Dry mortar mixture for the production of drainage mortar and method using this dry mortar mixture

Description

[0001] The invention relates to a dry mortar mixture for producing a drainage mortar and a method for producing a paved surface in a bound construction using this drainage mortar.

[0002] DE 20 2004 011888 U1 discloses the production of a drainage mortar by adding only enough water to a dry mix with a cement content of 250-350 kg / m3 and aggregate (e.g., chippings with a grading curve of 2 to 5 mm or 5 to 11 mm, or round aggregate with a grading curve of 4 to 8 mm) to achieve a soil-moist consistency. Water permeability is achieved through the low cement content and the use of so-called "single-grain grading curves" (i.e., the fine grain fraction is omitted, and the grading curve of the aggregate used should be as narrow as possible). Alternatively, a factory-mixed drainage mortar (e.g., Sopro BM 610 or Baumix paving drainage mortar), which are also characterized by the use of "single-grain aggregate," can be used as a water-permeable mortar.

[0003] Outdoor areas paved with paving stones or slabs are currently created using two different techniques. In both cases, a solid base is first created, for example by compacting a bed of gravel. The subsequent construction methods then differ. In one technique known as unbound construction, a layer of gravel or sand is applied to the compacted base. The paving stones or slabs are then laid and positioned on this loose base. The space between the paving stones or slabs is usually filled with filler gravel or sand. No machinery is required to evenly distribute the gravel over the base and to evenly lay the paving stones or slabs, so the effort required for this work technique is relatively low.In contrast, with the bound construction method, a mortar bed of drainage mortar is created on the solid subsurface. The drainage mortar is mixed mechanically and spread evenly over the solid subsurface. Paving stones or slabs are then laid in the unhardened drainage mortar. After the drainage mortar, also known as bedding mortar, has hardened, the space between the paving stones or slabs is usually filled with a jointing mortar based on epoxy resin or cementitious binder. For the bound construction method, a mixing device is usually required on site to mix the drainage mortar. In practice, this mixing process is time-consuming and laborious.

[0004] The invention is based on the object of providing a dry mortar mixture for producing a drainage mortar for paved areas in bound construction, which is easy to process, and of offering a method for producing such a paved area in bound construction using this dry mortar mixture.

[0005] The invention is achieved by a dry mortar mixture for producing a drainage mortar having the features of patent claim 1 and by a method for producing a paved surface in a bonded construction having the features of patent claim 10. Further advantageous embodiments of the invention are listed in subclaims 2 to 9 and 11 to 16. The method and the dry mortar mixture are specifically coordinated with one another, so that they are explained together below.

[0006] To create a paved surface using a bonded construction method, the dry mortar mix according to the invention is evenly distributed in dry form on a solid, water-permeable substrate in the first process step. Unlike the prior art, the dry mortar mix is ​​not mixed with water in the first step to form a mortar, which is then applied to the solid substrate in a moistened state with the desired water content. This eliminates the need for a mixing machine on the construction site to produce a moistened mortar from a dry mortar mix.

[0007] Subsequently, in the process according to the invention, paving stones or slabs are placed on the dry mortar mix and optionally pressed into the dry mortar mix such that the tops of the stones or slabs are uniformly high in a paved area. The paved area prepared in this way is then evenly sprayed with a fine mist with a partial water quantity of 1.2 to 2.0 l / m². This is where the special composition of the dry mortar mix according to the invention comes into play. This contains 20 to 40 wt.% of a binder mixture, 1 to 5 wt.% of hydrophilic, inert fibers, optionally 0 to 40 wt.% of further aggregates and aggregate up to 100 wt.%, i.e., the aforementioned components add up to 100 wt.%. The binder mixture contains, based on the dry mortar mix: 1 to 10 wt.% of a first binder component consisting of amorphous CSA cement, 0.1 to 5 wt.% quicklime as a second binder component, 5 to 15 wt.% alumina cement as a third binder component and 1 to 15 wt.% CEM I R cement as a fourth binder component.

[0008] The fine spray now penetrates through the joints and gaps between the paving stones or slabs to the underlying layer of dry mortar mix. Because only a small amount of water is applied, and very carefully in the form of a fine spray, the water penetrates the dry mortar mix only very slowly. In the initial solidification stage, the addition of water causes the CSA cement to react very quickly with the quicklime and the added water. This creates a protective hardening on the surface of the dry mortar mix, particularly in the area that is first accessible to water penetrating through the joints or gaps between the paving stones or slabs. An amorphous CSA cement is a very fast-reacting cement based on calcium sulfo aluminate.The presence of the second binder component further accelerates the reaction rate of the amorphous CSA cement. In addition to the amorphous CSA cement, an amorphous CA cement (calcium aluminate) mixed with sulfur trioxide can be used. After applying the fine spray, a period of at least 8 minutes is allowed to elapse, during which the dry mortar mix below the paving surface receives protective hardening from the fine spray. The paving surface is then treated with a main water quantity of at least 0.35 liters per kilogram of applied dry mortar mix. The main water quantity now also penetrates through the gaps and joints between the paving stones or slabs to the dry mortar mix, but there it encounters the protective hardening of the mortar mix on its upper surface.Thanks to the hydrophilic, inert fibers contained in the dry mortar mix, the dry mortar mix below the paving stones or slabs does not collapse, but has an inherently water-permeable structure. The majority of the water can now slowly penetrate through the protective hardening into deeper layers of the dry mortar mix and react there with the dry mortar mix. At the same time, the protective hardening created in the first stage prevents the majority of the water from penetrating the dry mortar mix too quickly and carrying particles from the dry mortar mix towards the substrate. Instead, the majority of the water slowly penetrates the dry mortar mix and initiates the setting reactions there, beginning with the first stage of hardening, the reaction of the amorphous CSA cement and, if applicable,of the amorphous CA cement mixed with sulfur trioxide with the quicklime as the second binder component and the water. The dry mortar mix is ​​increasingly permeated by more water slowly penetrating it, so that the alumina cement as the third binder component increasingly reacts with the quicklime as the second binder component and the water in a second setting stage. This second setting stage ensures that the paved area is quickly walkable. In a third hardening stage, the CEM I R cement as the fourth binder component reacts with the main amount of water to ensure that the desired final strength is achieved. CEM I R cements are well known. The R stands for rapid and forms a subgroup of CEM I cements that set particularly quickly. A CEM I 52.5 R or a CEM I 42.5 R cement according to EN 197-1 is particularly preferred in this case.These have proven to be particularly suitable in the binder mixture and in the intended process.

[0009] Using the dry mortar mix according to the invention and the method according to the invention, a paved area can be produced in a bound construction using a dry mortar mix, without the need for a mixing machine on site to produce a moistened mortar before application to the solid subsurface. Internal tests have also shown that omitting process steps c) and d) and using a conventional dry mortar mix to produce a drainage mortar did not produce satisfactory results.Only because the three aforementioned stages of hardening of the mortar mixture take place one after the other in such a way that the first stage reacts very quickly, the second stage more slowly than the first stage, but faster than the third stage, and the third stage more slowly than the first stage and also slower than the second stage, although of course a subsequent setting stage can already start the reaction before a previous stage has completely reacted, is a paved area in a bound construction method obtained whose final strength is comparable to the final strength of conventionally produced paved areas in a bound construction method.

[0010] The first binder component is advantageously present in a proportion of 7 to 8 wt.%, based on the dry mortar mix. The ratio of calcium oxide to aluminum oxide in the first binder component is particularly preferably 1.5:1 to 1.9:1, in particular 1.6:1 to 1.8:1. The aforementioned proportions in the first binder component have proven particularly advantageous for the desired application of the dry mortar mix.

[0011] In a particularly preferred embodiment of the invention, the second binder component, quicklime, is present in a proportion of 1.5 to 2.5 wt.% based on the dry mortar mix. This narrow range has proven particularly advantageous for the intended use of the dry mortar mix.

[0012] Alumina cement is advantageously included as the third binder component in a proportion of 12 to 14 wt.% based on the dry mortar mix. Irrespective of this, the alumina cement preferably contains calcium oxide and aluminum(III) oxide in equimolar amounts, with a deviation of up to + / - 10%. For the purposes of this invention, alumina cement is understood to mean alumina cement in accordance with the EN 14647 standard. These proportions and ratios have each independently proven to be particularly suitable for the intended use of the dry mortar mix.

[0013] In a particularly preferred embodiment of the invention, the fourth binder component is present in a proportion of 5 to 10 wt.% based on the dry mortar mix. This narrow range has proven particularly advantageous for the intended use of the dry mortar mix.

[0014] In a particularly preferred embodiment of the invention, the dry mortar mix is ​​free of any additional binders other than the four aforementioned binder components. Irrespective of this, the dry mortar mix is ​​advantageously free of setting retarders. The dry mortar mix according to the invention and the method according to the invention, in which such a dry mortar mix is ​​used, are specifically coordinated with one another. Binders other than the aforementioned binder components, and independently of these, setting retarders, would adversely affect the desired effect of the gradual solidification of the dry mortar mix in three essentially successive stages. Such setting retarders include, for example, organic fruit acids or hydrous or anhydrous calcium sulfates, such as gypsum or anhydrite.

[0015] In a particularly preferred embodiment of the invention, the dry mortar mix contains 10 to 20 wt.% lightweight aggregates according to EN 13055. This makes the dry mortar mix easier to process without adversely affecting the final strength of the paving surface produced with the dry mortar mix. In addition, this lightweight aggregate increases the water permeability of the drainage mortar produced with it and prevents small particles from being transported towards the subsurface with incoming water. Pumice or crushed expanded clay is particularly preferably used as the lightweight aggregate. These two components are open-pored. The surface of pumice or crushed expanded clay is rough, which causes fine binder particles to adhere and embed themselves, thus preventing them from being washed out of the dry mortar mix and creating a microstructure that promotes drainage.

[0016] In a particularly preferred embodiment of the invention, in step c) of the method according to the invention, the paved area is sprayed with a fine spray mist with a water quantity of 1.4 to 1.8 l / m 2< , in particular 1.5 to 1.7 l / m 2<. Irrespective of this, the fine spray mist particularly preferably has an average droplet size of 0.03 mm to 0.10 mm. These embodiments of the method have surprisingly each independently proven to be particularly suitable for achieving the rapid formation of a protective hardening on the upper side of the dry mortar mix during the first hardening stage and at the same time preventing the particles contained in the dry mortar mix from being washed out.

[0017] In an advantageous embodiment of the invention, the dry mortar mix is ​​applied in step a) to a thickness of 5 to 7 cm without compaction. "Without compaction" in the context of this invention means that the dry mortar mix applied in step a) is not subsequently compressed and solidified, for example, with a vibrating machine, but instead that paving stones or slabs are placed directly onto the dry mortar mix in step b). Naturally, this step b) slightly compresses and solidifies the dry mortar mix.

[0018] The paving stones or slabs processed in step b) are particularly preferably moistened with an adhesive slurry on their contact surfaces on the dry mortar mix before they are placed on the dry mortar mix. The adhesive slurry ensures a good bond between the paving stones or slabs on the one hand and the mortar mix on the other. Irrespective of this, the paving stones or slabs are particularly preferably positioned next to one another in step b) in such a way that an open joint remains around each paving stone, which is visibly filled with water up to the upper edge of the paving stones or slabs at least once in step e). Particularly preferably, the open joints around each paving stone or slab are visibly filled with water up to the upper edge of the paving stones or slabs more than once.The water standing in the joints then slowly penetrates the dry mortar mix through the protective hardening and gradually reacts with the underlying dry mortar mix without significantly entraining particles of the dry mortar mix toward the subsurface. Regardless of this, any open joint remaining around each paving stone or slab is preferably filled with a joint filler material, particularly an epoxy resin-based or cementitious binder-based joint mortar, after the paving surface has been created and mixed with the water in steps c) and e). The filler material further stabilizes the paved surface.

[0019] In a particularly preferred embodiment of the invention, the hydrophilic, inert fibers are formed from basalt or glass fibers. The basalt or glass fibers advantageously have a length of 4 to 8 mm. These embodiments have proven particularly suitable in the dry mortar mix with regard to the intended use in the process according to the invention.

[0020] In a particularly preferred embodiment of the method, a period of at least 10 minutes is waited in step d) before the method continues with step e). The desired protective hardening of the upper surface of the applied dry mortar mixture in the areas below the joints and gaps between the paving stones or slabs can thus develop sufficiently even at lower temperatures.

[0021] For the purposes of this invention, a dry mortar mix is ​​understood to be a mixture of binders, aggregate, and optionally additives. This mixture is then mixed with water during processing to produce a mortar that then hardens.

[0022] In a particularly preferred embodiment of the invention, no additional water is applied to the paving surface during steps b) to d). This allows the desired protective hardening to initially form particularly well on the upper surface of the dry mortar mixture. Embodiment of the invention

[0023] A solid, water-permeable subsurface in the form of a compacted gravel surface is created. The dry mortar mix according to the invention is applied in dry form to this subsurface and evenly distributed to a thickness of 6 cm. The dry mortar mix according to the invention contains 7 wt.% amorphous CSA cement, 2 wt.% quicklime, 13 wt.% alumina cement, 8 wt.% CEM I 52.5 R cement, 15 wt.% pumice, and aggregate with a grain size of 1.25 to 2.5 mm up to 100 wt.%. The dry mortar mix is ​​not compacted. Paving stones are immersed in a bonding slurry with their contact surface on the dry mortar mix, thereby wetting them. The stones are then placed on the dry mortar mix (bedding layer) and pressed into the dry mortar mix to the desired height using a rubber hammer. The dry mortar mixture is compacted.An open gap (joint) remains between the individual paving stones. The surface is sprayed with a fine water spray. A partial water quantity of 1.2 to 2.0 l / m² is applied. The water input is so small and carefully that no fine-particle components of the dry mortar mix are washed out. A period of 10 minutes is waited, during which the dry mortar mix below the paving surface is given a protective hardening by the fine spray. The main quantity of water is then applied to the prepared paving surface by pouring water from buckets and / or using a garden hose, without a sharp jet, until the joints are visibly filled with water up to the top edge of the paving stone.This hydrostatic pressure in the joint promotes vertical and horizontal wetting of the entire bedding layer. After 30 minutes, the paving surface is wetted again with water to ensure that the bedding layer is sufficiently supplied with water for complete hydraulic setting. It was found that the surface created in this way is load-bearing after 24 hours (at an ambient temperature of 20°C). The joints of the paving surface are then filled with a water-permeable, epoxy resin-based joint mortar.

Claims

1. Dry mortar mixture for the production of a drainage mortar containing: - 20 to 40 wt.% of a binder mixture, - 1 to 5 wt.% hydrophilic, inert fibers, - optionally 0 to 40 wt.% other concrete aggregates and - aggregate until 100 wt.% is reached, wherein the binder mixture contains, based on the dry mortar mixture: - 1 to 10 wt.% of a first binder component consisting of amorphous CSA cement, - 0.1 to 5 wt.% of quicklime as a second binder component, - 5 to 15 wt.% of alumina cement as the third binder component and - 1 to 15 wt.% of CEM I R cement as the fourth binder component.

2. Dry mortar mixture according to claim 1, characterized in that the first binder component is contained in a proportion of 7 to 8 wt.% based on the dry mortar mixture.

3. Dry mortar mixture according to one of the preceding claims, characterized in that the ratio of calcium oxide to aluminium oxide in the first binder component is in each case 1.5 to 1 to 1.9 to 1, in particular 1.6 to 1 to 1.8 to 1.

4. Dry mortar mixture according to one of the preceding claims, characterized in that the second binder component is contained in a proportion of 1.5 to 2.5 wt.% based on the dry mortar mixture.

5. Dry mortar mixture according to one of the preceding claims, characterized in that alumina cement is contained in a proportion of 12 to 14 wt.% based on the dry mortar mixture.

6. Dry mortar mixture according to one of the preceding claims, characterized in that the alumina cement contains calcium oxide and aluminum III oxide in equimolar amounts with a deviation of up to + / - 10%.

7. Dry mortar mixture according to one of the preceding claims, characterized in that the fourth binder component is contained in a proportion of 5 to 10 wt.% based on the dry mortar mixture.

8. Dry mortar mixture according to one of the preceding claims, characterized in that the dry mortar mixture is free of further binders apart from the four binder components.

9. Dry mortar mixture according to one of the preceding claims, characterized in that the dry mortar mixture is free of setting retarders.

10. Process for producing a paved surface using the bound construction, in which a) a dry mortar mixture according to one of the preceding claims is evenly distributed in dry form on a solid, water-permeable substrate, b) paving stones or slabs are placed on the dry mortar mixture and pressed onto the dry mortar mixture in such a way that the tops of the stones or slabs in a paved surface are of uniform height, c) the paved surface prepared in this way is evenly sprayed with a fine spray mist with a partial water quantity of 1.2 to 2.0 l / m2, d) a period of at least 8 minutes is waited for during which the dry mortar mixture below the paved surface is given a protective hardening by the fine spray mist, e) the paved surface is mixed with a main amount of water of at least 0.35 liters per kilogram of dry mortar mixture processed.

11. Process according to claim 10, characterized in that in step c) the paved surface is sprayed with a fine spray mist with a water quantity of 1.4 to 1.8 l / m2, in particular 1.5 to 1.7 l / m2.

12. Process according to one of claims 10 or 11, characterized in that the dry mortar mixture is applied in step a) with a thickness of 5 to 7 cm without compaction.

13. Process according to one of claims 10 to 12, characterized in that the paving stones or slabs processed in step b) are wetted with an adhesive slurry on their contact surfaces with the dry mortar mixture.

14. Process according to one of claims 10 to 13, characterized in that the paving stones or slabs are positioned next to one another in step b) in such a way that an open joint remains around each paving stone or slab, which is visibly filled with water up to the upper edge of the paving stones or slabs at least once in step e).

15. Process according to one of claims 10 to 14, characterized in that the fine spray mist has an average droplet size of 0.03 millimeters to 0.10 millimeters.

16. Process according to one of claims 10 to 15, characterized in that in step d) a period of at least 10 minutes is waited for.