Experimental Study on Biaxial Dynamic Compressive Properties of ECC

Area of Science:

• Materials Science
• Civil Engineering
• Structural Engineering

Background:

• Engineered Cementitious Composites (ECC) offer enhanced ductility and toughness compared to traditional concrete.
• Understanding ECC behavior under complex stress states is crucial for advanced structural applications.

Purpose of the Study:

• To investigate the biaxial dynamic compressive behavior of Engineered Cementitious Composites (ECC).
• To establish a failure strength standard and constitutive relationship for ECC under biaxial dynamic loading.
• To quantify the influence of lateral pressure and strain rate on ECC mechanical properties.

Main Methods:

• Biaxial dynamic compression tests were performed on eight types of ECC using an improved hydraulic servo structure testing machine.
• Tests were conducted at various lateral pressure levels (0 to 1.0) and strain rates (10⁻⁴ to 10⁻² s⁻¹).
• Failure modes, stress-strain curves, peak stress, peak strain, deformation modulus, and compressive toughness index were analyzed.

Main Results:

• Lateral pressure influences ECC cracking direction; strain rate has minimal effect on failure morphology.
• Increased lateral pressure and strain rate enhance ECC's limit failure strength and peak strain, with minor elastic modulus improvement.
• A two-stage biaxial failure strength standard and a normalized constitutive relationship were established for ECC.
• ECC toughness increases with lateral pressure but decreases with higher strain rates.
• ECC ultimate strength under biaxial dynamic load surpasses that of plain concrete.

Conclusions:

• ECC demonstrates superior performance under biaxial dynamic loading compared to plain concrete.
• The established failure standard and constitutive model provide valuable insights for ECC design and application.
• Lateral pressure and strain rate are critical parameters influencing ECC's mechanical response and toughness.