In India, aging buildings and seismic threats pose serious safety risks. Structural cracks and spalling are more common in urban zones where older buildings meet rising loads. Many people assume demolishing is the only solution, but that’s not true.
Instead, preventive measures like column strengthening can extend the structure’s life by decades. One effective method that professionals now recommend is Micro‑Concrete Jacketing. It ensures structural integrity without disturbing the functionality of the property.
What Is Micro‑Concrete Jacketing?
As a structural strengthening technique, micro-concrete jacketing involves enclosing weak or damaged columns with high-flow, non-shrink micro-concrete. This process restores durability and increases the load-bearing capacity.
Micro-concrete does not require compaction, in contrast to conventional concrete. It generates a dense layer that adheres to the existing structure and flows smoothly into small places. Because of this, it’s perfect for updating or modifying older structures without tearing them down.
It is the best option for Indian conditions due to its strength, simplicity of use, and compatibility with steel reinforcement.
When Should You Use This Method?
Effective and durable structural repairs are essential in India’s earthquake zones and humid environment. Usually, micro-concrete jacketing is utilized when:
- The concrete has deteriorated, fractured, or spalled.
- Seismic retrofitting is required for structures.
- Columns must support more weight.
- The building has been undermined by fire or weather damage.
- In older buildings, preventive maintenance is necessary
This approach is both rehabilitative and preventive. When safety is a top priority, it’s particularly helpful in residential buildings, hospitals, schools, and industrial facilities.
Tools and Materials Required
Make sure you have all the tools and supplies you’ll need before you start. This is a brief list:
- Micro-concrete mix (either on-site designed or pre-packed)
- Stirrups and reinforcement bars made of steel
- Formwork (metal or wood)
- Agent for bonding
- An anti-corrosive coating and rust remover
- Water supply and curing equipment
- Safety gear (helmet, mask, gloves, PPE kit)
The strength of the jacket is directly impacted by the caliber of each component. Use only materials that have been tested and are IS-compliant.
Step 1: Structural Assessment and Planning
Do a structural audit first. After assessing the extent of the damage, engineers decide whether Micro-Concrete Jacketing is the best course of action. In this stage, the dimensions of the jacketing, load calculations, and reinforcing detailing are completed.
This stage consists of:
- Visual examination and core cutting
- Carbonation depth investigation and steel corrosion testing
- Designating the area for jacketing and destruction
- Selecting the environmentally friendly micro-concrete mix
Don’t omit this step. A thorough evaluation guarantees that the technique satisfies safety and structural requirements.
Step 2: Surface Preparation and Demolition
After determining which section has to be jacketed, use chipping tools to remove any loose concrete. Fully expose the primary reinforcement bars. All loose objects that could impede bonding should be removed.
Steps include:
Removing the previous concrete cover with a chip (usually 20-30 mm)
Using a wire brush to remove rust from rebar
Using protective primer and rust remover
Using water or air jets, clean every surface.
Here, the objective is to create a solid, clean surface that will give the new jacket a tight hold.
Step 3: Fixing Reinforcement Bars and Formwork
Add more steel reinforcements now. These consist of stirrups and vertical rebars positioned at precise intervals. If additional grip is required, anchoring dowels may be added.
After that, surround the column with formwork. To prevent the micro-concrete slurry from leaking, it needs to be waterproof.
Ensure:
Rebars are positioned and properly tied according to the designs.
Concrete cover is maintained with clear cover blocks.
Formwork features appropriate bracing and tight joints.
This phase determines the final jacket’s form and efficacy. Make sure stability is maintained and take accurate measurements.
Step 4: Applying the Bonding Agent
Apply a bonding agent to the old column surface prior to pouring the micro-concrete. This guarantees that the new and old concrete layers will adhere perfectly.
Use a roller or brush to ensure even application. Let the agent get sticky before moving forward. Avoid pouring micro-concrete on a dry or untreated surface as this will result in weak spots and poor bonding.
For the newly reinforced column to behave monolithically, this step is essential.
Step 5: Pouring Micro-Concrete
Now that the bonding agent has been applied and the formwork has been fixed, the micro-concrete can be poured. It should be combined in accordance with structural requirements or manufacturer instructions.
Follow this approach:
Using a mechanical stirrer, combine the micro-concrete and clean water.
Keep the water-to-cement ratio at the suggested level.
Pour via a chute or funnel to prevent segregation.
Despite the fact that micro-concrete self-compacts, only use vibrators when instructed
Ensure that the pour is constant. Do the pour all at once to avoid chilly joints.
This is the primary step where the column gains its strength and shape from the Micro-Concrete Jacketing.
Step 6: Curing and Finishing
After pouring, give the micro-concrete a full day to set without being disturbed. Curing should start after the initial setting to prevent shrinkage and cracking.
For best results:
For seven to fourteen days, keep the surface wet.
Use plastic sheets or hessian cloth to cover the area.
Steer clear of intense sunlight or precipitation when curing.
The jacket will reach its maximum strength and form a strong link with the original column if it is properly cured. This has an immediate effect on how long the repair will last.
Step 7: Final Inspection and Quality Control
Carefully remove the formwork after it has dried. Check thoroughly for voids, honeycombing, and surface flaws.
Checklist includes:
Verification of dimensions and alignment
Rebound hammer and visual tests
Core sample (if necessary)
Records of the structural improvement
The last phase in the Micro-Concrete Jacketing process is quality control. It guarantees structural safety and long-term performance.
Advantages of Using This Method
Selecting Micro-Concrete Jacketing has various benefits, especially for Indian project managers and property owners:
- Very little disruption to building inhabitants
- Compaction is not required during application.
- Strong and impervious to chemical attacks
- Cost-effectiveness and quicker repair schedules
- Ideal for confined or crowded areas
- Long-term improvement in both structure and appearance
It’s a preventative measure that lowers the need for future repairs while safeguarding your investment.
Where Is It Most Commonly Used?
This approach is widely used in many different areas in India. Typical usage cases include of:
- Apartments with multiple stories
- Government buildings that have aged
- Metro infrastructure and train stops
- Flyovers and bridges
- Facilities for business and industry
Growing structural issues and the requirement for regulatory compliance are driving up demand for Micro-Concrete Jacketing in urban areas like Bengaluru, Delhi, Pune, and Mumbai.
Micro-concrete jacketing is a preventive investment as well as a repair option. Property owners in Indian cities need to take proactive measures to reinforce their properties as the infrastructure matures.
This approach provides stability, strength, and speed without destroying anything. Early action through jacketing assures long-term safety, regardless of whether you’re a government agency, commercial property manager, or housing society.
When done properly, it improves the building’s durability for many years to come in addition to repairing damaged columns
