Water reducing agent formulation process: how to avoid deterioration

Water-reducing agent is a high-performance water-reducing agent and a cement dispersant used in cement concrete applications. Widely used in highways, bridges, dams, tunnels, high-rise buildings and other projects. This product is green and environmentally friendly, non-flammable and non-explosive, and can be safely transported by train and car. Synthetic raw materials of carboxylic acid water reducing agent: (1) Unsaturated acid: maleic acid, maleic anhydride, acrylic acid, methacrylic acid, etc.; (2) Polyalkenyl macromonomer: polyalkenyl hydrocarbon, ether, Alcohol, etc.; (3) Polystyrene sulfonate or ester; (4) (Meth)acrylate, ester, diphenol, acrylamide, etc.

Use deionized water to prepare aqueous solutions with a concentration of 20% from acrylic acid, sodium methacrylate sulfonate, ammonium persulfate, and polyoxyethylene allyl ester macromonomer. In a three-necked flask equipped with a stirrer, reflux condenser and thermometer, the monomer and initiator are added dropwise in batches. After the addition is completed, the reaction is maintained at 75°C for a certain period of time. After the reaction is completed, adjust the pH value to 7-8 with a NaOH aqueous solution with a concentration of 20% to obtain a yellow or reddish-brown water-reducing agent with a concentration of approximately 20%.

Methods to avoid deterioration of water-reducing agent First, pay attention to the storage environment. In order to avoid the deterioration of this type of chemical additives, we must pay attention to the environment when storing them. If there are moisture components, corrosive gases or substances in the environment, they are likely to corrode the additives, leading to changes in main properties and the emergence of irreversible properties. Therefore, when storing them, be sure to Pay attention to environmental issues. Second, pay attention to its shelf life. When storing and using water reducing agents, we must also pay special attention to their shelf life. It is understood that each additive has a shelf life and can only be used within the shelf life, otherwise the use will be ineffective or disadvantageous. For this reason, you must check the shelf life before use. This is the easiest way to prevent deterioration.

Testing the compatibility of admixtures and cement: How to test the compatibility of admixtures and cement is a new and old problem. The compatibility issue between admixtures and cement should be paid equal attention by admixture and cement manufacturers. In many actual construction situations, even cement and admixtures that fully meet quality standards will be incompatible when used as raw materials to prepare concrete. The main phenomenon: when using a batch of admixtures or resupplying admixtures, the slump of the concrete often appears to be large or small, the slump loss is fast or slow, the setting time is long or short, and sometimes bleeding occurs. . The method to test whether the admixture is compatible with cement is to test the fluidity of the water-reducing agent, that is, compare the same batch of admixtures with newly imported cement and the original cement to determine whether it is an admixture. The problem occurs due to the agent. On the premise of identifying the situation, the method is generally to adjust the amount of admixture or appropriately adjust the concrete mix ratio, and at the same time contact the admixture manufacturer or cement manufacturer.

</p