In industry, we often add water-reducing admixtures to concrete, mainly because of its many achievements in industry. Adding early-strength water-reducing admixtures in specific construction can save costs, reduce expenses, and at the same time improve product quality, thereby achieving certain economic and technical effects. The editor of Yulong New Materials Co., Ltd. has sorted it out for everyone.
1. Tests have proven that while maintaining the strength of concrete, 10%-20% of cement consumption can be saved.
2. When the water consumption remains unchanged, the slump can increase by 10 to 20cm.
3. The water permeability can be reduced by 40%--80%, which improves the ability of waterproofing, impermeability, frost resistance, chemical corrosion resistance, steel bar corrosion, and alkali aggregate reaction prevention.
4. Improve the phenomenon of bleeding and segregation.
5. With the workability unchanged, the water can be reduced by 10% to 25%, and the concrete strength can be increased by 15% to 25%, especially the early strength improvement is more significant.
6. High-efficiency water-reducing agents with water reduction rates above 20% to 25% can be used to prepare high-strength concrete and high-performance fluid concrete.
7. Retarding water reducing agent can slow down the heat release rate of cement hydration and delay the peak temperature of hydration heat.
8. In order to meet the pumping workability requirements and the water-cement ratio limit of pumped concrete, water-reducing agents need to be used. In particular, large-fluid concrete that is pumped over long distances generally requires a high-efficiency water-reducing pumping agent with a water-reducing rate of more than 20%.
Water-reducing agents can achieve the above functions mainly because of their significant advantages:
1. As a third-generation water-reducing agent, the water-reducing rate of early-strength water-reducing agents is significantly higher than that of For naphthalene-based water-reducing agents and other types of water-reducing agents, when achieving the same water-reducing rate, the dosage of early-strength water-reducing admixture is much lower than that of naphthalene-based water-reducing agents, and the water reducing rate can be as high as 45%.
2. According to a large amount of practice, naphthalene-based water-reducing agents generally have relatively large slump losses. Generally speaking, increasing the dosage helps reduce slump losses, but naphthalene-based water reducing agents reduce slump losses. Concrete will easily segregate if a little more water agent is added, so it is difficult to adjust if the material is not good. However, the concrete prepared with early-strength water-reducing agent can still meet the pumping requirements after 1 hour.
3. As the dosage increases, the ultimate water-reducing rate of the early-strength water-reducing agent is much higher than that of the naphthalene-based water-reducing agent. When the dosage of naphthalene-based water-reducing agent is around 2.0%, the ultimate water-reducing rate is basically reaches the limit, which shows that early-strength water-reducing admixture is more suitable for formulating high-strength concrete with low water-cement ratio.
4. When the dosage is appropriate, the concrete prepared with early-strength superplasticizer has excellent workability, no segregation or bleeding, and the concrete has a uniform appearance and color. When used to prepare high-grade concrete, the concrete has good cohesion and is easy to mix.
5. A large number of staff said: Early-strength superplasticizer products have good stability, no stratification or precipitation occurs during long-term storage, and no crystallization occurs at low temperatures.
6. The production process of naphthalene-based water-reducing admixtures has certain pollution to the environment. However, early-strength water-reducing admixtures adopt environmentally friendly and green synthetic production processes, which can save cement, improve concrete performance, and promote green concrete, Sustainable development of low-carbon concrete technology
Application of early-strength water-reducing agents in actual construction
1. For ordinary water-reducing agents and early-strength water-reducing agents in actual work , pH value, density (or fineness), and water reduction rate should be tested before construction and application. It can be used only after meeting the requirements. The determination of the optimal dosage must meet the design strength, workability, durability and engineering environmental conditions. For performance requirements such as economy, a reasonable dosage can be obtained through trial preparation based on the recommended dosage provided by the supplier. Excessive dosage of early-strength water-reducing agent will cause severe bleeding of cement concrete and massive loss of cement slurry, resulting in insufficient compactness and thus affecting the strength.
2. According to research, water reducing agent should be prepared into a uniform solution. The harmful effect of admixture precipitation is the same as that of excessive admixture dosage. Undissolved solid precipitates in the solution should be removed every day. According to the needs of the project, ordinary water-reducing agents and early-strength water-reducing agents can be used in combination with other miscible admixtures.
3. Mixing other small admixtures compatible with cement into the early-strength water-reducing agent can reduce slump loss in hot weather. When transporting cement concrete with a mixer truck or tank truck, it should be used at the pouring site. The early-strength water-reducing agent can be added twice, and the material can be discharged after rapid stirring and uniformity. Do not add more water, and quickly complete pouring, vibrating, finishing, etc.; use a retarded early-strength water-reducing agent.
4. The health maintenance link is a key link to ensure that the cement concrete structure does not crack and micro-cracks. Therefore, the cement concrete structure of the highway project mixed with ordinary water reducing agent and early strength water reducing agent should be strengthened and repaired as soon as possible. Keep warm and moisturize. Cement concrete components mixed with ordinary water-reducing admixtures are not suitable for steam curing; cement concrete components mixed with retarding water-reducing admixtures must be allowed to stand still for a period of time to allow the cement concrete to form a certain structural strength before they can be steam-cured. Cement concrete mixed with early strength water reducing agent can be cured by steam curing. </p
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