CS210901B1 - Modified cement compound - Google Patents

Description

The invention solves the possibility of prefabrication of building structures by plaster treatment, using a modified cement mixture.

Up to now, the interior surface treatments of building structures with thin-layer plasters have been made on the construction site with screed materials, which are produced on the basis of dispersion binders. They are supplied in a pasty consistency, including an aqueous component. This type of plaster has low moisture resistance / wet abrasion max. 120 seconds cannot be used in prefabricating building structures in factories, as the plaster does not tolerate atmospheric effects during storage and transport. Further disadvantages are processing, use and storage constraints, as well as the ineffective transport of the aqueous component and the difficulty of packaging materials.

The above-mentioned deficiencies are solved by a cement modified mass containing dolomitic sand, lime hydrate, hydroxyethylcellulose, aeration agent and active silica prepared by homogenization of these components in the dry state. It is characterized in that it contains 1 to 10 wt. active silica in the form of dried silica gel with a specific surface area of 20 to 300 m / 1 g. By mixing the cement modified mass with an aqueous component, the properties of the silica to absorb a considerable amount of water required to hydrate the hydraulic binders are exploited. These then hydrate even in a thin deposited layer;

The plaster prepared from this mass then resists atmospheric influences and allows the prefabrication of the structural elements without the limitations mentioned for the lint masses produced on the basis of dispersion binders.

Modified cement mass is prepared from powder components manufactured in Czechoslovakia in the following composition:

.IN

White cement • 30 until 40 7th wt. Dolomitic sand belt grain up to 0.6 mm 50 until 70 7th hrao t. / grain 0-0.056 mm 5 to 10 Z, wt. 0.056-0.3 mm 50 to 60 Z. wt. 0.3-0.6 mm 25 to 30 Z. wt. Hydrated lime hydrate / ČSN 72 2240 / Silicon dioxide / specific surface 15 until 30 7th hmo t 20 to 300 π) 2 / g s until .10 7 Hmo t Rydroxyetylcelulóza 0.4 until 5 7 hmo t Aerator Lígrasoi 0.0 1 until θ » 1 7 hmo t

The components are homogenized and packaged in paper bags and mixed with water at the point of use. The plaster is adjusted to a consistency of 9 to 14 divisions of the immersion cone (ČSN 72 2441). The increase in elasticity modulus of the oriquette is achieved by adding 2 to 5 wt. to the weight of the mixture. It is applied manually or mechanically in thicknesses of 1 to 10 mm and smoothed into the plane by means of steel, felt or other trowels. The mechanical-physical properties of the prepared plaster are as follows:

Adhesion to concrete (after 28 days) higher than 0.25 MPa

Volumetric changes up to 10 mm thickness without cracks

Processing time to bet. 20 to 25 minutes

Wet abrasion resistance / after 28 days / greater than 600 seconds.

The modified cementitious compound after mixing with the aqueous component containing the dispersion can be used for interior plasters and other types of substrates / fibreboard, chipboard and asbestos cement, heraclitis, as well as interior plasters for spatial prefabricated components when assembled in prefabricated panels and as sealant for bonding glass / ceramic mosaic, tiles, ceramic tapes /.

Claims (2)

Cement modified composition comprising dolomic sand, cement, lime hydrate, hydroxyethylcellulose, aerating agent, characterized in that it contains 1 to 10 Z, wt. % of active silica having a specific surface area of 20 to 300 m / g.