Question

3. Corrosion of reinforcement is function of external factors (environmental) and internal factors related to materials. What are these factors?

4. Polymer concrete may be used for new construction or repairing of old concrete. What is the main advantage over ordinary concrete.

5. Explain the main difference between asphalt pavement and concrete pavement

6.   a- What are the most common used bituminous materials for

                  pavement ?:

2. what are the types of petroleum asphalts are used in pavement construction.
3. Why asphalt fail and crack?

Answer 1

Problem.3

The corrosion of reinforcement is like the cancer of the RCC the fresh concrete provides a peotective covering to the steel because it has highly alkaline nature (pH above 12) but with the passage of time the alkaline nature declines and it creates the acidic environment for the corrosion. It happens mainly die to the ingress of the water or HCL.

Thus the main inyernal factors that are responsible are:

1. permeability of the concrete.

2. It further depends upon the amount of cover that is given to the concrete.

3. Also if there are more than one metal used for reinforcement, for example some aluminium ties with steel, it can create the cell with potential difference and thus start the electrochemical process of corrosion.

And the environmental factors those are responsible:

1. Type of environments such as, humid air, acidic, salty or alkaline water. So it matters is concrete is in humid areas or dry areas. On earth or in water.