Applied to ①Coatings Epoxy resin accounts for a large proportion of applications in coatings, and it can be made into varieties with different characteristics and uses. Their common characteristics: (1) Excellent chemical resistance, especially alkali resistance. (2) The paint film has strong adhesion, especially to metal. (3) It has good heat resistance and electrical insulation. (4) The paint film has good color retention. However, bisphenol A-type epoxy resin coatings have poor weather resistance. The paint film is easily powdered and loses its luster outdoors and is not full. Therefore, it is not suitable for outdoor coatings and highly decorative coatings. Therefore, epoxy resin coatings are mainly used as anti-corrosion paint, metal primer, and insulating paint, but coatings made of heterocyclic and alicyclic epoxy resins can be used outdoors. ② In addition to poor adhesion to non-polar plastics such as polyolefins, epoxy resin also has good adhesion to various metal materials such as aluminum, steel, iron, and copper; non-metallic materials such as glass, wood, concrete, etc.; and thermosetting plastics For example, phenolic, amino, unsaturated polyester, etc. all have excellent bonding properties, so they are called universal glue. Epoxy adhesives are an important variety of structural adhesives.
③ Electronic and electrical materials have been widely used in the insulation and packaging of high and low voltage electrical appliances, motors and electronic components due to its many unique advantages such as high insulation performance, high structural strength and good sealing performance of epoxy resin. The application is developing rapidly. Mainly used for: (1) Casting of electrical appliances and motor insulation packages. Manufacturing of integral fully sealed insulating packages for high and low voltage electrical appliances such as electromagnets, contactor coils, transformers, dry-type transformers, etc. It has developed rapidly in the electrical appliance industry. From normal pressure pouring and vacuum pouring, it has developed to automatic pressure gel molding.
2) It is widely used for potting insulation of devices equipped with electronic components and circuits. It has become an indispensable and important insulating material in the electronics industry. (3) Electronic grade epoxy molding compound is used for plastic packaging of semiconductor components. It has developed extremely rapidly in recent years. Due to its superior performance, it has a tendency to replace traditional metal, ceramic and glass packaging. (4) Epoxy laminated plastics are widely used in the fields of electronics and electrical appliances. Among them, epoxy copper-clad laminate has developed particularly rapidly and has become one of the basic materials in the electronics industry. In addition, epoxy insulating coatings, insulating adhesives and electrical adhesives are also widely used. ④Engineering plastics and composite materials Epoxy engineering plastics mainly include epoxy molding compounds and epoxy laminated plastics used for high-pressure molding, as well as epoxy foam plastics. Epoxy engineering plastics can also be regarded as a generalized epoxy composite material. Epoxy composite materials mainly include epoxy fiberglass (universal composite materials) and epoxy structural composite materials, such as pultruded epoxy profiles, winding hollow rotary products and high-performance composite materials. Epoxy composite material is an important structural material and functional material in high-tech fields such as chemical industry, aviation, aerospace, and military industry. ⑤Civil construction materials: Mainly used as anti-corrosion flooring, epoxy mortar and concrete products, high-grade pavements and airport runways, rapid repair materials, and grouting materials for foundation reinforcement., construction adhesives and coatings, etc.
When using sleeve grouting connection technology, the effective height of the section is equal to ( ).
The semi-grouting sleeve uses straight threads to connect the steel bars at the prefabricated component end, and the on-site assembly end uses grouting to connect the steel bars. Since the anchoring length of the steel bars required for the straight threaded connection end is smaller than that required for the grouting connection end, the size of the semi-grouted sleeve joint is smaller, and the semi-grouted sleeve is mainly suitable for connecting to components (walls, columns).
The two ends of the full grouting sleeve joint are connected to the steel bars by grouting. Since the anchorage length of the steel bars required at the direct grouting connection end is longer, the size of the full grouting sleeve is longer than that of the semi-grouting sleeve. Fully grouted sleeves are suitable for steel connections to members (walls, columns) and transverse members (beams).
Grouting sleeve is also called grouting sleeve joint or sleeve grouting joint. The grouting sleeve is a combination of specially processed sleeves, supporting grouting materials and steel bars. When connecting the steel bars, the fast-hardening non-shrinkage grouting material is injected, and the steel bars and sleeves are connected by the bonding and occlusion between the materials. Sleeve grouting joints have the advantages of reliable performance, wide applicability, and easy installation.
The grouting sleeve connection technology is suitable for reinforced concrete structure engineering, steel structure engineering, bridge engineering, offshore oil exploration platform engineering, offshore wind power towers and other fields.
Grouting sleeve connection technology is a new steel structure connection method produced due to the needs of engineering practice and technological development. The emergence of this connection method makes up for the traditional steel structure connection method (mainly including welding and bolted connections), and has been rapidly developed and applied.
What can the wind do?
When sleeve grouting connection technology is used, the effective height of the section is equal to (one-half of the height of the sleeve inner cavity from the ground).
1. Sleeve grouting connection technology is a commonly used pile foundation connection technology, which is suitable for the foundation of bridges, highways, railways and other projects.
2. In the sleeve grouting connection technology, prefabricated piles, steel pipe piles, etc. of bridge piers or abutments are inserted into the grouting sleeve, and the connection is achieved through the close matching of the outer diameter of the sleeve and the grouting material. . This can improve the connection strength and connection quality, reduce project quality risks and construction period risks, and also reduce the impact of foundation construction on the surrounding environment.
3. In the sleeve grouting connection technology, the effective cross-sectional height is equal to one-half of the height of the sleeve inner cavity from the ground. This is because the greater the height of the sleeve inner cavity from the ground, the greater the grouting material in the sleeve. The more uniform the distribution inside the barrel, the higher the quality of the grout and the stronger the connection.
At the same time, the effective height of the section is also affected by factors such as the inner diameter of the sleeve and the characteristics of the grouting material, and needs to be calculated and designed according to specific conditions.
Sleeve grouting connection method:
In actual engineering applications, the sleeve is pre-embedded into the connection end of the component during the production of prefabricated components. During on-site constructionThe exposed steel bars of the other connecting component are inserted into the sleeve, and after the component is installed and positioned, the steel bars are connected through grouting.
Compared with welding, straight thread mechanical connection and other methods, the use of sleeve grouting connection can reduce the workload of steel bar pre-processing, the steel bars will not produce secondary stress and deformation during on-site construction, and the relative strength can be accepted. Larger T deviation and other advantages.
Grout sleeve:
Grout sleeve is also called grout sleeve joint or sleeve grout joint. The grouting sleeve is a combination of specially processed sleeves, supporting grouting materials and steel bars. When connecting the steel bars, the fast-hardening non-shrinkage grouting material is injected, and the steel bars and sleeves are connected by the bonding and occlusion between the materials. Sleeve grouting joints have the advantages of reliable performance, wide applicability, and easy installation.
The grouting sleeve connection technology is suitable for reinforced concrete structure engineering, steel structure engineering, bridge engineering, offshore oil exploration platform engineering, offshore wind power towers and other fields.
Grouting sleeve connection technology is a new steel structure connection method arising from the needs of engineering practice and technological development. The emergence of this connection method makes up for the traditional steel structure connection method (mainly including welding and bolted connections), and has been rapidly developed and applied.
Wind can help people do the following things:
1. Make food: Wind can accelerate water loss, such as air-dried meat Categories, air-dried fruit pulp, etc. Xinjiang raisins are a typical dried food.
2. Blow dry clothes: Wind can accelerate the evaporation of water on clothes, speed up water loss, and make clothes dry faster.
3. Wind energy generation and irrigation: The wind can drive the windmill blades to rotate, and then the speed increaser increases the rotation speed to prompt the generator to generate electricity. Wind power is pollution-free, clean energy, and renewable. Ancient people also used windmills to water crops.
4. Help fruit trees and crops to bloom and bear fruit: Wind can blow away pollen, fertilizing fruit trees and crops to bloom and bear fruit.
5. Power-assisted sailing ship: In ancient times, ships without a power system relied on wind energy to move, which greatly reduced the voyage time.
6. The wind will blow away the dark clouds and haze: When the dark clouds block the sun, it is the wind that drives them away, allowing the sun to shine on the earth again. When pollution is serious in winter, it can blow away the smog.
7. In the hot summer, the wind brings us coolness and drives away mosquitoes and flies.
8. Bring rainfall: Wind can blow clouds, promote the exchange of dry, cold and warm and moist air, and adjust the temperature and humidity of the air. This is what the ancients said: "The clouds turn into rain, and the dew turns into frost." Wind can send clouds and rain to distant places, completing the water cycle on the earth. In summer, warm and moist air blowing from the ocean brings abundant rainfall.
Wind is also a "double-edged sword". It can not only help people, but also have a negative effect on people's lives.
It can spread pathogens and spreadPlant diseases; high-altitude winds are the meteorological conditions for locusts and other pests to migrate long distances; strong winds can cause mechanical scratches on leaves, crop lodging, broken trees, and falling flowers and fruits, affecting yields; strong winds can also cause soil erosion and sand dune movement, thus destroying farmland. wait. In addition, wind has greater dangers. Blind reclamation in arid areas will cause land desertification due to wind.
Strong winds and blizzards in pastoral areas can scatter livestock and aggravate freezing damage; some special properties of local winds often cause wind damage; salty tidal winds blowing from the sea can cause high and low temperatures. Foehn winds and hot dry winds have seriously affected the flowering, fruit setting and grain filling of fruit trees.