This chapter on Ready Mixed Concrete has been a part of the original ASTM STP 169 publication since Stanton Walker authored it in 1955 and 1966. Richard Gaynor authored the chapter in 1978. He has been a member of the ASTM Subcommittee C 09.40 responsible for ready mixed concrete specifications C 94 and C 685 since the early 1960s and was its chairman from 1974 through 1990.