其他摘要：Brittle or quasi-brittle materials such as concrete or rocks typically present localized failure modes due to cracking processes which usually start from internal material defects such as micro-cracks or non-homogeneous weak zones. Recently, several studies have been carried out on the fracture mechanical behavior of concrete materials by taking into account some aspects such as material strength, presence of reinforcing fibers, aggregate size effects, presence of nano-particles, etc. In this work both plain and fiber reinforced concrete composite (FRCC) are analyzed and modeled with two different approaches. On one hand, a continuum (smeared-crack) formulation based on nonlinear microplane theory is proposed. While on the other hand, a discontinuous constitutive theory is formulated to model the cracking response of fiber reinforced mortar-mortar interfaces. The well-known “Mixture Theory” is considered in both models to describe the fiber effects on the failure behavior of FRCC. The interaction between concrete/mortar and steel fibers in terms of fiber debonding and dowel effects are similarly treated in both macroscopic and interface models. The main objective is to comparatively evaluate the capabilities of the proposed models and numerical tools to capture the significant improvements of post-cracking behavior of fiber-reinforced concrete when different fiber contents and directions are considered. Different amount and type of metallic reinforcing fibers are examined, studying their benefits by bridging cracks and providing resistance to crack opening processes.
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