09.Water reducer

Water reducer can improve the fluidity of gypsum slurry and the strength of gypsum hardened body. And it is usually used for gypsum self-leveling mortar and plaster.
At present, the domestic water reducers are arranged in terms of fluidity and strength effect as polycarboxylic acid retarding water reducer, melamine high-efficiency water reducer, tea-based high-efficiency retarding water reducer, and wood sulfonate water reducer.
When using water reducer in gypsum dry-mixed building materials. In addition to considering water consumption and strength, attention should also be paid to the setting time and fluidity loss of gypsum building materials over time.

10.Waterproofing agent

The biggest defect of gypsum products is poor water resistance. Areas with high air humidity require higher water resistance of gypsum dry-mixed mortar.
Generally, the water resistance of gypsum hardened body is improved by adding water-hardening admixtures. In humid or saturated water conditions, adding water-hardening admixtures can make the softening coefficient of gypsum hardened body reach above 0.7. Thereby meeting the strength requirements of the product. Chemical admixtures can also be used to reduce the solubility of gypsum (i.e., increase the softening coefficient). A water-resistant way to reduce the adsorption of gypsum to water (i.e., reduce the water absorption rate) and reduce the erosion of gypsum hardened body (i.e., isolation from water).
Gypsum waterproofing agents include ammonium borate, sodium methylsiliconate, silicone resin, emulsified paraffin, and silicone emulsion waterproofing agents with better effects.

11.Active activators

Activation treatment of natural and chemical anhydrous gypsum can make it adhesive and strong. So as to be suitable for the production of gypsum dry-mixed building materials. Acidic activators can accelerate the early hydration rate of anhydrous gypsum, shorten the setting time, and improve the early strength of gypsum hardened body.
Alkaline activators have little effect on the early hydration rate of anhydrous gypsum. But can significantly improve the later strength of gypsum hardened body. And some hydraulic cementitious materials can be generated in the gypsum hardened body, which effectively improves the water resistance of the gypsum hardened body.
The use effect of acid-base composite activators is better than that of single acidic or alkaline activators. Acidic activators include potassium alum, sodium sulfate, potassium sulfate, etc. Alkaline activators include quicklime, cement, cement clinker, calcined dolomite, etc.