lecture 8

What is the main cause of D-cracking in concrete?

• More rapid freezing rate

• Increased porosity

• Non-frost resistant coarse aggregate

• Increased moisture saturation

What is the most common form of freeze-thaw damage in concrete?

• Spalling

• D-cracking

• Surface scaling

• Paste failure

How can concrete be protected from freeze-thaw damage?

• Increase porosity

• Reduce capillary porosity

• Use non-durable aggregate

• Keep concrete dry

What is the purpose of air entrainment in concrete?

• Increase moisture saturation

• Protect the matrix from freeze-thaw damage

• Reduce capillary porosity

• Increase freezing rate

What is the critical factor that determines concrete deterioration in freezing-thawing sequence?

• Strength development

• Air spacing

• Water content

• Aggregate type

What is the main mechanism of freeze-thaw damage in concrete?

• Internal micro-cracking

• Surface scaling

• Paste failure

• Aggregate failure

What is the main contribution of voids to freeze-thaw damage in concrete?

• Increased freezing rate

• Increased number of cycles

• Increased moisture saturation

• Increased porosity

What is the role of air entrainment in concrete?

• Enhance strength development

• Improve workability

• Reduce bleeding

• Enhance freeze-thaw resistance

How do voids contribute to freeze-thaw damage in concrete?

• Trap moisture

• Accelerate chemical reactions

• Provide pathways for expansion

• Enhance bonding between particles

What factor plays a crucial role in preventing freeze-thaw damage in concrete?

• Aggregate size

• Water-cement ratio

• Admixture content

• Temperature during curing