Mortar mixture for thermal insulation and/or as fire protection and for universal applications, and methods for the production and use thereof

Abstract

A mortar mixture for horizontal surfaces or as casting mortar in molds has at least 20% of the mortar mixture by volume being balls composed of expanded silica sand or expanded perlite with the balls being glazed and closed at the surface thereof and filled with air. The expanded perlite balls are mixed with binding agents, additives as binders, an air-void forming agent, chemical admixtures as liquefiers, quick-setting binders, or a combination thereof, and composed of polymers. The method for producing the mortar mixture is performed by sorting perlite sand into various grain sizes by a grading curve. Each individual grain size is then expanded in a trickling channel having multi-stage temperature zones so that the surface of the balls is glazed. The glazed, expanded perlite so produced are mixed together into a homogenous mixture by adding binding agents and cellulose, air-void forming agent, chemical admixtures or a combination thereof.

Claims

1. A mortar mixture for internal and external reinforcement and finishing plaster of building envelopes, comprising: glazed, closed-cell balls selected from the group consisting of expanded silica, expanded perlite and a combination thereof, having a compressive strength of 0.7-5.0 N/mm.sup.2 and support grains filling at least 20% of a volume; and, a binder formed as an aqueous polymer dispersion filing at least a portion of a remaining volume of said volume, thereby yielding a reinforcing and finishing plaster in a pasty form, wherein the reinforcing and finishing plaster has a composition based upon a volume of 1,000 liters of: 40050 liters of glazed, extended perlite having a grain size of 0.1 mm to 0.5 mm; 40050 liters of glazed, extended perlite having a grain size of 0.5 mm to 0.8 mm; 12025 kg of Portland cement as a binder; 8025 kg of hydraulic lime as a softening binder; 200 g of cellulose as an additive; 20-60 g of air-voids forming agent; and, the remaining volume comprising a chemical additive selected from the group consisting of a plasticizer, a quick binder, a polymer support grains and a combination thereof.

2. The mortar mixture for internal and external reinforcement and finishing plaster of building envelopes according to claim 1, wherein said glazed, closed-cell balls has a grain size of 0.2 to 2 mm and the support grains have a grain size of up to, and including, 5 mm, and with the reinforcing and finishing plaster having a density of 0.1-0.4 kg/l.

3. The mortar mixture for internal and external reinforcement and finishing plaster of building envelopes according to claim 1, wherein said reinforcing and finishing plaster has a density of less than 1,000 kg/m.sup.3.

4. The mortar mixture for internal and external reinforcement and finishing plaster of building envelopes according to claim 3, wherein said reinforcing and finishing plaster has a value of 40-60 mW/mK.

5. A method for preparing a mortar mixture, comprising: glazed, closed-cell balls selected from the group consisting of expanded silica, expanded perlite and a combination thereof, having a compressive strength of 0.7-5.0 N/mm.sup.2 and support grains filling at least 20% of a volume; and, a binder formed as an aqueous polymer dispersion filing at least a portion of a remaining volume of said volume, thereby yielding a reinforcing and finishing plaster in a pasty form, said method comprising the steps of: sorting perlite support grains by particle size distribution in a trickle channel; glazing the perlite support grains in multi-stage temperature zones for creating said glazed, closed-cell balls; preparing a homogeneous mixture of said glazed, closed-cell balls with one or more grain sizes, the homogeneous mixture of said glazed, closed-cell balls comprising a volume of 20% or more of said mortar mixture and having a compression strength of 0.7 to 5.0 Nmm.sup.2; adding cellulose; adding an air-voids foaming agent; adding a binder; and, creating a homogenous mixture for yielding a reinforcing or finishing plaster for use as a mortar mixture.

6. The method for preparing a mortar mixture according to claim 5, wherein said glazed, closed-cell balls have grain sizes between 0.1 mm to 2.0 mm and is homogeneously mixed with: 12025 kg of Portland cement as a binder; 8025 kg of hydraulic lime as a softening binder; 200 g of cellulose as an additive; 20-60 g of air-voids forming agent; and, the remaining volume comprising a chemical additive selected from the group consisting of a plasticizer, a quick binder, a polymer support grains and a combination thereof, wherein the reinforcing and finishing plaster has a composition based upon a volume of 1,000 liters.

7. The method for preparing a mortar mixture according to claim 5, wherein said glazed, closed-cell balls have grain sizes between 0.1 mm to 2.0 mm and is homogeneously mixed with an aqueous polymer dispersion as the binder.

8. The method for preparing a mortar mixture according to claim 5, wherein said glazed, closed-cell balls have grain sizes between 0.1 mm to 2.0 mm and is homogeneously mixed with: 30%-60% with a diameter of 0.1 mm to 0.5 mm; 20%-50% with a diameter of 0.5 mm to 0.8 mm; 10%-30% with a diameter of 0.8 mm to 1.0 mm; 0%-10% with a diameter of 1.00 mm to 2.00 mm, said glazed, closed-cell balls being homogeneously mixed with: 12025 kg of Portland cement as a binder; 8025 kg of hydraulic lime as a softening binder; 200 g of cellulose as an additive; 20-60 g of air-voids forming agent; and, the remaining volume comprising a chemical additive selected from the group consisting of a plasticizer, a quick binder, a polymer support grains and a combination thereof, wherein the reinforcing and finishing plaster has a composition based upon a volume of 1,000 liters.

9. A building structure, comprising: a wall or floor structure coated with a mortar mixture containing glazed, closed-cell balls with a compressive strength of 0.7-5.0 N/mm.sup.2, wherein said glazed, closed-cell balls comprises at least 20% by volume of said mortar mixture.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) Referring now to the figures, the figures explain the gentle pumping process and the use of the perlite insulating plaster. In addition, the manufacturing of the perlite insulation plaster and its composition will be disclosed and its properties will be subsequently discussed. The application of the plaster mixture in a finishing plaster is carried out manually, wherein a major advantage is the fact that, first of all, this finishing plaster corresponds approximately to only one-fifth of the weight of a conventional finishing plaster applied to the same surface area; and secondly, since the dispersion is not absorbed by the expanded perlite, a homogenous application of the finishing plaster is greatly facilitated. The figures show the following:

(2) FIG. 1: a schematic view of the construction of a screw pump for the application of a perlite insulating plaster;

(3) FIG. 2: the application of a perlite insulating plaster onto an external wall by means of a perlite insulating plaster pump system.

DETAILED DESCRIPTION OF THE DRAWING FIGURES AND PREFERRED EMBODIMENTS

(4) Raw perlite is a chemically and physically transformed volcanic rock (obsidian), which has a white, powdery appearance. The raw perlite contains up to 2% of water and it has a density of 900-1,000 kg/m.sup.3. It is a natural building material, which is very suitable as expanded perlite for insulation and which is very light. The raw material is formed in seismically active zones and it is therefore naturally renewed and thus available over the long-term. The product can be easily recycled and it can be disposed of together with other mineral construction materials based on conventional building protection rules and possibly reused again. Traditional perlite, which is expanded by inflating in the conventional process, is open-celled, it has a low compressive strength and correspondingly it is not suitable as an addition to mortar on which high requirements are made. In multi-step annealing using rising temperatures of up to 800 C. to 1,000 C., it is possible to expand perlite's volume 10-15 times. The density of the expanded product is then only 80-400 kg/m.sup.3. The expanded perlite also has an exceptionally light weight. The expansion of perlite through air blowing has been known for years. However, the air-blowing method used up until now leads to open-cell, fractured perlite. In contrast, at the core of the present insulating board is the fact that a novel type of perlite is used, which consists of glazed balls having closed cavities. The process for manufacturing these novel perlites is carried out in several stages in a gravity oven provided with several temperature zones. Each individual grain size is then exposed to several temperature zones in a trickle channel which has increasing temperatures. Here, the perlite grains are extended by being filled with blown air so that the surface of the balls is glazed. The particles that are usually produced in this manner have for example the following ball diameters: 0.1 mm to 0.5 mm 0.5 mm to 0.8 mm 0.8 mm to 1.0 mm 1.0 mm to 2.0 mm
As opposed to fractured perlite, these novel glazed balls have a very low water absorption capacity. In order to improve open-cell perlites with respect to their water absorption capacity, the perlites were, up until now, coated, for example with bitumen. Another variant is to impregnate open-cell perlites with paraffin or to refine them with silicon and use them as fillers. However, the perlites processed in this manner are not very suitable for use as insulating plasters because the compressive strength of these products is as small as before the processing and corresponds only to approximately 0.2 N/mm.sup.2.

(5) Such closed balls are created as mentioned above by expanding silica sand or with the perlite air blowing treatment. These balls, which have different diameters, are characterized by a specific gravity of only 80-400 kg/m.sup.3. They are therefore extremely light as well as extremely heat-insulating, with a value of 20 to 35 mW/mK, and as they also have a high compressive strength of 0.8-6.0 N/mm.sup.2, they are suitable for the manufacturing of a perlite-based insulating plaster. This takes into account in terms of the volume 75% to 90% of such glazed balls, which are therefore provided with a closed surface, air-filled balls from expanded silica sand or air-filled perlite containing binders, additives, an air entrapment agent and/or other chemical additives which are homogenously mixed. A particularly advantageous mixture has the following composition: 45025 liters of glazed, expanded perlite with a grain size of 0.1 mm to 0.5 mm 45025 liters of glazed, expanded perlite with a grain size of 0.5 mm to 0.8 mm 12020 kg of Portland cement used as a binder 8020 kg of hydraulic lime used as a softening binder 20 grams of cellulose used as an additive 20-60 grams of an air-void forming agent. chemical additives such as plasticizers or fast binders, polymers and/or other additives. A similar insulating plaster for insulating building envelopes weight depending on the specific composition only about 260 to 350 kg/m.sup.3, and it provides after pumping for over 20 meters (!) a value of 40-50 mW/mK.

(6) Another formula for such a mortar mixture may be as follows:

(7) TABLE-US-00001 8-22 volume % mineral binders, such as reactive additives based on cement, lime or on a volcanic basis, >20 volume % glazed, closed-cell balls with a high compressive strength of 0.7-5.0 N/mm.sup.2 58-72 volume % sands with an ideal screen size or/and special supplements 50-300 g mineral additions such as cellulose or/and other additions 20-100 g air-void forming agents or foaming agents small amounts chemical additions such as plasticizers, polymers and other additions 100% volume Total
With this formula, the amount of the closed-cell balls is smaller because the sands are only partially replaced. The insulating effect is also correspondingly smaller.

(8) The pumping of traditional perlites or aerogels is a delicate process. When the plaster is pumped with a pressure of 5 to 20 bars through the hose of a professional plaster machine, the mechanical stress destroys traditional perlite or aerogel in the insulating plaster. To prevent that from happening also with the present mortar mixture having glazed, close-cell balls and to make sure that its excellent value will be preserved as much as possible, the mortar must be supplied and applied with a special screw pump. This screw pump, which is schematically illustrated in FIG. 1, is equipped with a special pump cylinder 3, in which the screw 1 is rotating about the axis 6. The pump cylinder 3 is covered by a further pressure-resistant pipe 4. The intermediate space 5 between the pump cylinder 3 and the exterior pipe 4 can be regulated by being impacted with air pressure or oil pressure. This makes it possible to achieve that elastic soft wall of the pump cylinder 3 conforms in the area of the screw 1 to the exterior edges of the windings of the screw 1 and projects the cylinder wall with a curved from into the interior part of the pump cylinder 3, which is to say that it is slightly curved between the windings of the turning screw 1. The perlite thus cannot be crushed on the exterior edges of the screw windings, as the cylinder wall 3 will yield elastically beforehand. By and large, the perlite insulating plaster is thus conveyed very gently in this manner, so that only a minimal reduction is obtained even after pumping over a distance of 20 meters and its thermal insulation properties will be reduced only minimally.

(9) FIG. 2 illustrates how this mortar mixture is applied for thermal insulation and/or for protection from fire. The wall to be coated is prepared ahead of time for the application of the plaster. After that, the mortar mixture, or the special insulation plaster is poured through a funnel 9 into a pump carriage 8 in which pumping operations are carried out with a soft and elastic, flexible pump cylinder 3 which is impacted by external pressure. The insulating plaster is pumped by the pump carriage 8 while water is added with an ideal ratio so that it adheres to the wall to be provided with insulation. The pressures are then exerted up to 8 bars and pumping distances of up to 20 m or more can be overcome without a significant deterioration of the insulating plaster. The applied insulating plaster is water permeable and it has a value of approximately 40 to 50 mW/mK. This means that a much less strong insulating plaster layer needs to be sprayed on than usual. In addition to that, this insulating plaster is clearly less expensive to manufacture than for example airgel insulating plaster. This insulating plaster can be also used for embedding of a reinforcement made for example of glass. Such a reinforcing plaster is in practice applied to old, cracked plasters or to EPS-based insulating plates. The coated wall that has been treated in this manner may then be covered with a dispersion-based finishing coat or with an open-pore silicate paint and although the layer structure remains permeable to vapor, it is thermally insulating.

(10) An embodiment for carrying out the mortar as a mortar mixture for manufacturing and for applying a finishing mortar will be explained next: 75-95 volume percent of expanded closed-cell perlite having an expanded grain diameter of 0.2 to 2 mm was mixed with support grains, preferably consisting of silicate sand with a diameter of 0-5 mm. The dispersion and other additions formed the remaining volume of the mixture. The additional support grains are important so that the closed-cell perlites are not destroyed during the grating of the surface of the dispersion plaster and so that accordingly, a desired surface structure can be built with visible, large grains. Thanks to the extremely low weight of the expanded perlite, the density of the finished product, which is to say, the finishing plaster in the container that is ready for application, corresponds only to approximately 30% of a conventional dispersion plaster consisting of sands. A container with the same volume is thus 3-4 times lighter! Instead of a container that weighs 25 kg, only 5-9 kg thus must be transported on the construction site. An important advantage is also that this light finishing plaster material can be applied manually with much less effort. The plasterer/bricklayer now has only 30% of the weight on the trowel and the wiping is thus much simpler and less stressful. The light dispersion plaster adheres better to the wall and remains there. This also means that thicker layers can be applied. Heavy, conventional finishing mortar often tends to fall off, which is avoided with this novel finishing plaster. Yet another advantage is that the expanded closed-cell perlites are not strongly hydroscopic and therefore do not draw any dispersion or water components from the mixture. Therefore, this makes it possible to save on the dispersion, which is generally expensive. Since no water will be drawn off, the material can remain open longer and therefore can be also processed for a longer period of time.