9.13.3. Alkali-Aggregate Reaction (AAR)

Try these first

1. 1.

   What does AAR stand for?

   Hint

   Think about the components involved in concrete.

2. 2.

   Name one type of AAR.

   Hint

   There are two main types; one involves silica and the other involves carbonate.

3. 3.

   What causes Alkali-Aggregate Reaction?

   • A reaction between alkalis and reactive aggregates
   • A reaction between water and cement
   • A reaction due to temperature changes

   Hint

   Focus on the key materials involved.

4. 4.

   True or False: The Alkali-Silica Reaction is less common than the Alkali-Carbonate Reaction.

   • True
   • False

   Hint

   Think about which type is frequently discussed in concrete chemistry.

5. 5.

   Design a concrete mix using pozzolanic materials and low-alkali cement to minimize AAR risks. Explain your reasoning.

   Hint

   Consider the proportions of each component in your design.

6. 6.

   Evaluate the impact of environmental conditions on AAR in concrete structures. Discuss how changes in humidity or temperature influence this reaction.

   Hint

   Think about the relationship between moisture and expansion in AAR.