Sources: ASTM International, West Conshohocken, Pa.; National Concrete Masonry Association, Herndon, Va.
The ASTM C595-12 Standard Specification for Blended Hydraulic Cements defines requirements for a new powder: Type IL, portland-limestone blended cement, which includes 5–15 percent limestone as an ingredient. Adoption of Type IL product has the potential to reduce environmental impact of cement production by about 10 percent, while maintaining performance characteristics concrete producers require for specified mixes. The requirements for Type IL cement are the most significant change to C595 in 2012.
Similar cements have been used in Europe and other places around the world for several decades and have demonstrated the performance and durability expected in finished concrete. The equivalent to ASTM C595 is AASHTO M240. The 2012 version of M240 is anticipated to be published in August and will also include provisions for Type IL cement with identical requirements. Print copies or pdf of the C595-12 standard can be ordered through the ASTM Store at www.astm.org.