Concrete sealing and curing agent knowledge

1、Introduction to the concrete sealer and curing agent industry
As for the first developed concrete hardener in the United States. At that time, it was one of the preferred options for subsequent treatment of concrete floors because it gave concrete the following characteristics: dust prevention, improved wear resistance, improved compression resistance, and improved flexural strength. At the same time, due to the change in the chemical composition of the concrete surface, also enhanced the concrete's ability to resist weathering and ultraviolet erosion, thereby neutralizing and improving the life of the concrete. Since the beginning of XX, China has gradually begun to have domestic concrete sealer and curing agent manufacturers, thus breaking the foreign technology monopoly. Moreover, due to the development that is more in line with China's national conditions, domestic concrete sealer and curing agent technology has surpassed foreign technology. This can be seen from many existing engineering data of well-known domestic large enterprises. The leading technology and construction operation of China's domestic concrete sealer and curing agent, as well as the price advantage.

2、Overview of the concrete sealer and curing agent market in China
Why has the concrete sealer and curing agent had a history of decades abroad, but has only entered the Chinese market in the past decade? This starts with cement. In foreign countries such as the United States, fly ash is rarely added to cement. In addition, the United States has high requirements for the grade of concrete during construction and strict monitoring. Therefore, under such a premise, the life of the building and the quality of the project are best guaranteed. Therefore, there is not much market demand for concrete sealers in the United States, and China is a major coal-producing country, so where does the fly ash left by burning coal go? The main use is to add it to ordinary-grade civilian cement. This is a fact that can be compared. In the Republic of China period, cement was imported, and the color of cement used to make buildings was not gray or white. However, the color difference of cement used in construction today (especially ordinary civilian grades) can be appreciated as an abstract work of art, which is also the main reason for the current wave of Portland cement projects. The addition of fly ash to cement not only affects the color difference but also has a great impact on weathering, dust, and life. After the rise of China's national economy, the construction industry has become very popular in China. Under such a premise, a large number of factories have sprung up like mushrooms after rain, and the market for concrete sealers in China has also expanded at the same time.

3、Introduction to Concrete Sealing and Curing Agents
After concrete hardeners set off a boom in industrial flooring in China, various domestic products have also sprung up on the market. From the product point of view, concrete sealing and curing agents are generally divided into two categories: organic and inorganic. Inorganic ones are further divided into two categories: acidic and alkaline. Of course, organic materials are expensive and often difficult to meet customers' environmental protection and fire protection requirements; inorganic alkaline materials are mostly slow to increase hardness and have limited effects. After construction, the hardness and other indicators of the product are difficult to meet the qualified requirements, and they are forced to wax or apply other resin layers to prevent dust after construction, and the price is high. However, inorganic acidic materials can fully meet customer needs in terms of hardness, compression resistance, flexural resistance, and other indicators after construction.

4、Introduction to the construction of concrete sealing and curing agents
The first aspect is grinding. Because domestic industrial floors all pursue a high-brightness indicator, during construction, they are often polished with diamond soft grinding discs first, or even polished with stone renovation standards to make the concrete floor as bright as a mirror, and then concrete sealant is applied to achieve the effect of high-brightness of the construction floor; or after the floor is completed, high-brightness floor wax is applied to meet customer needs.
The second aspect is to apply concrete sealant. Because most domestic construction parties' concrete sealants are imported and expensive, in the fierce competition, everyone saves chemicals to achieve the purpose of cost saving, and it has evolved into a common construction method of spraying chemicals; this directly leads to insufficient dosage of chemicals and insufficient reaction time of chemicals, so even if good quality acidic imported concrete sealant is used, it still cannot achieve a good sealing and curing effect. Some domestic manufacturers with independent technology generally adopt the construction method of soaking concrete floors with chemicals because they produce their chemicals at a very low cost. This ensures sufficient dosage of chemicals and complete reaction time of chemicals, which greatly guarantees the construction quality.

5、Difficulties commonly encountered by concrete sealers and curing agents in China
At present, the most common industrial floors in China, such as epoxy resin, diamond, and plastic flooring, are all constructed with a layer of covering on the original ground, while concrete sealers and curing agents use agents to react with the concrete layer directly on the concrete floor, changing the chemical structure of the concrete surface to achieve the purpose of sealing and curing. The above description determines that the construction effect of industrial floors such as epoxy resin, diamond, and plastic flooring is not affected by the original ground, while concrete sealers and curing agents can only be what the ground looks like before the construction of concrete sealers, and it is the same after the construction of concrete sealers and curing agents, but the color becomes slightly darker. Grinding the ground and waxing the ground are efforts to change the appearance of the ground, but once the ground is extremely flat and wavy like surging waves, the countless pits that cannot be polished by the grinder can only be helpless except for consuming astronomical manpower with a portable polisher. This is also the reason why the construction party of concrete sealers and curing agents is picky about customers now.
In general, to achieve a bright effect, in addition to the ground conditions, it also depends on the ground grinding technology, including machinery, grinding discs, and operator experience and technology; and to achieve the mechanical effect of hardening, in addition to choosing what kind of agent, it also depends on what construction method is used.

6、Real selling points and customer groups of concrete sealers and curing agents
Disadvantages of concrete sealers and curing agents for the construction of floors: not as good as epoxy, plastic, and other floors in terms of appearance; Advantages of concrete sealers and curing agents for the construction of floors
Dustproof (up to 100,000 levels), wear-resistant, pressure-resistant, weather-resistant, no wheel marks (polished floors), lifespan is generally more than 20 years.
Customers for concrete sealers and curing agents for the construction of floors: those who do not have high requirements for aesthetics, but have certain dust prevention requirements, are always troubled by wheel marks, and have high requirements for the life of the floor. Recommended construction sites for concrete sealers and curing agents: Currently, the most widely used sites include garages (including aircraft maintenance hangars, such as Guangzhou Baiyun Airport), shopping malls (Walmart, B&Q, etc.), storage terminals (Shenzhen Shekou Terminal, especially large logistics warehouses), electronics factories (such as Foxconn, BYD, etc.), machinery factories (such as Sany Heavy Industry, Nanzhu Electric, Wuling Automobile, etc.), factory terminals, etc.

7、Why choose acidic concrete sealers and curing agents
The working principle of alkaline concrete sealers and curing agents: is that silicates penetrate concrete and combine with calcium in concrete to form calcium silicate precipitation that is insoluble in water. At the same time, silicates crystallize in concrete due to water loss, thereby blocking the pores of concrete to achieve a dense and filling effect.
Because the chemical structure of concrete is not changed, it cannot prevent corrosion; because there is little free calcium in concrete, especially old ground, alkaline concrete sealing, and curing agents can not meet the hardness requirements, and after the insufficient hardness is destroyed, the crystallized silicate absorbs water again and dissolves and loses, so the whole sealing and curing are temporary, especially the alkaline concrete sealing and curing agent is alkali metal silicate, sodium salt, and potassium salt are cheap, but they will make a concrete return to alkali, so they cannot be used; lithium salt will not return to alkali, but the price is high, and the procurement channel is limited to a few cities in China. The working principle of acidic concrete sealing and curing agent: through direct reaction to concrete, chemical reaction with concrete, thereby changing the chemical structure and molecular space arrangement of the surface concrete, to achieve the effect of sealing and hardening, and because the chemical structure of the surface has changed, it can prevent corrosion from general acid and alkali chemicals and ultraviolet rays, and acidic concrete sealing and curing agent does not contain alkaline metals, so there is no so-called sodium-based, potassium-based and lithium-based.

8、The role of alkaline concrete sealer
Alkaline concrete sealers are generally divided into first, second, and third generations. They are the replacement of alkali metals. The first and second-generation alkali metal ions cannot be used in concrete, because this will aggravate the salt precipitation phenomenon in the concrete itself and make the concrete weather faster. The third-generation lithium ions, because of their special physical and chemical properties, are widely used in foreign countries to protect buildings mainly including bridges and ship docks. However, the purpose of their use is not to harden concrete, because it cannot meet the hardening requirements, but to protect the steel structure in the concrete to delay corrosion and extend the life of the building. It is recognized that chloride ions are the first killer of corroding the steel structure of buildings, which is particularly serious in buildings near the sea; because lithium ions can penetrate deeply into concrete, replace chloride ions, and protect the steel structure. Therefore, lithium ions are widely used in the protection of building steel structures abroad, but they are pale and powerless to improve the mechanical and strength properties of concrete structures.

9、Current application and development of concrete sealers in China
Because concrete sealers are only for ground construction, the flooring industry in China is currently engaged in this business, mainly for factories and warehouses. Because the concrete sealer and curing agent only improves the mechanical indexes by a percentage based on the original concrete, and because it does not change the color of the floor, the flooring industry now uses corundum floor with a concrete sealer and curing agent to produce a new floor variety: (corundum) wear-resistant floor, which is the best floor in the industry. It improves the mechanical properties of the floor such as wear resistance based on the strong wear resistance of the corundum floor. At the same time, the hardener solves the problem of dust and sand on the corundum floor, and the corundum floor makes up for the defect of the concrete hardener that does not change the color of the floor.

10、Differences between domestic and imported concrete sealers and curing agents
(1) Penetration depth: Under standard C25 concrete conditions, the penetration of imported concrete sealers and curing agents can reach 5mm, while Deligu concrete sealers and curing agents can penetrate the ground 10~30mm;
(2) Glossiness: The glossiness of imported concrete sealers and curing agents is relatively low after being applied to the ground, unlike Deligu concrete sealers and curing agents, which can have a marble-like gloss after construction;
(3) Scope of application: Imported concrete sealers and curing agents can only be used on new ground, not on old ground, while Deligu concrete sealers and curing agents can be used on both new and old ground, with a wide range of applications;
(4) Price: Import tariffs and transportation costs are high, so the price of imported concrete sealers and curing agents is often more than 5 times that of Deligu concrete sealers and curing agents.

11、What is the cause of white spots after concrete sealers and curing agents are applied?
The most commonly accepted reason for white spots is that too much curing agent is applied, and the curing agent that fails to penetrate the concrete evaporates and crystallizes on the surface, forming white crystals, which are common white spots. The common treatment method is to use a grinder with water for grinding, and the specific mesh size depends on the actual ground.

12、How to choose single-component and two-component concrete sealers and curing agents?
For new ground and ground with a dense base, a single-component can be preferred, which is simple and convenient to construct and beautiful; for old cement ground and loose ground, a two-component concrete curing agent must be selected, which can also make a hard and beautiful ground.