Corrosion Inhibitor

Product Description

DCI® S corrosion inhibitor is a liquid added to concrete during the batching process. It chemically inhibits the corrosive action of chlorides on reinforcing steel and pre-stressing tendons in concrete. It also promotes strength development at all ages.

DCI® S is recommended to protect all steel reinforcement, posttensioned and pre-stressed concrete that will come in contact with chlorides from de-icing salts or the marine environment.

  • Piers & coastal structures
  •  Sea defenses
  •  Foundations in saline ground water
  •  Structures close to the coast
  •  Parking structures
  • Bridge decks/abutments

It may also be used to protect concrete where chloride is already present in the mix constituents, or on the rebar surface.

Corrosion Mechanism

Corrosion occurs in the presence of oxygen, moisture and an electrolyte. As chlorides attach the reinforcing steel, the salt intensifies the electrolyte properties of the concrete, degrading the normal passivating layer, thereby creating a corrosion cell. As the reaction proceeds, rust is formed. It migrates away from the bar, leaving more iron to be corroded. This process continues and two situations develop:

1. The reinforcement reduces in effective thickness, resulting in flexural failure of the structural member.

2. Iron, as it oxides, expands to four times its original volume. This expansion results in physical disruption of the concrete, evident as cracking, straining, crazing and spalling. The process accelerates.

Corrosion Inhibitor

DCI® S corrosion inhibitor is a patented system based on Calcium Nitrite which interacts with the embedded steel in concrete to prevent salt attack. By chemically reacting with the embedded steel the passivating layer is maintained unbroken when chlorides penetrate the concrete cover zone. Corrosion initiation is significantly delayed, and the rate of corrosion, after eventual initiation, is controlled at a slower rate.

When added to concrete in sufficient quantity, as determined by the anticipated chloride ion content of the concrete over the design life of the structure, DCI® S maintains an active corrosion controlling system within the concrete matrix.

Typical Properties

Appearance  light brown liquid
Specific Gravity 1.27–1.30 at 20 °C
Calcium Nitrite Minimum 30%
Freezing Point -15 °C

Compatibility with Cements

DCI® S can be used with all types of Portland Cements, including cement replacement materials.

Compatibility with other Admixtures

DCI® S is compatible with other liquid admixtures, providing they are added separately to the mix.

It is already formulated with a retarding component to offset the acceleration in set normal with Calcium Nitrite.

A moderate increase in dosage rate of air entraining agent may be required to attain the normal specified level of air.

Method of Use

DCI® S is supplied ready for use. It should be added to concrete preferably at the same time as the mix water. It should not be added directly to the cement.

Mix water adjustment is essential to account for the water in DCI® S and maintain the desired w/c ratio. The mix water added at the batch plant must therefore be reduced to compensate for the addition of the corrosion inhibitor. The adjustment factor is 0.84 litres of water per litre of DCI® S.

Addition Rates

Range: 10 litres–30 litres per cubic metre of concrete

The project specification will indicate the addition rate, which is pre-determined on the basis of projected chloride ion ingress over the life of the structure.

The performance of DCI® S is best assessed after preliminary tests on site using the actual mix constituents under consideration to determine the effect on concrete properties.

Effects of Overdosing

Overdosing of DCI® S will normally produce an increase in workability, and in certain circumstances this could be accompanied by a reduction in setting time. Provided overdosed concrete is properly cured, ultimate strength will generally be no lower than that of normal concrete.


It is preferable that liquid admixtures for concrete should be introduced into a mixer by means of automatic dispensing equipment. Such equipment is available and can be supplied on request.

Health and Safety

For further information see the DCI® S SDS (Safety Data Sheet) or consult GCP Applied Technologies.


DCI® S is available in 210 litre, non-returnable drums.

Alternatively, 1000 litre IBCs or bulk deliveries can be arranged.


DCI® S should be stored in original containers or suitable closed tanks, preferably out of direct sunlight and protected from extremes of temperature.

Storage Life in Manufacturer’s Drums & IBCs: 

12 months from the date of manufacture

Storage Life in Bulk Storage:

12 months from the date of manufacture

Technical Service

The Technical Service Department of GCP is available to assist you in the correct and best use of our products. These resources and advice are at your disposal entirely without obligation. Please contact:

Emirates Chemicals LLC
Festival Tower, Suite 1701
Dubai Festival City
P.O. Box 5006
Dubai, United Arab Emirates
Tel: +971 4 2329901
Fax: +971 4 2329940
Email: meinfo@grace.com

gcpat.uk | United Kingdom customer service: +44 (0) 1480 478421

We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations, and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation, or suggestion is intended for any use that would infringe any patent, copyright, or other third party right.

DBM is a trademark, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

© Copyright 2020 GCP Applied Technologies Inc. All rights reserved. 

GCP Applied Technologies (UK) Ltd, Gate St, Dukinfield SK16 4RU.

This document is only current as of the last updated date stated below and is valid only for use in the United Kingdom. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on www.gcpat.uk. Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2022-11-24