Extreme heat or cold weather can have a significant impact on the quality of freshly-poured concrete. In Tanzania, temperatures are usually hot; even in winter it rarely reaches single-digit temperatures. Therefore, it is important to time construction projects right so that temperatures are not too warm when pouring concrete.
Cooler temperatures slow the curing process down and ensure that the concrete reaches its optimal strength before drying out. The structural bonds that give concrete its strength take time, so if it dries too quickly, the concrete will become brittle and more prone to cracks.
The ideal temperature range for pouring concrete is between 10°C and 32°C – the sort of temperatures often found in Tanzania. However, during hot summers, there are ways to improve concrete quality when pouring in hot conditions, including using the right equipment and techniques to keep the concrete at a lower temperature.
Tips on pouring concrete when it’s hot
Concrete that is poured in hot weather will have a high early strength but the final quality will be substandard. With proper planning and the right tools, you can pour concrete in hot weather using the following techniques:
- Hire sufficient contractors and have enough equipment to reduce the time between the start of pouring and the completion of the curing process.
- Plan to pour the concrete early in the morning or late in the evening when temperatures are cooler.
- Put up shade cloth over the freshly-poured concrete to keep it out of direct sunlight. Place windbreaks around the construction site to reduce the effects of wind evaporation.
- Keep the concrete damp by spraying water over its surface or use a damp covering fabric such as wet burlap.
- Prolonged mixing increases the temperature of concrete so pour it as soon as it’s ready.
- Spray water on concrete forms (wooden frames) and loosen them once the concrete has just set. Pour water down the sides of the forms too.
- Use larger aggregates in the concrete as these prevent it from shrinking due to heat and water evaporation. Spray the pile of aggregates with water before adding them to the concrete mix as this will cool them down.
- Keep conveyors, wheelbarrows, chutes and concrete-carrying equipment under the shade if possible. Spray water on them to reduce their temperature.
- Spray the ground with water to keep it moist and cool before pouring in the concrete.
Construction projects are best planned for the cooler months when temperatures are lower and there is less likelihood of rain. The concrete pouring phase should ideally take place when the annual temperatures are at their lowest – often between June and August in Tanzania.
LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges.
LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo brand for over 30 years. Our head office and fully-integrated plant are located in the Mbeya Region in Southwest Tanzania.
At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.
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