Source: Portland Cement Association

The American Association of State Highway and Transportation Officials’ (AASHTO) Subcommittee on Materials and ASTM International’s Committee C01 on Cement recently passed ballot proposals to harmonize remaining significant differences between the portland cement standard specifications AASHTO M 85 and ASTM C150. The 2009 editions of the standards are anticipated to be available in late July and will include provisions for use of up to 5 percent inorganic processing additions, a Type II (MH) designation for cement for moderate heat of hydration and moderate sulfate resistance, simplified fineness requirements, and improved clarity for sulfate content provisions.

The result of a six-year cooperative effort, the harmonized standards enable more efficient use of natural resources and cement manufacturing technology, while ensuring a basis for improved quality of concrete construction. In doing so, they strengthen the sustainable development attributes of concrete construction. This effort to improve the specifications will continue as AASHTO and ASTM address new business items resulting from the balloting process in both organizations.

AASHTO M 85 and ASTM C150 have existed as parallel standards for portland cement since the 1940s. State departments of transportation reference one (or sometimes both) of these standards when specifying portland cement for concrete construction.