2.9. Alkali-Aggregate Reaction (AAR)

Try these first

1. 1.

   What materials in cement can cause AAR?

   Hint

   Think about the chemical components of cement.

2. 2.

   What is the outcome of AAR on concrete?

   Hint

   Consider the pressures that might build up.

3. 3.

   What causes the expansion in AAR?

   • Alkali reaction with calcium
   • Alkali reaction with silica
   • Alkali reaction with air

   Hint

   Consider which materials in cement are reactive.

4. 4.

   True or False: AAR can lead to cracking in concrete.

   • True
   • False

   Hint

   Think about the implications of material expansion.

5. 5.

   Given a scenario where a newly constructed pavement begins to crack after a rainy season, analyze the potential causes and propose solutions.

   Hint

   Think about how weather influences chemical reactions!

6. 6.

   Assuming you have a concrete design specification, outline the concrete mix considering AAR implications.

   Hint

   What materials help mitigate alkalis?