FR2716692A1 - High strength thin wall and floor tiling - Google Patents

Abstract

In thin wall and floor tiling formed of prefabricated tiles of any size or shape and of less than 20 mm thickness, consisting of decorative sand and cement mortar, the novelty comprises the combination of high performance cement mortars, using fluidisers, plasticisers and super-plasticisers, with a delayed demoulding process using inexpensive moulds which accompany the tiles during hardening.

Description

The present invention relates to the manufacture of a tile or thin paving based on mineral cement mortar.

Since the middle of the XIXth century, we have made tiles from compressed cement mortars by a process patented by Mr LARMANDE. (Patent nO 17.22I of September 20, I853)
The technique consisted in pouring in a steel mold a liquid grout of cement and colored fine sand, to cover it with a layer of powdered cement allowing to absorb the excess water, then to add a layer of very dry fine mortar . The set could create decorative effects molded in the first layer called decor; these patterns being obtained by the use of partitions called dividers, removable partitions used to compartmentalize, during the first layer, colored mortars of different colors. These partitions were removed after pouring the decorative layer, itself followed by a layer of mortar with a very thick structure, and the assembly was pressed and immediately removed from the mold.

All three layers: decoration, dusting, then fine mortar were pressed under strong pressure. The purpose of this pressure is to ensure diffusion of the water loaded with cement and of the soluble salts, through the three layers. This pressure was generally greater than 100 Kg / cm2, see 150 Kg / cm2. It was used to compact the layers, to combine them definitively, and to set up the structural mortar applied last and poured very dry. It was necessary to apply this pressure for a certain time in order to allow the water to percolate through this mortar, and the excess water to be expelled and discharged, by this tightening, through the joints of the molds.

After pressing, tile by tile, the pieces were removed from the mold and handled by hand while still damp and soft; that is to say before the hydraulic setting specific to cements, setting which followed by the very slow hydration reaction, gave the tiles their solidity. Waits of the order of 6 weeks allowing total hydration achieved in a very humid atmosphere gave the final tile.

However, the manufacturing process described above essentially consists of manual and very slow steps. Due to the high pressure used, the manufacturing was done in heavy cast iron molds, expensive and difficult to handle.

Because of the immediate release before setting, many parts were deformed, veiled, chipped or broken during their release and handling.

The high pressure pressing was slow, each tile requiring for its molding 3 to 5 minutes by immobilizing the press during this time. Also the production of these tiles has collapsed in our industrialized countries, and we find it in countries where the labor is very cheap. This manufacturing process is more of a craft than an industrial production.

These tiles were made with simple, rustic, poorly developed raw materials, which in the past led to strong thicknesses of the order of 20 to 25 mm, giving very heavy tiles to handle during transport and on construction sites.

At present, these tiles are still produced by the traditional process (in certain North African countries for example). All these products, even optimized, lead to tiles at least 15 to 20 millimeters thick for floors, thin 10 mm tiles being too fragile to be usable for floors and being reserved for vertical tiling of walls. Manufacturing by the immediate release technique prevents the use of the concepts of formulated mortars, in particular because the formulated products are too liquid, cannot be removed from the mold by themselves before setting without the presence of the mold, and that formulas with organic chemistry additives or organic additions stick to the tools, not allowing immediate release. Consequently, this process does not make it possible to progress in the quality of the products, therefore does not make it possible to reduce the thicknesses and the weight thereof. The excessive price of each tool does not allow deferred release systems that would mobilize these tools for several hours. As a result this industry, however French in origin, has collapsed, very manual manufacturing processes, heavy equipment, slow pressing leading to manufacturing still artisanal.

The present invention aims to manufacture a thin tile of cement mortar which incorporates the same richness and decorative quality as the old art, while combining a high performance product which can easily be produced in thin, lower layers at 20 mm: for example from 8 to 12 millimeters. This tile will no longer be produced by the immediate demolding technique after high pressure molding but by an economical casting which will accompany the product before setting, which will allow both the small thicknesses and the lightening of the parts obtained.

It is the object of the present invention to produce a tile whose composition is that of the mineral composite matrices formulated, which makes it possible to obtain high performance, both in surface hardness, in resistance to impact, bending while being thin products.

By high performance composite formulations is meant composites combining sands and mineral flours with well-studied particle size curves, so as to leave as few voids as possible between the grains.

As binder, silica-limestone cement of the PORTLAND type is used, in weightable proportions ranging from 10 to 60% of the total formula. It is also possible to use faster cements, either Prompts cements, or cements of the family of Calcium Aluminates, such as refractory Aluminous cements whose mechanical strengths develop faster than those of cements of the type
Portland. It is also possible, in the spirit of the invention, to use combinations of Portland and Aluminous cements, which give setting times which are adjustable at will.

It is also possible to use ternary mixtures of Portland cements, aluminous and sulphates and / or carbonates which also give high strengths in very short times. These mixtures are known and described in the literature.

In the spirit of the invention, chemical additives will be added which allow easy installation and good flow without the need to add too much water which is harmful to high performance. We know, in fact, that the lower the amount of water used to mix a mortar, the higher the resistance.

Such chemical additives are found commercially, under the names of casein for example, and it is known that casein extracted from milk is a remarkable spreading agent for mortars. However, there are also synthetic additives derived from lignosulfonates, from certain phosphonates or from water-soluble aminoplasts such as the additive called MELMENT (registered trademark).

These additives are well known and widely used in so-called high performance and very high performance concrete used on certain large construction sites.

These additives make it possible to reduce the amount of mixing of mixing water in proportions such that the mortars produced no longer contain, after curing the cements, excess porosity other than that very fine left free between the own crystals of the binders. These porosities left open have dimensions of the order of microns and therefore do little or no water or solvents enter. Thus, the mortars obtained are not sensitive to stains.

It has been surprisingly discovered, in the context of the present invention, that by using such compositions of fine mortars with high performance, it is possible to fill molds easily and without defects without having to resort to high positioning pressure. In the spirit of the invention, these very liquid and high performance formulations will be combined with simple and economical molds made from materials such as:. wood
plastics
light alloys
It was also discovered that although not using a profession, products were obtained whose mechanical strengths were higher than those of traditionally manufactured products. The use of simple and economical molds, for example made of polystyrene, PVC, acrylic, etc., makes it possible to produce tiles in a large number of small individual molds. These tiles are then kept in the so-called economical molds for the time necessary for the mortar to set and acquire sufficient strength so that the tiles can be removed from the mold without risk and handled easily.

To facilitate the placement of the mortar in these molds, conventional techniques can be used which aid in the placement of the mortars and concretes, namely simple and rapid compression, vibration, vibro-compression, rolling or calendering. , etc.

The vibration will have the additional advantage of evacuating any bubbles that may have remained on the surface during casting.

The method according to the invention also makes it possible to easily achieve rich and numerous decorative effects according to the traditional method using removable partitions called dividers or kinds of compartments, well known in the profession, which are used in the mold for pouring the various colors. of the first layer while being removed thereafter.

Among the preferred preparations of the invention, we will retain
A- for the decorative layer, of thickness from I to 5 mm, preferably from 2 to 4 mm, compositions based on formulations of the type:
1- silica sands and / or limestones with fine grain sizes less than about a millimeter, ... from 500 to 900 parts by weight.

we can add larger granular elements introduced in small proportions, of the order of a few% intended to create decorative effects. These elements may be minerals, colored coated minerals, pieces of metal, pieces of plastic, glass, noble rocks of the porphyry type, marble, ore ... (these elements do not exceed the sizes of a few millimeters) .11 it is also possible to use granules or fine metal powders as aggregates such as bronzes, coppers and steels, in particular stainless steel, metal cast irons in order to obtain metallic effects in decoration.

 2- Cement of the defined type PORTLAND and / or ALUMINOUS and / or SUL FO or CALCO ALUMINOUS preferably fine and high strengths in proportions of I00 to 500 parts by weight.

For light or bright shades, white cements will be used.

 3- water reducing additives used by the profession, such as melamine derivatives, lignosulfonate derivatives, phosphate derivatives, etc. We can also use casein or natural or synthetic proteins.

These elements are present in proportions ranging from 0.1 to 4% of the weight of the cement, preferably from 0.2 to 2%.
4- Metallic oxides intended to give color, most colors being easily achievable (iron, chromium, zinc, titanium, vanadium, cobalt, ect, etc.) at the rate of a few percent. Such oxides are readily found commercially.

We can also use colored natural sands, ocher, earth which will give very beautiful natural effects.

 5- We can add other usual additives in mortars, such as water repellents such as zinc stearates, magnesia, or salts of fatty acids that are soluble or compatible in water, or even water repellent silicones, these products being present at 0.05 to 1% of the total weight.

6- It is also possible to use thermoplastic resins in emulsions or in emulsifiable powder as is known to do in resistant mortars and concretes. Such products are found commercially under the names such
SIKALATEX (registered trademark) of the company SIKA, RHODOPAS (registered trademark) of the company RHONE POULENC, VINNAPAS (registered trademark) of the company VINNAMUL, etc. These resins are generally added in proportions of 0.3 to 5% dryness relative to the total weight, preferably 0.5 to 2%.

B- For compositions of the structural layer, white cements can still be used, but the economy leads to using gray cements of the High type
Resistors such as CPA 55, doped or not with aluminous cements such as refractory molten cements or compatible refractory cements.

A layer of mortar 5 to 15 mm thick, preferably 7 to 10 mm, can be used. The composition of this mortar will be a formulation with high resistance, in particular to flexion and impact, comprising: - washed or ground natural sands with a fineness of less than 3 mm, in pro portions of 500 to 900 parts by weight.

- cement as indicated in proportions of 500 to 100 parts by weight - a water-reducing plasticizer as indicated in proportions of 0.2 to 3% of the weight of the cement
It will be possible to use conventional additions of reinforcements such as resins as indicated above, short mineral fibers, organic or metallic vegetables in order to increase the mechanical performance, fibers usual in the mortar and concrete industries, for example short polypropylene fibers. drawn, or acrylic, or glass, of maximum length of 5 millimeter, preferably of the order of a millimeter. It is also possible to reinforce the resistance to the impact of the tiles by adding veils or grids of long fibers or reinforcements such as glass fibers, acrylic fibers, polyaramid fibers, etc., arranged at the bottom of the mold, or in the first three millimeters of the tiling. They can be arranged in the form of fabrics, or in the form of non-woven but glued grids, of mesh of a few millimeters.

Molds: As materials for the molds, we can use - wooden molds - metal molds that do not corrode, stainless or treated against corrosion.

- Or rigid and hard plastics from plates that are machined and cut into as many elements as necessary to make the molds. They can also be made from polyester resin, such as polyesters reinforced with hot-molded glass fibers, called "prepregs" - or from rigid and hard foams of plastics such as polyurethane foam.

EXAMPLES
Example I - We will use molds made of bars and plates of smooth PVC (polyvinyl chloride) assembled according to the model in the form of rectangular molds. These molds define spaces 30 X 20 cm in horizontal dimensions and 1 cm in height. The PVC is carefully oiled, cleaned and oiled again after each use.

A fine green mortar is prepared, for example, by operating a batch in which the following elements are introduced in order by parts by weight (wt): - crushed silica sand F I5 from the company Silica and Kaolin = 300 p in p - limestone flour BL 24 from the company OMYA = 395 p. in p.

- PORTLAND CPA55 white cement = 300 p. in p.

- MELMENT superplasticizer (registered trademark) = 4.5 p. in p.

- Green Oxide of GN Green Chrome from the company BAYER: = 5 p. in p.

- Mixing water = 84 p. in p.

The quantitative ratio of water to cement is therefore 0.28 per I here and despite this low rate, the mortar is very liquid.

The whole is energized for three minutes in a planetary mortar mixer and poured into the mold to a thickness of approximately 3 mm. Once in place, the mold and its mortar are vibrated for 20 seconds with a small concrete vibrator.

Then, a mixture is mixed comprising: - coarse sand-lime sand 0.5 to 1.5 mm = 400 p. in p - fine limestone 0.2â 0.5 mm = 350 p. in p - gray cement CPA 55 = 250 p. enp - MELMENT superplasticizer = 0.4 p. in p - water = 85 p. in p
Despite the low water / cement ratio, the product is fairly liquid and flows easily into the molds.

This second preparation is poured over a thickness of 7 mm into the mold on the first layer which has not yet hardened and the two layers are again vibrated for 20 seconds.

We see that the mixture is much too liquid to be used in the traditional process, and that if we want to unmold it, it sticks to the mold, disintegrates if we remove the walls of the mold, and that what remains of the tile spreads out into a formless dough if you want to turn it out. So the traditional process is not suitable.

Then, after an hour of rest, the upper level is stamped with a metal punch comprising slight parallel undulations of amplitude 5 mm, depth I mm and the inscription of the trademark.

The mortar (two layers) is kept in the mold which is sent to a hot (25 "C) and humid (95% to 100% RH) enclosure for 24 hours.

The new hard tile is easily removed from the mold. The mold is cleaned, recycled and the tile is sent to conservation under water for 5 days at around 400C. After this time, it came out of the water and sent to dry slowly in a room of average humidity around 60 to 70% RH, temperature 20 C to complete its hardening and dry regularly.

A green tile is obtained.

Example # 2:
Decorative layer:
Decor mortar molded in very liquid paste under a thickness of 4 mm.

The following are successively introduced into the mixer: 1- crushed marble from the OMYA company, name DURCAL I30, from 50 to 300 microns
= 30 parts by weight 2- limestone flour less than I00 microns DURCAL 40 (from the OMYA Company)
30 p. in p.

3-white cement CPA 55 = 40 p. in p.

4- BAYFEROX 920 colored oxide from BAYER = 2 p. in p.

5- water repellent zinc stearate = 0.3 p. in p.

6- MELMENT water reducer = 0.8 p. in p.

7- SIKALATEX resin registered trademark SIKA = 2 p. enp.

8- water to obtain a fluid grout = 12 p. in p.

The assembly after mixing for 5 minutes is poured into a compartmentalized mold of polyethylene plates adjusted to form a square of 25 × 25 cm and over a thickness of 4 mm.

The grout is then covered with a fine mortar made from gray cement, obtained by energetic mixing and whose formula is for this example:
Reinforced structure layer of composition: - silico-limestone sand of O, IOO at 2 mm = 75 p. in p.

- gray cement CPA 55 = 25 p. enp.

- FONDU aluminous cement from Lafarge = I p in p - SIKALATEX resin (SIKA) = 3 p. in p.

- glass fibers cut to 3 mm = I, 5 p. in p.

- mixing water = 8 p. in p.

- lignosulfonate water reducing additive = 0.4 p. in p. (Galloryl reference
CPFI)
This mixture is energized for five minutes.

5 mm of this mortar is poured onto the decorative layer previously described which has not yet been taken, then a glass grid of I cm mesh is placed flat on this mortar, for example the CHOMARAT grid reference WG 2IO, of 220 g / m2, cut into a square with dimensions equal to those of the tile, here 20 X 20 cm, and once placed on this mortar, it is pressed with a steel piston, and vibro-compression is carried out for one minute. Then, the compression punch is removed and the bottom and the walls of the mold are kept.

The whole is sent to a warm room (around 50-60 "C) and very humid (at saturation) for 14 hours.

The tile has become hard and demouldable. It is unmolded, the mold is cleaned, recycled and the tile is stacked with other elements manufactured in succession and then kept in the same room for 5 days until obtaining a high hardening.

The tile thus obtained is very solid. The impact resistance is tested in the following way: the tile is sealed on a 10 cm thick concrete plate using a commercial adhesive mortar. It is left to dry for 7 days at 20 ° C., then it is placed on the ground, horizontally and a steel ball weighing 300 grams with a drop height of 50 cm is dropped on it. We see that the tile does not split.

Example # 3
During the manufacture of the tile according to Example I, we come, behind and on the still soft structure mortar, placed in its mold, to apply a pre-cut piece to the exact dimension of the said tile, of a non-woven of polymer fibers , and / or glass. In this example, a pre-cut element of the Rotaflex 809 A non-woven fabric from the Chomarat Company is applied, weighing 140 grams per m2.

It is pressed on the wet mortar, and it is rolled to make it penetrate into the said mortar. This non-woven fabric has a needled veil of polyester fibers, and a grid of long glass fibers. After hardening, this non-woven fabric is barely visible. However, it can be seen that its presence multiplies by a coefficient of I, 5 the impact resistance of said tile put in the position of use and glued to a support by a conventional tile adhesive, compared to a control.

It is also noted that, if during its use, such a tile is broken, the presence of this nonwoven reinforcement retains between them integral with the assembly of any fractured pieces. So, this product can be applied against walls
and in the event of a possible rupture of a piece, falls to the ground likely to injure are avoided. Such an advantage can be useful as an anti-sysmic product: in the event of an earthquake, fragments will not be projected onto the inhabitants.

More generally, the invention covers the following subjects: - Formulation of floor tiles based on fine cement mortars comprising from 40 to 90 parts by weight of fine sands less than 5 mm, from 10 to 60 parts by weight of Portland and / or aluminous type cement, 0.2 to 3 parts by weight of the cement of fluidifying additives, from O to 5% of the total count on the dry basis of emulsions of polymer resins compatible with cements, from O to 5 % by weight of short mineral, metallic and / or real and / or polymeric fibers less than 5 mm in length, from 0 to 1% of water repellents for cementitious compositions, mixing water in sufficient quantity but preferably with a quantity of water relative to the cement less than or equal to 0.35 by weight, while being fluid enough to allow a good spreading and a good filling of the mortars in economical molds which will accompany the tile until its setting time , time from which and the tile can be handled without risk.

 - Cured tiles thus obtained made up of a single mortar of homogeneous color and thickness ranging from 6 to 20 mm - Cured tiles thus obtained made up of two layers, a decorative layer of varied color, united or capable of reproducing various decorative effects according to the process of partitioning usual in the profession and of thickness 1 to 6 mm and of a layer of structure placed behind of thickness 2 to 19 mm.

- Cured tiles thus obtained, made up of three successive layers: a layer of fine decoration mortar, a layer of thicker mortar of structure and a layer of fine cementitious fiber cement mortar, tensile, comprising short woven, meshed fibers, or non-woven, or presented in grids, introduced during manufacture and embedded in the mass or applied to the lower surface of the tile.

Claims (8)

1 - Thin tiles made of prefabricated plates of all widths or shapes,  and of thickness less than 20 millimeters, for floors and walls, made of cement and sand mortars with rich decorative effects, characterized by the fact that high performance cement mortars are used, using plasticizers, plasticizers and superplasticizers. deferred demolding process using economical molds which accompany the tile in its hardening. 2- Tile according to claim nl, characterized in that the composition used is based on fine cement mortars comprising from 40 to 90% by weight of fine sand less than 5 mm, from 10 to 60% by weight of type cement HARBOR LAND and / or aluminous, from 0.2 to 3% by weight of the cement of fluidizing additives, from 0 to 5% of the total count on the dry basis of emulsions of polymer resins compatible with cements, from 0 to 5% by weight short mineral and / or metallic and / or glass and / or polymeric fibers less than 5 mm in length, from 0 to 1% of water-repellents for cementitious compositions, mixing water in sufficient quantity but preferably with a quantity of water relative to the cement less than or equal to 0.35 by weight while being fluid enough to allow good spreading and good filling of the mortars in economical molds which will accompany the tile at least until its time of setting, time from which the tile can be handled without risk. 3- Tile according to claim 1 or 2, characterized in that it contains in its structure long fibers, placed in the form of fabrics or grids with large meshes, or non-woven with meshes of a few millimeters, for example of 1 cm, and thus having increased resistance to bending and impact, and a reduction in risks during fractures, useful in particular in anti-seismic coatings. 4- New method of manufacturing floor and wall tiles according to the preceding claims characterized in that the fact of using high performance formulations allows to easily fill by simple flow with or without vibration, economical molds that accompany the tile during the whole time of its hardening. 5- Tile obtained according to one of claims 1 to 3, or obtained by the process according to claim 4, characterized in that it consists of a single mortar of uniform color and thickness ranging from 6 to 20 mm. 6- Tile obtained according to one of claims 1 to 3, or obtained by the method according to claim 4, characterized in that it consists of two layers, a decorative layer of varied color, solid or capable of reproducing various decorative effects according to the partitioning process usual in the profession and of thickness 1 to 6 mm, and a layer of structure, placed behind, of thickness 2 to 19 mm. 7- Tile obtained according to one of claims I to 3, or obtained by the process according to claim 4, consisting of three successive layers: a layer of fine decoration mortar, a layer of larger mortar of structure and a layer of fine cementitious fiber-reinforced mortar, tensile, comprising short woven, meshed, or non-woven fibers, or long fibers presented in grids or fabrics, introduced during manufacture and embedded in the mass or applied to the lower surface of the tile. 8- Decorative tile obtained according to one of claims 1 to 3, or obtained by the process according to claim 4, and whose decorative effect is obtained by the use in the formulation of the decor layer, of metallic aggregates of iron, stainless steel, bronze, cast iron, and developing appropriate metallic effects.