What does spalling refer to?

Spalling refers specifically to the chipping or pitting of concrete or masonry surfaces. This phenomenon occurs when moisture penetrates the surface of these materials, often exacerbated by freeze-thaw cycles, heat, or chemical reactions. When the moisture expands as it freezes, it exerts pressure on the surface, causing small pieces to break away or chip off. This can significantly affect the integrity and aesthetics of structures made from concrete or masonry, making it crucial for fire investigation technicians to recognize and understand spalling as it may indicate underlying issues related to fire damage or structural integrity.