Which of the following is commonly used as retarder in ...

May. 13, 2024

Which of the following is commonly used as retarder in ...

Retarder increases the initial setting time of cement while accelerators reduces the setting time of cement.

For more information, please visit mortar retarder suppliers.

Some commonly used retards are: Organic retardants include unrefined calcium, sodium, NH4, salts of lignosulfonic acids, hydrocarboxylic acids, and carbohydrates.

Inorganic retardants include oxides of lead and zinc, phosphates, magnesium salts, Calcium Sulphate, Gypsum, fluorates and borates.

Some Commonly used accelerators are: Calcium chloride, Potassium carbide, Sodium Chloride etc

Here Both Calsium sulphate and Gypsum are correct but the most appropriate answer is Gypsum

What are Retarders in Concrete Used For

Concrete admixtures and additives are among the most popular materials used to modify several properties of concrete in plastic and hardened states. They can help increase the strength, workability, unit weight and hardening of concrete.

Some of the most common admixtures include concrete retarders, concrete accelerators, superplasticisers, plasticisers, and air entraining admixtures.

How Concrete Retarders Work

The main aim of using retarders in concrete is to extend or delay the cement paste’s setting time. The stiffening or setting is due to the chemical reaction between the cement and water in the concrete. The reaction is referred to as hydration.

Concrete retarders slow down the hydration process. This keeps the concrete in its plastic stage and more workable for longer. Concrete retarders are used when more time to place the concrete is needed during transportation or a complex placing condition. The retarders are helpful when putting concrete at increased temperatures or using concrete transported over a long distance.

Additional reading:
Sodium Formate Granule vs. Sodium Acetate: Which is Superior?
How Sodium Formate Granules Transform Sustainable Practices?
5 Tips for Selecting the Right Organic Fertilizer Blend
Unlocking Benefits of Clear Potassium Formate Liquid
How Potassium Formate Could Revolutionize Agriculture Practices?
Conveyor Belts: What Is It? How Does It Work? Types, Parts
Unlocking Benefits of Potassium Diformate in Feed Additives

The company is the world’s best Self-Leveling Compound Manufacturer supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

When water is added to cement, there is a fast initial hydration reaction, after which there is a slight formation of hydrates for about 2-3 hours. The exact reaction time depends on the temperature and cement type, the time before the cement starts to harden is called the dormant period. The dormant period is characterised by an increase in hydration rate and increase in the rate at which calcium hydroxide is formed.

The retarding admixture slows down the end of the dormant period and the commencement of the hardening and setting phase. When used alone, retarders allow concrete vibration to avoid the formation of cold joints when the concrete is placed between layers.

It is essential to note that the retardation mechanism is short-term. After a certain period, the effects of the retardation mechanisms stop, and hydration continues.

Setting of Concrete

The concrete setting is the transition process of converting concrete from plastic to a hardened state. The cement properties significantly affect the setting time.
Other factors affecting the setting include:

Suitable temperature
Cement content
Water cement ratio
Admixtures
Type of cement
Type and amount of aggregate
Relative humidity

Common types of concrete retarders

The most commonly used concrete retarder is calcium sulphate. Sugar is also an effective and common retarding admixture used for delaying the setting time of concrete without a detrimental effect on the strength of the concrete.

Other organic and inorganic materials used as retarders include:

Acids (tartaric and citric)
Phosphonates
Cellulose products (sucrose, glucose)
Sodium gluconate
Rochelle salt and cream of tartar
Lignosulphonates
Starches
Hydroxycarboxylic acids
Borates

Shop Quality Concrete Retarders Today

At Bisley, we are committed to supplying quality raw materials for various industrial applications. Contact us today to discuss your next project and how we can deliver the required materials.

View our range of Concrete Admixture Retarding Products

Are you interested in learning more about daily grade cellulose ether? Contact us today to secure an expert consultation!

Additional reading:
How to Select the Right Potassium Formate Solution?
Sbr Powder Imports in World from India
Unlocking Sodium Formate Powder: Uses, Benefits, and FAQs
How to Select Calcium Formate for Cement Applications?
How to Cut Conveyor Belt: Tools and Safety Tips
Everything You Need To Know To Find The Best Stone Breaking Chemical
Enhancing Concrete Strength with Calcium Formate Benefits