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What is early strength agent? Classification and application analysis of early strength agent

Release time:

2022-05-31

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　　early strength agentIn foreign countries, it is often called accelerator, which literally means an additive that can shorten the setting time of cement concrete. It is actually an early strength agent. However, according to the GB8076-2008 concrete admixture standard, it is required that the early strength agent or the early strength water reducing agent should not have much influence on the setting time of concrete, and the difference between the setting time of the early strength agent and the early strength water reducing agent is required to be 90min.

Concreteearly strength agentIt is one of the early use of admixtures in the development of admixtures, people have developed a variety of early strength agents in addition to chloride and sulfate, such as sulfite and chromate, and organic early strength agent, such as triethanolamine, calcium formate and urea. On the basis of early strong admixtures, the production and application of early strong water reducing agent, early strong antifreeze, early strong pumping agent and other composite admixtures. This kind of early strength agent has been used in practical engineering, which plays an important role in improving concrete performance, improving construction efficiency and saving investment cost.

Due to the long winter and large land area in Northeast, North and Northwest China, it is necessary to add early strength agent and early strength water reducing agent to improve the early strength development of concrete. Early strength agent and early strength water reducing agent are often used in construction, when the winter temperature in East China and South China is lower than 10 °. In order to tension reinforcement as soon as possible, speed up the turnover of formwork and the utilization rate of pedestal, early strength agent is widely used in the production of concrete components. According to statistics, the total amount of early strength agent and early strength water reducing agent used in China every year exceeds 200000 tons.

Based on the chemical composition,early strength agentIt can be divided into three categories: strong electrolyte inorganic salts, water-soluble organic compounds, organic compounds and inorganic compounds. 1. Chloride salt early strength agents mainly include calcium chloride, sodium chloride and aluminum chloride. The reasonable incorporation of chloride salt early strength agent will be beneficial to the development of early strength of concrete. The application history of chlorine-based early strength agent is long, and the application effect is obvious. but chlorine saltearly strength agentIt is only allowed to be added to plain concrete without rigid reinforcement. For reinforced concrete, especially concrete with prestressed reinforcement and metal embedded parts, such admixtures should be used with caution. (2) Organic. Triethanolamine is a commonly used organic compound early strength agent. Triethanolamine is a kind of surface active agent, which is mixed into cement concrete and plays the role of catalyst in the process of cement hydration. It can accelerate the hydration of C3A and the formation of ettringite. Triethanolamine is often used in combination with chloride early strength agent, and the effect of early strength agent is better. 3, composite type. Through the compounding of a variety of early strength agents, as well as the compounding of early strength agents and water reducing agents, a better modification effect can be obtained than a single early strength agent.

　　early strength agentScope of application: 1. This product does not contain chloride ions and has no corrosive effect on steel bars. Applicable to all civil and industrial buildings, prestressed reinforced concrete components, mortar, etc. 2,early strength agentSuitable for construction at low temperature in early winter and early spring. 3, early strength agent for Portland cement, especially slag cement reinforcement and modification.

Key words:

Early strength agent

The difference and connection between early strength agent and accelerator.

Effect of early strength agent

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