Which of the following environmental factors negatively affects the durability of concrete?

Explanation:

High temperature and humidity variations:

1. Concrete durability is negatively impacted by significant fluctuations in temperature and humidity.

2. These variations can cause thermal expansion and contraction, leading to cracks and weakening of the concrete.

3. Additionally, moisture changes can lead to cycles of wetting and drying, which can result in deterioration due to processes like freeze-thaw damage.

 Additional Information Durability of Concrete

1. Resistance to Weathering:

   • Concrete must resist weathering effects like rain, wind, and temperature changes, which can cause surface wear and deterioration over time.

2. Corrosion Resistance:

   • Reinforced concrete must resist corrosion of steel reinforcement. This is influenced by the quality of concrete, proper mix proportions, and adequate cover over the reinforcement.

3. Water Resistance:

   • Concrete should have low permeability to prevent water penetration, which can cause freezing and thawing damage, or allow harmful chemicals (like chlorides or sulfates) to attack the concrete.

4. Abrasion Resistance:

   • Concrete exposed to high wear, such as in pavements or industrial floors, should be resistant to abrasion to maintain surface integrity.

5. Shrinkage and Cracking:

   • Proper curing and adequate mix design prevent shrinkage and cracking, ensuring the long-term durability of concrete structures.

6. Exposure Conditions:

   • Concrete must be designed based on the exposure conditions (e.g., exposure to chemicals, freeze-thaw conditions, or seawater), ensuring the mixture is adapted to withstand the specific environmental conditions.

7. Temperature Fluctuations:

   • Concrete exposed to large temperature variations can experience expansion and contraction, which might lead to cracking if not properly designed or cured.

8. Cement Quality:

   • The type and quality of cement used in the mix affect the durability. Higher-grade cements are better suited for environments with harsh conditions.

9. Proper Curing:

   • Curing ensures that concrete gains sufficient strength and durability by maintaining proper moisture levels during the early stages of setting.

10. Chemical Attack Resistance:

    • Concrete must resist the effects of chemical attacks like those from acidic soils, sea water, or industrial effluents that can cause degradation.

11. Design and Maintenance:

    • Proper design, including reinforcement details and quality control during construction, ensures long-lasting concrete durability. Regular inspection and maintenance also enhance the service life of concrete structures.