147 ALASKA 2020 DIVISION 500 – STRUCTURES SECT ION 501 CONCRETE FOR STRUCTURES
501-1.01 DESCRIPTION . Furnish, place, finish, and cure Portland cement concrete for structure
construction. Use the class of concrete noted on the Plans unless otherwise specified. CLASSES OF CONCRETE Class A: General us e concrete Class A -A: Concrete where improved strength and durability is required Class P : Concrete where strength in excess of 5000 psi is required Class DS: Concrete for drilled shaft foundations
501-1.02 Definitions .
ADMIXTURE. A material other than wat er, aggregate, hydraulic cement, pozzolan, and fiber reinforcement, added to the batch before or during mixing, used as an ingredient of a cementitious mixture to modify its freshly mixed, setting, or hardened properties. Air-Entraining Admixture. An admi xture causing the development of a system of microscopic air bubbles in concrete, mortar, or cementitious material paste during mixing, usually to improve its workability and resistance to damage by freezing and thawing. Set-Accelerating Admixture. An admi xture causing an increase in the rate of hydration of the hydraulic cement and shortens the time of setting, increases the rate of strength development, or both. Set-Retarding Admixture. An admixture causing a decrease in the rate of hydration of the hydra ulic cement and lengthens the time of setting, decreases the rate of strength development, or both. Water -Reducing Admixture. An admixture either increasing slump of freshly mixed mortar or concrete without increasing water content or maintaining slump wit h a reduced amount of water, due to factors other than air entrainment. AGITATION. The process of providing motion in mixed concrete just sufficient to prevent segregation or loss of plasticity. BLEED WATER. The autogenous flow of water emerging from newly placed concrete, and caused by the settlement of the solid materials within the mass. The relative quantity of mix water that will bleed can be estimated by AASHTO T 158. CAMBER. For prestressed concrete members, camber is the net upward deflection of an eccentrically prestressed concrete member due to the combined loads, shrinkage, creep, and eccentricity of the prestress force. For non- prestressed members, camber is a deflection intentionally built into a structural element or form to improve appearance or to nullify the deflection of the element under the effects of loads, shrinkage, and creep. CEMENT. A binding material that sets and hardens by hydration and is capable of doing so underwater, sometimes called hydraulic cements. CEMENTITIOUS MATERIA L. Hydraulic cements and pozzolans with cementing properties. CHAMFER. A beveled edge or corner formed into finished concrete.