Epoxy resin and its application technology and products have long been widely used in the field of civil engineering and construction, and have accumulated and withstood the data of long-term application durability assessment for nearly thirty years, also have promoted and developed many new uses on this basis. The following focuses on the application of epoxy resin in building materials coating, adhesive, epoxy resin cement mortar, concrete reinforcement, etc.
- Epoxy resin construction coatings
Due to the application of epoxy resin coatings, a series of reforms have been caused in construction works.
- Sanitary ware coating The cement sanitary ware manufactured on site with cement mortar or prefabricated, such as bathroom bathtub, vanity top, bathroom floor, wall, etc. are coated with epoxy resin coating on their surface, because epoxy resin coating can have good adhesion with porous cement surface, so that it is isolated from air, water, sunlight, external corrosive dirt, salt, chemical detergent, etc., and the coating surface is bright and can be The surface of the coating is bright and can be made into different vivid colors. The coating film has good water resistance, general media corrosion resistance, wear resistance, heat resistance and durability. It can replace tiles or enamel products and is easy to maintain.
With the development of China’s rural construction, the sanitary equipment in the farmhouse also increasing, and replacing ceramic products with cement products with epoxy resin porcelain paint is an important application of epoxy resin construction coating.
In principle, solvent-based or solvent-free epoxy resin coatings can be applied
- Kitchen room coating
Kitchen wainscoting, floor, cooktop, and sink need to be impermeable, resistant to general acid and alkali, and resistant to water, heat and oil. And it should be easy to clean. Epoxy resin coating is the most suitable for these performance requirements, can effectively protect the cement surface and bright and beautiful, bright and pleasing to the eye, can prevent the adhesion of water, mosquitoes, flies, cockroaches, insects and microorganisms and other erosion effect.
- Epoxy resin floor coating
The polyvinyl alcohol polymer cement floor developed in recent years, if the surface is coated with epoxy resin self-leveling floor coating (commonly known as: porcelain paint coating or color paint coating in China) as the cover layer of cement flooring, it can make this cement floor with the effect of glass tile. In industrial buildings, such as: according to the installation workshop, hospital, pharmaceutical workshop, purification workshop, office building, etc. are currently using this type of coating, its durability in at least ten years without maintenance.
Epoxy resin coating, coated on the wooden floor its wear resistance and durability greatly exceeds the ordinary floor paint, and polyurethane coating as good. It is suitable for ground coating in public places, such as gymnasiums, meeting rooms, hotels and other wooden floors.
- Corrosion resistant coating
China’s epoxy resin coating for concrete storage tank wall of the protective coating research and application has nearly forty years of history. Concrete tanks have more advantages than steel tanks, in the construction of 500 ~ 5000 cubic meters of large concrete tanks, the project cost and technology are cheaper than steel and easy. China built a large number of reinforced concrete tanks in the mid and late 1960s, the volume of 500 to 5,000 cubic meters were underground, semi-underground or cave-type structure. Its concrete tank wall using a modified amine curing agent formulated without fusing agent epoxy resin coating, and closed with phenol ketone imide moisture-curing type of bad oxygen resin coating to adapt to the characteristics of the construction in a humid environment and confined space. These storage tanks, storage of petroleum crude oil and its oil products, epoxy resin coating for aviation gasoline, aviation kerosene pollution of the index – gum content to achieve the storage of aviation gasoline indicators, after more than thirty years of use of good results. The volume of small concrete oil tanks with epoxy resin coating for oil resistance and impermeable layer in 50-100 cubic meters is widely distributed in the storage of agricultural oil in rural areas and oil storage pools in gas stations, which not only saves steel, but also is convenient to construct, and the practice for many years proves that epoxy resin coating is a good oil resistant coating.
Epoxy resin coating is not only resistant to petroleum, but also resistant to vegetable oil. Concrete pools and tanks painted with non-toxic curing agent can store cooking oil, and the test of managerial test and biological toxicity proves non-toxic.
- Concrete pipe coating
Every year, a large number of concrete pipes are installed as water, sewage and other fluid pipelines. Only from 1995 to 1998, the country laid a variety of caliber concrete pipe for water transmission, agricultural drainage up to 323,800 kilometers, in order to reduce fluid friction, reduce fluid and suspended matter on the wear and tear of the pipe body, to achieve the purpose of energy saving, and leakage prevention, many pipes to be coated with epoxy resin asphalt coating.
- Oil pipeline, gas pipeline heavy anti-corrosion epoxy resin powder coating
China’s major projects in the development of the west, the first major project is the “West-East gas transmission”, “West-East oil transmission” project, are used in large diameter seamless steel pipe (length: 12 meters, diameter: 1.1 meters), long distance laying, while buried deep in the ground. The project requires more than 30 years of corrosion prevention. The inner wall of the steel pipe is coated with high polymer reduction (less) resistance (force) coating; the outer diameter of the steel pipe is coated with hot-melt epoxy resin corrosion prevention powder coating, according to the technical requirements of the coating thickness: 300μm ~ 400μm. “West-East gas transmission” main line is 4300 km long, calculated by this thickness, the need for heavy anti-corrosion epoxy resin powder coating of about 6000 tons; the length of branch pipeline (pipeline caliber is smaller than the main pipeline) is longer than the main pipeline. At present, China has made a breakthrough in the formulation and manufacturing technology of heavy anti-corrosion epoxy resin powder coating, special epoxy resin and curing agent can be mass-produced, so that the steel oil and gas pipeline special heavy anti-corrosion epoxy resin powder coating to achieve localization.
- Adhesives for construction
Epoxy resin is a kind of structural adhesive with excellent performance, about 5-15% of the total annual output of epoxy resin in the world is used as adhesive.
Since 1946, Ciba developed the epoxy resin adhesive with the brand name of Araldite, and since the 1950s, the epoxy resin adhesive has effectively solved the bonding problem between new and old cement mortar layers and new and old concrete layers, as well as completely solved the bonding layer interface moisture, humidity, alkaline substances and other influencing factors. As a result, it has been used in a large number of applications and opened up a new and largest market for epoxy resin. Japan has been rapidly developing the technology and market of epoxy resin construction adhesive since 1960s, which is used in almost all fields of construction and cement products.
China started to use epoxy resin adhesives in construction projects since 1966. After more than 30 years of practical application and examination, it has proved the bonding effect and the reliability of the structure of epoxy resin adhesives in construction projects. Nowadays, epoxy resin adhesives are widely used to bond and repair concrete members, protecting the steel bars in the cracked part of concrete damaged by stress cracking or vibration from rusting and playing the role of mechanical structure. The use of epoxy resin adhesive to bond and strengthen various prestressed reinforced concrete products, such as: cement concrete dams, gates, bridges, concrete pressure pipes, electric culm, railroad concrete railroad sleepers and other prefabricated parts of the repair, due to cracks or broken parts in production or use, to improve the product qualification rate and quality assurance, become an indispensable and important material.
In construction projects, epoxy resin adhesive can replace rivets, nails, welding and other structural jointing processes. Bonding various metal products, natural stone, marble, artificial plate and other metal and non-metal products, can achieve the bond with the concrete, the bond can withstand the action of gravity and fast curing positioning and no seams according to the requirements of the installation.
The requirements of epoxy resin adhesive, in technical performance, in addition to achieve mechanical properties and other basic conditions, should also have a good use of viscosity at room temperature. And in the vertical direction, the top construction of the glue does not flow (i.e., thixotropic effect); high and low temperature curing speed and curing degree in the environment to be basically the same; wet air and wet substrate can be cured (water-based); low or non-toxic; non-flammable or non-combustible (solvent-free or less solvent), easy to use in large quantities, easy to operate, and easy to clean.
Domestic construction epoxy resin adhesive binder has a variety of products marketed, such as: epoxy resin type building structure adhesive, general-purpose building structure with anchor adhesive, high-strength building structure with anchor adhesive, cement crack grouting adhesive, etc.. However, with the development of China’s construction projects, the existing commercialized epoxy resin construction adhesives cannot fully meet the new technical requirements. Therefore, the continuous development of epoxy resin adhesives with various technical requirements for construction projects is the requirement of the market, which can also bring benefits and reputation to enterprises.
The epoxy resin adhesives used in construction projects can be basically divided into several categories:
- Concrete “whole project” bonding
Large cement concrete projects, such as: bridges, tunnels, dams, reservoirs, high-rise buildings, wharves, deep-sea projects, offshore oil fields and other projects, the design requires the connection between the cement concrete components, so that the structure of the project as a whole, to ensure mechanical stability. In engineering, these constituent members are prefabricated, and even cast-in-place ones cannot be poured into a huge whole at one time. Thus, the problem of improving and solving the integrity of the connection parts between concrete is an important issue in concrete engineering.
Newly mixed cement mortar and concrete, the bond strength of the hardened cement mortar and concrete surface is very low, the bond layer is not durable, and the bond layer is soon detached. Research shows that the epoxy resin adhesive, in the hardened cement mortar and concrete surface between the bond, and then test the bond strength and tensile strength, in the case of force, is the cement mortar layer and concrete layer was pulled off and the adhesive layer was not pulled off. It shows that the strength of the epoxy resin adhesive layer exceeds the tensile strength of the cement concrete material and the adhesive has a structural role.
This excellent bonding performance of epoxy resin adhesive is soon widely used in construction projects, solving the bonding problem between cement and concrete, making the engineering process of the whole structure possible and promoting the development of construction and large-scale overall projects. In recent years, some famous buildings in the world, such as: the roof of Sydney Opera House, the platform of North Sea oil field in UK, Hong Kong Club exhibition hall, Narita Airport in Tokyo, Japan, etc., all use epoxy resin adhesive to bond the components to realize the whole structure.
The epoxy resin used is mainly modified bisphenol A epoxy resin, and most of the curing agents are modified aromatic amines or end-amino polyether’s, together with reactive tougheners and fillers, and all the formula components can be localized.
- Repair of buildings
The building in use, concrete structure part often cracks. Or due to poor treatment of joints and other reasons, the phenomenon of leakage. Performance in elevated road surface, column, roof, wall and floor, basement, etc. Affected the production and life, in the past are repaired with asphalt, must be in the dry surface to carry out and repair at no structural effect, so that the mechanical distribution of the patch and other parts of the state is different, so that over time and stress cracking occurs, and eventually the structure strength decline.
The use of epoxy resin adhesives that can be used on the wet surface and cured in water, for example: modified bisphenol A epoxy resin, water-based modified aromatic curing agent and water-absorbent filler formulated adhesive, can be repaired in time when there is leakage, the actual application has achieved excellent results.
This kind of epoxy resin adhesive, in the construction of a wide range of uses, in water conservancy projects are often used for underwater repair of dams, but also widely used in the repair of docks, bridges and cement ship repair. After repairing, the original integrity is maintained and the original performance of the structure is kept.
- Repair of cement products
There are nearly 500 professional factories in China producing cement poles, cement pressure pipes, various cement pipes, prefabricated building wall panels, supporting components such as railroad sleepers and bridge components. In the production or transportation process, it is often damaged by non-destructive damage, resulting in cracks or bumps, these situations do not affect the structural performance of the products, but affect the use (such as: appearance, water penetration, etc.) effect. Such cases, the use of epoxy adhesive repair is the most effective.
We have used special epoxy resin construction adhesive cement products repair paste to repair the cement poles of a project of the Ministry of Railways, after 5 years of natural aging, the repair can maintain the original state, improve the utilization rate and service life of the poles, save money and receive good economic benefits. We repair the wall of a cement pressure pipe produced by a factory, which has a leakage phenomenon. After the water pressure test failed cement pipe, pumping away the water, immediately use epoxy resin adhesive in the water seepage parts of the repair construction, wipe dry the obvious water, coated with adhesive repair, in the wet surface after curing, and then test the water pressure, test qualified. Changed the previous must wait for the base surface to dry before repairing the situation, improve the work efficiency.
- Adhesive of decoration and decoration materials
Modern architecture, not only requires a reasonable structure, and the building’s interior and exterior decorative works are equally important to certain high-grade buildings (such as hotels, senior shopping malls, gymnasiums, swimming pools, halls, exhibition halls, etc.), the decorative cost is basically almost equal to the cost of the main building works, and may even exceed.
In technology, it mainly solves the bonding problem between various decorative materials and concrete, such as: marble, artificial marble, artificial stone, tiles, mosaic, etc. and mortar or concrete walls (interior and exterior walls), ground paste or for exterior maintenance. For aluminum alloy, metal decorative materials and concrete surface bonding; wood, veneer board and concrete surface paste; ceiling materials decoration, gravity effect of decorative lamps, central air conditioning duct installation, etc. The construction process is not allowed to use nail joint and fixed, with epoxy resin adhesive to joint and positioning, greatly simplifies the press installation process of these projects, the structure is solid and stable. At present, epoxy resin anchor adhesive is widely used in construction projects to fix metal ceiling and metal structural parts and other load-bearing components, which can save 80% of wood and 30-50% of working hours, simplify the installation process and provide reliable performance. After investigation, several construction projects using epoxy resin anchoring adhesive have been continuously field tested for more than five years, with no minor displacement, reliable and safe.
Three years ago, Shanghai started a major landscape construction project, the “flat to slope” project of residential buildings, in which epoxy resin anchoring adhesive was used to fix the metal frame and concrete. The examination result shows that after the steel and concrete are bonded with epoxy resin anchor adhesive, the adhesive layer can withstand more than 10 tons of tension without damage. This landscape project has been fully carried out in Shanghai.
- Repair of building ceramic facilities
In the epoxy resin adhesive selection, epoxy resin adhesive that can be cured in wet surface and water is most suitable for the installation and repair of architectural ceramic facilities, such as: sanitary ware, tiles, floor tiles, wall tiles, bathtubs, bathrooms, washbasins and other installation and repair.
For example, the artificial marble vanity basin, due to improper use and cause the corners of the vanity basin broken and cracks, the past with mortar repair often poor results and scrap. Now with epoxy resin building bonding agent color mixing bonding, repair basically can be similar to the original marble, construction operation is simple, the value of 600 yuan of artificial marble vanity basin (crack broken length 65mm, width O.5 ~ 0.9mm) only cost O.80 yuan repair fee.
- Epoxy resin composite products
Epoxy resin as the matrix resin and glass fiber or cloth made of epoxy resin FRP products, but also unsaturated polyester resin, vinyl resin, etc. as the matrix resin FRP products. But in special cases, such as the requirement of heat resistance, resistance to organic solvents and inorganic acids, alkalis, oils and other media corrosion and high strength requirements of structural products, but also must use epoxy resin as the matrix resin.
These products are: integral oil storage tanks and tanks, which are used to store and transport petroleum products. Combined with cement storage tank to bear corrosive media (such as acid, alkali, organic solvent) storage tank, which can be subject to hot and cold changes. Boats with structural strength, able to withstand the effects of seawater and atmosphere.
- Polymer cement mortar and concrete and admixtures
In all man-made building materials, cement is the largest production, the most widely used and the most important building materials. Concrete and cement products based on cement have become the material basis of modern civilization for more than one hundred and seventy years. However, there are some shortcomings of cement and concrete hinder the development of modern construction technology, they can not adapt to the needs of modern construction projects, such as slow hardening, especially in the cold climate is more significant; low tensile and flexural strength; dry shrinkage, dense and poor impermeability; poor corrosion resistance to various media.
In recent years, the rapid development of polymer-based concrete and cement, polymer additives for concrete applications, effectively improve and enhance the performance of cement and concrete, becoming an indispensable component of modern concrete. Polymer additives have brought new breakthroughs in construction engineering and technology, epoxy resin is one of the polymer additive materials.
- Epoxy resin cement mortar and concrete
The development of domestic and foreign material science today has made epoxy resin cement mortar and concrete develop into a specialized discipline with considerable research results. Epoxy resin is used to replace all or part of cement as cementing material to make the aggregate (sand, stone, etc.) bonded and cured, and this process and product is called epoxy resin cement mortar or epoxy resin concrete.
Epoxy resin cement mortar is made of water-soluble resin emulsion with surfactant, then mixed with cement, sand, etc., and hardened together with cement hydration, in which epoxy resin can be cured by adding water-based amine curing agent. Water-soluble epoxy resin can be modified by bisphenol A epoxy resin and made into water emulsion of resin by adding high efficiency surfactant; water-soluble epoxy resin can also be used, such as glycerol epoxy resin, ethylene glycol epoxy resin, melamine epoxy resin, pentaerythritol epoxy resin, aniline epoxy resin and other epoxy resins with molecular structure, which are low viscosity water-soluble epoxy resins, which are easy to mix with water and cement. These epoxy resins are low viscosity water-soluble epoxy resins, which can be easily mixed with water and cement, and are used more in epoxy resin cement mortar.
- Cement and concrete reinforcement additives
The hydrophilic water-soluble epoxy resin has a special effect on the hydration reaction process of cement. Research shows that the water-soluble epoxy resin can improve the dispersion degree of cement particles and make the cement particles finer, so as to improve the effect of hydration reaction. As a result, the properties of epoxy resin cement mortar and concrete are improved after hardening.
From the physical and chemical tests and concrete research already know that the water-soluble epoxy resin, whether it is ionic or non-ionic type has this effect. And the functional group contained in the molecule of epoxy resin emulsion is the effect on the hydration reaction of cement is different. Generally, it is the molecule containing the amine structure that can significantly increase the speed of cement hydration reaction – accelerating the hardening; while the one containing the hydroxyl structure has the opposite effect of delaying the hardening (retarding the setting effect). By applying this change in chemical structure, we can make an enhanced additive that can regulate the speed of cement hardening — a conditioning agent. Due to the appearance and application of water-soluble epoxy resin cement mortar and enhancement additives, the traditional concrete and cement products can not only improve the process, but more importantly, improve the performance, and can be matched with the materials according to the mechanical requirements of engineering design, not only in the structural strength but also in the appearance of decorative effect has completely changed the coarse, heavy, monotonous appearance of the past.
- Epoxy resin grouting material
Major construction projects, such as: underground buildings, reservoirs, dams, docks, elevated roads, bridges, high-rise buildings, storage tanks and other large concrete projects, due to stress, external forces or earthquake damage to produce cracks, leakage and may lead to accidents, it is necessary to repair all kinds of cracks. Epoxy resin grouting technology is used to mechanically or pump the epoxy resin material under pressure into the deep layer of the crack and form a reinforcement layer with carbon fiber cloth and epoxy resin compound on the outer surface of the crack, and the resin cured to play the dual purpose of plugging and reinforcing, repairing the original facilities. Epoxy resin grouting material and technology is not only in the maintenance, but also in the foundation engineering and other aspects of this technology is very important. Epoxy resin as grouting material has been widely used, the remarkable effect of this technology is that its bonding force and cohesion far exceeds that of cement concrete, and the mechanical properties and strength of the repair are much higher than that of the original concrete, which is reliable and stable.
- Other uses:
Impregnated concrete, with low viscosity room temperature curing or ultraviolet curing epoxy resin solution, impregnated concrete products and cement products, curing at room temperature or under ultraviolet radiation, so as to form a layer of resin bonding layer at a certain depth on the surface of the concrete, changing and mentioning its concrete products and cement products of leakage resistance, corrosion resistance of various media.
China’s construction industry will play the role of economic pillar in the development of the national economy, large-scale capital construction and civil construction, it is inevitable that a large number of various construction materials, the demand for polymer materials will increase significantly, a variety of cement products, the production and number of concrete projects will also increase significantly, all these, a large number of applications of synthetic polymer materials, to develop chemical building materials. The demand of epoxy resin in China has reached more than 290,000 tons in 2002, but the amount of epoxy resin used in construction projects and building materials only accounts for about 6%-8% of the annual demand of epoxy resin, about 1.7-2.3 million tons, and the gap with the world level is still big. According to the forecast of relevant departments, by 2006, the amount of epoxy resin used in construction projects in China will increase to 10-12% of the annual demand.
To meet this development, there are few varieties and quantities of epoxy resins, curing agents and auxiliaries that meet the technical performance and process requirements of construction projects and building materials, which need more research and accelerated promotion and application. It can be estimated that the next five years will be a period of rapid development and in-depth popularization of epoxy resin and application technology in the field of construction engineering in China, and it is also a professional field and hot spot for the growth of epoxy resin demand in China.
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