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An alkali - free liquid accelerator for spraying c

Source: http://www.heqichem.com/news/11.html   Release time: 2018-11-06

The accelerating agent is a kind of chemical admixture which can make cement concrete quickly coagulate and harden. Because of the extensive application of the accelerator, the performance and quality of the accelerator are particularly important.

There are two kinds of accelerator, dry powder and liquid. The liquid accelerator is divided into basic liquid accelerator and no-alkali liquid accelerator according to its alkali content.

In the construction of shotcrete, there are two common processes of dry spraying and wet spraying, dry spraying USES powder accelerating agent, and wet spraying USES liquid accelerating agent. Traditional shotcrete construction mainly USES the dry spray technology, construction dust big, poor working environment, not only had a greater influence on the physical and environmental hazards, to construction personnel and shotcrete strength loss after springback amount is high, the sprayed concrete hardening (usually around 30%), easy to crack, poor durability, is not conducive to guarantee the quality of sprayed concrete engineering and service life. Therefore, the spraying concrete construction is turning to the wet spraying technology to solve the above problems existing in the dry spraying construction. At present, alkali free liquid accelerator is widely used in important engineering or permanent supporting shotcrete project to avoid concrete structure cracking, alkali aggregate reaction damage to concrete structure and adverse effect on bad environment.

Liquid accelerator is usually made of aluminum sulfate, aluminum hydroxide, sodium fluoride, organic alkyl amine and acrylamide. In recent years, the development of low-alkali or no-alkali liquid accelerator has become an important subject in domestic and foreign research. At present, low-alkali or no-alkali liquid accelerator products sold on the market and their effects are not ideal enough. Judging from the use feedback, they have disadvantages such as large dosage, high resilience, poor compatibility with water condensation and unstable product storage.

Alkali - free liquid accelerator is the development direction of accelerator and the inevitable trend of engineering application. It is against this background that the company and Beijing university of technology successfully launched HQ alkali-free liquid accelerator and its series of raw materials through long-term cooperative research. The research results have been appraised by China building materials association, the main performance indexes of its products have reached or exceeded the same products at home and abroad, and the results belong to the international advanced level.

Yunnan kaiwei new materials co., LTD. Is established by the investment registration of kunming heqi industry and trade co., LTD. It is a high-tech and environmental-friendly service enterprise, focusing on the waste of chemical enterprises as the main raw materials, researching new materials, developing and applying fields, and gradually promoting the recycling economy and industrialization development of waste gas and materials in the chemical industry.

My company r &d and production without alkali liquid accelerator and its parent material, respectively in Pakistan, Laos, and more than 20 in the construction of major projects at home and abroad, and so the first successful application of the product is simple and easy, stable storage transportation, processing and manufacturing superior performance characteristics and the market and the project's full recognition and praise, has the good promotion and application prospect.

4. Technical characteristics of HQ alkali-free liquid accelerator

(1) low dosage (3%_7% of cement quality), fast setting and short initial and final setting interval of cement concrete;

(2) good adaptability to cement, which can meet the standard performance indicators and requirements of jc477-2005 "accelerator for Shotcrete" and ASTM c1141-08standard Specification for Admixture for Shotcrete.

(3) the early strength of concrete is high, and the 1d strength of adhesive sand specimens can exceed 10MPa, and the later strength decreases less, and the 28-day strength ratio can reach 90% ~ 100%.

(4) there is no adverse effect on the durability of concrete. As the alkali free accelerator does not contain any alkaline substance, it greatly reduces the damage effect on concrete caused by the introduction of alkaline substances, such as alkali aggregate reaction. At the same time, the content of Cl- was strictly limited and the corrosion of steel was avoided.

(5) no dust in the process of spraying and reduce the amount of rebound, so as to protect the health of construction personnel and reduce the waste of materials;

(6) hardened concrete has good compactness and anti-permeability and can be prepared with high-strength jet concrete.

5. Implementation standards

Jc477-2005 China building materials industry standard

ASTM C1141/C1141M -08 Standard Specification for Admixtures forShotcrete

6. Application field

Underground engineering: the supporting lining of shotcrete concrete for mining roadways, traffic tunnels, hydraulic tunnels, underground railway and all kinds of caves (underground power station, warehouse, etc.).

Rock engineering: protection wall of slope, foundation pit, reservoir, embankment channel, pool, etc.

Repair and reinforcement works: repair and reinforcement of Bridges, sea walls, DAMS, docks, cooling towers, chimneys and buildings, as well as repair of building structures caused by chemical corrosion, fire, earthquake, blast impact overload or poor construction;

Protection engineering: fire prevention and anti-corrosion layer of various structures, and waterproof plugging engineering;

Refractory engineering: construction and repair of chimneys and thermal furnaces.

7. Processing technology of HQ alkali free liquid accelerator

The parent material (A) of HQ alkali-free liquid accelerator produced by our company was dissolved in the quantitative water, and was stirred and dissolved, and the auxiliary material (B) was added slowly at the same time of stirring, and fully stirred for about 30-50 minutes, so that it was completely dissolved, that is, the alkali-free liquid accelerator was prepared. The production process is simple and does not pollute the environment.

We are committed to provide alkali - free liquid accelerator raw materials for domestic and foreign admixture enterprises, and provide technical support.

8. Usage and matters needing attention

A. HQ alkali-free liquid accelerator is a alkali-free inorganic salt complex aqueous solution, which should be added to the accelerator material cabin of the jet for use during injection.

B. According to the variety, dosage and water-cement ratio of cement, the development of coagulation promotion and concrete physical property can be adjusted by changing the content of cement.

C. Ambient temperature will affect the condensation rate and early performance of shotcrete. Its specific dosage should be determined by test adjustment according to performance requirements and environmental conditions.

D. Reducing water-cement ratio as much as possible can improve the durability and ultimate mechanical properties of shotcrete. Superplasticizer can be added with the addition of accelerating agent.

E. The thickness of shotcrete layer shall not be less than 10cm, and the thickness of shotcrete side wall shall not be less than 15cm. HQ alkali-free liquid accelerator can make shotcrete better bond with rock surface, reduce rebound and effectively mesh shotcrete layer.

F. Compared with reference concrete samples without accelerating agent and fully vibrated, the shotcrete rate can reach 90%.

G, conventional shotcrete: when the dosage of cement is 400 ~ 500kg/m3(the type and dosage of selected cement depends on the performance requirements of concrete), the dosage of this product is generally 3% ~ 7% of the cement content in concrete, and the best is 4% ~ 6% (the higher the dosage, the faster the setting time).

H. Do not mix with other accelerating agents for spraying concrete. If other types of accelerating agents are used, please clean the whole equipment with water.

This product is slightly acidic and slightly corrosive. Please avoid prolonged contact with the skin. If it is splashed on the skin, please clean it with water immediately.

9, packaging

200 liter plastic containers, 1000 liter plastic cans, or in bulk or packed according to customer's need.

10, storage

Solid shelf life is one year; The liquid accelerator is stored in a sealed plastic container to prevent frost or direct sun exposure, with a shelf life of 6 months.


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