Crack Evaluation of Concrete Using Mechanochromic Sensor.

Area of Science:

• Materials Science
• Structural Engineering
• Sensor Technology

Background:

• Concrete structures are susceptible to deformation and cracking, especially in harsh environmental conditions.
• Accurate monitoring of concrete degradation is crucial for structural integrity and safety.
• Existing monitoring methods may have limitations in real-time assessment and environmental resilience.

Purpose of the Study:

• To evaluate the effectiveness of a mechanochromic sensor for monitoring concrete deformation.
• To assess the sensor's performance under various environmental conditions, including low temperatures and freeze-thaw cycles.
• To investigate the sensor's capability in detecting and quantifying cracks in concrete members.

Main Methods:

• Attaching mechanochromic sensors to concrete specimens using Loctite adhesive.
• Applying tensile stress and inducing cracks in concrete beams while recording the process.
• Analyzing image data to correlate sensor discoloration with deformation and crack width.
• Testing sensor performance in low-temperature environments and after freeze-thaw cycles.

Main Results:

• The mechanochromic sensor detected concrete deformation up to 0.01 mm through a discoloration reaction.
• Sensor performance was unaffected by the concrete surface finish.
• The sensor's discoloration ability recovered within 2 hours after a freeze-thaw test at temperatures around 15°C.
• Real-time monitoring of cracks and deformation in concrete beams was achieved using the sensor's discoloration.

Conclusions:

• Mechanochromic sensors offer a viable method for real-time monitoring of concrete deformation and cracking.
• The sensor demonstrates resilience and functionality in cold and winter environments.
• Further research can explore the sensor's potential for precise crack width measurement through naked-eye imaging.