Natural pozzolans are used with portland cement for economy and beneficial modification of certain properties of fresh and hardened portland cement concrete. Use of Raw or Processed Natural Pozzolans in Concrete (ACI 232.1R-00) provides a review of the current use of raw or processed natural pozzolans in concrete and an overview of the properties of natural pozzolans and their proper use in the production of hydraulic-cement concrete. This report also provides information and recommendations for the selection and use of natural pozzolans generally conforming to the applicable requirements of ASTM C 618 and CSA A23.5. Topicscovered in the report include:

Effect of natural pozzolans on concrete properties;

Discussion of quality control and quality assurance; and

Guidance regarding handling and use of natural pozzolans in specific applications.