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Comparison of Flexible and Rigid Pavement
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| Flexible Pavements | Rigid Pavements |
| - Deformation in the subgrade is transferred to the upper layers | - Deformation in the subgrade is not transferred to subsequent layers |
| - Have low completion cost but repairing cost is high | - Have low repairing cost but completion cost is high |
| - Have low life span | - High life span |
| - Surfacing cannot be laid directly on the subgrade but a subbase is needed | - Surfacing can be directly laid on the subgrade |
| - Road can be used for traffic within 24 hours | - Road cannot be used until 14 days of curing |
| - Have low flexural strength | - Have high flexural strength |
| - Damaged by oils and certain chemicals | - No Damage by oils |
Source: http://www.aboutcivil.org/types-of-pavements.html
Answer the following questions.
1. What role do roads play?
2. How can you characterize the benefits from the investment in road sector?
3. What types of road surfaces were used in the past?
4. What do the variety of pavement types depend on?
5. What groups of pavement types are distinguished?
6. Why are flexible pavements called so?
7. What are rigid pavements composed of?
8. What are the principles of state highway agencies in choosing the pavement type?
9. What are the basic differences between flexible and rigid pavements?
Say if the sentences concerning Text 3A are true or false.
1. Flexible pavements are composed of a PCC surface course.
2. Roads are used as a mode of communication in areas where railways are not developed much.
3. Variety of pavement types depends on the instruments used.
4. Roads form the infrastructure for the cutback of economic activity of the country.
5. Rigid pavements do not require maintenance.
6. Rigid pavements have high repairing cost.
Date: 2015-12-12; view: 757; Нарушение авторских прав