In the first article of this series, we discussed the challenges faced by structures in coastal areas, particularly the limitations of cementitious materials in resisting harsh environmental conditions. One of the major threats to these structures is chloride attack, which was addressed in the previous article. Another significant factor affecting the stability and durability of coastal structures is humidity.
Impact of Humidity on Coastal Structures
Humidity in coastal regions causes gradual material decay in structures. It affects concrete structures in distinct ways, gradually compromising their strength and durability.
One of the primary concerns is that humidity acts as an efficient carrier of contaminants. Coastal atmospheres contain high levels of salinity in the form of chlorides and other corrosive salts. When exposed to high humidity, these salts can easily enter the concrete matrix, accelerating deterioration.
Prolonged exposure to humid conditions accelerates chemical reactions between corrosive salts and cement components. These reactions often lead to the leaching of essential compounds responsible for concrete’s binding properties. Over time, this process weakens the structural integrity of the concrete.
Impact on Reinforcement Steel
Among the most concerning effects of coastal humidity is its interaction with reinforcement steel. Since moisture can penetrate the concrete core, it reaches the embedded steel reinforcement. Under favorable conditions for corrosion, the steel begins to deteriorate. Once initiated, the corrosion process continues unless systematic preventive measures are implemented. This corrosion not only reduces the cross-sectional area of the reinforcement but also leads to expansion, which causes cracking and spalling of the concrete cover, further exposing the reinforcement to damage.
Preventive Measures
To mitigate the effects of humidity and prevent corrosion in coastal structures, several protective measures can be adopted:
- Adopting Standard Construction Practices
- Ensuring high-density concrete with minimal porosity is essential for reducing moisture ingress. Proper compaction, curing, and material selection contribute to improved durability.
- Ensuring high-density concrete with minimal porosity is essential for reducing moisture ingress. Proper compaction, curing, and material selection contribute to improved durability.
- Corrosion Prevention in Existing Structures
- In structures where corrosion has already been detected, the deteriorated cover concrete should be removed. Sacrificial galvanic anodes can be placed at strategic locations to slow down the corrosion process and extend the life of the structure.
- In structures where corrosion has already been detected, the deteriorated cover concrete should be removed. Sacrificial galvanic anodes can be placed at strategic locations to slow down the corrosion process and extend the life of the structure.
- Use of Corrosion Inhibitors
- Blending corrosion inhibitors with repair materials or new concrete mixtures can help reduce the rate of reinforcement corrosion by forming a protective layer around the steel.
Conclusion
Humidity plays a significant role in accelerating deterioration in coastal structures, mainly by enabling the penetration of corrosive salts and affecting reinforcement steel. Without proper intervention, these issues can compromise the longevity and safety of buildings. By implementing advanced construction techniques, corrosion prevention strategies, and protective materials, the durability of coastal structures can be significantly enhanced. A proactive approach to maintenance and repair ensures that these structures remain safe and functional for an extended period.
About the author;
Er. Chirag K. Baxi is the Director of Prudent Forensic Consultancy Private Limited and General Manager of K K Retroflex Solutions. He specializes in Corrosion Control Measures for concrete and steel surfaces, Damage assessment with the FORENSIC ENGINEERING approach and Structural rehabilitation of concrete and steel structures in the Industrial environment. He holds a degree in BE (Civil Engineering) and has completed MBA (Construction Management).
The author has invented CONCARE B 14 (which has been granted a patent) that makes concrete structures sustainable even with salty, saline, untreated or even seawater without deterioration in any of the end properties of constructed elements. He has written (two) drafts of IS Codes on the topic of “Carbon brick lining” and “PolyPropylene Glass lining” which are under the final stage of approval at BIS.
About 40 Technical papers on National and International platforms are authored, published and presented by the author. He has been recognized by several Institutes for his significant contribution to the Civil Engineering Industry.
