Temperature control for aggregates in concrete plants

At first glance, concrete production is regarded as a relatively robust industrial process. In reality, however, aggregates, water and binders are sensitive to temperature fluctuations.

In winter in particular, frozen aggregates can significantly disrupt production, whilst high summer temperatures also alter the material properties. At bauma in Munich, CureTec is therefore showcasing a system that addresses precisely this issue: an aggregate heating system for concrete plants with heating and cooling functions. The focus is on the so-called AggTherm system. The system works by blowing hot air directly into the silos where aggregates such as gravel or rock are stored. The aim is to keep the temperature of the materials constant and thereby create more stable production conditions. This area is becoming increasingly important, particularly in the concrete industry. This is because the quality of concrete depends not only on recipes or mixing ratios, but also heavily on the temperature conditions during processing.

CureTec develops AggTherm system for aggregate silos

The system presented uses hot air at temperatures of up to 120 degrees to precisely control the temperature of aggregates in silos. The technology is primarily used in concrete plants where products such as paving stones, pipes or precast elements are manufactured. The aggregates form a central component of the resulting concrete. If gravel or rock becomes too cold or individual areas freeze, the production process changes significantly. Particularly in winter, moisture within the materials can lead to ice formation. This complicates the dosing process and affects the workability of the concrete. CureTec therefore deliberately describes the system not merely as a conventional heating system, but as a flexible temperature control solution for varying weather conditions. This is because the system can not only heat the aggregates but also cool them down when outside temperatures are high. It is precisely this combined approach that is proving attractive to many concrete manufacturers. Whereas frost protection used to be the main focus, today the control of high material temperatures is increasingly coming to the fore.

Concrete production is sensitive to temperature differences

The importance of such systems is closely linked to the properties of concrete. Temperature influences the hydration of the cement, i.e. the chemical process of hardening. Even minor fluctuations can affect strength, working time or surface quality. Frozen aggregates are particularly problematic. Ice not only alters the moisture balance within the mix but can also lead to uneven material properties. In precast plants or with high-quality concrete products, this quickly leads to quality issues. In summer, however, the problem shifts in the opposite direction. Highly heated aggregates can raise the temperature of the fresh concrete and shorten the working time. This becomes increasingly critical, particularly with large production volumes or long transport routes. Key features of the system presented:

• Temperature control of aggregates in concrete plants
• Injection of air heated to up to 120 degrees
• Prevention of ice formation in winter
• Cooling function at high outside temperatures
• Use for gravel, stones and mineral aggregates

Aggregate heating is gaining importance in precast construction

The demand for consistent quality is rising, particularly in industrial concrete construction. Precast elements, paving stones and concrete pipes are now produced under highly standardised conditions. Temperature fluctuations have a significantly greater impact there than on traditional construction sites. Added to this is the economic pressure on concrete plants. Production interruptions caused by frost or quality issues result in high costs. Temperature control systems are therefore increasingly becoming part of modern plant design. The trend towards automated concrete plants is also reinforcing this development. The more production processes are digitised and standardised, the more important it becomes to have controllable conditions for materials and processing. It is interesting to note that requirements vary greatly from region to region. In cold climates, the focus remains on frost prevention. In hot regions, however, cooling concepts are becoming increasingly important for controlling the temperature of fresh concrete.

Climatic extremes are transforming the concrete industry

The presentation at bauma also highlights a broader shift within the building materials industry. Extreme weather and greater temperature fluctuations are increasingly altering production processes in the concrete sector as well. Long heatwaves, sudden frosts or damp winters are having a much greater impact on the materials logistics of many plants than in the past. At the same time, demands on quality assurance and production safety are rising. CureTec is thus positioning itself in a relatively specialised field, one that is, however, becoming increasingly relevant to the day-to-day operations of many concrete manufacturers. This is because stable material temperatures are decisive not only for processing, but often also for energy consumption, production speed and the consistent quality of industrial concrete products.