PROBLEMS AND QUESTIONS

1. Sketch and show the dimensions of the most realistic contact areas for a dual tandem axle load of 40,000 lb with a tire pressure of 100 psi. If the contact areas are assumed as rectangles, what should be the dimension of the rectangular area?

2. Why is the limiting shear failure method of flexible pavement design rarely in use today? Under what situations could the method be used?

3. What is meant by the mechanistic-empirical method of pavement design? Is it possible to develop a wholly mechanistic method of pavement design? Why?

4. Why are flexible pavements generally built in layers with better materials on top?

5. Explain why rigid pavements pump whereas very few flexible pavements do so. Under what conditions would a flexible pavement result in pumping? On which pavement does pumping occur more frequently, airport or highway? Why?