Why is heat of hydration significant in concrete construction?

• A. It can lead to temperature gradients within the concrete, potentially causing cracking and affecting strength development
• B. It accelerates color development
• C. It prevents shrinkage
• D. It eliminates need for curing

Answer: (A)

Heat released during cement hydration raises the temperature inside concrete. In large pours, this can create temperature gradients between the hot interior and cooler surface, causing differential expansion and contraction during curing. Those mismatched movements generate tensile stresses that can crack the concrete and affect how quickly and uniformly it gains strength. Managing this heat is essential to minimize cracking and ensure consistent strength development.

Other statements miss the main issue: hydration heat doesn’t primarily drive color development, curing remains necessary even with heat, and it can actually contribute to drying shrinkage rather than prevent it.