Four-Point Bending Test of Gradient ECC Concrete

In structural engineering, flexural performance testing of concrete beams is a key step in evaluating their load-bearing capacity and crack propagation behavior. As a common experimental method, four-point bending testing accurately simulates the loading state of concrete beams in actual service. However, conventional strain measurement methods usually rely on strain gauges or displacement sensors; these contact methods can be affected by installation position and environmental factors, and cannot fully capture the strain distribution on the beam surface. To address these issues, the Haytham binocular 3D visual strain gauge, with its non-contact measurement and high-precision strain capture, provides a more comprehensive and accurate means of analysis for four-point bending tests of concrete beams.

1. Non-contact measurement

The Haytham binocular 3D visual strain gauge adopts non-contact measurement, capturing the 3D deformation of the concrete beam surface through binocular cameras. This approach avoids the contact errors that can be introduced during the installation of conventional strain gauges or sensors, as well as physical disturbance to the beam, ensuring measurement accuracy and authentic test results.

2. Full-field strain distribution capture

The system monitors the full-field strain distribution on the concrete beam surface rather than being limited to local measurement points. Using digital image correlation (DIC) technology, it precisely computes the strain changes at each point on the beam surface, providing researchers with comprehensive strain distribution maps. This full capture capability enables more precise observation of crack formation, propagation, and strain concentration regions.

3. High-precision 3D strain analysis

The Haytham binocular 3D visual strain gauge performs 3D strain analysis on high-resolution images acquired by binocular cameras, capturing the minute deformation and strain concentration regions of the concrete beam during four-point bending. This high-precision 3D analysis allows the system to accurately monitor the mechanical behavior of the concrete beam, especially in high-strain regions and at critical stages of crack development.

4. Real-time strain monitoring and data visualization

The system features real-time strain monitoring, generating stress-strain curves during the test and displaying the measurement results visually. This real-time data and visual presentation help researchers keep track of the mechanical response of the beam during loading—especially at the critical moments of strain concentration and crack propagation—providing immediate feedback for in-depth analysis.

5. Crack monitoring and propagation analysis

In four-point bending tests of concrete beams, crack formation and propagation are key concerns. The Haytham binocular 3D visual strain gauge precisely monitors crack initiation, width changes, and propagation paths, and provides detailed strain gradient data. This is highly valuable for analyzing crack propagation mechanisms and evaluating the failure mode of the beam, and can provide a scientific basis for design optimization and safety assessment of concrete structures.