When using Roman concrete in seawater, which effect occurs due to its pozzolanic hydraulic reaction?

💡 Explanation

Exposure to seawater causes tobermorite crystals to fill microcracks within Roman concrete via mineral precipitation because the pozzolanic ash reacts with seawater. This densification, not sulfate attack or expansive hydration, therefore makes Roman concrete more durable rather than weaker, as would plain cement.

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