ABSTRACT
The vertical, single shaft kilns were used for burning limestone to produce quicklime 2000 years ago. Romans used such vertical kilns to burn pozzolanic lime. The term pozzolan applies to the incoherent pyroclastic-sialitic rocks occurring in the neighborhood of PozzouliItaly, and it has subsequently been extended to include a wide range of both natural and inorganic materials differing in nature, composition, and structure.
