ASTM Committee C12 on Mortars and Grouts for Unit Masonry was formed in 1931. C12 meets twice a year, usually in June and December, with approximately 50 members attending two days of technical meetings capped by a discussion on relevant topics in the Mortar industry. The Committee, with a membership of approximately 230, currently has jurisdiction of 15 standards, published in the Annual Book of ASTM Standards, Volume 04.05. C12 has 8 technical subcommittees that maintain jurisdiction over these standards. Information on the subcommittee structure and C12's portfolio of approved standards and work items are available from the List of Subcommittees, Standards and Work Items below. These standards have and continue to play a preeminent role in all aspects important to the industry of mortar used with masonry units, including burned clay, shale, sand-lime, concrete and stone.