 mm.

[0098] At this point, size 0.3518 mm steel fibres were added (commercial product: Matassina La Gramigna 18), in percentage by volume equal to 0.42% with respect to the volume of the mixture, corresponding to a percentage by weight of 1.4%, and the mixing was protracted for other two minutes at slow speed. After this time, the fluidity of the mixture with the steel fibres was measured as described above, and found to be equal to 303 mm.

[0099] So, 4416 specimens were prepared according to EN 196-1, Methods of testing cementDetermination of strength, and then subjected to flexural test according to standard ASTM C1018-97 modified as described.

[0100] The data obtained from the flexural tensile strength test were processed to obtain the total tensile strength energy. The obtained tensile strength energy value was equal to 1.94 J (N.Math.m), with respect to 0.30 J of a comparison specimen obtained from the same mixture but without the addition of fibres. However, a layering of the fibres was observed on the bottom of the mould after the failure of the specimens, indicating a non-homogenous distribution of the fibres in the high-fluidity cementitious mixture. FIG. 3 shows that the fibres visibly emerge in the failure section.

[0101] In general, the finished products obtained from a composition of the invention may vary in a wide range of shapes and dimensions, including thickness, provided that the essential requirements according to the invention as described above are respected, i.e. the products can be injection moulded, are homogenous and smooth to the touch, have a homogenous colour, do not display faults, such as air bubbles, shrinkage crazing or curling, and have the desired mechanical properties as a whole.

[0102] Examples of product applications thus made are: cladding panels for continuous and ventilated faades, panels for fencing, marquises, flooring sheets and tiles, sunshade elements, sun protection systems, furniture items, vertical partition elements.