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 outcome occurred more rapidly when pre-Columbian chinampas lacked proper maintenance?
• Which outcome results when Roman road construction exceeds maximum grade limits?
• In Alhazen's experiments with lenses, which consequence results with increased surface curvature?
• Which constraint limited pre-Columbian chinampa agriculture, if the surrounding lake's nitrogen input significantly decreased over multiple decades?
• Which risk greatly increased during Roman ballista operation near fortress walls facing counter-fire scenarios?
• Which risk increases given unsupported masonry arch construction?