WO1994005605A1

WO1994005605A1 - Building material

Info

Publication number: WO1994005605A1
Application number: PCT/FI1992/000233
Authority: WO
Inventors: Asko Sarja; Hemming Paroll; Matti Lanu
Original assignee: Valtion Teknillinen Tutkimuskeskus
Priority date: 1992-09-02
Filing date: 1992-09-02
Publication date: 1994-03-17
Also published as: AU2493392A

Abstract

A building material which in addition to a mineral binder (2) contains reinforcing fibres (3). The binder (2) which contains fibres is formed into a cellular structure. The cells are formed by adding to the basic mass formed by fibres (3) and binder (2) such grains (1) which are lighter than the basic mass and are poor thermal conductors.

Description

Building material

This invention relates to a building material, which in addition to mineral binder contains reinforcing fibres, whereby the binder which contains fibres is formed into a cellular structure by adding to the basic mass formed by the binder and the fibres such cell-forming grains which are lighter than the basic mass and are poor thermal conductors.

At the present time many different fibre materials are in use and have been patented as building materials. Such materials are described, for example, in the printed patent specifications GB 1405090, GB 1406442 and US 441944 and in the printed application specifications WO 89/01916, WO 90/06901 and EP 0310100 Al, EP 0220649 Al, EP 0240167 A3, EP 0261971 Al and EP 0271825 A3. In these materials different quantities of fibre reinforcements of various types are used in cement mortars or in concrete. The fibres are synthetic fibres, for example, polypropylene, polyethylene, polyary- lenethioether or polyacrylonitrile.

Such materials are also known wherein, in order to achieve low weight and thermal insulation, light and heat- insulating particles, such as porous polystyrene balls, are added to the cement mortar or concrete. Such solutions are described i.a. in the following printed application speci¬ fications NL 84 00426 (= FI 85 3837), WO 85/0350, WO 88/05765 and GR 63.097 (= FI 811977).

Good strength properties are obtained with fibrated cement-based materials. However, their density is high and no satisfactory thermal insulation capacity is obtained with them for use in constructions requiring such. By using light particles in cement mortar or concrete the thermal insulati¬ on capacity of the material can be improved and its density lowered. However, such a material is brittle and its tensile strength is poor, thus limiting the use of the material. When aiming at a material which is coherent in use, its density cannot usually be lowered under approximately 300 kg/sq.m. , whereby the thermal insulation capacity is rather poor with a thermal transmittance coefficient in excess of 0.15 W/mK. This invention is intended to eliminate the weaknesses of the known materials mentioned above and to bring about a material featuring a high tenacity and strength also in terms of tensile strength along with a good thermal insula- tion capacity.

The building material according to the invention is characterized by that the fibres are polypropylene, poly- acrylatenitrite, glass, aramid or carbon fibres. In this way the thermal insulation capacity is multiplied compared with earlier solutions. At the same time a material is obtained which is very tough even when subjected to tensile stress.

The basic idea of this building material is a cellular material structure formed of a mineral composite. The cellu¬ lar structure consists of a strong fibre mineral and it provides the material with considerable strength and tough¬ ness. The cellular fibre mineral is formed with the aid of soft particles which are mixed into the mass. The soft particles may be optimized in regard to their size, size distribution and shape. Such are, for example, poly- s- tyrene and polyurethane particles. The soft particles impro¬ ve the thermal insulation capacity of the material.

The building material is a three-component composite having the following sub-materials in accordance with Figure 1: - soft particles 1 (for example, polystyrene, poly¬ urethane) as balls or grains of other shapes. The grain size distribution is optimized according to the requirements of the individual application. A suitable granular size is normally between 0.5 and 3 mm. - a supporting cellular mineral composite 2 providing strength, rigidity and fire endurance and consisting of: a hydraulic binder (for example, cement or blast-furnace slag binder, which may contain silica, fly ash, fine mineral aggregate and other mix components) and a fibre content 3 which is high compared to the binder quantity (for example, polypropylene, glass, aramid or carbon fibres) . A suitable fibre length is 5-20 mm and a suitable fibre diameter is 10- 200 μm. By changing the component proportions the material may be formed into different versions with different strength, thermal insulation capacity, fire endurance and weather resistance according to the requirements of different appli- cations.

The following possibilities of using the material are especially advantageous:

- simple production at a prefabrication plant or on the building site, - allowing production of products which are easy to transport and install owing to low weight and easy workabi¬ lity (sawing, milling) ,

- so high a strength and toughness that supporting vertical and horizontal structures may be made of the mate- rial,

- in suitable versions providing sufficient thermal insulation together with considerable strength, and

- fire retardant, whereby the material may be used even in demanding fire classes. The heat insulation is suitable i.a. in walls of high- rise buildings and small houses as well as in wall, base and foundation blocks of small houses. Other possible applica¬ tions are i.a. equipment installation floors, partition walls and base and upper floors. There are also many possi- ble applications in renovation, such as partitions, sound- insulation and pipe-installation layers in floors and walls, insulating and shaping layers in base and upper floors, filling-in casts and additional thermal insulations.

The proportions of components in the building material of the invention can be varied within the following limits (limits expressed as percentage by volume) : soft particles 5 - 90 % by v. fibre materials 1 - 10 % by v. hydraulic binder 3 - 30 % by v. - mineral aggregate 0 - 50 % by v. additives 0 - 1 % by v. mix components 0 - 20 % by v. The following is an example of mix proportions (the figures are expressed as percentage by weight) : soft particles

Even in preliminary tests the following characteris¬ tics were achieved with a thermal insulation material of this kind:

Heat Supporting insulation material

- dry density 160.00 kg/sq.m. 1500 kg/sq.m.

- compression strength (ka.) 0.37 MPa 100 MPa

- compressive strain

(ka.) 34.00

- flexural strength

(ka.) 0.31 MPa

- thermal insulation capacity λ = 0.059 W/mK (moist) λ = 0.053 W/mK (dry)

The material may be mixed using ordinary power mixers.

Claims

1. A building material, which in addition to a mineral binder (2) also contains reinforcing fibres (3) , whereby the binder (2) which contains fibres is formed into a cellular structure by adding to the basic mass formed by fibres (3) and binder (2) such cell-forming grains (1) which are ligh¬ ter than the basic mass and are poor thermal conductors, characterized in that the fibres (3) are polypropylene, polyacrylatenitrite, glass, aramid or carbon fibres.

2. A building material as defined in claim 1, charac¬ terized in that the binder (2) is cement or blast-furnace slag.

3. A building material as defined in claim 2, charac¬ terized in that the binder (2) also contains silica, fly ash, mineral aggregate and/or other mix materials.

4. A building material as defined in any one of claims 1-3, characterized in that the fibre length is 5-20 mm.

5. A building material as defined in any one of claims 1-4, characterized in that the fibre diameter is 10- 200 μm.