Influence of Temperature on Properties of Concrete

Influence of Temperature on Properties of Concrete

Key Points & Concepts

1. Introduction:

   • Temperature significantly affects both the fresh and hardened properties of concrete.
   • Understanding these effects is crucial for construction practices and ensuring the durability and strength of concrete structures.

2. Effects on Fresh Concrete:

   • Workability: High temperatures reduce the workability, making the mix stiffer and more challenging to handle.
   • Setting Time: Elevated temperatures accelerate the setting process, reducing the time available for mixing, transporting, and placing the concrete.
   • Bleeding & Segregation: Minimal at high temperatures, but can lead to weaknesses in the structure.

3. Effects on Hardened Concrete:

   • Strength Development: Initial strength gain is faster at high temperatures, but long-term strength can be adversely affected.
   • Durability: High temperatures can increase the likelihood of thermal cracking and reduce durability.
   • Shrinkage and Creep: High temperatures can lead to increased shrinkage and creep, impacting structural integrity over time.

4. Mitigation Strategies:

   • Use of admixtures to control the set time and improve workability.
   • Precooling of concrete components or mixing water.
   • Shading and windbreaks to reduce exposure to heat.
   • Curing practices that maintain adequate moisture and temperature control.

5. Practical Considerations:

   • Adjustments in mix design may be necessary to counteract the high-temperature effects.
   • Enhanced quality control and monitoring during the concrete mixing, placing, and curing processes.

Summary

Understanding the impact of temperature on both fresh and hardened concrete properties is essential for ensuring the strength, durability, and overall performance of concrete structures. Employing appropriate strategies to mitigate adverse effects can help in achieving the desired results in high-temperature conditions.