Which mechanism primarily allowed Roman concrete structures to withstand centuries of weathering compared to earlier mortars?

💡 Explanation

When volcanic ash is mixed into Roman concrete, a pozzolanic reaction occurs because the ash reacts with lime and water to form calcium-silicate-hydrate, creating a dense and durable cementitious matrix. Therefore, increased durability results, rather than increased strength (iron), protection (polymer), or faster curing (steam) which rely on different chemical processes.

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