By providing adequate moisture, optimal temperatures, and the right amount of time for the material to set, it becomes stronger, and more resistant to freezing, thaw, abrasion, scaling etc.

Temperature plays major role in strengthening concrete. It directly affects the rate of hydration, and as a result, its durability. Strength development occurs more quickly at higher temperatures that it does at lower temperatures. Ideally concrete should be cured between 60 - 80 degrees F.

The amount of time taken for proper curing depends on:

• The specific strength required
• The mixture proportions
• The ambient weather and other exposure conditions
• The properties, including size and shape, of the concrete member

Maintaining the curing period for as long as possible should be the goal of all projects.

During this process, if concrete is exposed to the environment, then factors like humidity and wind conditions should also be considered. These contribute to the rate at which moisture is lost from the concrete, thus leading to cracks, poor surface quality, and reduced durability.

The curing process is carried out right after placing and finishing. It is comprised of;

This function is relevant during the early stages of concrete hardening and includes:

These techniques are used when the ambient temperature is significantly higher than the freezing levels, with low humidity in the air.

Fogging helps to minimize plastic shrinkage and cracking while the concrete undergoes the final setting phase.

This is generally used to cure flat slabs of concrete, like footpaths and pavements, on a smaller scale. The curing water temperature should be kept at least 20° lower than the concrete’s own temperature, in order to prevent thermal stresses from occurring.

Once the concrete has sufficiently hardened, a wet covering saturated with water is used to avoid potential damage to its surface.

To prevent the loss of mixing water from the surface of the concrete, the following steps are generally recommended;

These curing compounds, if applied after the final finishing process, effectively reduce the evaporation of mixing water from concrete. They come in two types; translucent, or white pigmented. The latter is often recommended for hot, sunny weather conditions to reflect incoming solar radiation.

By covering wet concrete with impervious paper or plastic sheets, evaporation can be reduced. However, care should be taken to ensure that the surface is hard – to prevent damage while placing these materials.

One of the main goals of curing concrete in cold weather is to accelerate strength gain by supplying enough heat, and moisture. Examples of methods to do that include:

These are embedded near the surface of the concrete elements to protect it from freezing during cold weather.

Steam curing can be done by either applying highly pressurized steam in autoclaves, or by using live steam at atmospheric pressure.

Insulation blankets can be used to cover the concrete surfaces that are subjected to harsh weather conditions during the curing process.

When curing in extreme weather conditions, it’s a good idea to take some extra care.

For cold weather, some techniques require heated enclosures, special curing compounds, and evaporation reducers. The curing period will also be longer due to a reduced rate of strength gain.

In hot weather, curing and protecting the concrete becomes even more important due to rapid moisture loss. For this, sun/windscreens, fogging, and evaporation retardants are used commonly. The curing period is also reduced, since strength gain is a lot faster due to the heat.