3.9.1. Types of Deleterious Substances

Try these first

1. 1.

   What do deleterious materials do to concrete?

   Hint

   Think about harmful substances.

2. 2.

   Name one type of deleterious substance.

   Hint

   You learned about them in class.

3. 3.

   What is a deleterious material?

   • A substance that enhances concrete performance
   • A substance that negatively affects concrete
   • A material used only for aesthetic purposes

   Hint

   Focus on the negative impact.

4. 4.

   True or false: Only large particles can be deleterious.

   • True
   • False

   Hint

   Think of the different sizes and types you learned.

5. 5.

   Consider a concrete mix that exceeds the allowable limit for clay. Discuss how it affects the overall performance of the concrete in a structural application.

   Hint

   Link the performance issues with increased water demands.

6. 6.

   You have aggregate samples containing organic impurities. What tests would you recommend to check if they meet the permissible limits as per IS: 383, and what actions should be taken if they exceed the limits?

   Hint

   Remember the role of the color test.