SE500226C2

SE500226C2 - Double skinned reinforced insulated panel for partition or outer walls - has thin outer skins of concrete reinforced with steel or plastics fibres oriented by vibratory casting method on each side of insulating fill

Info

Publication number: SE500226C2
Application number: SE9201859A
Authority: SE
Inventors: Sture Baeckman
Original assignee: Baeckman Bygg Ab S
Priority date: 1992-06-17
Filing date: 1992-06-17
Publication date: 1994-05-09
Also published as: SE9201859D0; SE9201859L

Abstract

The panels are manufactured in casting table moulds (7) under a hopper (2) for mixing the concrete and reinforcing fibres. The reinforcement comprises a mixture of steel and polypropylene fibres, with polypropylene only, on external faces. A vibrator (4) assists the uniform mixing of concrete and fibres. A damper (3) controls the discharge from the hopper (2), and guide vanes (8) direct the orientation of fibres with the assistance of a discharge vibrator (6). A wiper (10) controls the thickness of deposited material. After placing the first skin, core insulation is added, followed by the second concrete skin.

Description

15 20 25 30 35 500 226 2 eller cellplast. I mellanväggar, och i s.k. utfackningselement behöver inte elementen vara bärande, utan de tunna betongskivor- nas egen hållfasthet är fullt tillräcklig, och elementen blir därigenom lätta. För bärande element göres endast avstyvningar av fiberbetong, som dock inte behöver öka elementens vikt med mer än 20 - 22 kg/m2. 15 20 25 30 35 500 226 2 or cellular plastic. In partitions, and in so-called unfolding elements, the elements do not have to be load-bearing, but the own strength of the thin concrete slabs is fully sufficient, and the elements thereby become light. For load-bearing elements, only stiffeners of fiber concrete are made, which, however, do not need to increase the weight of the elements by more than 20 - 22 kg / m2.

Uppfinningen avser också ett sätt att tillverka väggelement av armerad fiberbetong, vilket kännetecknas av att först gjutes en innerskiva av betong armerad med orienterade stålfibrer och plastfibrer, att isolering därefter lägges på och att slutligen en ytterskiva gjutes av samma fiberbetong som innerskivan, varvid elementet i sin gjutform vibreras under gjutningarna så att en stark förbindning fås mellan betongskivorna och isole- ringen genom att deras ytskikt diffunderar in i varandra.The invention also relates to a method of manufacturing wall elements of reinforced fiber concrete, which is characterized in that an inner board of concrete reinforced with oriented steel fibers and plastic fibers is first cast, that insulation is then applied and that finally an outer board is cast of the same fiber concrete as the inner board. mold is vibrated during the castings so that a strong connection is obtained between the concrete slabs and the insulation by their surface layers diffusing into each other.

Enligt uppfinningen sammangjutes sålunda mycket tunna fiber- betongskivor med mellanliggande isolering till hållfasthets- mässigt samverkande och mycket lätta väggelement och genom att en blandning av stål- och plastfibrer i betongen fäster i isole- ringsskiktet vid formens vibrering.According to the invention, very thin fibrous concrete slabs with intermediate insulation are thus merged into strength-cooperating and very light wall elements and by a mixture of steel and plastic fibers in the concrete adhering to the insulating layer during the vibration of the mold.

Blandningen av orienterade stål- och plastfibrer förbättrar betongskivornas motståndskraft mot slag och ger ett segare _ brott. Plastfibrerna, företrädesvis polypropen, förhindrar mikrosprickor att uppstå i skivorna och hindrar stålfibrerna från att sedimentera vid gjutformens vibrering. I ytterskivorna för fasadelement är dessa plastfibrer den enda armeringen i de yttersta 5 mm, som hålles fria från stålfibrer för att undvika rostutslag.The mixture of oriented steel and plastic fibers improves the impact resistance of the concrete slabs and gives a tougher break. The plastic fibers, preferably polypropylene, prevent microcracks from occurring in the sheets and prevent the steel fibers from settling during the vibration of the mold. In the outer panels for facade elements, these plastic fibers are the only reinforcement in the outer 5 mm, which is kept free of steel fibers to avoid rust.

Uppfinningen skall beskrivas utförligare i form av ett exempel med hänvisning till den åtföljande figuren. I en form göts en skiva, den avsedda innerskivan 1, med en tjocklek av 12 mm och armerad med 1,2 vol% stålfibrer och 0,3 vol% polypropen- fibrer. Gjutningen och armeringen av skivan med orientering av fibrerna skedde på det sätt som angivits i vår förutnämnda patentansökan. Ovanpå lades en isolering 2 av 200 mm mineralull, på denna göts den 18 mm tjocka ytterskivan 3, 4, varvid först ett 13 mm tjockt lager 3 göts på samma sätt som innerskivan, och därefter ett översta 5 mm tjockt lager 4 göts innehållande enbart polypropenfibrer som armering. För att i viss mån kompri- mera betongen och öka vidhäftningen till mineralullen vibrerades 10 15 20 25 30 35 500 22ö 3 formen vid gjutningen. Elementet kunde avformas dagen efter gjutningen, och betongskivorna hade mycket god vidhäftning till isoleringen.The invention will be described in more detail by way of example with reference to the accompanying figure. In a mold, a board, the intended inner board 1, was cast with a thickness of 12 mm and reinforced with 1.2 vol% steel fibers and 0.3 vol% polypropylene fibers. The casting and reinforcement of the board with orientation of the fibers took place in the manner specified in our aforementioned patent application. An insulation 2 of 200 mm mineral wool was placed on top, on which the 18 mm thick outer board 3, 4 was cast, whereby first a 13 mm thick layer 3 was cast in the same way as the inner board, and then a top 5 mm thick layer 4 was cast containing only polypropylene fibers. as reinforcement. In order to compress the concrete to some extent and increase the adhesion to the mineral wool, the mold was vibrated during casting. The element could be demoulded the day after casting, and the concrete slabs had very good adhesion to the insulation.

Fibermängder av 1,0 - 1,5 vol% stålfibrer med en längd av 25 - 40 mm och en diameter av 0,3 - 0,4 mm, och 0,2 - 0,5 vol% polypropenfibrer med längden 6 - 12 mm och diametern 35 - 250 um gav goda resultat men även dimensioner och mängder utanför dessa gränser exempelvis med andra partikelstorlekar i betongen.Fiber quantities of 1,0 - 1,5 vol% steel fibers with a length of 25 - 40 mm and a diameter of 0,3 - 0,4 mm, and 0,2 - 0,5 vol% polypropylene fibers with a length of 6 - 12 mm and the diameter 35 - 250 μm gave good results but also dimensions and amounts outside these limits, for example with other particle sizes in the concrete.

Vanligen användes en kornstorlek <5 mm och företrädesvis <3 mm i betongen, och 300 - 400 kg cement/m3 betong. Isolering med 100 - 300 mm mineralull eller tunnare isolering med cellplast är lämplig, och företrädesvis 200 mm mineralull är tillräcklig och ekonomiskt fördelaktigast för de flesta väggar.Usually a grain size <5 mm and preferably <3 mm is used in the concrete, and 300 - 400 kg cement / m3 concrete. Insulation with 100 - 300 mm mineral wool or thinner insulation with cellular plastic is suitable, and preferably 200 mm mineral wool is sufficient and economically most advantageous for most walls.

För att få ett mått på vidhäftningen mellan fiberbetong och isolering, en egenskap som är väsentlig för elementens funktion som bärande enhet samt med tanke på vindbelastning, undersöktes skjuvbelastningen. Genomsnittliga skjuvbelastningen blev vid mineralullsisolering 28 kPa. Den karakteristiska hållfastheten enligt BBK 79 blir fk=23 kPa.In order to obtain a measure of the adhesion between fiber-reinforced concrete and insulation, a property that is essential for the elements' function as a load-bearing unit and with regard to wind load, the shear load was examined. The average shear load with mineral wool insulation was 28 kPa. The characteristic strength according to BBK 79 is fk = 23 kPa.

Ett väggelement med bredden 2,4 och höjden 3,0 m belastades med en tryckkraft av 114 kN, motsvarande 3 gånger brukslasten i ett aktuellt fall. Inga nämnvärda deformationer kunde iakttas under inverkan av lasten, och brottbelastningen ligger således väsentligt högre. Fiberarmeringen gör det lämpligt att även utbyta konventionell betong mot höghållfast betong, med tryck- hållfasthet 80 - 120 MPa.A wall element with a width of 2.4 and a height of 3.0 m was loaded with a compressive force of 114 kN, corresponding to 3 times the service load in a current case. No appreciable deformations could be observed under the influence of the load, and the breaking load is thus significantly higher. The fiber reinforcement makes it suitable to also replace conventional concrete with high-strength concrete, with compressive strength 80 - 120 MPa.

Vid böjprovning blev böjmomentet 14,6 kNm/m. Som jämförelse är böjmomentet vid normal vindbelastning 0,36 kNm/m, dvs. 1/40 av momentet vid provningen. Denna styvhet hos elementet beror på att ytterskiva och innerskiva samverkar via skjuvspänningar i isoleringen. Den maximala skjuvpåkänningen vid provbelastningen kan beräknas till 158 kPa, som är väsentligt högre än de värden som erhölls vid rena skjuvningsprov enligt ovan. Brand- och belastningsprov har också gjorts, och elementen har därvid visat sig ha en avskiljande och bärande funktion under 120 minuter, motsvarande brandklass 120 A.During bending testing, the bending moment was 14.6 kNm / m. For comparison, the bending moment at normal wind load is 0.36 kNm / m, ie. 1/40 of the torque during the test. This stiffness of the element is due to the fact that the outer plate and the inner plate interact via shear stresses in the insulation. The maximum shear stress at the test load can be calculated to 158 kPa, which is significantly higher than the values obtained in pure shear tests as above. Fire and load tests have also been carried out, and the elements have been shown to have a separating and load-bearing function for 120 minutes, corresponding to fire class 120 A.

Claims

10 15 20 25 30 500 226 H BAIENIKBY

Composite wall element with sides of concrete and with intermediate insulation of mineral wool or cellular plastic, characterized in that the concrete is reinforced with 1.0 - 1.5 volt steel fibers and 0.2 - 0.5 volt plastic fibers oriented in such a direction that the wall element is given maximum strength against expected stresses and that the element with the cast sides and the intermediate insulation is vibrated during the casting so that a strong connection between insulation and fiber concrete sides is achieved.

Wall element according to claim 1, thanked by the fact that the cast sides are made of high-strength concrete with compressive strength of between 80 and 120 MPa.

Wall element according to one of Claims 1 to 3, characterized in that an outer layer is applied for use in external facades, which contains only the plastic fibers without any steel fibers.

Wall element according to one of the preceding claims, characterized in that the supporting elements have stiffeners of fiber concrete.

A wall element according to any one of the preceding claims, characterized by a shear strength exceeding 28 kPa, a bending moment of 14.6 kNm / m or more, a fire class of A 120 and that a 2.4 x 3.0 m element can be loaded with a compressive force of 114 kN. _

6. A method of manufacturing wall elements of reinforced fiber concrete characterized in that first an inner board of concrete reinforced with oriented steel fibers and plastic fibers is first cast, that insulation is then applied and that finally an outer board is cast of the same fiber concrete as the inner board, the element vibrating in its mold during the castings so that a strong connection is obtained between the concrete slabs and the insulation by their surface layers diffusing into each other. '

7. A method according to claim 6, characterized in that for facade elements the inner board is made 1.0 - 1.5 cm thick and the outer board 1.5 - 2.0 cm with a 0.5 cm surface layer without any steel fibers, that the insulation is made of 20 cm mineral wool and that the boards in load-bearing elements are provided with stiffeners of fiber concrete during casting.