Mechanical Properties and Damage Evolution of Concrete Materials Considering Sulfate Attack

Area of Science:

• Materials Science
• Civil Engineering
• Durability of Concrete

Background:

• Sulfate attack is a major cause of concrete degradation.
• Understanding concrete's response to sulfate environments is crucial for infrastructure longevity.

Purpose of the Study:

• To evaluate the durability of concrete with varying fly ash content under sulfate attack.
• To analyze the mechanical properties and micro-structural changes.
• To develop a damage model for sulfate attack on concrete.

Main Methods:

• Uniaxial compressive strength test
• Split tensile test
• Ultrasonic impulse method
• Scanning Electron Microscopy (SEM)
• X-ray Diffraction (XRD)

Main Results:

• Concrete properties (mass change, elastic modulus, strength coefficients) initially increased then decreased under sulfate attack.
• 10% fly ash content demonstrated optimal sulfate resistance.
• A damage model was established, showing exponential relationships between damage variables and significant regression effects of erosion time and fly ash content.

Conclusions:

• Sulfate attack leads to micro-crack formation and propagation due to ettringite and gypsum expansion.
• The developed damage model accurately predicts concrete deterioration under sulfate attack.
• Fly ash content is a key factor in mitigating sulfate-induced damage.