TRANSPORTATION ENGINEERING

The design procedure recommended by the American Association of State Highway and Transportation Officials Important Variables used in AASHTO Design Method 

1- Pavement Serviceability Index

 2- Reliability 

3- Standard Deviation

 4- Resilient Modulus

 5- Drainage Coefficient

 6- Layer Coefficient 

7- Equivalent Single Axle Load 

8- Structural Number

TRANSPORTATION ENGINEERING

Types of Pavements: 

• Rigid pavement (Concrete Slab) The wearing surface of a rigid pavement is usually constructed of Portland cement concrete such that it acts like a beam over any irregularities in the underlying supporting material.

 • Flexible pavement (Asphalt Concrete) The wearing surface of flexible pavements is usually constructed of bituminous materials such that they remain in contact with the underlying material even when minor irregularities occur.