What is gypsum-based self-leveling mortar?
Gypsum-based self-leveling is a new type of ground leveling material that is green, environmentally friendly and high-tech. By utilizing the good flowability of gypsum-based self-leveling mortar, a large area of finely leveled ground can be formed in a short time. It has the advantages of high flatness, good comfort, moisture insulation, mildew resistance, insect resistance, etc., and is easy to construct and quick to survive. It is suitable for leveling floors indoors, such as leveling cushions for laying carpets, floors, and floor tiles in hotels, commercial office rooms, and home decoration.
The main materials of gypsum-based self-leveling mortar are as follows:
1.Cementitious material: The cementitious material of gypsum-based self-leveling mortar is high-quality building gypsum. The raw materials for producing building gypsum are mainly natural gypsum containing calcium sulfate or industrial by-product gypsum after pretreatment and purification, and the building gypsum powder that meets the national standard is obtained by calcining at a reasonable process temperature.
2.Active admixtures: Fly ash, slag powder, etc. can be used as active admixtures for self-leveling materials. The purpose is to improve the particle gradation of the material and improve the performance of the hardened material. The active admixture and the cementitious material can improve the compactness and later strength of the material structure through the hydration reaction.
3. Retarder: The setting time is an important performance index of self-leveling materials. Too short or too long time is not conducive to construction. The retarder stimulates the activity of gypsum, adjusts the supersaturated crystallization speed of dihydrate gypsum, and keeps the setting and hardening time of self-leveling materials in a reasonable range.
4. Water reducing agent: In order to improve the compactness and strength of self-leveling materials, it is necessary to reduce the water-binder ratio. Under the condition of maintaining good fluidity of self-leveling materials, it is necessary to add water reducing agents. Water reducers compatible with different building gypsums can be used to make sliding between material particles easy, thereby reducing the amount of mixing water required and improving the structure of the hardened material.
5. Water retaining agent: Self-leveling materials are constructed on the ground base, and the construction thickness is relatively thin, and the water is easily absorbed by the ground base, resulting in insufficient hydration of the material, cracks on the surface, and reduced strength. Generally, low-viscosity (less than 1000) cellulose ether (HPMC) is used as the water-retaining agent. Cellulose ether has good wettability, water retention and film-forming properties, so that the self-leveling material does not bleed and is fully hydrated.
6. Defoaming agent: The defoaming agent can improve the apparent performance of the self-leveling material, reduce the air bubbles when the material is formed, and have a certain effect on improving the strength of the material.