The Concrete Manual reflects the Bureau of Reclamations continuing effort to bring to its construction staff members information on the latest advances in concrete technology which would be useful to them in administering contracts for construction of the Bureaus water resource development projects throughout the western States. Evolving from a set of loose-leaf blue-printed instructionsAlthough fundamental precepts of good concrete practice do not change. Continued research and development of the technology bring about significant improvements that keep concrete in the forefront as a versatile dependable and economical construction material. This Eighth Edition of the Concrete Manual underscores this progress; it embraces substantial supplemental information relating to many of these improvements in concrete control and technology. This latest edition of the manual also includes a brief discussion of concrete- polymer materials new composites which have considerable potential in construction. Information on the manufacture of concrete pipe has been supplemented and revised. Shotcrete containing coarse aggregate used for tunnel support is discussed and methods for removing stains from concrete surfaces arc now described in detail.