Rationale

Concrete building brick manufactured to meet C55 are machine-made using dry-cast concrete in a similar manner to other dry-cast manufactured concrete products including C90 (Loadbearing CMU), C129 (Nonloadbearing CMU), C139 (Catch Basins and Manholes), C1372 (SRW Units), C1623 (Masonry Lintels), C1634 (Facing Brick and other Facing Units), C1877 (Adhered CMU) and C1884 (Ballast Units). Until recently, only C1372, Specification for Dry-Cast Segmental Retaining Wall Units, referred to ‘Dry Cast’ in the title of the specification. In December 2024, ‘Dry-Cast’ was added to the title of C90-24a, Specification for Dry-Cast Loadbearing Concrete Masonry Units. In addition to adding ‘dry-cast’ to the title, an updated definition of ‘dry-cast’ was added to C90 and C1372 and ‘dry-cast’ was added to the keywords. To maintain consistency, this ballot item is proposing to add ‘Dry-Cast’ to the title of C55 as well as add a definition of ‘dry-cast’ and include it in the keywords. Similar ballot items will be drafted for the other related standards listed above. While it may not be strictly necessary to add the definition of ‘dry-cast’ to each of these standards, the task group thinks it will improve understanding and clarity to the users of the standard and will maintain consistency amongst all the standards. Note that an additional change is being made to update the Scope and Keywords of C55 to reference ‘hydraulic cement’ instead of ‘portland cement’ to increase clarity and reflect the introduction into the marketplace of portland-limestone cement (PLC) meeting the requirements of C595 IL blended cement.