Cooling System for aggregates

In areas with high air temperatures and strong solar radiation, special measures are required to reduce the temperature of fresh concrete. 

Until now, large quantities of concrete have typically been cooled by adding flake ice instead of water. However, in the case of high-quality concrete types, the temperature reduction achieved by adding crushed ice is limited, as otherwise the permissible water content would be exceeded. Since cooling with crushed ice cools the surface of the coarse aggregates, a significantly higher temperature remains inside the coarse aggregates.

Our system for cooling the aggregates is fully automatic and uses very little energy. Because the coarse aggregates are cooled completely, the concrete temperature immediately after production is close to that at the installation site.

Two watertight silos are installed as active storage for each of the 10/20 grain sizes. While the aggregates are cooled in one silo using 6°C cold water in flow-through mode, concrete is produced from the other two silos containing the cooled aggregates. The cold and mixing water is produced by chillers and stored in cooling water tanks.

Just as excessively high outside temperatures make it necessary to cool the aggregates in order to produce high-quality concrete, it is also necessary to heat the aggregates when outside temperatures drop too low.

To this end, we have developed a heating system, which we tested for the first time in the Fehmarn Belt Tunnel project. During concrete production in winter, the aggregates were heated, which made the concrete easier to process, achieved the desired strength and prevented any cracking.