CZ7641U1 - Dry lime mixture for preparing lime mortar - Google Patents

Description

The invention relates to a dry lime mixture for the production of lime mortar and to a method for producing lime mortar for grouting and / or reinforcing and / or filling cavities and / or adhering a heterogeneous and / or separate lime plaster, in particular individual layers of historic plaster painting.

BACKGROUND OF THE INVENTION

The compositions used hitherto for grouting and / or reinforcing and / or filling cavities and / or gluing of the heterogeneous and / or separated lime plasters, in particular the individual layers of the historic plasters, preferably the plasters under the historical wall painting, contain cement and / or gypsum as inorganic binder. These materials are not compatible with the historical plaster due to their composition and physical properties. Moreover, the non-lime binders contain substances irreversibly contaminating the historic masonry with undesirable compounds. By reacting with the original plaster, these compounds produce co-products which are detrimental to its condition in the long term.

A further disadvantage of the existing compositions is seen in the fact that they are often not one-component dry compositions which do not have a controlled composition. Their physicochemical properties are not comparable with those of traditional lime plasters, they often impose a disproportionate strain on the preparation and application of mortar, they are not stable for long periods after mixing with water, they do not have sufficient fluidity to fill cavities in the plaster (in case of grouting) , do not have a sufficiently long open time (in the case of bonding compounds) and the necessary thixotropy (in the case of bonding compounds).

The essence of the technical solution

These drawbacks are largely eliminated by a dry lime mixture for the production of lime mortar, according to the present invention, which comprises 10 to 90% by weight of 25% by weight of lime binder, 90 to 10% by weight of filler, and 0.05 up to 6% by weight of at least one organic additive modifying the rheological properties of the mortar.

The main advantage of this solution is that they are one-component dry mixtures that have a composition and physico-chemical properties comparable to those of traditional lime plasters, by having a controlled feedstock composition not contaminating the plasters with unwanted compounds, for the preparation and application of mortar, they have a sufficiently long shelf life in the dry state (at least for the minimum shelf life of the individual components), after mixing with water they are stable for a long time interval (at least 60 min) in the case of grouting mixtures), they have a sufficiently long open time (in the case of mixtures for bonding) and the necessary thixotropy (in the case of mixtures for bonding).

For proper composition, it is preferred that the binder is a very fine lime binder, preferably a very fine lime hydrate, and contains quartz sand, preferably specially ground quartz sand as filler, that the organic additive is at least one thickening agent in an amount of 0.05 to 1 wt. %, based on the total weight of the dry blend based on cellulose ethers, preferably methylhydroxy cellulose, or that the organic additive is at most one redispersible polymer powder dispersion in an amount of 0.5 to 5% by weight based on the total weight of the dry blend, preferably vinyl acetate / ethylene copolymer with polyvinyl alcohol as protective colloid or that the organic additive is at most one superplasticizer in an amount of 0.05 to 1% by weight based on the total weight of the dry mixture, preferably based on lignosulfonates, preferably sodium lignosulfonate, or that the organic additive is at most

One preservative in an amount of from 0.5 to 2% by weight based on the total weight of the dry mixture, which must correspond to the dosage of organic impurities and the risk of the site.

Examples

Example 1

Injection mixture: very fine lime hydrate 21 wt% ground quartz sand 75 wt. % methylhydroxycellulose 0.2 wt. % redisperg. polym. resin 3.3 wt. % sodium lignosulfanate 0.5 wt. % Example 2 Bonding compound: fine lime hydrate 22 wt% quartz sand 75 wt.% methylhydroxycellulose 0.7 wt. % redisperg. polymer, resin 2.3 wt. % Example 3 Mixing compound: fine lime hydrate 83 wt. % quartz sand 15 wt% methylhydroxycellulose 1 wt. % redisperg. polymer, resin 1 wt. %

Industrial applicability

The industrial applicability of the dry lime mixture for the production of lime mortar, according to this solution, is especially for the rehabilitation of traditional lime masonry and plaster, preferably for the rehabilitation of historical buildings, especially for repairs of masonry under the wall painting.

Claims (6)

Dry lime mixture for the production of lime mortar, characterized in that it contains 10 to 90% by weight of lime binder, 90 to 10% by weight of filler and to this base is added 0.05 to 6% by weight of at least one organic additive modifying the rheological properties of the mortar . The dry lime mixture according to claim 1, characterized in that the lime binder comprises a very fine lime binder, preferably a very fine lime hydrate, and contains quartz sand, preferably specially ground quartz sand, as a filler. The dry lime mixture according to claim 1, characterized in that the organic additive is at least one thickening agent in an amount of 0.05 to 1% by weight. 7641 U1, based on the total weight of the dry mixture, based on cellulose ethers, preferably methylhydroxycellulose. The dry lime composition according to claim 1, wherein the organic additive is at most one redispersible polymer powder dispersion in an amount of from 0.5 to % By weight based on the total weight of the dry mixture, preferably a vinyl acetate / ethylene copolymer with polyvinyl alcohol as protective colloid. Dry lime composition according to claim 1, characterized in that the organic additive is at most one superplasticizer in an amount of 0.05 to 1% by weight based on the total weight of the dry lignosulfonate-based composition, preferably sodium lignosulfonate. 6. The dry lime composition according to claim 1, wherein the organic additive is at most one preservative in an amount of from 0.5 to 2% by weight based on the total weight of the dry composition.