The ambient temperature changes the properties of the concrete because it interferes with the hydration of the cement. Depending on the weather, the mixture may have a faster or slower hardening, which should be analyzed by the concrete. If the concrete hardens before arriving at the work, it can be refused by the builder, who not only buys the volume of concrete, but also properties, such as strength and degree of rebate.

In Brazilian works, fissures and pathologies caused by environmental issues are usually motivated by high temperatures and low humidity in the air. But there are multiple strategies to work around this. One of them is the reduction of the temperature at the launch, with the use of the concrete cooled with ice.

This solution is much used in the concreting of large volumes, as in dams and foundations blocks. To reduce water consumption, concrete cooling at the time of launch can also be done with the application of nitrogen.

Simpler, another effective practice is the cooling of the gravel to be used in the trace. Sometimes the simple act of wetting the gravel with water is sufficient to lower the surface temperature and minimize heat problems.

To help control the hydration of the concrete, the concreting plane can also predict the previous cooling of the forms and reinforcement and change the time of concreting. The schedule can be made so that the launch happens sooner or at dusk, at times when the sun is warmer.

To help builders to control the harmful effects of heat on concrete in the fresh state:

1- The application must be made immediately after the arrival of the concrete in the work

The vibrators must be available in a quantity adequate to the size of the concrete

2 - concrete mixer trucks and concrete pumps should not be exposed to the sun

3 - the concreting of beams and slabs should be done in reduced fronts

4 - Low air humidity and high wind speed are also adverse conditions that need to be circumvented at the risk of generating pathologies such as retraction cracks. The addition of fibers to the trace is one of the measures that help to avoid problems.

The healing, in turn, should be accompanied by actions such as the continuous use of water to prevent evaporation very fast. The greater the care of concrete curing, the better its mechanical performance and strength tends to be, and the less likely it is that plastic cracking will occur.

Aggregates decompose or transform another crystalline/amorphous form and extremely expand at certain temperatures according to their mineralogical characteristics. Moreover, the elevated temperatures impair hydrated cement phases (CH and CSH) in cocrete. As a results, concrete is broken. 

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