We all know that the use of a new type of gypsum mortar as the insulation material in construction can improve the insulation performance of the outer wall insulation layer, reduce the indoor heat loss, and also avoid the uneven heating among various users, so in the construction of the building It has been widely used. Moreover, the cost of this material is relatively low, which saves the cost of the project, and has high thermal insulation and moisture resistance.
Raw material selection and function
1. Lightweight aggregate of vitrified beads
The most important ingredient in the new gypsum mortar is vitrified microbeads, which is a commonly used thermal insulation material in modern construction and has good thermal insulation properties. It is mainly made of an acid glass material and processed by high-tech processing. From the surface of the mortar, the particle distribution of the material and its irregularity are like a cavity with many holes. However, during the construction process, the texture of this material is actually very smooth, and the wall is well sealed, the material is very light, and the heat insulation is also very good. It has the characteristics of high temperature resistance and wear resistance.
In general, the thermal conductivity of vitrified microbeads is a more prominent feature, especially the thermal conductivity on the surface is the strongest, and the heat resistance is also very high. Therefore, during the use of vitrified microbeads, the construction personnel should control the distance and area between each particle in order to achieve the thermal insulation and thermal insulation function of the thermal insulation material.
2. Chemical gypsum
Chemical gypsum is another important component of mortar. It can also be called industrial reclaimed gypsum, which is mainly composed of waste slag of calcium sulfate, so its production is very convenient, which can realize the effective use of resources and save energy. With economic development, many factories emit industrial waste and pollutants such as desulfurized gypsum such as phosphogypsum every day. Once these wastes enter the atmosphere, they will cause air pollution and affect people’s health. Therefore, chemical gypsum can be said to be a renewable energy source, and it also realizes the utilization of waste.
According to the statistics of various pollutions, phosphogypsum is a relatively polluting substance. If the factory does not emit phosphogypsum once, it will cause river pollution to the surrounding environment, but this substance can become the main chemical gypsum. ingredient. Researchers completed the process of turning waste into treasure and formed chemical gypsum by screening and dehydrating phosphogypsum.
Desulfurized gypsum can also become flue gas desulfurized gypsum, which is an industrial product formed by desulfurization and purification treatment, and its composition is basically the same as natural gypsum. The free water content of desulfurized gypsum is generally relatively high, much larger than that of natural gypsum, and it has strong cohesiveness. It is also prone to many problems in the entire production process. Therefore, the production process of architectural gypsum cannot be the same as that of natural gypsum. Special drying process should be adopted to reduce its water content. It is formed by sifting it through a certain temperature. Only in this way can it reach the national certification standards and meet the requirements of thermal insulation construction.
The preparation of chemical gypsum thermal insulation mortar must use building chemical gypsum as the main production material. Vitrified microbeads often use light aggregate. Researchers have changed their properties through additives to meet the needs of construction projects.
When preparing thermal insulation mortar, construction personnel should pay attention to the characteristics of building chemical gypsum viscosity and large amount of water, etc., and scientifically and rationally choose additives.
(1) Composite retarder
According to the construction requirements of gypsum products, the operable time is an important indicator of its performance, and the main measure to extend the operable time is to add a retarder. Commonly used gypsum retarders are alkaline phosphate, citrate, tartrate, etc. Although these retarders have a good retarding effect, they also affect the later strength of gypsum products. The retarder used in chemical gypsum thermal insulation mortar is a compound retarder, which can effectively reduce the solubility of hemihydrate gypsum, slow down the rate of crystalline germ generation, and slow down the crystallization process. The retarding effect is obvious and the strength is not lost.
(2) Water retention thickener
In order to improve the construction of new gypsum mortar, improve water retention, fluidity and sag resistance, usually need to add cellulose ether. Using methyl hydroxyethyl cellulose ether can better play the role of water retention and thickening, especially in summer construction can still play a better role.
(3) Redispersible latex powder
In order to improve the cohesion, flexibility and adhesion of the mortar, redispersible latex powder should be used as an admixture. Redispersible latex powder is a powdered thermoplastic resin obtained by spray drying and subsequent processing of a polymer emulsion. The polymer in the mortar mixture is the continuous phase, which can effectively suppress or delay the generation and development of cracks.
Generally, the bonding strength of mortar is achieved by the principle of mechanical occlusion, that is, it is gradually solidified in the gaps of the base material; the bonding of the polymer is more dependent on the adsorption and diffusion of macromolecules on the bonding surface. Hydroxyethyl cellulose ether acts together to infiltrate the surface of the base layer, making the surface of the base material close to the surface of the mortar, thereby improving the adsorption between them, and the bonding performance is significantly improved.
(4) Lignin fiber
Lignin fiber is a natural material that absorbs water but does not dissolve in water. Its function is its own flexibility and the three-dimensional network structure formed after mixing with other materials, which can effectively reduce the drying shrinkage of the mortar during the mortar drying process, thereby improving the crack resistance of the mortar. In addition, the three-dimensional space structure can lock the water of 2-6 times its own weight in the middle, which has a certain water retention effect; at the same time, it has good thixotropy, and the structure will change when external forces act (such as scraping and stirring). And arranged in the direction of movement, the water is released, the viscosity is reduced, and the workability is improved, which can improve the construction performance. Tests have shown that lignin fibers should be short and medium in length.
The use of heavy calcium carbonate (heavy calcium) can change the ease of mortar and reduce costs.
The proportion of new gypsum mortar
Construction chemical gypsum: 80%～86%;
Composite retarder: 0.2%～5%;
Methyl hydroxyethyl cellulose ether: 0.2% to 0.5%;
Redispersible latex powder: 2%～6%;
Lignin fiber: 0.3%～0.5%;
Heavy calcium: 11%～13.6%;
The mixing ratio of mortar is rubber compound: vitrified microbead=2:1～1.1.
New gypsum mortar construction process
1) Clean the base wall surface;
2) Wetting the wall surface;
3) Hanging vertical, nested square, elastic plaster thickness control line;
4) Brush the interface agent;
5) Make gray cakes and standard bars;
6) Wipe chemical gypsum vitrified micro-bead insulation mortar;
7) Acceptance of the top layer;
8) Plaster anti-crack mortar and press into alkali-resistant glass fiber mesh cloth at the same time;
9) After acceptance, plaster the plaster;
10) Smoothing and calendering;
The new gypsum mortar is one of the important thermal insulation materials in construction engineering. It has good thermal insulation and thermal insulation properties, which can reduce the input cost of construction engineering and achieve energy conservation and environmental protection in construction engineering.