Question

1. Name and discuss the actions that should be taken before an existing road is resurfaced.

2. What is the consequence on the asphalt mix, if the maximum stone size is increased?

Answer 1

Q1.

- Firstly any potholes or other defects are patched and the surface made level.

- Then crews spray the existing road surface with a coating of hot bitumen and cover it with stone chippings.

- The chippings are rolled into the bitumen to form a water-resistant protective layer which makes the road less slippery and extends its life.

- As soon as the bitumen has set, we sweep the road to remove any loose chippings but the nature of the treatment means there will be some loose chippings on the road surface until it beds down.

Q 2

i) Rutting

ii) The triaxial test results indicated that for the same asphalt content and lateral pressure, the strength of the mixes tended to decrease with increased aggregate size.

iii) with increased stone size preparation of asphalt mix becomes difficult.