FOSROC-Dec

Dear [FNAME]

Reinforcement in RCC structures is subject to corrosion, due to the ingress of elements such as chlorides, sulphates, and carbon dioxide into the concrete. Auramix BCI, by Fosroc, is a revolutionary organic bipolar corrosion inhibitor, that when added into fresh concrete, reacts with the reinforcing steel to form a protective layer. This layer prevents the build-up of rust on the surface of the reinforcement. The use of Auramix BCI can delay the onset of corrosion, prolong the time to initiation of corrosion, thereby reducing corrosion rate.

Auramix BCI, is available as a liquid additive, allowing for easy charging into the concrete, at the batching plant, or in the transit mixer on site. It is environment friendly, non toxic, and safe to use.

When reinforcement is embedded into fresh concrete, the formation of cathodes and anodes across the surface of the steel, sets off an electrochemical reaction. In concrete’s alkaline medium, this reaction results in the formation of a passive protection layer on the steel surface.

With reference to the Pourbaix diagram as above, a reduction of concrete pH, pivots the reinforcing steel from a zone of passivity to a zone of corrosivity. Thus, the passive protective film is destroyed, and corrosion occurs.

Over the course of time, concrete structures may develop cracks from drying shrinkage, overloading, creep, soil or subbase settlement and other environmental factors. These cracks allow the ingress of aggressive chemicals like chlorides, sulphates and carbon dioxide, that reduce the pH of the concrete.

Its unique formulation of blended amines gives Auramix BCI a high affinity to the reinforcing steel. It has the ability to react in both the liquid & vapour phases. The reaction results into formation of precipitates on the surface of the embedded reinforcement, that increase the corrosion potential at the cathodes and anodes. This delays the onset of rust formation.

Auramix BCI has the following key features and benefits:

• Eco friendly, Free from nitrates or nitrites.

• Does not get consumed by cement hydration, rather reacts with the embedded reinforcement.

• No adverse effects on fresh properties of treated concrete.

• Ensure corrosion protection, irrespective of the grade of concrete.

• Compatible with other PCE or SNF based water reducers for concrete.

• Compatible with various types of cement and supplementary cementitious material.

• Extensively tested as per international standards.

Auramix BCI is suitable for the below applications:

Auramix BCI has been tested for various short term and long term tests, as per international testing standards, to evaluate its corrosion inhibiting efficiency. Test reports are available as per the below test criteria.

1. Modified corrosion testing – JIS Z 1535

This is a short-term qualitative testing method which evaluates the vaporisation efficiency and the affinity of the corrosion inhibitor towards the reinforcing steel.

2. Rebar weight loss via Immersion Test – ASTM G1

This is a short-term quantitative testing method which evaluates the reactivity of the corrosion inhibitor with the reinforcing steel, and reduction in the corrosion rate of treated steel.

3. Effect on embedded reinforcing steel – ASTM G109

This is a long-term quantitative testing method which evaluates the effect of corrosion inhibiting efficiency of steel embedded into treated concrete.