ACI 544.8R-16 PDF Download

ACI 544.8R-16 is a standard that focuses on the indirect method to obtain the stress-strain response of fiber-reinforced concrete (FRC) materials. The objective of this standard is to develop proper design procedures for FRC materials by considering the contribution of fibers to the post-cracking behavior.

The standard acknowledges that conducting closed-loop tension tests for FRC materials is challenging. Therefore, the standard introduces methods based on indirect measurement of tensile properties using flexural tests. These methods aim to estimate the uniaxial tensile stress-strain response of strain-softening and hardening FRCs from flexural beam-test data.

The standard discusses different approaches for data reduction and presentation of flexural test results in terms of an equivalent tensile stress-strain response. These approaches can be categorized into two general categories: the elastic equivalent approach and the inverse analysis method. The elastic equivalent approach includes various test methods proposed by different code agencies.

The standard also presents back-calculation methods based on the finite element method and analytical closed-form solutions. These methods utilize moment-curvature relationships and load-deflection responses obtained from beam tests. By using these methods, equivalent parametric tensile stress and strain relationships can be obtained for different types and volume fractions of FRC materials.

The standard concludes by providing results from the study of a range of FRC materials. These results indicate that the back-calculated post-peak residual tensile strength is approximately 30 to 37 percent of the elastically equivalent flexural residual strength for specimens with different fiber types and volume fractions.