In concrete pavements, what can initial drying shrinkage and first cold weather cause?

• A. Cracking at regular intervals
• B. Cracking only at edges
• C. No cracking
• D. Uniform expansion

Answer: (A)

Drying shrinkage and the chill of early cold weather create restrained contraction in a concrete pavement. As the slab loses moisture and cools, it tends to contract, but being held in place by the base, joints, and adjacent concrete generates tensile stresses. Concrete has limited tensile strength, so those stresses cause cracks to form where the slab is restrained, typically at regular intervals between joints. This is why cracking at regular intervals is expected in pavements. Cracking only at edges or no cracking would ignore the interior restraint and shrinkage, and uniform expansion contradicts the effect of contraction from drying and cold.