Specialized construction applications

Specialized construction applications are considered to be those that contain materials that are not routinely used in conventional structural or mass concrete (ACI 116R, 1990), those that are not proportioned using procedures given in the American Concrete Institute Standard Practice 211.1 (ACI 211.1, 1991), or those that are placed with equipment or by methods that require additional attention from the contractor to ensure the required quality is achieved. The techniques of mixing, batching, transporting, consolidating, protecting, and placing concrete have drastically changed during the past few decades. The reasons for these drastic changes include the following: • Owners demanded that cost escalation of new construction must be kept under control. • These demands required the development of accelerated construction techniques and new materials. • Governmental agencies initiated regulations that required better protection of the environment. • Construction had to be accomplished with fewer workers; consequently, new techniques being developed had to use innovative equipment and materials.