Which statement best describes spalling in concrete?

• A. It is a complete fracture through the member
• B. It is a surface peeling with no depth
• C. It is caused by chemical attack
• D. It is a partial fracture with surface material breaking away under loading

Answer: (D)

Spalling is a partial fracture of the concrete surface where chunks of the outer layer break away under loading. This means the damage involves a fracture plane near the surface, with material actually separating rather than just peeling off the surface. It differs from a complete fracture that runs all the way through the member, and from superficial surface peeling (scaling) that doesn’t involve a true fracture. Spalling often results from internal stresses, such as corrosion of reinforcing steel pushing outward or from aggressive freeze–thaw cycles. So, the best description is a partial fracture with surface material breaking away under loading.