Predicting the Tensile Behaviour of Ultra-High Performance Fibre-Reinforced Concrete from Single-Fibre Pull-Out Tests

Area of Science:

• Materials Science
• Civil Engineering
• Structural Engineering

Background:

• Ultra-high performance fiber-reinforced concrete (UHPFRC) exhibits complex tensile behavior.
• Accurate prediction of UHPFRC tensile performance is crucial for structural design.
• Existing models may not fully capture the influence of fiber characteristics at crack interfaces.

Purpose of the Study:

• To develop a prediction model for the tensile behavior of UHPFRC.
• To integrate the force contributions of individual fibers crossing a crack plane.
• To establish a method for analyzing fiber characteristics and orientation for improved predictive accuracy.

Main Methods:

• Developing piecewise linear models for fiber force contributions based on orientation and embedded length, fitted to single-fiber pull-out test data.
• Analyzing fiber characteristics within a crack plane using micro-computed tomography (micro-CT) imaging of concrete samples.
• Introducing a stochastic fiber model with a one-parametric orientation distribution for generalized predictions.
• Presenting simple estimators for the orientation parameter using in-plane fiber orientations.

Main Results:

• The proposed model effectively integrates the force contributions of fibers crossing the crack plane.
• Piecewise linear models accurately represent force-slip relationships based on fiber parameters.
• Micro-CT analysis provides detailed insights into fiber distribution and orientation at the crack interface.
• The stochastic fiber model, coupled with orientation estimators, enables more generalizable predictions.

Conclusions:

• The developed prediction model offers a robust approach to simulating the tensile behavior of UHPFRC.
• The integration of fiber pull-out mechanics and stochastic modeling enhances prediction accuracy.
• The method provides valuable tools for engineers to design and analyze structures utilizing UHPFRC.