TIL ancient Romans recycled broken pottery into concrete

I was reading a report from a dig outside Ostia and found out they mixed crushed amphora shards into mortar for harbor walls. The pieces actually made the concrete stronger against salt water, not weaker. Apparently this was common practice for centuries, but we only confirmed it through chemical analysis in the last decade. I always thought broken pots were just trash, but they were basically the original aggregate. It made me wonder how many other everyday things we assume were throwaway actually had a second life back then. Has anyone else run across examples of ancient recycling that surprised them?

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felix3857d ago

Guess pottery shards beat plastic pellets for longevity.