What is the definition of thermal cracking in concrete?

Thermal cracking in concrete refers specifically to cracking that occurs as a result of temperature variations. When concrete is subjected to changes in temperature, it expands when heated and contracts when cooled. If the temperature changes are significant and occur rapidly, these movements can create internal stresses within the concrete. When these stresses exceed the tensile strength of the concrete, cracking occurs.

This phenomenon is particularly important in scenarios where large masses of concrete are exposed to direct sun or have differing temperature exposures, leading to differential expansion or contraction. Understanding thermal cracking is crucial for ensuring the durability and longevity of concrete structures, as uncontrolled thermal cracking could lead to structural issues or compromises in material integrity.

Options pertaining to moisture loss, physical impact, or chemical reactions involve different mechanisms and factors that create stress and cracks in concrete, but they do not specifically relate to the effects of temperature changes, which is the core concept of thermal cracking.