Which risk increases when water freezes inside a Roman aqueduct's conduit?

💡 Explanation

The risk of keystone failure increases because water expands upon freezing, exerting outward pressure in a process known as cryofracture. This stress weakens the arch's structural integrity, therefore threatening the keystone's position, rather than sedimentation or cement dissolution.

• Which long-term degradation becomes prominent when water interacts with pietra dura inlay within unsealed Mughal-era structures?
• Which positional error arises when a sextant's mirrors misalign slightly?
• Which risk increased for medieval stone fortifications lacking rounded bastions?
• Which consequence results when a medieval alchemist's lens introduces chromatic aberration into observations?
• Which consequence resulted from deploying concentrated ballista fire against medieval castle walls?
• Which effect led early Chinese crossbow triggers to fail under high tension?