NL2006381C2

NL2006381C2 - Light weight fibre-reinforced building article having fire protection properties and manufacturing method thereof.

Info

Publication number: NL2006381C2
Application number: NL2006381A
Authority: NL
Inventors: Erwin Coenraad Murk
Original assignee: Murk
Priority date: 2011-03-14
Filing date: 2011-03-14
Publication date: 2012-09-17

Description

P30675NL00/JV

Light weight fibre-reinforced building article having fire protection properties and manufacturing method thereof

The invention relates to a fiber-reinforced building article having fire-retarding properties, and a manufacturing method thereof. Fiber-reinforced building articles like panels, blocks and bricks having fire-retarding properties are useful as fire protection for buildings and other civil engineering constructions, like tunnels. Building articles of 5 this kind are made from different starting materials, for example by casting. Spray coating is another well known method of providing a suitable fireproofing layer on this kind of constructions. Typically the layer thickness thereof is at least about 4 cm.

For example, EP-A1-1462424 has disclosed a fibre-reinforced building article having 10 fire protection properties, which article comprises a matrix of a binding material comprising an aluminous cement, a carboxylic ether based plasticizer, a fugitive material, filler and alkali resistant glass fibres, and at least one fiber layer of alkali resistant glass fibers, incorporated in said matrix. The commercial product produced according to this patent application is a panel comprising two outer glass fiber mats 15 and an intermediate glass fiber mat incorporated in the matrix of aluminous cement and other components. The thickness is at least about 25 mm such as 28 mm in order to achieve the desired strength and fireproofing properties. The specific gravity is about 1500 kg/m3.

20 For renovation purposes e.g. providing older tunnels especially those having a limited height or width, of a new fireproofing layer the thickness of the panels may cause some problems in the design. In order to ensure an unlimited passage of traffic, in particular transport trucks, every millimeter counts. Furthermore, the commercial plates have a considerable weight, necessitating quite a number of anchors per 25 square meter for fastening the panels to the basic structure of the construction. The weight is also important in view of storage, transport and handling.

Thus, in the art there is a need for fireproofing building articles like panels having a relatively small thickness and/or a reduced weight.

30 2

An object of the invention is to satisfy this need at least partially.

According to a first aspect the invention provides a fiber-reinforced building article having fire-retarding properties, the article comprising a matrix comprising a Portland 5 cement and an aggregate comprising at least a filler, a fugitive material and alkali resistant glass fibers, which matrix is bonded to two cover layers comprising an alkali resistant glass fiber fleece at two main surfaces of the article.

The fireproofing fiber-reinforced building article according to the invention has a 10 sandwich configuration. Between two cover layers of alkali resistant glass fiber fleece material a matrix is contained. The matrix penetrates into the glass fiber fleece in order to achieve an appropriate bonding. However, the cover layer is not completely embedded in the matrix as in the building article according to EP-A1-1462424. The matrix comprises a binding material and an aggregate. The binding material is based 15 on Portland cement. The aggregate comprises a blend of at least a filler, a fugitive material and alkali resistant glass fibers. Surprisingly it has been found that these starting materials allow manufacturing a lightweight fireproofing panel having a relatively small thickness and density. Due to these properties a panel according to the invention can be transported and handled more easily than a panel of the same 20 size made according to EP-A1-1462424. E.g. a panel according to the invention having a thickness of 15 mm and a density of only 700 kg/m3 can be manufactured. Such a board passes the standard test RWS, providing an interface temperature of 360 °C after 2 hrs and 371 °C after 135 minutes. The relatively small weight of a panel allows reducing the number of fastening anchors to 10 per 3 m2, optionally in 25 combination with glue. Furthermore, it is possible to stick a panel according to the invention to a substrate using a commercially available glue EMPE, available at Pull Rhenen B.V, without anchors. The small thickness is very useful in renovation, such as renovating tunnels and business offices, where a new fire protection is to be applied, because the available passage and space is not reduced substantially when 30 a panel is mounted to an existing fireproofing structure.

The Portland cement can be any of types 1-5 according to EN 197. However, types 1 and 2 are preferred. Typically, the Portland cement is present in an amount of 30-90 wt.%. Generally, the more Portland is used, the higher the density of the ultimately 35 produced article.

3

Advantageously the filler is present in an amount of several percent to about 30%. Preferred examples of filler materials comprise sand, cellulose, bauxite and clay, in particular China clay, and mixtures thereof. Clay is also useful as a thickener, if necessary.

5 A fugitive material is a material that is fugitive on exposure to fire, thereby creating escape routes for the gases that are generated by firing of the matrix. Suitable examples of fugitive material are cellulose based particulates, such as sawdust, and particles of organic polymers melting or evaporating upon exposure to fire, in 10 particular polyolefines and polyaromatics. Organic polymer particles, in particular expanded polystyrene particles are preferred, as cellulosic materials might retain water, requiring excessive drying conditions in time and/or temperature. The fugitive material is preferably present in an amount up to about 10%.

15 Commercially available ready-to-use dry mortars for spray coating comprising already Portland cement, fugitive material, glass fibers and some additional components like Monokote® Z-146T, Z-156T and Avikote AV 650, can be used as a starting material comprising at least a part of the required components for manufacturing a building article according to the invention.

20

Typically, the alkali resistant glass fibers are chopped fibers having a length up to 18 mm, e.g. 12 mm. The amount of glass fibers is not particularly limited. The appropriate amount is dictated by the end application of the panel, in particular the required strength.

25

The alkali resistant glass fiber fleece used as a cover layer in the building article according to the invention is a thin layer holding the matrix together. Fleeces are available at lower weight per area than similar glass fiber mats or rovings.

30 The matrix may contain other components, if necessary. Examples thereof are adhesives like methylcellulose, thickeners, set retarders/set accelerators. Contrary to EP-A1-1462424 a plasticizer is not needed.

Advantageously the shape of a building article according to the invention is adapted 35 to the (shape of) structure to be protected, such as a flat or curved wall, column and the like. One preferred building article according to the invention has the shape of a flat panel. Other suitable shapes include building bricks and building blocks. In a 4 preferred embodiment the building article has a thickness of less than 25 mm. More preferably the thickness is in the range of 10-20 mm.

If desired, e.g. in view of strength, a building article according to the invention may 5 comprise one or more reinforcing layers. If present, a preferred reinforcing layer comprises a glass fiber mat or roving.

Advantageously the density of the building article ranges from about 500 to about 800 kg/m3, more preferably 600-780 kg/m3.

10

According to a second aspect the invention provides a method for manufacturing a fiber-reinforced building article having fire protection properties as defined hereinbefore. This method comprises casting an aqueous mixture of binding material comprising a Portland cement, a filler, a fugitive material and alkali resistant glass 15 fibers between two glass fiber fleece layers in a mould in order to obtain a preform, and allowing the thus obtained preform to dry.

The method according to the invention comprises a mixing step, wherein the solids are blended with a suitable amount of water. The solids: water ratio is preferably 1 : 20 0.38-0.61. A particular advantage of light weight construction is that after casting and initial hardening the products can be stacked directly upon one another.

Advantageously the method according to the invention is performed similar to the method described in EP-A1-1462424, except that a bottom glass fiber fleece is 25 introduced into the mould prior to casting the mortar.

The preferred embodiments described above for the building article according to the invention are similarly applicable to the method according to the invention.

30 The present invention is further illustrated by the following example.

125 kg. Avikote AV 650 - a ready to use dry mortar mixture comprising Portland cement, expanded polystyrene particles and glass fibers, available at AVI -, 1.25 kg glass fibers having a length of 12 mm from Kast GmbH, and about 62.5 kg water 35 were thoroughly mixed in order to prepare a starting material mixture. A rectangular mould was provided with a bottom layer of glass fiber fleece material of 45 g/m2. The mixture was casted in the mould on the glass fleece material and the a top layer of 5 the same fleece material was put on top of it. The thus produced building article was allowed to dry at least for 4 days. The final product had a thickness of 15 mm. The standard RWS test showed that after 2 hrs exposure of one main surface to a fire, the temperature at interface had been raised to 361 °C, whereas 380 °C is the 5 maximum allowable upper limit.

Claims

A fiber-reinforced building article with fire-retardant properties, wherein the article comprises a matrix of a Portland cement-containing binder, and an aggregate comprising at least one filler, a sacrificial material and alkali-resistant glass fibers, which matrix is connected to an alkali-resistant on the main surfaces of the article fiberglass fleece comprising a cover layer.

The article of claim 1, wherein the sacrificial material is selected from the group consisting of particulate cellulosic material, organic polymer particles, and mixtures thereof. 10

The article of claim 1 or 2, wherein the filler is selected from the group consisting of sand, bauxite, and clay, and mixtures thereof.

4. Object according to any of the preceding claims, further comprising an internal reinforcement comprising one or more glass fiber mats.

The article of any one of the preceding claims, wherein the article is a panel.

The article of any one of the preceding claims, wherein the article has a thickness of less than 25 mm.

The article of claim 6, wherein the thickness is 10-20 mm.

8. Object according to one of the preceding claims with a specific weight of 500-800 kg / m3, preferably 600-780 kg / m3.

9. A method for manufacturing a fiber-reinforced building article with fire-retardant properties according to any one of the preceding claims, which method comprises casting an aqueous mixture of at least one binder comprising cement, a filler, a sacrificial material, and alkali-resistant glass fibers between two glass fiber fleece layers in a mold to obtain a preform and allow the preform thus obtained to dry.

The method of claim 9, wherein the mixing ratio of solids to water is in the range of 1: 0.38 -0.61.