The longterm effect on concrete in hot weather | Converge.io

April 19, 2023

Concrete is a versatile and widely used construction material known for its strength and durability. However, the long-term performance of concrete can be significantly impacted by the climate in which it is placed, particularly in hot climates. This article will discuss the long-term effects that a hot climate can have on concrete and strategies to prolong the lifespan of concrete in hot climates.

Read more: Read up on under water concreting and long term effects of cold weather on concrete.

The 4 main long-term effects of hot climate on concrete

Hot climates present several challenges for concrete, including increased rates of evaporation, higher curing temperatures, and potential for cracking. Some of the long-term effects of hot climate on concrete include:

1. Reduction in strength

The effect of temperature on concrete strength can be significant in hot climates. High temperatures during the curing process can cause concrete to cure too quickly, resulting in reduced strength and durability. This can lead to increased risk of cracking and other structural issues over time.

2. Increased risk of cracking

In hot weather concrete is more susceptible to cracking due to the rapid evaporation of moisture from the surface. As the concrete dries too quickly, it can shrink and develop internal stresses, leading to cracks. Cracks in the concrete can compromise its structural integrity and may require costly repairs.

3. Increased permeability

High temperatures can increase the permeability of concrete, allowing water and other substances to penetrate its surface more easily. This can lead to issues such as corrosion of reinforcing steel and deterioration of the concrete over time.

4. Accelerated aging

Hot climate can accelerate the aging process of concrete, leading to a shorter service life. This is particularly true for concrete exposed to direct sunlight, as UV radiation can break down the chemical bonds in the cement paste, resulting in a weaker material.

Read more: We explain what happens to concrete when it freezes and how you can protect concrete from rain and frost.

Cracked concrete

How to prolong the lifespan of concrete in hot climates

Prolonging the lifespan of concrete in hot climates requires careful planning, appropriate mix design, and adequate maintenance. By considering the challenges posed by high temperatures, such as thermal expansion and contraction, drying shrinkage, and the alkali-aggregate reaction, it is possible to enhance the durability and performance of concrete structures. Here are some key strategies for extending the lifespan of concrete in hot climates:

Mix Design

Selecting the right concrete mix is essential for ensuring the long-term durability of concrete in hot weather. Consider the following when designing the mix:

  1. Use aggregates with a low coefficient of thermal expansion to minimize the effects of temperature changes on the concrete.
  2. Incorporate supplementary cementitious materials, such as fly ash or slag, to reduce the alkali content in the concrete and help mitigate the alkali-aggregate reaction.
  3. Adjust the water-to-cement ratio to minimize drying shrinkage potential. Lower ratios can help reduce shrinkage, but be cautious not to compromise workability.

Curing Techniques

Proper curing is crucial for ensuring the strength and durability of concrete in hot climates. Implement these practices during the curing process:

  1. Maintain adequate moisture levels by using fogging systems, evaporation retarders, or curing compounds to prevent excessive drying and cracking.
  2. Schedule the concrete pour during cooler hours of the day, such as early morning or late evening, to avoid rapid curing due to high temperatures.
  3. Monitor the concrete's temperature and moisture levels during curing and make adjustments as needed to ensure optimal conditions.

Construction Practices

Implementing appropriate construction practices can further prolong the lifespan of concrete in hot climates:

  1. Install expansion joints at strategic locations to accommodate the movement caused by thermal expansion and contraction.
  2. Ensure proper concrete cover over reinforcing steel to provide adequate protection against corrosion.

Maintenance

Regular inspection and maintenance are essential for preserving the structural integrity of concrete structures in hot climates:

  1. Routinely inspect the concrete for signs of damage or deterioration, such as cracks, spalling, or corrosion.
  2. Address any identified issues promptly by sealing cracks, repairing damaged areas, or applying protective coatings as needed.

Read more: Learn more about the ideal weather for concreting. Is it concreting in rainy weather, freezing conditions or with high humidity?

Frequently asked questions

How does concrete respond to heat?

Concrete responds to heat by speeding up the curing process and gaining strength quickly. However, concrete setting quickly also means that it will not be able to reach its full strength because it sets too quickly.

How much does concrete expand in heat?

Concrete expands when it gets hot, and the amount it expands depends on the materials used and how much the temperature changes. Generally, concrete expands between 8 to 12 millionths of an inch for each inch of its size, for every degree Fahrenheit increase in temperature.

How do you protect concrete from high heat?

There are many ways to protect freshly poured concrete from high heat. One can for example use cool water for the concrete mixture or use shades to protect the worksite from sunlight. Learn more about concreting in hot weather in our article. 

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