To avoid rebaring in building construction, it is essential to ensure proper design, construction practices, and maintenance. Here are some measures that can help minimize the need for rebaring:
Adequate Structural Design: 
Ensure that the structural design of the building is done by qualified engineers, considering factors such as load calculations, appropriate reinforcement placement, and corrosion protection measures.

Quality Control during Construction:
Implement strict quality control measures during construction to ensure proper installation of reinforcement. This includes using experienced labor, proper placement of rebars, accurate bar bending, and maintaining the required concrete cover over the reinforcement.

Use High-Quality Materials: 
Choose high-quality reinforcement bars and other construction materials to ensure their durability and resistance to corrosion.

Concrete Mix Design: 
Optimize the concrete mix design by using suitable cementitious materials, proper water-cement ratio, and incorporating supplementary cementitious materials (such as fly ash or silica fume) to enhance durability and reduce the risk of corrosion.

Adequate Concrete Cover: 
Provide sufficient concrete cover over the reinforcement to protect it from environmental factors, such as moisture and chloride ingress.

Drawbacks and Risks of Rebaring in Construction Structures:

Rebaring in construction structures may be necessary in certain cases, but it can come with drawbacks and risks, including:

Structural Integrity: 
Rebaring involves drilling holes and inserting new reinforcement, which can weaken the existing structure if not done properly. The process may compromise the structural integrity and load-bearing capacity of the building.

Cost and Time: 
Rebaring is a labor-intensive process that requires additional time and resources. It can significantly increase construction costs and cause project delays.

Structural Compatibility: 
The new rebar should be compatible with the existing structure in terms of size, material, and design. Incompatibility can lead to stress concentrations and potential structural issues.

Corrosion Risk:
 If the rebaring process is not done correctly or if proper corrosion protection measures are not implemented, it can increase the risk of corrosion and subsequent deterioration of the reinforcement and the overall structure.

Quality Control Challenges: 
Rebaring introduces additional complexities in terms of quality control. It requires careful coordination and inspection to ensure proper installation and compatibility with the existing structure.

Chemicals for Rebaring in RCC Construction:

When it comes to corrosion protection of reinforcement, there are several chemicals and methods available. Some commonly used chemicals include:

Corrosion Inhibitors: 
These chemicals are added to the concrete mix or applied to the reinforcement surface to inhibit the corrosion process and protect the rebar from rusting.

Epoxy Coatings: 
Epoxy coatings provide a protective barrier to the reinforcement, preventing direct contact with moisture and corrosive agents.

Galvanizing: 
Galvanizing involves coating the reinforcement with a layer of zinc to protect it from corrosion.

Cathodic Protection: 
This method involves applying a direct electrical current to the reinforcement to prevent corrosion by making it the cathode in an electrochemical cell.

The selection of the most suitable chemical or corrosion protection method depends on factors such as project requirements, environmental conditions, and local regulations. It is crucial to consult with experienced engineers and corrosion specialists to determine the best approach for rebaring and corrosion protection in a specific construction project.