EP3351684B1 - Method for setting a road surface - Google Patents

Description

The present invention relates to a method for the construction and maintenance of a road surface for underground garages and parking garages from a cementitious composition, which contains an additive that improves the water-repellent and water-sealing properties of the cementitious composition or the concrete.

A parking garage is to be understood as a one-storey or multi-storey building that has a parking space for vehicles inside the building, which is therefore covered by the building. For the purposes of this document, a garage, in particular a large garage, also represents a parking garage.

According to the state of the art, it is known to design road surfaces for underground garages and parking garages from asphalt or mastic asphalt, which has the disadvantage of the dark color, among other things. It is also known to carry out these coverings with surface protection systems (OS systems) which are applied in the form of polymer-containing layers as protection to a concrete surface. The above-mentioned methods are relatively complex and the pavements that are erected are susceptible to wear. It would be desirable to build a concrete pavement. However, concrete has the disadvantage that conventional concrete only insufficiently meets the requirements for chemical resistance, abrasion resistance, water resistance and crack bridging. Especially when constructing industrial floors, it is therefore known to subsequently provide an erected concrete screed with a sealing layer made of a solution containing water glass, which impregnates the concrete up to a few mm below the surface. It is disadvantageous that the impregnated layer is relatively thin, which means that the floor has to be repaired after wear and tear, and that crack healing is not sufficient or continuous when impregnated.

According to the state of the art, it is known that buildings, dwellings, bridgeheads, bridge piers, harbor moles, dams, sewers, tunnels, foundations standing in the water or other structures made of concrete, in which there is moisture on the concrete or even water, with sealant additives to be modified so that moisture cannot penetrate, and there is no significant moisture penetration of the hardened concrete.

The sealant additives known today mainly differentiate between hydrophobic and crystallizing sealant additives.

Hydrophobic sealants contain, for example, alkaline earth metal salts of fatty acids, which reduce the capillary water absorption of the concrete. For example, when using calcium sterates or calcium oleates, the molecules align themselves on the surfaces of the concrete due to their surfactant structure, i.e. also on the inner surfaces of cracks or capillaries, in such a way that the long non-polar hydrocarbon chains are directed away from the solid surfaces and the polar caboxylate groups adhere to one another attach the solid surfaces. This significantly reduces the wettability of the concrete surfaces.

In the case of crystallizing sealant additives, soluble carbonates and organic acids, such as tartaric acid or fumaric acid, are added to the fresh concrete. These connections lead to the formation of crystal structures in the capillaries of the concrete, as a result of which these are closed and the penetration of water is thereby reduced. In any case, the closing of cracks in the concrete by crystallization requires the presence of water or moisture, so that this only takes place when it comes into contact with water. This explains that these additives are only intended for concrete that has sufficient contact with water or moisture, such as waterlogging from the ground.

The documents reveal concrete admixtures for crystalline sealing Schomburg GmbH: "Safety data sheet Betocrete C16", May 12, 2016, pages 1-7, XP055386410 and Schomburg GmbH: "Betocrete C16, concrete admixtures for crystalline sealing, technical data sheet", May 12, 2016, pages 1-2, XP055386418 .

From the EP2292568A is an improved sealant additive for the production of cementitious compositions or concrete is known, which also ensures a good seal of the structure in the area of hydraulic engineering and reduces the risk of moisture penetration of the concrete, wherein it is described that cracks of up to 0.3 mm in contact with water be closed by crystallization of the sealing additive.

The JP H02 145469 A describes a fast-curing asphalt concrete.

The object of the invention is to provide a method for erecting a road surface for underground garages and parking garages, which is formed from concrete and meets the requirements with regard to watertightness, durability and crack bridging.

According to the invention, it is proposed to design the road surface as a layer of concrete which is thick compared to the prior art and has a layer thickness of 2 cm-10 cm, which contains a crystalline sealing agent added to the concrete over the entire layer thickness, the road surface being on an existing concrete suspended ceiling or a concrete floor slab is applied and after drying it is supplied with sufficient water to ensure a permanent crack bridging.

The invention is based on the idea of using concretes which are designed for constant contact with water, for example as a casing for drinking water containers for the pavement, since these are waterproof, chemical-resistant and hard and therefore wear-resistant. However, the use of these concretes as a road surface for underground garages and parking garages appeared until The present invention was not possible, or was in any case not carried out, since the required crack bridging did not seem possible. This can be explained by the fact that the concretes were developed for use in permanently moist environments and the crack bridging by crystallization requires a certain amount of moisture or wetness. In the case of floors in underground garages and parking garages, however, this contact with moisture does not exist or is not guaranteed permanently, so that the concrete would form cracks, as a result of which the floor would no longer be sealed against oils and other organic liquids.

The solution according to the invention for this problem of supplying the concrete floor "artificially" or in a defined intended way with water may appear simple in retrospect, but the present invention eliminates a longstanding misconception and creates a new advantageous possibility for the production of road surfaces .

The advantage of the present invention is the use of conventional concrete as the basis for the road surface, which is an inexpensive and easy-to-use building material. Concrete has the advantage over asphalt that it can be light to white and can therefore be colored as desired. The use of the preferably colorless or transparent crystalline sealant does not change or impair the appearance of the concrete. It is also advantageous that crystalline crack bridging takes place over the entire layer thickness of the concrete covering, which means that the entire concrete layer is designed as a wear layer, and the covering cannot therefore be repaired after a surface coating that is a few millimeters thick has worn. It is particularly advantageous that the road surface can be applied as a layer in one operation, which saves labor and time, since sealing is not required in a later step, as with OS systems.

In any case, the concrete admixture for the concrete covering according to the invention contains a crystalline sealing agent which, upon contact with water, leads to crystallization, the crystallization resulting in an increase in volume which leads to the closing of cavities and cracks.

Standard concrete such as C30 / 37 is suitable as concrete.

A liquid crystalline waterproofing agent from SCHOMBURG GmbH with the brand name Betocrete® C-Series, in particular Betocrete C16 or Betocrete C21, is particularly preferably used as a concrete additive. It is an aqueous salt solution with metal soaps containing potassium carbonate, sodium carbonate or lithium carbonate.

These crystalline sealants are among others in the EP 2292568 A described, the content of which is summarized in the following paragraphs.

The preferred sealant additive for cementitious compositions accordingly contains at least one synthetic and / or natural wax in aqueous dispersion or emulsion. Under "wax" or "waxing" as part of the description of the EP 2292568 A understood animal and vegetable waxes, which also include lipids, for example. The main components of such waxes are esters of fatty acids with long-chain, aliphatic, primary alcohols, the so-called wax alcohols. Furthermore, under "waxing" in the sense of EP 2292568 A for example, also understood jojoba oil or similar substances that do not consist of triglycerides and are therefore not fatty oils, but are chemically considered liquid waxes. In addition, "waxes" in the sense of EP 2292568 A also synthetic waxes, which are mainly obtained from petroleum and which consist, for example, of paraffin or hard paraffin. After all, "waxes" are in the sense of EP 2292568 A also natural waxes that have been chemically modified or completely synthesized, such as, for example, polyethylenes or copolymers or, for example, also from Soy wax obtained from hydrogenation. The wax or waxes used in the production of the advantageous sealant additive preferably contains at least one ester of higher aliphatic fatty acids, which preferably have C30-C34 alcohols. The advantageous sealant additive also preferably contains at least one water-soluble or water-dispersible metal salt of the C8-C34 fatty acids. The metal salt or salts of the C8-C34 fatty acids are preferably alkali metal, alkaline earth metal and aluminum salts. Particular preference is given to selecting from the group of water-soluble or dispersible metal salts of C8-C34 fatty acids, such as, for example, potassium caprylate, potassium caprinate, calcium laurate, sodium myristate, sodium palmitate, potassium oleate, lithium stearate, sodium stearate, potassium stearate, calcium stearate, magnesium stearate, aluminum di- and stearate.

The advantageous sealant additive preferably also contains water-soluble carbonates in addition to one or all of the above components. By adding such carbonates, the effect of crack healing upon contact with water is achieved, which has previously been used to advantage in hydraulic engineering.

The added water-soluble carbonates serve as carbonate sources in hardened concrete, from which carbonate ions dissolve when water enters through cracks or capillaries and diffuse into the cracks and capillaries. There is a carbonation and thus a closure of the cracks or the capillaries.

The water-soluble carbonates and hydrogen carbonates are particularly preferably selected from a group which contains alkali carbonates and ammonium carbonates, such as, for example, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, lithium carbonate, lithium hydrogen carbonate and ammonium carbonate, ammonium hydrogen carbonate and combinations thereof and the like.

Alkali carbonate is preferably contained in the crystalline sealant in a proportion of 10-25% by weight.

The crystalline sealant in liquid form with a mass of 2 to 3%, based on the mass of the cement formulation, is preferably added to the mixed concrete, or already to the mixing water, but at least 7 kg per m ^{3 of} the mixed concrete.

• Schritt 1 besteht, wenn benötigt, in der Vorbehandlung des Untergrunds, welche in einer gründlichen Reinigung und Aufrauhung der Betonzwischendecke bzw. der Betonbodenplatte besteht, um die Haftung des nachfolgenden Betonbelags zu verbessern. Zum Aufrauen wird der Untergrund bevorzugt gestrahlt, insbesondere durch Kugelstrahlen. Die Vorbehandlung umfasst weiters die Befeuchtung des Untergrunds mit ausreichend Wasser. Das Aufrauen und Befeuchten des Untergrunds hat sich in Versuchen als ausreichend herausgestellt, um eine ausgezeichnete Haftung des erfindungsgemäßen Betonbelags zu erreichen. Zur Vorbehandlung des Untergrunds eignet sich aber auch das Auftragen von Epoxidharz-Haftgrundierungen oder zementösen Haftgrundierungen.
• Schritt 2 besteht im Auftrag des mit dem flüssigen kristallinen Abdichtungsmittel vermengten Betons auf den Untergrund mit einer Schichtstärke von 2 cm bis 10 cm, bevorzugt mit einer Schichtdicke von 2,5 cm bis 4 cm.
• Schritt 3 besteht im Flügelglätten und eventuellem Feinschliff des Betonbelags.
• Schritt 4 besteht im mehrmaligen Einlassen des ausgetrockneten Betonbelags mit Wasser bis zur Sättigung. Bevorzugt geschieht dies 2- bis 3-mal unmittelbar nach erfolgter Austrocknung des Bodens, sodass ein initialer Schutz und ein Aufhärten des Bodens durch Kristallisation gegeben sind.
• Schritt 5 besteht in der wiederkehrenden Versorgung des Bodens mit Wasser, was vorteilhaft mit der Reinigung des Bodens verbunden werden kann. Durch die besonders wesentliche Zufuhr von Wasser in zeitlichen Abständen wird erreicht, dass in eventuell zwischenzeitlich aufgetretene Risse Wasser eindringen kann und so in diesen die Kristallisation in Gang setzt, was zum Zuwachsen der Risse führt. Dadurch kann eine zuverlässige Rissüberbrückung bei Rissen von bis zumindest 0,4 mm Breite erreicht werden.

An exemplary particularly preferred method according to the invention for erecting the road surface is as follows:

• If necessary, step 1 consists in pre-treating the substrate, which consists in thoroughly cleaning and roughening the concrete false ceiling or the concrete floor slab in order to improve the adhesion of the subsequent concrete covering. The surface is preferably blasted for roughening, in particular by shot peening. The pretreatment also includes moistening the surface with sufficient water. In experiments, roughening and moistening the substrate has proven to be sufficient to achieve excellent adhesion of the concrete covering according to the invention. However, the application of epoxy resin primers or cementitious primers is also suitable for pretreating the substrate.
• Step 2 consists in applying the concrete mixed with the liquid crystalline sealant to the substrate with a layer thickness of 2 cm to 10 cm, preferably with a layer thickness of 2.5 cm to 4 cm.
• Step 3 consists of smoothing the wings and possibly fine-tuning the concrete surface.
• Step 4 consists of repeatedly pouring the dried concrete covering with water until it is saturated. This is preferably done 2-3 times immediately after the soil has dried out, so that there is initial protection and hardening of the soil through crystallization.
• Step 5 consists in the recurring supply of water to the floor, which can advantageously be combined with cleaning the floor. The particularly significant supply of water at intervals ensures that water can penetrate into cracks that may have occurred in the meantime and thus initiate crystallization in them, which leads to the cracks growing together. This enables reliable crack bridging for cracks of up to at least 0.4 mm in width.

The time period for the irrigation and cleaning intervals depends, among other things, on the layer thickness of the concrete covering and can best be determined by tests; a guideline is around 6 months.

It is also less preferred to produce an entire floor slab or an entire false ceiling from the material of the concrete covering according to the invention, and indeed already in the course of the concreting work when the structure is erected, so that the floor slab or the false ceiling itself forms the pavement covering according to the invention. The disadvantage of this is the higher costs, since instead of the 2 cm to 10 cm thick pavement, the entire floor slab or an entire false ceiling would have to be provided with the crystalline sealing agent.

Claims (5)

1. A method of preparing a ground surface made of concrete for an under-ground or over-ground parking garage, wherein one layer of concrete, which contains a crystalline sealant, is applied at a layer thickness of at least 2 cm, characterised in that, immediately after the concrete has dried out, water is applied to the concrete to the point of saturation at least once, preferably 2 to 3 times, wherein the application of water is thereafter continuously repeated at time intervals.
2. The method of claim 1, characterised in that the ground surface is applied to a premade bottom plate or intermediate ceiling, wherein the ground surface is applied at a layer thickness of at most 10 cm, preferably at most 4 cm.
3. The method of claim 2, characterised in that the bottom plate or intermediate ceiling is made of concrete and is cleaned, roughened and wetted as a way of preliminary treatment.
4. The method of any one of claims 1 to 3, characterised in that the crystalline sealant is added to the liquid concrete, or already to its tempering water, as an aqueous saline solution with metallic soaps, which contains an alkali carbonate.
5. The method of any one of claims 1 to 4, characterised in that the ground surface made of concrete is trowelled and/or sanded prior to the initial application of water.