MC Bauchemie

The need for Concrete Coating. Why we Should?

Reinforced Concrete is one of the most versatile and widely used construction material on account of its constructability and durability. It is used in a variety of exposure conditions and can be designed specifically for durability. However in harsher environmental conditions of today and due to extreme requirements of speed, economy and construction practices, it's durability is severely affected.

In almost all cases, lack of adequate cover to reinforcement is the key culprit in deterioration of concrete structures. From material science point of view, the durability of a concrete structure is a direct function of achieving specified cover in terms of dimensions as well as quality. Considering construction practicality, completion deadlines, speed and economy, it becomes virtually impossible to cast specified cover. The outermost layer of concrete therefore becomes the weakest one.

A combination of the porous nature of the concrete and a weak cover lead to diffusion of detrimental materials like water, carbon dioxide, chlorides and sulphur dioxide into concrete where they find easy access to the reinforcement.

These materials or a combination thereof, lead to loss of passivity and corrosion of the steel and ultimately deterioration of the concrete, which leads to weakening of the RCC structure as a whole.
Therefore, the primary need to safeguard concrete is a protective coating that can form a physical barrier against moisture ingress and a chemical barrier against ingress of chlorides, CO₂ and So2. Paints and other decorative coatings are designed for aesthetic purposes and normally not for protection of concrete against carbonation, chloride attack, UV radiations and crack bridging properties.

Main reasons for deterioration of Concrete:
  • Low density/Low thickness reinforcement cover
  • Porous nature/wettability of concrete
  • Water Ingress through cover
  • Diffusion of CO2, SO₂ and Chlorides into concrete

Solution:
  • Provide high cover thickness to Reinforcement
  • Protect the concrete with a coating (not paint)!

MC Bauchemie Anti Carbonation Protective Coatings used in Atal Setu

Carbonation in reinforced concrete is one of the most common forms of deterioration of structures. It is the reaction of carbon dioxide in the environment with the calcium hydroxide in the cement paste. Due to carbonation, the protective oxide layer surrounding the structure's reinforcing steel breaks down and corrosion or rusting starts. Deterioration is much faster in structures such as bridges which are associated with the ingress of water and freeze/thaw cycling. Carbon dioxide from the atmosphere reacts with the concrete in these structures, leading to a loss of alkalinity and subsequent corrosion of the reinforcing steel. Once the concrete is rusting, concrete starts to stall and falls off leaving an open passage for contaminants to easily penetrate the concrete. The structural integrity of bridges can be compromised until it is protected with an anti-carbonation protective coating.

Anti-carbonation protective coatings protect bridges against the ingress of carbon dioxide and water, whilst allowing damp substrates to breathe without blistering. They protect concrete from carbonation by acting as a carbon dioxide barrier.

MC-Bauchemie is one of the specialist manufacturers and suppliers of anti-carbonation coating products in India. In this article we have focused on a project wherein their anti-carbonation protective products were used to meet the subsequent carbonation challenges in a bridge. Atal Setu Project [which was earlier known as Mandovi Bridge], in Goa, India is the project in focus. The surface protection work of the bridge was executed by using a range of MC-Bauchemie anti-carbonation protective coating products.

Application of MC-Bauchemie Anti- Carbonation Protective Coatings used Atal Setu

Structure Requirement:
The first Cable-Stayed Bridge by L&T in India situated in Goa over Mandovi river later named Atal Setu had a requirement of 1.5 lac m2 of surface area to be protected from environmental deterioration.

Anti-carbonation coating products used in the project:
Anti-carbonation coatings were used for surface treatments that have a high resistance to carbon dioxide. The products safeguarded the bridge structure from carbonation by acting as a carbon dioxide barrier. The range of products used was Emcecolorflex, MC- Nafuquick and MC- Primex 250.

Emcecolorflex

Emcecolor-flex is an acrylic polymer modified elastic elastomeric breathable, anti-Carbonation coating product. 70 tons of the product was used for the project. The primary reason for the selection of the product is that it has crack bridging and UV-resistant protective features that shields against environmental degradation. It is also water-based and solvent-free. It provides excellent protection for concrete structures such as bridges subjected to adverse climatic conditions.

The product is waterproof and has a low water vapour diffusion coefficient. This makes the coating breathable. It also has a high resistance to diffusion of carbon dioxide and thus has good anticarbonation properties. In addition, EmceColor-flex is crack bridging, which is advantageous in case of repair and protection of cracked facades, exhibiting hairline and shrinkage cracks.

MC- Nafuquick
It is a polymer-modified filler that provides a single layer of up to 6 mm. The product is ready to use, you just need to mix it with water. It is colourfast and offers light-resistant pigmentation

MC- Primex 250
It is an acrylic primer that rapidly dries and improves adhesion. It reduces absorbency, binds dust and is solvent-free.

Many benefits were obtained by incorporating the anti-carbonation coatings for the project in a welldesigned manner. These include prevention of water ingress and chemicals and de-icing salts from penetrating the structural deck of the bridge thereby preventing the steel reinforcing bars from corroding.

Mc Bauchemie anti-carbonation products

The right selection of anti-carbonation products is pivotal for bridge structures. The anti-carbonation product lines of Mc Bauchemie offer ultra-modern surface coating solutions relating to the protection and colouring of concrete surfaces. The pure, pro and vision variants are available within each product line. The construction chemical applicators are sure to find a tailored solution to their specific requirements. All the products are water-repellent, open to vapour diffusion, carbonation-retarding and resistant to UV, soiling and weathering.

Why BPT for Painting?

Rusting Process Slows Down

Slower rusting and degradation to building structure

Saves Costs

Saves costs and better building life thus reduced maintainance.

All Weather Protection

Weather hot or cold, always shines and does its job.

Some painters transform the sun into a yellow spot. Others transform a yellow spot into the sun. Reach out to us and allow us to transform your yellow spot to a sun!

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