Anti-crack plastering mortar

Abstract

The invention belongs to the field of building mortar, and provides anti-crack plastering mortar which comprises the following components in parts by weight: 120-200 parts of ordinary cement, 2-30 parts of special cement, 0-100 parts of admixture, 0-80 parts of filler, 560-880 parts of graded sand, 0.2-0.8 part of water retention thickener, 0.1-0.5 part of polymer, 0.1-0.5 part of fiber, 0-0.5 part of water reducing agent and 0-30 parts of antifreezing agent. Hydroxyl of polyvinyl alcohol and oxygen atoms on ether bonds in cellulose ether are associated to form hydrogen bonds, so that the super-superposition effect is achieved, and an extremely small amount of polyvinyl alcohol is compounded with the cellulose ether to achieve the anti-cracking reinforcing effect; natural sand is replaced by the tailing sand, so that the problems of risks caused by accumulation of the tailing sand and shortage of building mortar raw materials are solved, and thick-layer plastering without cracking is realized; the ordinary cement and the special cement are compounded for use, so that the constructability, early strength, crack resistance and durability of the mortar are obviously improved.

Description

technical field [0001] The invention generally belongs to the field of building mortar, and in particular relates to a crack-resistant plastering mortar. Background technique [0002] Building decoration materials mainly include ceramic tiles and coatings. [0003] Coatings have the characteristics of easy construction, bright colors, and low cost, so they are widely used. However, the paint is not only poor in dirt resistance and scrub resistance, but also its durability is its weakness. Discoloration and skin bursting are not uncommon. Therefore, many projects still choose to use ceramic tiles for facing. [0004] Dating back to the era of Qin brick and Han tile, ceramic tile veneer has a history of thousands of years in China. In terms of dirt resistance, scrub resistance, especially durability, ceramic tiles have incomparable advantages over paint-based finishing materials. [0005] However, accidents of ceramic tiles hollowing out and falling off, causing injury to ...

AI Technical Summary

Problems solved by technology

There are two main problems. One is that the main mineral composition of high alumina cement is monocalcium aluminate CA and dicalcium aluminate CA. 2 , the hydration reaction after encountering water first generates CAH 10 、C 2 AH 8 These two unstable crystals will later transform into stable C 3 AH 6 Crystal, crystal transformation will lead to increased porosity and reduced strength, that is, the durability of the hydration products of high alumina cement is very poor; in Portland cement, high alumina cement, gypsum ternary system, although the high alumina cement The main hydration product is ettringite AFt, but the stability of its system (especially in high alkali environment) is still very poor, and the stability and crack resistance of the mortar made of it are also very poor

The second is that the polymer latex powder is mainly acrylic ester. After it is made into mortar, it will be dispersed into an emulsion when it meets water when it is used. Because the acrylic ester colloidal particles in the emulsion are large (generally in the micron level), it is difficult to migrate with water, so only mixing When the amount is high (23-27 parts), it is possible to play a certain anti-cracking and strengthening effect after the film is formed; so the cost of the mortar made from it is very high, and it is not suitable for the plastering of the base of the general ceramic tile veneering project leveling

The main problems are: First, the cement content is too high, resulting in large shrinkage and easy cracking of the mortar

The second is that the quartz sand is too fine to be plastered in thick layers, which is costly and easy to crack

The third is to use styrene-butadiene emulsion and redispersible latex powder. The redispersible latex powder will disperse into an emulsion when it meets water. Because the latex particles are large (generally at the micron level), it is difficult to migrate with water. When it is high (31-60 parts), it is possible to resist cracking and strengthen after the film is formed; so the cost of the mortar made from it is very high, and it is not suitable for plastering and leveling the base of general ceramic tile veneering projects

Because the cement is sulfoaluminate cement, it coagulates and hardens quickly, so it is only suitable for small-scale repair projects; because it does not use water-retaining agent, it is not suitable for large-area use; because it uses more polyvinyl alcohol glue powder, the cost is high, so the comprehensive performance is not suitable for the plastering and leveling of the base of the general ceramic tile veneer project

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