Pavement Design (with examples)
Outline
- Pavement Purpose
- Pavement Significance
- Pavement Condition
- Pavement Types
- Flexible
- Rigid
- Pavement Design
- Example
Pavement Purpose
- Load support
- Smoothness
- Drainage
Pavement Significance
- How much pavement?
– 3.97 million Centerline miles in U.S.
– 2.5 million miles (63%) are paved
– 8.30 million lane-miles total
– Largest single use of HMA and PCC
- Costs
– $20 to $30 billion spent annually on pavements
– Over $100 million pent annually in WA
Pavement Condition
- Defined by users (drivers)
- Develop methods to relate physical attributes to driver ratings
- Result is usually a numerical scale
Present Serviceability Rating (PSR)
Present Serviceability Index (PSI)
- Values from 0 through 5
- Calculated value to match PSR
Design Parameters
- Subgrade
- Loads
- Environment
Pavement Types
1. Flexible Pavement :
- Hot mix asphalt (HMA) pavements
- Called “flexible” since the total pavement structure bends (or flexes) to accommodate traffic loads
- About 82.2% of paved U.S. roads use flexible pavement
- About 95.7% of paved U.S. roads are surfaced with HMA
Its types:
- Dense graded
- Open-graded
- Gap-graded
- 2. Rigid Pavement:
- Portland cement concrete (PCC) pavements
- Called “rigid” since PCC’s high modulus of elasticity does not allow them to flex appreciably
- About 6.5% of paved U.S. roads use rigid pavement
It’s Types:
- Jointed Plain Concrete Pavement (JPCP)
- Continuously Reinforced Concrete Pavement (CRCP)
Pavement Design:
1. Design Catalog Method
2. Empirical (1993 AASTHO)
Flexible:
Rigid:
3. New AASTHO Method (as yet unreleased):
- Mechanistic-empirical
- Can use load spectra (instead of ESALs)
- Computationally intensive
- Rigid design takes about 10 to 20 minutes
- Flexible design can take several hours
Power Point Presentation with solved examples has been embedded below for better understanding.