EP0086974A1 - Inorganic composite brick and method of manufacturing the same - Google Patents

Abstract

The parallelepipedal inorganic composite brick consists of a calcium silicate hydrate brick (1) which may contain air-filled channels and has an apparent density of 0.6 to 2 kg/dm<3>, combined with an inorganic insulant with an apparent density of 0.05 to 0.3 kg/dm<3>. It can be manufactured, for example, by filling the cavity (2) of a lime-sand brick blank with an expandable inorganic insulant precursor, which is expanded and subsequently the two are cured with superheated steam. Instead of the expandable insulant precursor, an already expanded insulant precursor of low density or a precured inorganic insulant may also be employed. <IMAGE>

Description

The present invention relates to an inorganic composite brick which consists of a calcium silicate hydrate brick in combination with an inorganic insulating material of low density. The invention further relates to methods for producing such composite stones.

Steam-hardened stones made of lime and sand (so-called lime sandstones) have been known for almost 100 years. Today they are manufactured industrially on a large scale. In addition to many advantages, however, they have the disadvantage of too high a thermal conductivity.

With a cullet bulk density, ie a density of the stone without air ducts, of 1.6 to 1.8 kg / dm ³ , masonry made of sand-lime bricks has a thermal conductivity of 0.8 - 1.0 W / mK. Walls made of these stones only a low thermal insulation capacity. It was therefore started several years ago to produce stones with cavities, so-called hollow blocks. These cavities cannot be enlarged arbitrarily due to structural requirements. Due to the manufacturing technology, only stones with round or oval holes can be formed. The load-bearing webs between two cavities or cavity and stone outer wall must have a sufficient thickness, partly because of the risk of buckling. In this way, sand-lime bricks with a proportion of holes of up to 50 vol.

The air present in these openings does not provide optimal insulation due to convection. For better thermal insulation it is therefore necessary when using to change from sand-lime bricks to a so-called double-shell construction. To do this, you can attach a layer of insulating material (PU foam, polystyrene foam, mineral fiber mat) in front of a load-bearing wall made of sand-lime bricks. This layer must be protected against rain by another sand-lime brick wall. Another method of the double-shell construction is that the air gap between the two walls is filled with insulation beads (perlite, polystyrene balls). Both processes lead to high manufacturing costs.

By incorporating light silicate additives such as Pumice or perlite and more or less extensive replacement of sand can reduce the body density and thus improve the thermal insulation. In the lime sandstone or lime sand block blocks thus produced, the specifically light aggregates are largely homogeneously distributed.

The body density and thus the thermal conductivity can also be reduced by introducing gas pores into the stone. For example, a finely divided, intimate mixture of lime, silica and water can be admixed with a metal powder that reacts with water to produce gas. After expansion and setting, the mass is hardened to a stone by high-tension steam. Further details can be found in German patents 404 677, 447 194 and 454 744.

The lime can also be completely or partially replaced by cement. The resulting products are commercially available as "gas concrete".

The foaming of the raw sand-lime brick can also be carried out by mechanically under-worked air instead of chemically released gas Required using foaming agents. A large number of organic compounds such as soaps, saponins, gelatins and resins are used as foaming agents. Both lime and cement are used as binders for setting the raw material. The resulting foam stone is also partially hardened by steam in an autoclave (European patent application 0038552).

European patent specification 7585 describes a process for producing fire-resistant lightweight building boards, in which a stable aqueous suspension of finely dispersed raw materials is first produced. The gel suspension sets and is cured by treatment with steam. Here the pores are created by the evaporation of water from the raw material. The same reference also mentions the possibility of producing insulation materials by combining differently dense but identical materials (column 16, lines 29 - 38). Here, a thin-walled outer cover layer with a higher density is coated with a specifically lighter thermal insulation zone. The adhesive bond between the two layers is achieved by chemical reaction under the conditions of hydrothermal hardening through the formation of phases of the same material.

It is conceivable to fill the cavities in hollow-block sand-lime bricks with organic insulating materials, such as polystyrene foam or polyurethane foam, for better thermal insulation. Since these organic insulation materials would be decomposed during the hydrothermal hardening of the sand-lime bricks, they can only be introduced after the autoclave treatment. Such a process is therefore complex and expensive. Another disadvantage of this method is that the bond between organic material and the sand-lime brick is not good in all cases and that the organic insulation is brownable.

It was therefore the task to create easily produced composite blocks from sand-lime bricks and non-combustible insulation materials with good mechanical resistance. The insulation materials used should preferably not be destroyed during the hydrothermal hardening of the sand-lime bricks.

Cuboid inorganic composite blocks have now been created which consist of a calcium silicate hydrate block, which may also have air-filled channels and which have a bulk density of 0.6 to 2 kg / dm ³ , in combination with an inorganic insulating material of bulk density 0.05 to 0.3 kg / dm ³ exist. These composite bricks have good mechanical resistance and good thermal insulation. A lime sandstone with a bulk density of 0.8 to 2 kg / dm ³ is preferred.

Lime sandstones with air-filled channels in the form of hollow blocks (e.g. KSHbl 16DF) or perforated stones (e.g. KSL 2 DF) or solid lime sand stones (e.g. KSV NF) are known from DIN 106. The external dimensions of the composite stone according to the invention are not critical. However, cuboid composite blocks with dimensions in accordance with DIN 106 are preferred.

As an inorganic insulation material with low density, i.a. Mineral fiber insulation materials, inorganic insulation materials containing phosphate, foamed glass and porous calcium silicate are used. For the mechanical resistance of the inorganic composite bricks, it is advantageous if less than 50% of the surface is formed by the specifically lighter insulation material.

It is advantageous if the inorganic insulating material, which is in combination with the calcium silicate hydrate, has one layer or a channel or more forms parallel layers or channels that run through the calcium silicate hydrate stone. These layers or channels can be arranged inside the composite stone. For reasons of easier production, however, it is preferred if the layers or channels are visible on at least one side, preferably at least two sides, of the composite stone. The layers or channels can run diagonally through the stone. In view of better mechanical properties, however, it is preferred if the layers of insulating material run parallel to one side of the cuboid or the channels of insulating material run perpendicular to one side of the cuboid.

As already mentioned above, the specifically light material of the inorganic insulation material is not as mechanically resistant as the sand-lime brick. It is therefore preferred that no edge of the cuboid is formed entirely from the inorganic insulating material. It is particularly preferred if all edges of the cuboid composite stone consist entirely of sand-lime brick. In most cases, the inorganic foam adheres well to the sand-lime brick. It is therefore also possible to dispense entirely with web connections and to form the composite stone as a sandwich. In this case, the two outer layers of the sandwich (i.e. two parallel sides of the composite stone) consist of sand-lime brick, between which a layer of inorganic insulation is arranged. These sandwich bricks are particularly well insulated due to the lack of cold bridges.

The composite blocks according to the invention can be produced by several processes.

For example, from a sand-lime brick raw material with at least 3% water content, a blank with at least one cavity can be formed into at least one cavity Fill an expandable inorganic insulating precursor in the space of the blank, allow it to expand and treat the raw stone with superheated steam of at least 2 bar and thus harden the sand-lime brick blank and the expanded insulating precursor. In general, steam curing takes place at 150 to 210 ° C.

Depending on the composition of the raw material, the blank can be produced in a rectangular manner in a manner known per se by pressure, shaking or pouring. It will generally have multiple cavities that can be of different sizes and shapes. It is not necessary, but preferred, to completely fill all cavities with preliminary insulating material. The body density of the sand-lime bricks can be reduced in a known manner to about 0.7 g / cm ³ by introducing air pores or by using light aggregates. This also slightly improves the thermal insulation of the lime sandstone part.

A particularly favorable process for producing an expandable insulating precursor is based on cement, polyphosphoric acid and a blowing agent and is the subject of DE-OS 31 40 011.

This process is characterized in that Portland cement, optionally together with alumina melt and / or oxides of calcium, zinc, aluminum and iron and / or hydroxides of aluminum and / or iron and polyphosphoric acid, has a content of at least 76% by weight. % P ₂ O ₅ , and a blowing agent effective in an acidic environment, optionally with the addition of fillers and / or reinforcing agents, produces a mixture by intensive mixing, the equivalence ratio (aluminum + magnesium + calcium + iron): phosphate being greater than 1, but not more than 3 and the The amount of blowing agent is measured so that 0.5 - 8 ml of gas per g of the mixture are released in the reaction with polyphosphoric acid, the foaming mixture is filled into a mold, for example the cavity of a blank, and if necessary it is brought to a temperature from the outside heated from 80 ° C. After the exothermic reaction has subsided, ie about 5 to 15 minutes after foaming, the expanded preliminary insulating material has solidified. By heating to 300 - 350 ° C or by treatment with superheated steam of at least 2 bar, it is fully cured to the insulation material.

When the foam cures due to the action of water vapor, the minimum reaction time depends on the temperature used. At 10 bar water vapor pressure, 1 hour is sufficient, at 4 bar about 2 hours. At 2 bar it takes about 10 hours to harden. Prolonged heating with steam does no harm, but increases the strength only slightly. The treatment will therefore be stopped when the desired mechanical properties have been achieved.

Preferred Portland cement types are PZ 35, PZ 45 and PZ 55, in particular PZ 35. The highest possible content of the compounds 2 CaO is desirable. SiO ₂ ; 3 CaO. Si0 ₂ and 3 CaO. Al ₂ O ₃ in the cement. Portland cement can also be partially replaced by mixtures of Portland cement and blast furnace slag (so-called smelter or blast furnace cement). It is preferred if - based on the sum of the pesticide proportions - the proportion of Portland cement is not less than 60% by weight, preferably not less than 70% by weight.

Based on the weight of Portland cement, up to 43%, preferably up to 30%, in particular 1. to 20% on alumina melting element and / or oxides of calcium, magnesium, zinc, aluminum and iron and / or hydroxides of aluminum and / or iron. It is particularly preferred if the amount of these fractions is 3-6 (based on the weight of the Portland cement). It is advantageous if these ingredients are used in finely ground form.

Commercial polyphosphoric acids with a content of at least 76% P ₂ 0 _{5 are} suitable for the reaction. Polyphosphoric acids with a content of 84% P ₂ 0 ₅ are preferred. The acids mentioned do not crystallize even after prolonged storage.

The main blowing agents used are carbonates, in particular carbonates containing water of crystallization, such as, for example, the basic magnesium carbonate of the formula 4 MgCO ₃ . Mg (OH) ₂ . 5 H ₂ O is used. Small amounts of alkaline earth carbonate are contained in Portland cement from the outset and also act as blowing agents.

Highly volatile organic compounds such as e.g. Fluorocarbons suitable. Organic compounds that decompose to gaseous products at elevated temperatures are also suitable, e.g. Azodicarbonamide and Azoisobutyronitrile.

The amount of blowing agent should be such that 0.5 to 8 ml of gas (measured at 80 ° C. and 1 bar) per g of the reaction mixture are released during the reaction with polyphosphoric acid. Gas quantities of 3-7 ml per g of the reaction mixture are preferred. The density of the insulating material can be regulated with the amount of blowing agent.

The reaction mixture can, without major influence on the mechanical and thermal properties of the final product tes, finely ground fillers are added. Even at 100 ° C, these fillers should neither react with polyphosphoric acid nor with metal phosphates. A wide range of industrial waste products, such as fly ash, can be used for this purpose, which mainly consist of silicon dioxide and are produced in the manufacture of ferro-silicon. Quartz flours, talc, kaolin, carbon black or finely ground graphite can also be used. If these fillers still contain reactive oxides, such as aluminum oxide, to a small extent, these must be taken into account when calculating the approach.

If, in addition to or instead of the powdery fillers, inorganic fibers are used as reinforcing agents, the mechanical stability of the foam obtained can be improved. These reinforcing agents should also be inert to polyphosphoric acid or metal phosphate. Short-cut glass or mineral wool fibers or carbon fibers are preferably used as reinforcing agents. In addition, smaller amounts of difficult-to-melt organic fibers, such as Incorporate aromatic polyamides as long as the resulting foam should not be exposed to temperatures above 300 ° C.

In order for this process to produce an expandable insulating precursor to proceed smoothly, it is necessary to mix the reaction products thoroughly. It is preferred to first mix the solid components, for example by grinding them together. To accelerate the reaction, small amounts of water (0.1-1% by weight based on polyphosphoric acid) can be added. The water is advantageously added in the form of salts containing water of crystallization (example: basic mag nesium carbonate or aluminum sulfate). If more than 1% hater is added, the reaction is often accelerated so that there is no sufficient processing time.

Additional substances can be added to modify the properties of the end product. Ground calcium silicate increases the viscosity of the reacting foam. Sodium silicate also has an effect, although here too there is the disadvantage that sodium salts can bloom or be washed out in use. Small amounts of boric acid also accelerate the reaction and increase the resistance of the foam obtained at higher temperatures.

The equivalent ratio is defined as the ratio of the total valence of the metals to that of the phosphate ions. A formula for the equivalent ratio is given in DE-OS 2 756 198, p. 13.

The mixture of polyphosphoric acid, Portland cement and possibly other components slowly foams. At the same time, the temperature rises. When a temperature of approx. 80 C is reached, the temperature rises rapidly to approx. 200 ° C, which is accompanied by a new expansion. If the temperature of 80 ° C is not reached automatically, it is necessary to heat the batch from the outside.

Depending on the proportion of Portland cement, the equivalent weight used and the amount of gas released, the properties of the foam obtained can be modified considerably. The volume ratio of solid to pores after gas evolution and solidification of the material can range from about 1: 5 up to 1:20, which means densities of 450 g / l or so. 100 g / l approximately corresponds. Volume ratios of solid to pores from 1: 8 (density 250 g / l) to 1:15 (density approx. 150 g / l) are preferred.

The foam obtained generally contains no organic components, is heat-stable up to over 1000 ° C. and does not release any toxic gases.

• 18 - 50 Gew. -% CaO
• ₂ - 20 Gew.-% Al₂O₃
• 10 - 35 Gew.-% SiO₂
• mindestens 15 aber weniger als 38 Gew.-% P₂0₅
• 0 - 1 Gew.-% Alkalimetalloxide
• ₀ - 8 Gew.-% B₂O₃
• ₀ - 8 Gew.-% ZnO, Fe0 und/oder Fe203
• 0 - 2 Gew.-% SO₃ und
• 0 - 5 Gew.-% C.

The foams obtained by the stated process generally have the following composition:

• 18-50% by weight CaO
• _2-20 wt .-% Al ₂ O ₃
• 10-35% by weight SiO ₂
• at least 15 but less than 38% by weight of P ₂ 0 ₅
• 0-1% by weight of alkali metal oxides
• ₀ - 8 wt% B ₂ O ₃
• ₀ - 8 wt% ZnO, Fe0 and / or Fe203
• 0-2% by weight of SO ₃ and
• 0 - 5% by weight C.

They can be with densities of 100 to 300 g / 1. They have open and closed pores with a diameter of 0.5 - 3 mm and show only a very low thermal shrinkage (less than 1%; measured after tempering the foam at 300 ° C for 5 min and cooling on the longest dimension of the test specimen).

• 53,26-0,217 . /P₂O₅/≥/CaO/≥-29,56-0,304. /P₂O₅/, wobei /CaO/ und /P₂O₅/ Gewichtsprozente an CaO und
• P₂0₅ bedeuten. Bevorzugte Gehalte an B₂O₃ liegen bei 0 - 5, insbesondere 0.5 - 2.5 Gew.-%. Bevorzugt sind ferner Schaumstoffe, in denen das Gewichtsverhältnis (Al₂O₃ + CaO): P205 1,0 : 1 bis 2,5 : 1, ins-
• besondere 1,2 : 1 bis 1,8 : 1, sowie Schaumstoffe, in denen das Gewichtsverhältnis SiO_{2 :} P₂0₅ 0,4 : ¹
• bis 1,4 : 1, insbesondere 0,7 : 1 bis 1,0 : 1 beträgt. Bevorzugte Bereiche der Zusammensetzung sind 30 - 45 Gew.-% CaO, 12 - 25 % SiO₂ und 20 - 30 % P₂O₅.

A preferred CaO / P ₂ O ₅ range is given by the equation

• 53.26-0.217. / P ₂ O ₅ / ≥ / CaO / ≥-29.56-0.304. / P ₂ O ₅ /, where / CaO / and / P ₂ O ₅ / weight percentages of CaO and
• P ₂ 0 ₅ mean. Preferred contents of B ₂ O ₃ are 0-5%, in particular 0.5-2.5% by weight. Also preferred are foams in which the weight ratio (Al ₂ O ₃ + CaO): P205 1.0: 1 to 2.5: 1,
• special 1.2: 1 to 1.8: 1, and foams in which the weight ratio SiO _2: P ₂ 0 ₅ 0.4: ¹
• is up to 1.4: 1, in particular 0.7: 1 to 1.0: 1. Preferred ranges of the composition are 30-45% by weight CaO, 12-25% SiO ₂ and 20-30% P ₂ O ₅ .

The expansion of the insulating precursor filled into the cavities takes place automatically and is accelerated by increasing the temperature. The blank filled with the expanded insulating precursor is called the rough stone. Treatment with superheated steam (hydrothermal conditions) is the same as for the known hardening of the sand-lime bricks. In most cases, the time to harden the sand-lime brick blank is also sufficient to harden the expanded preliminary insulating material. The insulation material forms a firm connection with the sand-lime brick. It is advantageous that no more energy is used in the joint curing of the blank and insulating precursor described than in the production of normal sand-lime bricks. This variant also manages with a minimum of operations.

The raw sand-lime brick used is free-flowing with a water content of 3 to 7%. In this case, the blank can be formed by applying pressure or shaking. However, with the addition of pore formers, air and cement, foamed lime sandstone raw materials can be produced which are pourable, e.g. by incorporating lime, sand and cement in a water / air foam. “Pore-forming agents” here are understood to mean surfactants or other known substances which are able to stabilize water / air visual spaces.

Instead of having the insulating precursor expand in the cavities of the sand-lime brick blank, it is also possible to fill an already expanded insulating precursor into the cavities, which are water-containing and damp is still flowable. This pre-insulating material passes either on its own or when heated or when treated with superheated steam into the actual low-density inorganic insulating material.

A flowable, no longer expanding insulating precursor can be made, for example, from very light additives such as Pumice or expanded pearlite and cement. This mass sets itself. The low density of the insulation material is created here by the cavities of the aggregates.

A particularly favorable variant of producing a non-combustible lightweight concrete with densities down to 200 g / l is the subject of DE-OS 31 10 658. This method is characterized in that 100 parts by weight of a mixture of 30 to 70 percent by weight of cement and 70 to 30 percent by weight of a conventional inorganic lightweight aggregate mixed with 0.03 to 0.3 parts by weight of a water-soluble cellulose ether and 80 to 120 parts by weight of an aqueous plastic dispersion with a solids content of 1 to 10 percent by weight to produce foam, the resulting foam is filled into a mold and allowed to harden .

Portland cement is particularly suitable as cement, preferably Portland cement of strength class PZ 35.

An essential component of the cement mixture is the inorganic lightweight aggregate. In the process mentioned, expandable granules are used in particular, the particles of which have diameters of at most 6 mm, preferably of at most 5 mm. Example of this are foam glass, pumice and expanded mica (vermiculite).

The aqueous plastic dispersion used is in particular a dispersion of a vinyl ester polymer or

of an acrylic acid ester polymer, the polymers being homopolymers or copolymers. The solids content of the dispersion is in the range from 1 to 10 percent by weight, preferably from 2 to 5 percent by weight.

An essential feature of the process is the use of a water-soluble cellulose ether, which acts as a foam stabilizer.

Methyl cellulose, carboxymethyl cellulose and methyl hydroxyethyl cellulose are particularly suitable.

The process is expediently carried out in such a way that first cement, light aggregate and cellulose ether are mixed with one another within a maximum period of 30 seconds and the plastic dispersion is then mixed into the mixture obtained. The mixing is preferably carried out in a compulsory mixer or in a drum mixer. After about 3 minutes, the mass begins to foam and after 5 to 10 minutes, the foaming has ended. The foam is then filled into molds (in the present case: openings of sand-lime brick blanks) and, if necessary, slightly compressed therein, preferably by shaking. The foam has hardened within a maximum of 15 hours.

Another way of producing flowable insulating precursors that no longer expand is to dry structurally viscous calcium silicate slurries of low density. Such calcium silicate slurries can be produced, for example, by the process described in European Patent 00 75 85 for the preparation of a calcium oxide / silicon dioxide starting mixture (but with the omission of the step of molding under dewatering). In In this case, the low density of the insulating material is generated by the evaporation of water from the dispersion used, with the simultaneous formation of cavities. A free-flowing lime sandstone raw material with a water content of 3 to 7% or a flowable, foamed lime sandstone raw material can also be used in this process.

The insulation materials obtained by curing have good compressive strength and can therefore support a building. Therefore lets. the geometry of the cavities in the sand-lime bricks changes for optimal thermal insulation. You can e.g. enlarge the (filled) cavities in the sand-lime brick and reduce the strength of the web connections between two cavities or cavity and the outside.

Another possibility for producing the parallelepiped-shaped inorganic composite blocks according to the invention is that at least 1 piece of an inorganic (already hardened) insulating material is introduced into a mold and, if necessary, fixed, surrounding it at least partially with a free-flowing sand-lime brick with 3 to 7% water content, the raw sand-lime brick is pre-consolidated by the application of pressure, the blank connected to the insulating material is removed from the mold and cured by treatment with superheated steam of at least 2 bar. Lime sandstone DIN molds are preferably used for this process. The action of pressure is preferably such that one presses with a suitably shaped stamp only on the raw sand-lime brick mass, but not on the broken solid insulation material. The insulation material introduced is preferably rod-shaped (with a round or square cross-section). At least one end face of the rod, but preferably both end faces, should end flush with the sides of the composite stone, ie the raw sandstone raw material should be surrounded. In the latter case, the height of the individually cut insulation part corresponds to that final stone height. In addition, the rod-shaped inorganic insulation material introduced should be embedded from all sides in raw sand-lime brick. If the introduced insulation material is plate-shaped, both plate surfaces are preferably covered with raw sand-lime brick so that a sandwich is formed.

The maximum possible pressures depend on the type of insulation used. Insulation materials with a higher density and greater compressive strength allow higher compression pressures than insulation materials with a low density.

Instead of a free-flowing raw sand-lime brick mass, a flowable, foamed raw sand-lime brick mass can also be used, which was produced with the addition of pore formers, cement and air. This raw sand-lime brick sets itself due to the cement content, but it does not fully harden. Therefore, after removal from the form of the sand-lime brick blank with the insulating material contained therein, it must subsequently be cured hydrothermally by treatment with superheated steam of at least 2 bar. In this method, too, it is preferred if the insulation material introduced is in the form of a rod or plate.

Mineral fiber insulation materials are also suitable for this process, in which the insulation material is cast. This creates a particularly good insulation / sand-lime brick connection.

If already cured insulation materials are used, they must be resistant to treatment with superheated steam. Foam glass, mineral fiber insulation materials, calcium silicate insulation materials, lightweight concrete and the phosphate insulation material according to PE-OS 31 40 011 are suitable, for example. This phorphet diremteff has a density of 200 g / l a compressive strength of approx. 60 N / cm ² . Here, maximum pressures of approx. 150 N / cm ² can be applied to the sand-lime brick mass.

The freshly expanded phosphate insulation material can also be used before curing. At this point it is e.g. easy to cut but not yet resistant to water. The compressive strength is lower than with the fully cured insulation.

• 1 Stunde Aufheizen auf 200°C,
• 4 Stunden Halten bei 200°C (entspricht einem Druck von 16 bar),
• 3 Stunden Abkühlen und Entspannen.

The blanks provided with the insulating material are hardened under conditions that are common in the sand-lime brick industry. The following cycle has proven itself, for example:

• 1 hour heating to 200 ° C,
• 4 hours holding at 200 ° C (corresponds to a pressure of 16 bar),
• 3 hours of cooling and relaxing.

The minimum temperature for curing is 120 ° C (2 bar). For reasons of the shortest possible cycle times, however, significantly higher temperatures are preferred.

Because of the excellent adhesion between the insulation material and sand-lime brick, sandwich stones can also be produced. The lime sand mass is pressed into the pores of the insulation material by the applied pressure, where it chemically and / or physically combines with the insulation material mixture during the hydrothermal hardening. An improvement in liability can include through a suitable shaping of the two components, e.g. through incisions, sawtooth patterns or undercuts.

To produce the composite step according to the invention, a cpandicrable insulating step can also be filled into cavities in finished Hohltloek limestone blocks, expanded and allowed to harden. When using the described in DE-OS 31 40 011 The pre-phosphate-based insulating precursor can be cured by heating to temperatures of 300 to 350 ° C or by treatment with superheated steam. The disadvantage of this variant is that the sand-lime brick has to be heated twice (during its manufacture and during the curing of the insulating precursor).

The composite stones according to the invention have a number of advantages over conventional sand-lime bricks. Thermal insulation is significantly improved compared to normal solid or hollow blocks. This gives you the opportunity to do without the complex and expensive double-shell construction.

The wall thicknesses of the new composite bricks can be reduced due to the reduced risk of buckling. For these reasons, the insulation components can also be arranged so that they optimally reduce the heat flow.

The high sound insulation of the. Lime sandstone remains. The heat storage capacity of a wall made of sand-lime bricks is also retained if the stones are arranged appropriately.

The use of inorganic insulation materials in sand-lime bricks leads to composite blocks that meet all requirements of DIN standard 4102, class A 1 (non-combustible). In the event of a fire, the materials do not release any toxic gases.

Some possibilities for the spatial arrangement of insulation material and sand-lime brick in composite stone with integrated thermal insulation are shown by way of example in FIGS. 1-10.

The outer dimensions of the drawn sand-lime bricks (24 x 17.5 x 11.3 cm) correspond to the 3DF format in accordance with DIN 106.

The sand-lime brick (1) is white, the insulation material (3) is dotted. The insulation parts extend from the top to the bottom of the stones, so that the bottom of the drawn stones looks exactly like the top. In Figure 1, two cavities (2) are also shown, which are still filled with insulation.

The stones according to Figures 1-6 are used to achieve the greatest thermal resistance of the wall so that the insulation layers run parallel to the wall. The symmetrically constructed bricks according to FIGS. 7-10 show no significant differences with regard to the insulation effect depending on the direction of installation. In the stones according to FIGS. 1, 5 and 7-10, all parts of the insulation material are surrounded on four sides by sand-lime brick. In the stone according to FIG. 4, all layers of insulation material are surrounded on three sides by sand-lime brick mass.

In the case of the stone according to FIG. 3, an insulation part is surrounded by sand-lime mass on two opposite sides (sandwich), two insulation parts are surrounded on three sides and an insulation part on four sides by sand-lime mass.

The following examples illustrate the invention.

example 1

• 220 g Portlandzement PZ 35, 60 g eines Füllstoffes (Flugasche aus der Ferrosiliciumherstellung mit 80 - 90 % SiO₂), 18 g eines fein gemahlenen Dolomits (Korngröße 10 µm), 3 g basisches Magnesiumcarbonat sowie 20 g Talkum werden fein gemischt. Diese Mischung gibt man unter Rühren zu 150 g einer linear kondensierten Polyphosphorsäure mit einem Gehalt von 84 % F₂O₅. Die Masse wird nach 1 Min. Mischzeit pastös und wird nach 75 sec. in den Hohlraum des Kalksandsteines gegeben. Die Masse beginnt nach 2 Minuten aufzuschäumen, nach 7 Minuten 30 sec. ist der Aufschäumungsvorgang beendet und der Hohlraum vollständig mit dem anorganischen Dämmstoff gefüllt. Ein Überschäumen wird durch Auflegen einer Platte verhindert. Der so gefüllte Kalksandstein wird nach 5 Minuten in einem Autoklaven mit Wasserdampf gehärtet. Die Aufheizzeit auf 170°C betrug 3 Stunden, die Härtungszeit 10 Stunden, danach wurde langsam während 5 Stunden abgekühlt.

A cast limestone KSHbl 30a (DIN 106) with the external dimensions 30 x 24 x 23.8 cm has a cavity of 4.8 x 20.8 x 23.8 cm at a distance of 1.6 cm from the narrow side. This cavity is filled with an inorganic insulation material as follows:

• 220 g of Portland cement PZ 35, 60 g of a filler (fly ash from ferrosilicon production with 80 - 90% SiO ₂ ), 18 g of a finely ground dolomite (grain size 10 µm), 3 g of basic magnesium carbonate and 20 g of talc are mixed together finely. This mixture is added with stirring to 150 g of a linearly condensed polyphosphoric acid with a content of 84% F ₂ O ₅ . The mixture becomes pasty after 1 minute of mixing time and is added to the cavity of the sand-lime brick after 75 seconds. The mass begins to foam up after 2 minutes, after 7 minutes 30 seconds the foaming process is complete and the cavity is completely filled with the inorganic insulation material. Foaming is prevented by placing a plate on top. The sand-lime brick filled in this way is hardened with steam in an autoclave after 5 minutes. The heating time to 170 ° C. was 3 hours, the curing time 10 hours, after which cooling was slow for 5 hours.

The adhesion between the insulation material and sand-lime brick is very good. A hollow block of sand-lime brick is thus obtained, the cavity of which is completely filled with an inorganic insulation material with a density of 165 g / l.

Example 2

In a cuboid shape Eit the base 24 x 17.5 em and the height 13 em 3 insulation boards with the dimensions 13.5 x 11 x 4 et are set and fixed vertically so that the sides 4 x 13.5 em the panels Beden touch, the plates are parallel to each other and are 3 cm away from each other as well as from the sides 17.5 x 13 cm of the mold and 2 cm from the sides 24 x 13 cm of the mold.

The insulation boards are inorganic and contain phosphate. They are made according to the procedure of Example 4.

4.6 kg of a moist lime sand mixture consisting of 80.5% sand (grain size 0 - 3 mm) and 13.5% Ca (OH) ₂ and 6.0% water is placed around the insulation boards in the Mold filled, evenly distributed, lightly shaken and pre-consolidated by light pressure. The lime sand mixture projects 1 to 2 cm above the top of the set slabs. The mold is closed with a 4 cm thick lid that is milled 2 cm deep at the positions where the insulation boards are located. A pressure of 2580 kp is applied to the lid for 3 seconds. The construction of the cover ensures that only the sand-lime brick mass is exposed to this pressure.

It is switched off and the removed blank is hardened by steam in an autoclave (heating time to 16 bar (= 200 ° C.) 2 hours, hardening time 4 hours, cooling for 4 hours).

A 3 DF lime sandstone with integrated thermal insulation (volume share of insulation 39%) is obtained, with firm edges, high compressive strength and an average density of 980 g / l. Such a stone is shown in Figure 1.

Example 3

• 40 g einer Flugasche (bestehend zu 80 bis 90 % aus Sⁱ⁰2)
• 12 g fein gemahlener Dolomit (Korngröße 10 um)
• 2 g basisches Magnesiumearbonat

werden in.einer Kugelmühle während 2 Stunden fein vermahlen.Production of a phosphate-containing insulation material.

• 40 g of a fly ash (consisting of 80 to 90% of S ⁱ⁰ 2)
• 12 g finely ground dolomite (grain size 10 µm)
• 2 g basic magnesium arbonate

are finely ground in a ball mill for 2 hours.

100 g of a linearly condensed polyphosphoric acid with a content of 84% P ₂ 0 ₅ are mixed with 2 g of glass fibers (length 3 mm, 0 5 µm), the powder mixture is added with stirring. During the stirring process, the mass is crumbly at first, it becomes pasty after 30 seconds with gentle heating. After 1 minute of mixing, the mass is placed in a metal mold. It expands to about 10 times the initial volume. The temperature slowly rises to 80 ° C over 5 minutes. When this temperature is reached, the reaction starts and the foam solidifies with a very rapid increase in temperature to 215 ° C. A small sample is wetted with water, the material reacts strongly acidic. The foam is removed from the mold after 10 minutes and placed in a laboratory autoclave (2 l). Add about 200 ml of water. The autoclave is heated to 150 ° C; this creates a pressure of 4.5 bar. After 2 hours the autoclave is switched off and allowed to cool. Ean receives a foam with a density of approx. 210 g / l with excellent pressure resistance.

The foam can be obtained by saying pieces with the desired dimensions.

Example 4

Production of a phosphate-containing insulation material.

• 170 g Portlandzement PZ 35
• 15 g fein gemahlener Dolomit
• 10 g Talkumpulver (Korngröße unter 20 µm) und
• 30 g Flugasche (SiO₂-Füller N der SKW Trostberg, ca. 80 - 90 % SiO₂)

während 2 Stunden fein gemahlen. Das Gemisch wird in 100 g Polyphosphorsäure (84 % P₂O₅) eingerührt und dann in eine Form gegossen. Die Temperatur steigt während 6 Minuten langsam auf 75°C, dabei bläht sich das Gemisch stark auf und reagiert unter Erwärmung auf 195°C. Der erhärtete Schaumstoff wird in einem Trockenschrank auf 300°C erwärmt und 5 Minuten bei dieser Temperatur belassen. Nach dem langsamen Abkühlen erhält man einen sehr festen Schaumstoff mit einem mittleren Porendurchmesser von 2 mm und einer Dichte von 180 g/l.Be in a ball mill

• 170 g Portland cement PZ 35
• 15 g finely ground dolomite
• 10 g talcum powder (grain size less than 20 µm) and
• 30 g fly ash (SiO ₂ filler N from SKW Trostberg, approx. 80 - 90% SiO ₂ )

finely ground for 2 hours. The mixture is stirred into 100 g of polyphosphoric acid (84% P ₂ O ₅ ) and then poured into a mold. The temperature slowly rises to 75 ° C in the course of 6 minutes, during which the mixture swells strongly and reacts with heating to 195 ° C. The hardened foam is heated to 300 ° C. in a drying cabinet and left at this temperature for 5 minutes. After slow cooling, a very firm foam with an average pore diameter of 2 mm and a density of 180 g / l is obtained.

Insulation pieces of the desired dimensions are obtained from the foam by cutting or sawing.

Example 5

In a cuboid shape with a base area of 20 x 20 cm and a height of 8 cm, pieces of Danish manikin with the dimensions 8 x 8 x 4 cm and 16 x 8 x 4 cm are inserted vertically in the arrangement according to FIG. 11, (4) meaning the shape .

The pieces of insulation were produced according to Example 4.

To produce a lime sandstone mass, a foam is first made from 1.2 l of water and 20 g of a foamer (foamer No. 1 from SKW Trostberg) by vigorous stirring. A mixture of 1600 g quartz flour (particle size range 0-315 µm, SiO content, approx. 99%), 530 g Ca (OH) ₂ and 200 g Portland cement PZ 55 are stirred into this visual chamber. The de-icing foam mass is poured into the mold so that the insulation pieces are full constantly surrounds.

After 2 hours it is switched off and the stone is hardened with steam for 10 hours at 170 ° C (= 8 bar).

After cooling, you get a lime sandstone 20 x 20 x 8 cm with integrated thermal insulation. The insulation content is 34% by volume. The average density is 500 g / l.

The same result is obtained if the phosphorus-containing insulating material used is cured in an autoclave using the method given in Example 3.

Example 6

Example 5 is repeated, but foamed glass with a density of 135 g / l is used as the insulating material. A sand-lime brick with integrated thermal insulation with an average density of 480 g / l is obtained.

Claims (21)

1. Cuboid-shaped inorganic composite block consisting of a calcium silicate hydrate block, which may optionally still have air-filled channels and which has a bulk density of 0.6 to 2 kg / dm ³ , in combination with an inorganic insulating material with a bulk density of 0.05 to 0.3 kg / dm ³ . 2. Composite stone according to claim 1, characterized in that the insulating material forms a layer or a channel or a plurality of mutually parallel layers or channels which pass through the calcium silicate hydrate stone. 3. Composite stone according to claim 2, characterized in that the layers or channels are visible on at least one side, preferably at least 2 sides, of the composite stone. 4. Composite stone according to claim 2, characterized in that the layers of the insulating material run parallel to one side of the cuboid. 5. Composite stone according to claim 2, characterized in that the channels of the insulating material are perpendicular to one side of the cuboid. 6. Composite stone according to claim 2, characterized in that no edge of the cuboid is formed entirely from inorganic insulation. 7. Composite stone according to claim 6, characterized in that all edges are made entirely of calcium silicate hydrate. 8. Composite stone according to claim 4, characterized in that it is designed as a sandwich, the two outer layers of calcium silicate hydrate stone exist between which a layer of inorganic insulation is arranged. 9. A method for producing an inorganic composite block according to claim 1, characterized in that a blank with at least one cavity is formed from a sand-lime brick raw material with at least 3% water content, an expandable inorganic insulating precursor is filled into at least one cavity of the blank, this is allowed to expand and the raw stone is treated with superheated steam of at least 2 bar and thus the sand-lime brick blank and the expanded insulating precursor are hardened. 10. A method for producing an inorganic composite block according to claim 1, characterized in that a blank with at least one cavity is formed from a sand-lime brick raw material with at least 3% water content, in at least one cavity of the blank a water-containing, flowable, already expanded inorganic insulating material. The preliminary stage is filled in and the rough stone is treated with superheated steam of at least 2 bar and the sand-lime brick blank and possibly the preliminary insulating material are hardened. 11. The method according to claim 9 or 10, characterized in that a free-flowing lime sandstone raw mass is used with a water content of 3 to 7%. 12. The method according to claim 9 or 10, characterized in that a flowable, foamed lime sandstone raw material is used, which was produced with the addition of pore formers, air and cement. 13. A method for producing an inorganic composite brick according to claim 1, characterized in that at least a piece of an inorganic insulating material is introduced into a mold and optionally fixed, it is at least partially surrounded by a free-flowing raw sand-lime brick with 3 to 7% water content, the Lime sandstone raw mass pre-consolidated by the application of pressure, removes the blank connected to the insulation material from the mold and hardens by treatment with superheated steam of at least 2 bar. 14. The method according to claim 13, characterized in that one presses with a suitably shaped punch only on the sand-lime brick raw mass, but not on the introduced insulating material. 15. The method according to claim 13, characterized in that the introduced insulating material is rod-shaped and, with the exception of at least one end face, it is completely surrounded by raw sand-lime brick. 16. The method according to claim 13, characterized in that the introduced insulating material is plate-shaped and both plate surfaces are covered by sand-lime brick raw material. 17. A process for the preparation of an inorganic composite block according to claim 1, characterized in that at least one piece of an inorganic insulating material is introduced into a mold and optionally fixed, at least partially surrounding it with a flowable, foamed lime sandstone raw material, with the addition of pore formers , Air and cement was made, the lime sandstone raw material is allowed to set, the blank connected to the insulating material is removed from the mold and cured by treatment with superheated steam of at least 2 bar. 18. The method according to claim 13 or 17, characterized in that the introduced insulation is rod or plate-shaped. 19. A method for producing an inorganic composite stone according to claim 1, characterized in that an expandable insulating precursor is filled into a hardened sand-lime brick with at least one cavity, which allows it to expand and harden. 20. The method according to claim 19, characterized in that the insulating precursor is cured under the action of heat. 21. The method according to claim 19, characterized in that the insulating precursor is cured with superheated steam of at least 2 bar.

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