New damage evolution law in plastic damage models for fiber‐reinforced cementitious composites

Abstract

Nowadays, fiber‐reinforced cement‐based composites (FRCC) can develop ductile behavior with high toughness when the matrix, fibers, and interface are optimally designed. These materials are promising solutions for constructing more resilient structures. In this context, the widespread use in large‐scale applications requires reliable models to predict the performance of FRCC structures. Usually, the studies on numerical modeling of FRCC apply the damage laws developed for quasi‐brittle concrete, making damage increase faster than really occurs in the presence of fibers. Therefore, the present paper proposes a new damage evolution model for FRCC based on energy dissipation concepts. It is assumed that the dissipated energy contributes fully to the evolution of the scalar damage and plastic strain variables, which is a technical advance from the previous works. The damage evolution is obtained with experimental envelopes of uniaxial stress–strain tests and the focal point from loading–unloading cycles. The results showed that the model accurately predicted experimental results using the damage‐plasticity framework. Furthermore, there are no empirical constants in the proposal, which means that it can be applied to any class of FRCC. An application regarding damage evaluation near a load transfer device in jointed plain cementitious pavements is presented. The damage distribution reveals that using FRCC materials has induced smaller damage values when compared with using conventional concrete. Consequently, cracking is reduced in such zones, increasing the structural life of the pavement.

Experimental study on mechanical properties of recycled aggregate concrete with polypropylene fiber under combined compression‐shear loading

“…Fibers are typically added to concrete to improve its properties. 6,[18][19][20] Indeed, as compared to unreinforced concrete, fiber-reinforced concrete is characterized by improved resistance to cracking, tensile strength, flexural strength, shear strength, ductility, and toughness. 21 Furthermore, adding fiber to RAC can not only improve the crack resistance, impact resistance, and ductility of concrete but also make up for some defects of RCA.…”

“…Based on the existing literature, it is found that PP fiber additions in concrete do not significantly change the compressive strength, 20,27 but these induce notably improved splitting tensile and flexural strengths. 20,25,27 More importantly, some researchers found that the drops in splitting tensile strength and flexural strength due to the substitution of NCA with RCA were to a large extent compensated by the addition of PP fibers. However, concrete in practical engineering, such as corbels, highways, bearing padding stones, and deep beams, is usually subjected to combined compression-shear loads during service.…”

“…Based on the previous studies, 20,25,27,41,42 this study aims to investigate the basic mechanical behavior of PPFRAC under compression-shear stress and supports the engineering application of PPFRAC. Therefore, direct shear tests were carried out on 24 PPFRAC specimens with different PP fiber contents, and the optimal PP fiber content of RAC under direct shear stress was obtained.…”