scope:

This test method covers the testing of ultra-high performance concrete materials (UHPC) in uniaxial tension. In particular, the method obtains the stress-strain behavior and mechanical response parameters of UHPC specimens in uniaxial tension.

This test method is intended for use as a means through which key tensile mechanical parameters of strain hardening fiber reinforced concretes, such as UHPC, are quantified. Use of this test method to assess the performance of strain softening fiber reinforced concretes, continuously reinforced concretes, or conventional concretes may be feasible; however, some aspects of the results analysis portion of the method (Sections 9 through 12) will not be applicable.

The values stated in either SI units or inch-pound units are to be regarded separately as standard. The inch-pound units are shown in parentheses. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

The text of this specification references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the specification.

The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.