FR2555633A1 - Components cast out of lightweight insulating concrete, method of manufacture and composition - Google Patents

Abstract

Components cast out of lightweight insulating concrete and method for their manufacture, characterised in that they are formed of an external layer reinforced with fibres and of a lightweight internal mass, both having a composition comprising an anionic agent and a colloid.

Description

 Light insulating concrete construction elements have advantages of lightness, high mechanical resistance and insulation which allow their use in many applications.

 Different compositions have already been proposed; in particular the French patent 81.71452 with its additive 82.06392 as well as the patent filed in ALGERIA under the number "6655 and finally the European patent 82.4016760 published under the number" 0074 908 describe a product using a cement mortar composition reinforced with fiber fibers glass. However, such products have serious drawbacks because the glass fiber, if it is not specially treated, is attacked by the alkalis produced by the mixture of hydraulic binders and water.

 It is also known that the manufacture of light insulating concrete obtained by mixing a hydraulic binder, polystyrene beads and water, presents difficulties in coating the beads due on the one hand to the hydrophobic nature of the polystyrene and on the other hand because each polystyrene ball is charged with electricity superficially.

 The subject of the present invention is an embodiment of molded parts made of light insulating concrete which makes it possible to avoid these drawbacks.

 The elements according to the invention are characterized in that they are formed from an outer layer reinforced with fibers and from a light internal mass, both having a composition comprising an anionic agent and a colloid, and more precisely, the outer layer being formed of the components a / b / ct d / f / g / h / i / and the inner layer of the components a / c / e / h / i / of the composition below, in percent dry matter weight.

a / - from 20 to 50% portland cement or sulphate
calcium, b / - from 20 to 50% of a mineral filler, c / - from 0.50 to 2% of a filler of pozzolanic character, d / - from 2 to 4% of enzymatic silicate fibers,
carbon, polyamide, e / - from 0.50 to 1% of insulating materials in general expan
s or fibrous, f / - from 0.02 to-D, lO% plasticizer of cement paste
plus charge, - - from 0.50 to 1% of setting accelerator, h / - from 0.01 to 0.10% of an anionic agent and of a colloid, i / - from 10 to 25% d 'water.

 The cement used is an artificial portland cement 55 R.

 Calcium sulfate is a plaster.

 The mineral fillers are siliceous materials of colors suitable for those which it is desired to obtain and with a particle size of 0.1 to 15 m / m.

The pozzolanic charge consists essentially of
- 50% SiO2
- 30% of AL202
- 10% Fe203
The silicate, carbon or polyamide fibers are roving in coils of 20 kg. The silicate fibers undergo an enzyme coating before use.
Na20 - CaO - zrO2 - Si 02.

 Insulating materials in general expanded are plastic materials: polystyrene, polyurethane, urea-formaldehyde resin: or mineral materials: rock fibers, expanded slag, expanded clay, expanded glass beads or vermiculite.

 The plasticizer is based on naphthalene sulfonate formaldehyde condensates.

 The accelerator is a sodium silicate.

 The anionic agent is supplemented with a powder colloid of the methyl cellulose type.

 The hydrophobic surface nature of the polystyrene beads is favorable for adsorption. In addition, the adsorption of colloids on the beads leads to coadsorption of cations and the attachment of anions to the surface of the adsorbed layers.

To carry out the invention, the invention provides a process in several phases - Mixing at high speed of the elements a / b / c / f / g /
h / i / composing the outer layer.

- Projection of this mixture on the walls of the mold.

- Projection of fibers cut to the desired length.

- Rolling and compression with a vibrating float.

- Slow speed mixing of elements a / c / e / h / i /
composing the internal mass.

- Introduction of this mixture into the mold coated with
first mix.

 Preferably, in the production of the outer layer the proportions of the constituents a / and b / are approximately equal.

The invention is illustrated and more fully described by the example below
A) In a mixer rotating at high speed and specially adapted for this use, the following is introduced
- artificial Portland cement 55 R ..... 50 kg
- silica .............................. 50 kg
- accelerator ....................... 1 kg 200
- anionic and colloldal agent ........ O kg 300
- water ................................. 19 kg
When the dough has become smooth, add
O kg 150 of plasticizer and mixing continues for thirty seconds.

 B) The paste thus obtained is sprayed onto the walls of a mold representing the desired object, using a pneumatic pump, to a thickness of 5 to 15 m / m.

The projection head contains a knife with several blades which cut the fiber which is projected at the same time as the cement-based paste. The projection cone must be adjusted in such a way that there is good interpenetration of the pulp and the fiber. The projected complex is then rolled to ensure good compaction or compressed by a vibrating trowel.

C) In another slow speed mixer, this is mixed - artificial portland cement 55 R ...... 123 kg - polystyrene beads of a
diameter from 1 to 5 m / m ............... 4 kg 100 - anionic and colloidal agent ......... O kg 700 - water ..... ............................. 47 kg
D) The light insulating concrete paste thus obtained is poured using a bucket or a peristaltic pump into the mold having received the projection described above. This mold is filled a few millimeters from the upper edge. The excess fibers projected during the first application are then folded down onto the light concrete. To close the box thus obtained, a new layer of mortar and fibers is sprayed. This cover is also rolled up as for the first application.

 The composition according to the present invention may comprise the integration into the mass of light insulating concrete of polystyrene blocks whose thickness is conditioned by the coefficient of thermal insulation which it is desired to obtain. The same operation can be carried out with blocks of rock wool which also improve the sound insulation coefficient.

 It is also possible in certain applications to decrease, until removing it, the external layer of mortar reinforced with fibers.

 In addition, if necessary, it is possible to incorporate into the light insulating concrete ribs of mortar reinforced with fibers which serve as stiffeners.

 It is also possible to replace one or the other of the aggregates used in the above example by those listed in the description above.

The present invention makes it possible to obtain construction elements which are both light (from 0.5 to 0.8 of the weight of the water) and very resistant, as follows from the tests below.
Billing resistance tests. A 5 cm diameter steel ball weighing 510 g falls from an increasing height and we observe the impact. After 10 successive tests on an exterior facing, with a drop height of 2.50 meters, there is no It is not possible to discern the slightest damage.

 Soft body impact tests. Ten tests standardized in class E prime 2 (risk of accidents or improper use in an area exposed to shocks from thrown or projected objects) allow the elements falling within the scope of the present invention to be classified in class I prime 2.

 Thermal insulation tests. An experimental setup derived from the NFX 10.021 standard of December 1972 made it possible to measure the thermal resistance R of a heterogeneous panel.

 The coefficient K is deduced from the thermal resistance using the surface resistances given by the DTU rules ThK or K = 1 / (1 / hui + 1 / he + R) according to our tests K = 0.33 W / C m2 is characteristic.

Sound reduction tests R according to AFNOR standards 531 - 045, S31 - 049, 531 - 050, S31 051. The principle of the measurement makes it possible to obtain R according to the formula R = L1 S L2 + 10 Lg
We thus obtained
R pink = 43 dB (A) and R route = 40 dB (A)
Fire stability tests carried out according to British standard BS476 gave the following classification
- section 4 - materials: non-combustible
- section 5 - classification P (hardly flammable)
- section 6 - fire propagation: class O
- section 7 - class 1 (non flame extension)
The flexural-compressive strength tests, the mechanical characteristics of the components of the present invention are determined using a JJ LLOYD T 5000 / sus testing machine. The important parameters for evaluating the quality of the material produced are the proportionality limit (LDP) and the modulus of rupture (MDR). The characteristic values obtained are:
LDP = 10 N / mm2 MDR = 27 N / mm2
All the test results listed above show the quality of the product obtained. In addition, they demonstrate the ability to produce various materials used in building and civil engineering.

 The following list of possible uses is not limitative.

- Facade panels with the use of gray cement or
white cement.

 - Architectural concrete façade panels.

- Thin wall elements on metal framework
or plastic.

 - Bulletproof elements.

 - Anti-noise wall elements.

 - Decorative elements for walls and ceilings.

 - Elements of street furniture.

 - Bodyguard of engineering structures.

 It is also possible to produce certain elements with the external layer alone without filling with the internal mixture or with an incomplete filling, the product obtained being a hollow or partially hollow body.

Claims (7)

 1. Light insulating concrete moldings, characterized in that they are formed from an outer layer reinforced with fibers and a light internal mass, both having a composition comprising an anionic agent and a colloid, and more precisely the layer  being formed from the components a / b / c / d / f /  g / h / i / and the inner layer of the components a / c / e / h / il  of the composition below, in percent by weight of dry matter a / - from 20 to 50% of portland cement or  calcium, bl - from 20 to 50% of a mineral filler, c / - from 0.50 to 2% of a filler of pozzolanic character, d / - from 2 to 4 9 of enzymatic silicate fibers,  carbon, polyamide, e / - from 0.50 to 1% of insulating materials in general  expanded or fibrous, f / - from 0.02 to 0.10% plasticizer for cement paste  more charge,  g / - from 0.50 to 1% setting accelerator,  hl - from 0.01 to 0.10% of an anionic agent and of a  colloid,  i / - from 10 to 25% water.  2. Method of making the parts according to the  claim 1, characterized in that a high speed mixing of the elements a / bj ci f /  g / h / i / of the composition, this mixture is projected onto  the walls of the mold, then we project the fibers according to  dl cut to desired length and incorporated,  a slow speed mixing of the  elements a / cl e / hl i / and we introduce this second  mixture in the mold coated with the first mixture.  3. Process and products according to any one  of the preceding claims, characterized in that  the proportions of components a / and b / of the layer  external are approximately equal.  4. Method according to any one of the claims  2 and 3, characterized in that a second projection of the mixture constituting the external layer is made on the opening of the mold once filled with the internal mixture.  5. Method and product according to any one of the preceding claims, characterized in that the thickness of the external layer is between 0 and 15 mm.  6. Method and products according to any one of the preceding claims, characterized in that the mass of light insulating concrete comprises blocks of polystyrene or rock wool.  7. Method and products according to any one of the preceding claims, in which the internal mass is at least partially constituted by a vacuum.