Major Pozzolan Changes to Know About
Recently, the ASTM C09.24 Subcommittee on Supplementary Cementitious Materials published C1945-24e1, Standard Specification for Raw or Calcined Natural Pozzolan for Use in Concrete. This document sets the stage for splitting these pozzolanic materials away from Coal Ash products as described in ASTM C618. Initially, the C1945 requirements for pozzolans will match what’s in C618 Class N. The C618 standard will continue to include Class N materials for a time but will be dropped in the future. Additionally, changes for pozzolan requirements will be made in forthcoming editions of the C1945 standard – stay tuned for more information as this new standard evolves and be sure to include it in your specifications going forward – these materials are an important part of concrete’s sustainable & resilient future.