RDA® Additive for Cement Aid

Additive for Cement Aid

Product Description 

RDA is a chemical additive to be interground during the manufacture of Portland and blended cements to retard the initial and final set of cement pastes and mortars.

RDA is based on an aqueous solution of hydroxylated organic compounds.


Physical Properties


Appearance: brown or blue liquid

Density (g/l): 1200-1250

pH: 6.5-7.5

Recommended Addition Rate 

According to GCP experience the addition rate of RDA is in the range of 250-1000 g/t of treated cement. However the optimum addition rate of RDA depends upon the degree of retardation required under job condition. Longer setting times or higher temperatures will require higher addition rates.

Deviation from the optimum cannot guarantee the expected results.


RDA controls effectively the setting process and permits significant extension of the board life.

Typical Application 

RDA is used wherever a delay in setting time will insure sufficient delivery, placement, vibration or compaction time. 

How to Use 

RDA should be added on to the feed belt or injected into the mill. For an accurate proportioning of RDA a volumetric metering pump is suitable. 

GCP can advise on the most appropriate dosing equipment.

Specification Compliance 

Approved for use under ASTM C465 specifications as a nonharmful processing addition. RDA has been thoroughly tested and is widely used in the cement industry.

Packaging and Handling 

RDA is supplied in 210 liter drums, in 1000 liter plastic containers or bulk.

Shelf life is 24 months if stored in manufacturer’s containers.

Storage Precautions 

RDA does not require particular precaution for the storage. RDA has to be protected from freezing.

For tanks and containers placed outside a heating system or a re-mixing device is suitable. It is also better to insulate exposed pipelines.

GCP personnel can help in designing the best system.

Handling Precautions 

RDA does not require particular precaution for health and safety. Please refer to the SDS (Safety Data Sheet). 

Accidental release or spillage is to be absorbed with an inert material, such as sand or sawdust. 

Tanks and containers can be cleaned with water.