Smart Solutions for Hot Weather Concreting


The construction industry is active and busy during the summer months due to the drier and longer days. However, there are unique challenges during dry weather like slump loss, excessive surface moisture evaporation, and rapid set times. The wind will also be a significant factor since it can accelerate the evaporation process.

These factors can cause excessive shrinkage that may result in cracking and other issues, including finishing difficulties. This can lead to various defects in concrete structures, so it is essential that you plan your concreting project before you give the go signal.

Here are some challenges and their solutions:

  • Slump loss

This phenomenon is related to the rapid reduction of free water in concrete, mainly due to evaporation. In fact, when there’s high ambient temperature, high wind speed, and low humidity, you can be sure that these conditions will accelerate the rate of slump loss.

The common solution is retempering or remixing the concrete by using water. However, this method may reduce the strength of concrete since there is an increase in the cementer/water ratio. The more appropriate solution is cooling the mix because this will lower the concrete’s temperature and minimise the slump loss issue. You can also use an admixture to control the set time.

  • Cracking and plastic shrinkage

Wind, high temperature, and low humidity can increase the speed of evaporation, especially on surface moisture. This condition can lead to plastic shrinkage and cracking. You can avoid this by keeping the concrete temperature low, erect sunshades, and using fog spray to keep humidity high and air temperature low.

It’s also possible to use an evaporation retarder, adding appropriate fibre, or setting concrete early in the morning or later afternoon can help in reducing cracks and shrinkage.

  • Accelerated set times

Hot weather may impact the setting time of concrete, leading to concrete drying too quickly. This condition will make finishing more difficult and increase the chances of cracking, especially on your concrete structure.

You can prevent this by using an admixture, a known solution for normalising the set time of concrete. It can also enhance the concrete performance and allow you to better balance the set time.

Concrete management during the summer season

If you are planning to build a patio or driveway during the summer months, you may want to consider some of these tips to protect your concrete:

  • Do not be tempted to order or place a considerable amount of ready-mixed concrete in your area that you can finish and cover.
  • Make sure you have the right equipment and labour to effectively and quickly place concrete. Delays in putting concrete may lead to higher concrete temperate, which will often cause slump loss.
  • Equipment, mixers, pump lines, and chutes must always be covered with wet burlap to reduce solar heat.
  • It is a must to install windbreaks during windy days.
  • You can also use refrigerated water, liquid nitrogen, or ice to cool the mix during batching.
  • To prevent premature water loss, you should wet down substrates before pouring concrete.
  • Always spray cool water to aggregate piles to keep them damp and cool.

Most importantly, get in touch with a professional concreting company like Bendigo Concreting because they can help you plan your project from start to finish. They also have a team of highly skilled and experienced concreters that know how to handle projects during the summer months.

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