EP0609629A1 - Process for making anti-slip paving stones and paving stones obtained according to this process - Google Patents

Abstract

The invention relates to a process for making paving stones (1) which have non-slip working surfaces, these comprising, in the plane of their working surface, the polished faces (3) of mineral elements (4) held within at least one binder layer (6), such as concrete, which constitutes at least one fraction of the thickness of a block of cured binder from which the paving stone is produced. It is characterised in that, in order to render such paving stones (1) anti-slip, by means of at least one chemical agent which is inactive on the mineral elements (4), after polishing but before laying, the binder (6) which appears between the edges (11) of the visible faces (3) of the mineral elements (4) is chemically etched on the working surface (2) of each paving stone. <IMAGE>

Description

The invention relates to a method of manufacturing non-slip tiles.

The invention relates to the manufacture of non-slip tiles, the surface of which is intended to be crushed, called useful surface, consists of polished faces of very hard mineral elements maintained in a concrete bed.

• on commence par couvrir le fond de moules de taille adequate avec des éléments minéraux tels des cassons de granit, de marbres ou autres pierres dures puis,
• on coule au moins un lit de béton sur ces éléments de manière à les emprisonner et,
• aprés prise du béton et/ou compression sous presse, on démoule les blocs pour les entreposer en vue d'un séchage complet au terme duquel,
• on usine notamment par abrasion chaque bloc au droit de sa face dans le plan de laquelle apparaissent les éléments minéraux et ce jusqu'au degré souhaité de polissage généralement dit grésage.

To make tiles of this type:

• we start by covering the bottom of molds of adequate size with mineral elements such as granite, marble or other hard stones, then,
• at least one bed of concrete is poured over these elements so as to trap them and,
• after setting of the concrete and / or compression in a press, the blocks are removed from the mold for storage for complete drying at the end of which,
• in particular, each block is machined by abrasion in line with its face in the plane of which the mineral elements appear, and this up to the desired degree of polishing, generally called grinding.

These slabs are then called to be laid and fixed to the ground by cement or any other process.

After laying, it is known to remove any cement stains by a very limited and superficial attack on the paving which leaves the binder of the block cassettes intact.

The useful surfaces of the slabs obtained according to this process have a very beautiful appearance but have the drawback of being particularly slippery, in particular when they are wet.

To overcome this drawback, it is known to break the continuity of each polished surface by producing areas of high roughness, such as narrow parallel and / or crisscrossed rough strips, which are produced by sandblasting on a mask previously affixed to the surface to be prepared.

This technique has good results but is particularly expensive and detracts from the appearance of the mineral elements.

Another technique closer to the invention consists in treating each freshly demolded slab by applying to its face in which the mineral elements appear, a coating the composition of which is chosen to delay the setting of the concrete locally, which allows later but in time useful to remove the non-crystallized concrete in order to create on a certain depth an absence of joint called reserve.

After surfacing and polishing, provided that the depth of the reserves has not been exceeded, each slab has, despite its polished appearance, a certain roughness due to the absence of concrete between the edges of the faces of mineral elements located in the plane of the useful surface of each slab.

Within the above-mentioned limits, this technique gives good results but is also expensive to implement.

A result which the invention aims to obtain is a method of manufacturing non-slip tiles which is less costly than those known independent of the importance of polishing and leading to a product offering an excellent appearance.

To this end, the subject of the invention is a method of the aforementioned type, in particular characterized in that, to make such slabs non-slip, by means of at least one chemical agent which is inactive on the mineral elements, after polishing but before laying, a chemical attack on the binder which appears between the edges of the visible faces of the mineral elements is carried out on the useful surface of each slab.

• figure 1 : vue partiellement et en coupe transversale une dalle aprés préparation en vue du traitement,
• figure 2 : vue partiellement et en coupe transversale, une dalle aprés traitement selon le procédé de l'invention.

The invention will be clearly understood on reading the description below made by way of nonlimiting example with regard to the attached drawing which schematically represents:

• FIG. 1: partially and cross-sectional view of a slab after preparation for treatment,
• Figure 2: view partially and in cross section, a slab after treatment according to the method of the invention.

Referring to the drawing, it can be seen that the slab 1 has a surface 2 intended to be walked on, said useful surface which consists essentially of plane faces 3 of mineral elements 4 held in a layer 5 of binder 6 such as concrete.

• on dispose des éléments minéraux 4 sur le fond de moules (non représentés), chacun de taille adéquate,
• on coule au moins une couche 5 de liant 6 tel un lit de béton sur ces éléments 4 de manière à les emprisonner et à constituer un bloc,
• aprés compression et/ou prise du liant, on démoule les blocs 7 formant ainsi les dalles puis, on entrepose ces dits blocs en vue d'un séchage complet, aprés quoi,
• aprés un pré-séchage par exemple par repos de trois à quatre jours ou par étuvage de deux jours, on usine et on polit chaque bloc 7 au droit de sa face 8 que les éléments minéraux 4 affleurent de manière à rectifier son plan et à constituer la surface utile 2 de la dalle 1.

To make such tiles 1:

• there are mineral elements 4 on the bottom of molds (not shown), each of adequate size,
• at least one layer 5 of binder 6 is poured such as a concrete bed onto these elements 4 so as to trap them and form a block,
• after compression and / or setting of the binder, the blocks 7 are removed from the mold thus forming the slabs then, these said blocks are stored for complete drying, after which,
• after pre-drying, for example by resting for three to four days or by steaming for two days, each block 7 is machined and polished at right angles to its face 8 that the mineral elements 4 are flush so as to rectify its plane and to constitute the useful surface 2 of the slab 1.

In Figure 1, there is shown in strong dotted lines the volume taken from each poured block in order to prepare the useful face of a slab.

In a variant embodiment, each block also undergoes an operation that bevels its edges.

Remarkably, to make such slabs 1 non-slip, by means of at least one chemical agent 10 which is inactive on the mineral elements 4, after the operation of polishing but before laying, a chemical attack on the binder 6 which appears between the edges 11 of the visible faces 3 of the mineral elements 4 is carried out on the useful surface 2 of each slab 1.

Notably, during the chemical attack on the binder 6, the activity of the chemical agent 10 is controlled so as to limit the attack depth of the binder 6 to a predetermined value P.

To be able during the chemical attack, to control and in particular limit the depth of attack, prior to this step, each slab is soaked in line with its useful face 2 and this, to a predetermined depth with a fluid 12 known for its properties to limit the activity of the chemical agent 10 used.

Preferably, when the binder is concrete, hydrochloric acid is used as chemical agent, for example in 33% solution.

The chemical agent can be of any type capable of gnawing at the binder.

In this case, as the soaking fluid 12, water is used.

Advantageously, the treatment is carried out on concrete which is still incompletely dry and in particular less than twenty five to thirty days after molding.

For treatment, the chemical agent is deposited using a roller and a brush or by spraying in at least one pass, then rinsing is carried out.

These blocks located side by side on a conveyor are for this purpose brought to the treatment station and then to the rinsing station.

The distance between the stations and / or the forward speed of the transporter makes it possible to define the duration of the chemical attack.

Under the treatment area, an active agent recovery tank is provided, the elimination of which can be done in conjunction with limestone dust from polishing which will correct the pH before rejection.

Above the treatment area, a hood collects the acid vapors and evacuates them.

To constitute the mineral elements, we choose minerals insensitive to the chosen chemical agent, such as granite, porphyry, silica or quartz.

Claims (4)

Method for manufacturing slabs (1) with useful non-slip surfaces and comprising in the plane of their useful surface the polished faces (3) of mineral elements (4) trapped in at least one layer of binder (6) concrete, which constitutes at least a fraction of the thickness of a block of hardened binder in which the slab is made,
which method implements at least one step in which the polishing of each useful surface (2) of a slab (1) is carried out,
this process being CHARACTERIZED in that, to make such slabs (1) non-slip, by means of at least one chemical agent (10) inactive on the mineral elements (4), after polishing but before laying, the useful surface (2) of each slab a chemical attack on the binder (6) which appears between the edges (11) of the visible faces (3) of the mineral elements (4). Method according to Claim 1, characterized in that, during the chemical attack on the binder (6), the activity of the chemical agent (10) is controlled so as to limit the attack depth of the binder to a predetermined value (P). Method according to claim 1 or 2 characterized in that, in order to be able to control the depth of attack during the chemical attack, prior to this step, each slab is soaked in line with its useful face (2) and this on a predetermined depth with a fluid (12) known for its properties in limiting the activity of the chemical agent used. Slab (1) of the type with useful surfaces (2) non-slip and comprising in the plane of their useful surfaces the polished faces (3) of mineral elements (4) trapped in at least one layer (5) of binder (6 ), such as concrete, which constitutes at least a fraction of the thickness of a block (7) of hardened binder (6) in which the slab is made, characterized in that it is obtained according to the process of any one of claims 1 to 3.

Images