Heat-resistant concrete Refractory concrete Maximum heat resistance temperature

Heat-resistant concrete, also known as refractory concrete, is a special type of concrete that can withstand high temperatures (above 200°C) for extended periods while maintaining the required physical properties under high-temperature conditions. It is commonly used in thermal equipment and structures subjected to high temperatures, such as the foundation engineering of blast furnaces, converters, coke ovens in the metallurgical industry, and the inner linings of chimneys.

◆ Its refractoriness is similar to that of refractory bricks made from the same materials. However, since refractory concrete (castable) is not sintered, it experiences significant shrinkage during initial heating, resulting in a slightly lower load softening point compared to refractory bricks. Despite this, overall, its performance is superior to that of refractory bricks.

◆ Refractory concrete outperforms low-temperature binder materials, exhibiting higher compressive strength at room temperature. Additionally, due to the excellent integrity of the masonry, the furnace has better air tightness, is less prone to deformation, and may eliminate the need for an outer steel shell. The furnace's resistance to mechanical vibration and impact is also superior to brick masonry. For example, when used in the upper sidewalls of soaking pits, where mechanical wear and collision are severe, its lifespan is several times longer than that of brick masonry.

◆ It has good thermal stability, with most or all of the aggregate being clinker. The expansion of the aggregate offsets the shrinkage of the binder, resulting in relatively lower thermal expansion of the masonry compared to bricks, as well as reduced thermal stress. Moreover, the structure contains various network, needle, and chain-like crystalline phases, enhancing its resistance to low-temperature stress. For instance, when used for casting the furnace mouth and lid of a soaking pit, its lifespan can be extended to one and a half years.

◆ The production process is simple, eliminating the complex brick-making procedures. It can be manufactured into various prefabricated blocks and allows for mechanized construction, significantly accelerating furnace construction speed and improving efficiency by more than ten times compared to bricklaying. Additionally, waste bricks and other materials can be repurposed as aggregates, turning waste into a valuable resource.