Failure Analysis of Ultra High-Performance Fiber-Reinforced Concrete Structures Enhanced with Nanomaterials by Using a Diffuse Cohesive Interface Approach

Abstract

Recent progresses in nanotechnology have clearly shown that the incorporation of nanomaterials within concrete elements leads to a sensible increase in strength and toughness, especially if used in combination with randomly distributed short fiber reinforcements, as for ultra high-performance fiber-reinforced concrete (UHPFRC). Current damage models often are not able to accurately predict the development of diffuse micro/macro-crack patterns which are typical for such concrete structures. In this work, a diffuse cohesive interface approach is proposed to predict the structural response of UHPFRC structures enhanced with embedded nanomaterials. According to this approach, all the internal mesh boundaries are regarded as potential crack segments, modeled as cohesive interfaces equipped with a mixed-mode traction-separation law suitably calibrated to account for the toughening effect of nano-reinforcements. The proposed fracture model has been firstly validated by comparing the failure simulation results of UHPFRC specimens containing different fractions of graphite nanoplatelets with the available experimental data. Subsequently, such a model, combined with an embedded truss model to simulate the concrete/steel rebars interaction, has been used for predicting the load-carrying capacity of steel bar-reinforced UHPFRC elements enhanced with nanoplatelets. The numerical outcomes have shown the reliability of the proposed model, also highlighting the role of the nano-reinforcement in the crack width control.

Investigation of mesh dependency issues in the simulation of crack propagation in quasi‐brittle materials by using a diffuse interface modeling approach

“…The DIM approach possesses the advantage of naturally handling multiple cracking, including crack bifurcation and coalescence, without requiring any remeshing operations. Recently, some of the present authors have used the DIM approach for simulating the fracture behavior of concrete‐like structures subjected to both mode I and mixed‐mode loading 35–38 …”

Shear Strength of Hybrid Fibre-Reinforced Ternary Blend Geopolymer Concrete Beams under Flexure

“…They found that the CMR model was appropriate for predicting the ascending portion of the bond stress-slip response between the UHPFRC and the steel rebar. Umberto et al [29] developed a numerical model for tracing the structural response of steel bar-reinforced UHPFRC enhanced with nanomaterials.…”

Tension-Stiffening Effect Consideration for Modeling Deflection of Cracked Reinforced UHPC Beams

“…The use of nanofibers can further enhance the mechanical performance of UHPC since they can effectively bridge nano-cracks. The common nanofibers include carbon nanotube and 2 of 21 graphite nanoplatelets [13,14]. For example, the increase in graphite nanoplatelet from 0% to 0.1% enhanced the tensile strength of UHPC by 20% [13].…”

“…The common nanofibers include carbon nanotube and 2 of 21 graphite nanoplatelets [13,14]. For example, the increase in graphite nanoplatelet from 0% to 0.1% enhanced the tensile strength of UHPC by 20% [13].…”