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Pavement Analysis and Design  Definition  Pavement  – Pavement is the upper part of roadway, airport or parking area structure  – It includes all layers.

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Presentation on theme: "Pavement Analysis and Design  Definition  Pavement  – Pavement is the upper part of roadway, airport or parking area structure  – It includes all layers."— Presentation transcript:

1 Pavement Analysis and Design  Definition  Pavement  – Pavement is the upper part of roadway, airport or parking area structure  – It includes all layers resting on the original ground  – It consists of all structural elements or layers, including shoulders

2  What is Design?  – Conceived/developed plan for something to serve a specific function.  What is a pavement design?  – It is the process by which the structural components a road segment are determined taking into account the nature of the subgrade, density and traffic composition.

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4 Functions of the Pavement  – Reduce and distribute the traffic loading so as not to damage the subgrade  – Provide vehicle access between two points under all- weather conditions  – Provide safe, smooth and comfortable ride to road users without undue delays and excessive wear & tear  – Meet environmental and aesthetics requirement  – Limited noise and air pollution  – Reasonable economy

5 Pavement Design Phases  Highway design consists of three stages  – Geometric design (route selection or alignment design)  – Capacity design (number of lanes to meet traffic demand)  – Structural design to withstand loads and environment  Structural design consists of 3 steps  – Selection of materials (types of pavement)  – Proportioning of materials  – Layer thickness design

6 Requirement of pavement structure  1. Sufficient thickness to spread loading to a pressure intensity tolerable by subgade  2. Sufficiently strong to carry imposed stress due to traffic load  3. Sufficient thickness to prevent the effect of frost susceptible subgade  4. Pavement material should be impervious to penetration of surface water which could weaken subgade and subsequently pavement  5. Pavement mat. shd be non-frost susceptible  6. Pavement surface shd. be skid resistant

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24 Types of Pavement Failure  Failure criteria  Flexible Pavements  Fatigue Cracking,  Rutting,  Thermal Cracking,  Rigid Pavements  Fatigue Cracking,  Pumping or Erosion  Others: Faulting, spalling, joint deterioration

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34 Stresses and Strains in Asphalt Pavements

35 Stresses and Strains in Flexible Pavements  Pavement response to applied wheel load  – Stress & strain are produced in each layer  – Pavement vertically deflects  – Location and magnitude of responses determine type and extent of pavement deterioration and the rapidity of deterioration.  – Determined using the theory of elasticity (Hook’s Law)

36 Pavement Responses  Stresses, Strains, & Deflections  Load-Related  – Vertical  – Shear  – Tensile  – Compression  Non-Load-Related  – Tensile

37 Structural Response Models  Help determine pavement responses as a function of applied load (traffic or environmental)  Stress, Strain, Deflection

38  Responses are needed for two reasons:  1. Material characterization, and  2. Predicting pavement distress.

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46 Tension Compression

47 Stresses and Strains Flexible Pavements  Sources of Stress and Strain  - Load related  Vertical Stress and strain (rutting)  Shear Stresses and strain  Radial stresses and strain  – Shrinkage stresses and strain (cracking)  – Temperature-Induced Stresses and strains (cracking)

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