Water reducing agent is a type of water reducing agent that can reduce the necessary water demand in concrete, meet the required consistency requirements, and improve the workability of concrete.
The main functions of water-reducing agents include the following aspects: increase hydration rate, reduce plant water demand, increase strength, save concrete dosage; improve non-condensation Improve the workability of concrete to avoid segregation of concrete ingredients; improve waterproof concrete properties, reduce water absorption, prevent water seepage in concrete building structures, improve performance, and improve resistance to solvent irritation; reduce shrinkage of concrete during condensation, Avoid cracks in concrete components; improve cold resistance, which is beneficial to winter construction.
In the preparation process of concrete, mortar and slurry, adding a small amount (not exceeding 5% of the concrete dosage) can improve the quality of concrete, mortar and slurry. This kind of product that changes the properties of mortar or paste is called concrete admixture.
Adding magnesium water-reducing admixtures to concrete can improve the quality of the concrete, improve the characteristics of the concrete, reduce the water demand of the concrete, save concrete, and control costs. , accelerate the progress of the project. With the development of technology, water-reducing admixture has become the fifth necessary material in addition to concrete, large and small stones, admixtures and water. The addition of water-reducing admixture is the key to parameterizing the design of concrete mix proportions and improving the performance of concrete. this key measure. Therefore, the newly revised "Hydraulic Concrete Pouring Standard" (DL/T5144-2001) emphasizes that appropriate water-reducing agents must be added to hydraulic concrete.
Classification of water reducing agents
Concrete admixtures can be divided into the following according to their key functions Category 4:
(1) Water-reducing agent that improves the deformation properties of concrete during mixing and transportation. Including general water-reducing agent and high-efficiency water-reducing agent, air-entraining agent and pumping agent, etc.
(2) Water-reducing agent that adjusts the initial setting time and hardening characteristics of concrete. Contains retarder, retardant and accelerating agent, etc.
(3) Water reducing agent that improves the performance of concrete. Contains air-entraining agents, waterproof coatings, rust inhibitors, etc.
(4) Water reducing agent that improves the characteristics of concrete grades. Contains expansion agents, antifreeze, additives, etc.
The common types of water-reducing agents for hydraulic concrete mainly include water-reducing agents, retarders, air-entraining agents, and various composite water-reducing agents. , such as retarding water-reducing admixture or retarding high-efficiency water-reducing admixture, early-strength water-reducing agent, air-entraining water-reducing agent. According to special needs, other types of water-reducing admixtures are also mixed, such as pumping agents, waterproof coatings, antifreeze Agent these. National and national standards such as GB8076-1997 "Concrete Admixtures" and DL/T5100-1999 "Technical Specifications for Hydraulic Concrete Admixtures" often have strict requirements on the performance parameters and technical specifications of this water reducing agent. Different requirements must be adopted.
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