Shrinkage cracks are caused by thermal expansion and contraction of the concrete.

Shrinkage cracks are caused by thermal expansion and contraction of the concrete.

• A. True
• B. False
• C. Not Applicable
• D. Both

Answer: (B)

Shrinkage cracks come from the concrete drying and losing moisture as it cures, plus the small volume change that occurs during hydration. When the concrete wants to shrink but is restrained by forms, joints, or adjacent structures, those tensile stresses exceed the concrete’s strength and cracks form. Thermal expansion and contraction, on the other hand, are changes in length or volume caused by temperature changes and are a separate phenomenon; they can cause different types of cracking (thermal cracks) when restraint exists, but they are not the direct cause of shrinkage cracking. So the statement is not correct because shrinkage cracks are driven by drying and chemical shrinkage, not by thermal effects. In practice, controlling shrinkage cracking involves proper curing, limiting evaporation, and designing joints and reinforcement to accommodate restrained shrinkage.

Shrinkage cracks come from the concrete drying and losing moisture as it cures, plus the small volume change that occurs during hydration. When the concrete wants to shrink but is restrained by forms, joints, or adjacent structures, those tensile stresses exceed the concrete’s strength and cracks form. Thermal expansion and contraction, on the other hand, are changes in length or volume caused by temperature changes and are a separate phenomenon; they can cause different types of cracking (thermal cracks) when restraint exists, but they are not the direct cause of shrinkage cracking. So the statement is not correct because shrinkage cracks are driven by drying and chemical shrinkage, not by thermal effects. In practice, controlling shrinkage cracking involves proper curing, limiting evaporation, and designing joints and reinforcement to accommodate restrained shrinkage.