Evaluating the effects of various factors on mechanical performance of SC-FRCCs

Main objective of this study was to identify the different behaviors of Self Compacting Fiber Reinforced Cementitious Composites (SC-FRCCs) in terms of fresh and hardened state performance by considering the parameters such as specimen thickness/fiber length ratio (t/fL), specimen width/ fiber length ratio (w/fL), fiber type (straight or hooked), and fiber aspect ratio. Specimens were cast using same mixes, only fiber length, fiber type, specimen depth and specimen width were varied. Four different fiber lengths, two different fiber types, ten different specimen thickness and two different specimen width values were set. As a result, 14 different groups of specimen were obtained. A series of experiments were performed to examine the fresh and hardened state properties of SC-FRCCs by means of mini-slump flow, mold flow, fiber orientation, flexural strength and toughness, strain localization, crack propagation and crack typology. Results obtained from both traditional measurement methods and Particle Image Velocimetry (PIV) analysis, were combined and used in order to have a detailed understanding on how changing material parameters may affect the material behavior and the parameters used for structural design of fiber-reinforced cement based composites. Current codes for design of fiber reinforced concretes (FRC) were discussed and based on a chosen guideline CNR-DT, constitutive parameters were obtained accordingly, in order to assess and evaluate the effects of one of the studied parameters (t/fL) on the structural performance, to help further develop the standards for structural design of these materials. Finally, a relationship between the deflection and crack opening of SC-FRCCs were proposed based on t/fL ratio. The proposed relationships were employed to obtain deflection vs. COD relationships for other researchers' data given in literature and good results were obtained.