pozzolan

noun

Any material which, when combined with calcium hydroxide, exhibits cementitious properties; often used as an extender with Portland cements.

Pozzolan is a type of material used in construction.

意味（1）

Any material which, when combined with calcium hydroxide, exhibits cementitious properties; often used as an extender with Portland cements.

Both are what are called pozzolans, reactive materials that help make the concrete stronger.