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Bendable concrete makes infrastructure stronger and more resilient
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Bendable concrete makes infrastructure stronger and more resilient

Concrete: The Most Utilized Engineering Material

This section introduces concrete as the most utilized engineering material on Earth and highlights its advantages and disadvantages.

Concrete as a Construction Material

  • Concrete is the most widely used engineering material, with over two tons poured for every person on the planet. It is favored for its affordability, versatility in shaping, and availability of ingredients. However, it has a drawback of brittleness.

Bendable Concrete - Engineered Cementitious Concrete (ECC)

  • Professor Victor Lee conducted an experiment using steel reinforcement rods embedded in concrete to test its brittleness. The traditional concrete shattered under extreme loading, while his bendable concrete called ECC exhibited plastic behavior by bending without breaking. This property enhances structural safety during earthquakes or bomb blasts.
  • ECC displays four times more resistance to bending loads compared to standard concrete and can sustain over 300 times more ductility. It remains intact even after failure, unlike standard concrete that snaps into pieces. Microscopic fibers added to ECC enable load sharing and create tiny cracks that are self-healing with water and air.

Enhancing Structural Safety with Bendable Concrete

This section focuses on how bendable concrete can enhance structural safety under extreme loading conditions such as earthquakes or bomb blasts.

Safer Buildings with Bendable Concrete

  • The primary goal of enhancing structural safety led to the development of bendable concrete like ECC.
  • Bendable concrete's ability to withstand extreme loading without fracturing into pieces makes it ideal for ensuring occupant safety during major events like earthquakes or bomb blasts.
  • Mo Lee's test demonstrates how normal concrete fails suddenly under bending loads due to tension and compression forces acting on different parts of the specimen.
  • In contrast, ECC exhibits a gradual failure mode and requires four times more force to achieve catastrophic failure. It offers superior ductility and remains in one piece even after failure.

Self-Healing Properties of Bendable Concrete

This section explores the self-healing properties of bendable concrete and its potential benefits.

Self-Healing Capabilities

  • Bendable concrete, such as ECC, possesses self-healing capabilities due to the presence of microscopic fibers.
  • These fibers create tiny cracks that are as tight as human hair. When exposed to water and air, these cracks can heal better compared to regular cement or concrete.
  • The self-healing capacity of bendable concrete is advantageous for maintaining structural integrity over time.

Longevity and Durability of Bendable Concrete

This section discusses the longevity and durability of bendable concrete compared to standard concrete.

Corrosion Resistance

  • Standard concrete used in roads and bridges often experiences corrosion due to the presence of water and de-icing salts, leading to severe damage.
  • Accelerated corrosion experiments show that standard concrete fails after 120 hours, while ECC remains intact even after three times longer exposure.
  • ECC's ability to accommodate expansion caused by corroded steel without fracturing contributes to its durability.

The Future: Smart Roads with Self-Sensing Structures

This section presents the potential future advancements in construction materials, including smart roads with self-sensing structures.

Extending Service Life

  • The development of bendable concrete aims to extend the service life of infrastructure like roads up to 100 years.
  • By incorporating self-sensing capabilities into construction materials like bendable concrete, it becomes possible for structures to detect and report their condition, enabling timely repairs.

Conclusion

This section concludes the transcript by summarizing the benefits of bendable concrete and hinting at future advancements.

Benefits of Bendable Concrete

  • Bendable concrete offers enhanced structural safety, self-healing properties, and increased durability compared to standard concrete.
  • It has the potential to make buildings safer, extend the lifespan of roads, and pave the way for smart infrastructure with self-sensing capabilities.
Video description

Concrete is the single-most utilized building material due to its moldability and low cost. But the concrete is brittle, causing it to break and shatter easily. U-M researchers have developed a bendable concrete to combat that problem. About the Professor: Victor Li (http://www.cee.umich.edu/people/faculty/Victor+C.+Li) is a Professor of Civil and Environmental Engineering (http://cee.engin.umich.edu/) at the University of Michigan College of Engineering. His research interests includes the design, processing and characterization of smart fiber reinforced cementitious composites, for protective and sustainable built environments. My research group engages in interdisciplinary research linking industrial ecology and structural health monitoring with bio-inspired materials design to enhance harmony between the built and the natural environment.