Multi-Field Models of Fiber Reinforced Concrete for Structural Applications

Abstract

Short fiber reinforcement is added to concrete materials to improve a variety of performance measures related to structural safety, serviceability, and health diagnosis. Mesoscale models have been developed to understand the individual and collective actions of these fibers on various material properties. Those modeling efforts have predominately focussed on the mechanical (i.e., stiffness and strength) contributions of fibers. This paper introduces computationally efficient, semi-discrete representations of fibers within coupled mechanical and transport processes in cement-based matrices. Basic simulations are done to study: the use of conductive fibers for self-sensing; and the influences of fibers on early-age plastic settlement. It is found that the models can account for directional bias on fiber orientation, as may occur during material casting. With respect to plastic settlement, fibers may play competing roles: mechanical restraint offered by the fibers reduces settlement, whereas enhanced hydraulic conductivity along the fiber–matrix interface may increase settlement by facilitating the bleeding process.

Physicomechanical Behavior of High-Performance Concrete Reinforced with Recycled Steel Fibers from Twisted Cables in the Brittle State—Experimentation and Statistics

“…Conversely, the lowest slump values were observed when both the W/B and FC were at their maximum values. The slump of HPFRC exhibited a decrease as the aspect ratio of the fibers increased, which is a phenomenon also observed in ordinary concrete [68,69]. This decrease can be attributed to the increase in the specific surface area resulting from the addition of fibers.…”

Early-Age Cracking Behavior of Concrete Slabs with GFRP Reinforcement

“…Lack of cracking observed along the reinforcing bar suggests that plastic settlement is not a primary factor in initiating cracking, though further investigation is needed. In Pan et al [63], the VCLM was extended to simulate such hygromechanical behavior using the effective stress concept of Biot [64]. Transport of water in porous media is driven by gravity and described using Darcy's Law in rate format.…”

Homogenization of discrete diffusion models by asymptotic expansion

“…29,30 The dual network can be enhanced by the presence of short fiber reinforcement. 31 But even for such efficient mesoscale models, the computational requirements become unbearable in many practical applications. Reduction of this burden is possible via computational homogenization.…”

“…For example, the dual network is used to simulate hydraulic fracturing [17,18,19,20], deterioration due to the expansion of corrosion products [21], alkali-silica or other chemical reactions [22,23,24,25], chloride diffusion [26,27,28], or thermal spalling [29,30]. The dual network can be enhanced by the presence of short fiber reinforcement [31]. But even for such efficient mesoscale models, the computational requirements become unbearable in many practical applications.…”