As an important concrete admixture, water reducing agent is one of the important products in the new building materials pillar industry. The water-reducing agent not only reduces the amount of cement, effectively protects the environment, but also greatly improves the mechanical properties of high-strength concrete, and provides a simple and easy construction process. The earliest water-reducing agents used in my country are ordinary water-reducing agents such as sodium rosinate, sodium lignosulfonate and stearic acid soap, with water-reducing rates greater than 5% and less than 10%. However, it was quickly replaced due to its low water reduction rate and limited engineering applications.
At present, the water-reducing agents widely used in our country are mainly melamine series, naphthalene series, sulfamic acid series, modified lignosulfonic acid series, water-reducing agents and other high-efficiency water-reducing agents with a water-reducing rate of greater than 10%. Water reducing agent, the most widely used one is water reducing agent.
Water reducing agents play an important role in the advancement of my country's concrete technology and construction technology, improving the quality and service life of buildings, reducing energy consumption, saving cement and reducing environmental pollution. Almost all domestic construction research institutes and admixture manufacturers have conducted research and development on their production processes and application technologies. High-strength concrete and high-fluidity concrete due to the application of water-reducing agents are the third major revolution in the history of concrete development after reinforced concrete and prestressed concrete. It can be said that the technology and application of water-reducing agents represent the level of building materials and construction technology in a country.
The compound blending of water-reducing agent and lignosulfonate water-reducing agent or sulfamate-based high-efficiency water-reducing agent has a superimposed effect in terms of plasticizing and reinforcing effects, and can reduce the water content at 0.1%. On the basis of water agent, the compound addition of lignosulfonate water-reducing agent and sulfamate-based high-efficiency water-reducing agent can also help improve the slump retention of concrete; The compound blending of agent, melamine series high-efficiency water-reducing agent, and sulfamate series high-efficiency water-reducing agent will weaken its plasticizing effect, and the composite blending of the system water-reducing agent and the naphthalene series high-efficiency water-reducing agent will have a negative impact on the plasticizing effect. and slump retention have the greatest negative effects
Application of water-reducing agent
1. The dosage range of water-reducing agent (liquid agent) is usually within the weight of cement or cementing material About 0.5%-2%, the specific dosage is determined according to field tests.
2. Before use on site, experiments must be conducted in advance to determine the concrete mix ratio, sand rate, water consumption, and water-reducing agent content according to project requirements.
3. Functional small materials such as air-entraining agent, defoaming agent, and retardant can be compounded as needed during use, but attention should be paid to the compatibility of the compounded small materials with the water-reducing agent.
4. Water-reducing agents have a wide range of applications and can be used in various high-performance concretes such as high-speed railways, passenger dedicated lines, industrial and civil buildings, roads, bridges, ports, airports, and maritime infrastructure
p>Water-reducing agents have the characteristics of excellent dispersion and large flow state. They also have excellent properties such as low alkali, low chloride ions, low shrinkage, no pollution, low environmental load and obvious economic benefits, and are becoming more and more popular. Many projects, such as high-speed rail, subway, elevated, airport, nuclear power and other projects, clearly state in the bidding documents that the admixtures used must be system admixtures. These will definitely promote the future development of high-efficiency concrete water-reducing agents. How to select matching admixtures for raw materials and use them well has become the top priority in controlling the quality, performance and cost of concrete
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