FI76545B - HELT SJAELVNIVELLERANDE GOLVSPACKEL SOM KAN PUMPAS. - Google Patents

Description

1 76545

This invention relates to a pumpable and fully self-leveling floor screed comprising a hydraulic binder, a aggregate, fibers, additives and water.

The use of self-leveling floor screeds has long been known in the construction industry. The spreading properties of these products have made it possible to develop a new working technique, according to which screeds are most often pumped to the floor, where they flatten and harden into a surface that can be coated. Some of the products on the market are also suitable for manual leveling work.

The dry raw materials for self-leveling floor screeds are mixed with water on site to form a ready-to-use floor screed. A typical amount of water mixed with the dry raw materials is about 20-25% by weight * based on the dry materials. The basic raw materials are cement as a binder, sand, various fillers, gypsum as a shrinkage compensating agent and additives which improve adhesion and spreading properties.

It is already known to prime the substrate before carrying out the floor leveling work with a plastic dispersion-water mixture, the purpose of which is to improve the adhesion of the screed to the substrate, to prevent water from leaving the screed and to prevent air from entering the screed. Sometimes, in order to improve the adhesive properties, the so-called an adhesion bridge in which sand, cement or screed is added to a plastic dispersion-water mixture and the mixture is brushed on a substrate to be leveled.

Despite the measures taken to ensure infection, floor screeds require a good substrate. The base to be leveled must be strong and the surface clean, for example cement-2 76545. Special substrates such as wood floors are not normally suitable as a substrate for self-leveling floor coverings due to moisture movements in the wood.

The cement that binds the floor screeds shrinks as it dries and causes stresses in the screed. If the stresses are high and the substrate is weak or unsuitable for screeds, the screed may crack, detach from the substrate and break into pieces. Reinforcement of the screed, for example with a metal mesh, improves the situation somewhat, but the method is difficult in practice.

GB application 2,142,619 discloses a composition comprising cement, blowing agent, sand, water, a pore and a liquefying agent. This publication states that the the composition is self-leveling or at least partially self-leveling. It is clear from the publication that the mixture is pumpable, but that leveling aids are required for its rapid application over the substrate. Thus, the mixture described in this GB application 2,142,619 is so-called running concrete, which has a higher flowability than conventional base concrete and is used as a thick layer to reinforce a frame surface cast from base concrete, simultaneously acting as a reinforcement layer and a coarse screed. It is further mentioned in this publication that the composition may optionally contain a small amount of polypropylene fibers (less than 0.03% by weight) to improve the flexural strength of the formed concrete layer. Instead, there is no mention in the publication that the composition could contain an adhesion promoter.

The object of the invention is to provide a pumpable and fully self-leveling floor screed which avoids the above-mentioned problems and which, when dried and hardened, forms a coating which has good mechanical properties and which adheres firmly to its substrate.

3 76545 According to the invention, these objectives can be achieved very satisfactorily with a pumpable and fully self-leveling floor screed consisting of: cement: 10-40 wt.% * Dry sand: 25-60 wt. * Dry fly ash: 20-40 weight * dry matter adhesive: 0.1-5 weight * dry matter shrinkage compensator: 0.1-10 weight * dry matter liquefier: 0.1-1 weight * dry matter fibers : 0.05-3 wt.% Of dry matter water: 20-30 wt.% Of dry matter

The floor screed according to the invention can be prepared by mixing 20-30, preferably 22-26% by weight * of water, based on the dry matter, with the dry raw materials of the above composition.

For example, synthetic polymeric fibers such as polyolefin, polyacrylonitrile or polyvinyl alcohol fibers or carbon fibers or the like can be used as fibers in the floor screed according to the invention. Polypropylene fibers are particularly preferred. The typical length of the fibers is 1-20 mm, preferably about 5-7 mm.

For example, polyvinyl acetate (PVA) powder can be used as the adhesive.

For example, gypsum can be used as the shrinkage composite.

For example, Melment (trademark, manufactured by SKW) can be used as a liquid carrier, i.e. a spreading agent.

4,76545

The floor screeds according to the invention may further contain a small amount, preferably 1% by weight, of various additives used in similar types of products, for example antifoams and retarders, such as gypsum retarders.

The surprising properties of the floor covering of the fiber-reinforced road according to the invention include that, despite the addition of fibers, the product remains completely self-leveling and pumpable, as it could have been expected that the addition of fibers would generally lead to loss of these properties or at least substantially deterioration.

The fully self-leveling fiber-reinforced floor covering according to the invention also extends the field of application of floor screeds to surfaces traditionally considered to be problem areas. The lack of normal floor screeds has been found to be unsuitable for screeding substrates such as weak concrete, wood or various mass floors (eg magnesite floors or gypsum mass floors) used in renovation and repair construction. The fiber-reinforced floor screed according to the invention can be used for these applications.

The excellent application properties of the floor covering according to the invention are achieved by incorporating fibers in the leveling compound, in particular polypropylene fibers. Due to the strong mixing during the manufacturing process, the fibers do not stick to each other, but remain detached and evenly distributed throughout the pulp.

The invention is described in more detail below by means of an example and a comparative experiment.

EelrogrK & i

A powder mixture was prepared by vigorously mixing the following ingredients: 5,76545

Portland cement 24.0 weight * sand 35.8 weight * fly ash 33.0 weight *

Vinapol 1070 (PVA powder) 2.0 weight-X

Gypsum 3.0 weight *

Melment F 10 0.7 weight-X

antifoam 0.5 weight-X

gypsum retarder (GV2> 0.2% by weight * polypropylene fiber,

length 6 mm 0.8 weight-X

This dry product was mixed with 23% by weight of water based on the dry product.

The resulting screed is completely self-leveling And when cured, it forms a coating with excellent mechanical properties.

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A compression prism (prism A) was made from the screed prepared in the above example, and a compression prism (prism B) was correspondingly made from a screed that did not contain polypropylene fibers but otherwise corresponded to the screed described in the above example.

When the prism B is stressed, then with a certain stress the prism breaks, i.e. the prism B is brittle.

Instead, when the fiber-reinforced prism A is stressed in a similar way, the prism A remains together even at stresses in which the prism B breaks. In other words, the fibers hold the prism A together at stresses that the cement matrix cannot withstand.

1I t-. r * i "y 6 76545 These test results show that a fiber-reinforced product withstands higher stresses and deformations without degradation than a non-fiber-reinforced product.

In field conditions, e.g. in the case of weak substrates, the fiber-reinforced structure ensures the functionality of the product and the screed forms a kind of load-bearing structure which the fibers hold together.

Claims (6)

7 76545 A pumpable and fully self-leveling floor screed containing hydraulic binder, aggregate, fibers, additives and water, characterized in that its composition is: cement: 10-40 wt.% Dry matter sand: 25-60 wt.% Dry matter substances fly ash: 20-40 wt-X dry matter adhesive: 0.1-5 wt-X dry matter shrinkage compensator: 0.1-10 wt-X dry matter liquefier: 0.1-1 wt. -X dry matter fibers: 0.05-3 weight -X dry matter water: 20-30 weight -X dry matter Floor level according to Claim 1, characterized in that the fibers are synthetic polymer and / or carbon fibers, in particular polyolefin, polyacrylonitrile and / or polyvinyl alcohol fibers. Floor level according to Claim 1 or 2, characterized in that the length of the fibers is 1 to 20 mm, preferably 5 to 7 mm. Floor screed according to one of Claims 1 to 3, characterized in that polyvinyl acetate powder is used as the adhesive and gypsum as the shrinkage compensating agent. 1. Helt självnivellerande golvspackel som kan pumpas and som innehäller et hydrauliskt bindemedel, stommaterial, fib-rer, ti1lsatsmedel och vatten, kännetecknat av mossansätt-ningen: