Cement Additives

More than 100 additives for cement are available and these can be classified under the following categories:

• Accelerators: Accelerator is a chemical additive used to speed up the normal rate of reaction between cement and water which shortens the thickening time of the cement, increase the early strength of cement, and saves expensive rig time.
• Retarders: Retarders are chemical additives used to decrease the speed of cement hydration.
• Extenders:  Extenders are also known as water adsorbing or lightweight inert materials. 
• Weighting Agents: The main purpose of heavy weight additives is to restrain high formation pressures. 
• Dispersants: Dispersants also known as friction reducing additives are added to improve upon the flow properties of cement slurry. 
• Fluid loss control agents:  Fluid loss additive is also known as permeability plugging additive. 
• Loss circulation control agents:  Lost circulation additive is also known as macro plugging materials.
• Specialty agents: A number of cementitious materials used for cementing wells do not fall into any specific API or ASTM classification ​​​​​​​