Flexural creep of steel fiber reinforced concrete in the cracked state

• Fiber slenderness and content modify effect of load ratio on SFRC flexural creep.
• Fiber length does not have a significant effect on SFRC flexural creep.
• Increasing fiber slenderness leads to reduced creep strains.
• Creep control, fibers: no high amounts required, slender fibers is the best choice.

This paper aims at assessing the effect of a number of variables on flexural creep of steel fiber reinforced concrete in its cracked state, namely: fiber geometry (slenderness and length), fiber content, concrete compressive strength, maximum aggregate size, and flexural load. Notched prismatic specimens have been subjected to sustained flexural loads for 90 days following a test setup and methodology developed by the authors. Several experimental outputs have been measured: initial crack width, crack width at 90 days, and crack opening rates and creep coefficients at 14, 30, and 90 days. Multiple linear regression has been applied to relate these creep parameters to the variables considered. Semi-empirical equations have been obtained for these parameters. Statistical inference has been applied to identify the variables that have a statistically significant effect on SFRC flexural creep response. Fiber slenderness and fiber content have been found to significantly modify the effect that load ratio has on flexural creep response of SFRC.