The purpose of this paper is to propose new measurement guidelines for pre-stressing steel reinforcement wire indent geometries. The current guidelines for measuring pre-stressing steel reinforcement wire indent geometries are within ASTM A881M-10. These measurement guidelines provide instructions on measuring indent depth, indent side wall angle, and indent orientation. However, since the creation ASTM A881M-10 new measurements have been presented that serve as better predictors of wire performance than the current measurement requirements. The new measure guidelines presented in this research have been shown to have superior correlation to transfer length and the pull out force of pre-stressing steel reinforcement wires used in concrete railroad ties.
These measurement guidelines are intended to more completely quantify the surface profile of pre-stressing steel reinforcement wires and do so in a manner that adheres to the geometric dimensioning and tolerancing standards of ASME Y14.5-2009. The measurement guidelines presented in this research use the concept of minimal zone on a variety of different measurements. This includes measurements such as indent volume, indent surface area, and indent edge wall surface area. These new measurements are shown through a variety of statistical models to be strong predictors of transfer length and pull out force for the given reinforcement wire.
By presenting these new measurement procedures that define the surface geometry of reinforcement wire indent geometry in greater detail, suppliers can present more complete information of their wire type to consumers. Likewise, consumers will be able to more fully define the design requirements that are needed for their pre-stressed concrete railroad ties. The overall impact of the proposed changes will be the improvement of the quality control of pre-stressing steel reinforcement wires and the extended lifespan and durability of pre-stressed concrete railroad ties.