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Sika® CNI OM

CORROSION INHIBITING ADMIXTURE

Sika® CNI OM is a calcium nitrite-based admixture designed to inhibit the corrosion of steel in reinforced concrete. Sika® CNI OM contains a minimum of 15 % calcium nitrite by mass and meets the requirements of ASTM C 1582, Corrosion Inhibiting Admixture and ASTM C494, Type C, Accelerating Admixture.

Sika® CNI OM is recommended for conventional steel reinforcement as well as prestressed or post-tensioned concrete that will be exposed to chlorides from marine environments or deicing salts. Sika® CNI OM will extend the service life of structures by effectively inhibiting corrosion, in areas such as parking garage decks and support structures, bridge decks, marine structures and many others.
Sika® CNI OM may also be used in concrete elements where chlorides are added initially to the concrete mix.
Sika® CNI OM is a corrosion-inhibiting admixture that provides protection against corrosion in reinforced concrete structures. Sika® CNI OM:
  • Extends the service life of reinforced concrete structures.
  • Is recommended for use in all types of reinforced concrete, precast and/or prestressed concrete as well as ready mix applications.
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Usage

In the high alkalinity of concrete, reinforcing steel builds up a natural passivation layer. This layer protects the steel from corrosion. This passive ferric oxide layer however can be damaged by the presence of chlorides and combined with the presence of moisture and oxygen which will lead to corrosion of the steel.
Sika® CNI OM will help oxidize the steel to form ferric oxide, which resists chloride attack. This reduces the areas of ferrous oxide ions that are susceptible to attack by chlorides. Ferrous oxide creates a ferrous oxide complex (rust), if attacked by chlorides. In the presence of these chlorides, rust continues to generate in these areas (corrosion pits) and ultimately leads to staining, cracking and spalling of the concrete.   Sika® CNI OM fortifies the ferric oxide passivating layer prior to the penetration of chlorides. The nitrite ions in Sika® CNI OM will convert ferrous oxide to more resistant ferric oxide, thereby protecting the steel reinforcement from corroding.

Advantages

Sika® CNI OM is recommended for conventional steel reinforcement as well as prestressed or post-tensioned concrete that will be exposed to chlorides from marine environments or deicing salts. Sika® CNI OM will extend the service life of structures by effectively inhibiting corrosion, in areas such as parking garage decks and support structures, bridge decks, marine structures and many others.
Sika® CNI OM may also be used in concrete elements where chlorides are added initially to the concrete mix.
Sika® CNI OM is a corrosion-inhibiting admixture that provides protection against corrosion in reinforced concrete structures. Sika® CNI OM:
  • Extends the service life of reinforced concrete structures.
  • Is recommended for use in all types of reinforced concrete, precast and/or prestressed concrete as well as ready mix applications.

Packaging

200 L drums and 1000 L flow bins
Bulk supply in tanker trucks possible on demand

Colour

Pale yellow to greenish liquid

Product Details

Product Information

Shelf life

12 months minimum from production date if stored properly in original unopened packaging

Storage conditions

Sika® CNI OM should be stored in a dry area between 5°C and 35°C. Protect from direct sunlight

Specific gravity

~1.12 kg/l

 
Technical Information

Concreting guidance

The standard rules of good concreting practice for production and placing must be observed when using Sika® CNI OM in concrete. Refer to relevant standards.
Fresh concrete must be cured properly especially at high temperatures in order to prevent plastic and drying shrinkage. Use Sika® Antisol® products as a curing agent or apply wet hessian.

Application

Application Information

Compatibility

Sika® CNI OM can be used with Portland cements compliant with ASTM, AASHTO or CRD specifications. It can be used in combination with other
Sika admixtures including microsilica, water reducers, superplasticizers, set retarders and air entrainment agents.
Admixtures have to be added separately to the concrete mix in order to deliver the results required. Sika® CNI OM may slightly reduce the entrained air content and a higher dosage of the air entrainment agent may be required.
We recommend to perform trial mixes to establish the required performance when combining Sika® CNI OM with other products or admixtures.

Dispensing

Measure the required quantity manually or by automated dispenser. Add Sika® CNI OM directly into the freshly mixed concrete at the end of the batching cycle. When used in combination with other admixtures, care must be taken to dispense each admixture separately into the mix.
Mix water adjustment is necessary to account for the water in Sika® CNI OM and thus, maintain the required water/cementitious ratio. The batch water must be adjusted by reducing 0.850 kg of water per Liter of Sika® CNI OM.

Restrictions

When using Sika® CNI OM a mix design must be selected for the local material sources used and trial mixes performed to verify suitability.
If frozen and/or if precipitation has occurred, it may only be used after thawing slowly at room temperature and intensive mixing.
Sika® CNI OM should not be added to dry cement. Before pouring, suitability tests on the fresh concrete must be carried out. Due to the extended
workability take special care that formwork is properly installed and secured. In case the setting time of concrete is extended, if cured properly,
other properties may not be affected and higher ultimate strength is visualized.

 
Consumption

Recommended dosage

The recommended dosage rate will vary between 10 and 30 L /m3 of concrete, depending on the severity of the corrosion environment. In absence of a specified dosage rate, please contact your local Sika representative. Adjust water content accordingly. Sika® CNI OM may accelerate the setting time. In order to prevent slump loss or finishing characteristics, a set retarding admixture, like Plastiment®, may be required, especially in warm weather application. The full accelerating effect of Sika® CNI OM may be used for cold weather concreting.
Trial mixes must be performed to establish the exact dosage rate required.

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