What causes thermal cracking in concrete?

Thermal cracking in concrete primarily occurs due to temperature changes, which can create significant stress within the material. As concrete sets and cures, it generates heat (hydration heat), and as the temperature drops, the concrete can contract. If the temperature differentials are substantial, this contraction can exceed the tensile strength of the concrete, leading to cracks. Rapid cooling or heating can exacerbate this issue, causing stresses that the concrete is not able to accommodate.

Understanding this phenomenon is critical for construction and engineering professionals, as they need to implement measures such as proper mixing, the use of thermal breaks, and scheduling work to mitigate the impacts of extreme temperature fluctuations.