Gypsum Retarder

  • Overview
  • Packaging
  • FAQs
  • Advantages
  • Resources

It is not uncommon for industrial cement to contain higher ratios of gypsum than the cement used in more traditional concrete mixes. This characteristic means that industrial concrete mixes will also have a higher rate of false set. That’s why Fritz-Pak’s offers our powerful admixture, Gypsum Retarder in industrial-sized packaging. This unique admixture helps prevent premature stiffening due to a high degree of gypsum.

Why Use a Gypsum Retarder?

False set occurs when the gypsum in the cement mixes with water to form plaster of paris. The plaster dries very quickly, causing the cement to stiffen. This makes the concrete very difficult to work with and interferes with the hydration process. So, while the concrete appears hard it is not very strong. Adding Gypsum Retarder to the mix neutralizes the gypsum to prevent the formation of plaster of paris, and thereby prevent the false set of the concrete.

Benefits of Gypsum Retarder

Fritz-Pak’s Gypsum Retarder works great in Portland cement and Calcium Aluminate cement. The product contains a synthetic amino acid that does not produce any sort of strong odor. Since this admixture is primarily intended for industrial use, it does not come packaged in our signature water-soluble bags. Instead, we package Gypsum Retarder in 44-pound bags. This makes it easier to use for those large mixes.


If you need technical assistance regarding Gypsum Retarder, or if you would like to place an order for this product, give us a call at (214) 221-9494. Unfortunately, due to the type of packaging we have for this admixture, it is not available for purchase through the website store. Don’t forget to follow our social media pages for more information about how our products can improve your concrete.

9941944 lb. (20-kg) bag40
Does Gypsum Retarder have a strong or offensive odor?
No. Gypsum Retarder is a synthetic amino acid that does not have any odor.
Is Gypsum Retarder available in water soluble bags?
No. Gypsum Retarder is for industrial use, and it is only available in 44 lb. bags.
Will Gypsum Retarder retard portland cement or calcium aluminate cement?
No. Gypsum Retarder is specific for gypsum.
Can Gypsum Retarder be used in blends of cement and gypsum?
Yes. However you may have to increase the dosage of Gypsum Retarder.
The dosage rate of Gypsum Retarder is too low for effective plant addition. Can Fritz-Pak blend it with inert materials?
Yes. Diluted blends for easier plant addition can be made.
  • Slows the set time of gypsum and gypsum-containing materials
  • It is a high-strength retarder that is effective at low dosages
  • Purified material with no offensive odors
  • Dose-response is linear, making the determination of effective dosage easy
  • Can be used in cement-gypsum blends
  • Effective over wide range of pH
  • Efficacy does not diminish during storage