1. a volcanic ash or similar siliceous material that reacts with lime to form cement
Usage: technical; construction

Examples

• The ancient Romans used pozzolana from Mount Vesuvius to create durable concrete.
• Modern builders sometimes add pozzolana to cement mixtures for increased strength.
• The volcanic pozzolana gave the concrete its characteristic reddish color.
• Engineers tested the pozzolana’s reactivity with lime before using it in construction.
• Natural pozzolana deposits are found near many active volcanoes.
• The addition of pozzolana makes concrete more resistant to chemical attack.