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![COMPUTATION OF TRAFFIC FOR USE
OF PAVEMENT THICKNESS DESIGN
CHART
365 xA[(1+r)n – 1]
N = --------------------------- x D x F
r
N = Cumulative No. of standard axles to be catered for the
design in terms of msa
D = Lane distribution factor
A = Initial traffic, in the year of completion of construction,
in terms of number of commercial vehicles per day
F = Vehicle Damage Factor
n = Design life in years
r = Annual growth rate of commercial vehicles](https://image.slidesharecdn.com/seminar-190527080607/75/ppt-on-construction-and-design-of-flexible-pavement-23-2048.jpg)
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ppt on construction and design of flexible pavement
1) The document summarizes the design and construction of flexible pavements. It describes the typical layers of a flexible pavement from top to bottom including the surface course, binder course, base course, sub-base course, and subgrade. 2) It also discusses factors involved in the design of flexible pavements like traffic load, subgrade soil properties, climate, and required material properties. Common failure modes of flexible pavements include alligator cracking, rutting, and reflection cracking. 3) Design life, traffic calculations, and common tests for bitumen are also outlined. The advantages of flexible pavements include adaptability and ease of repair while the disadvantages include higher maintenance costs and shorter life under heavy traffic loads
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ppt on construction and design of flexible pavement
- 1. Seminar on DESIGN &CONSTRUCTION OFFLEXIBLE PAVEMENT DEPARMENT OF CIVIL ENGINEERING Under The Guidance of Submitted by MR.SHUBHAJITDEY SUSMITAMAITY ROLL NO – 33201316022 B.TECH ,3rd yr,6th sem
- 2. outline Pavement purpose Types ofpavement Layers of pavement Flexible pavement Typical layers of flexible pavement Seal coat Tack coat Prime coat Surface course Binder course Base &sub base course Load distribution Basic principle Factors for design pavement Failure for flexible pavement Design life Pavement thickness Test of bitumen Advantages & dis advantages of flexible pavement
- 3. Pavement purpose • Loadsupport • Smoothness • Drainage Road in 1919 – from DC to Richmond the Asphalt Institute
- 4. Types of pavement Flexiblepavement Rigid pavement
- 5.
- 6. Flexible pavement • FlexiblePavement • 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
- 7. Typical Layers inflexible pavement from top 1.Seal coat 2.Surface course 3.Tack coat 4.Binder course 5.Prime coat 6.Base course 7.Sub-base course 8.Natural subgrade 9.Compacted subgrade
- 9. SUB-GRADE The soil subgrade is a layer of natural or selected soil rom identified borow pits fulfilling the specified requirements & well compacted in layers to the desire density . It is the lowest layer of the pavement
- 10. SUB-BASE COURSE The sub-base courseis the layer of material beneath the base course. The primary functions are to provide structural support, improve drainage, and reduce the intrusion of fines from the sub- grade in the pavement structure
- 11. BASE COURSE The basecourse is the layer of material immediately beneath the surface of binder course . it provides additional load distribution and contributes to the sub-surface drainage. It may be composed of crushed stone, crushed slag, and other untreated or stabilized materials.
- 12. PRIME COAT Prime coatis an application of low viscous cutback bitumen to an absorbent surface like granular bases on which binder layer is placed. It provides bonding between two layers. Unlike tack coat, prime coat penetrates into the layer below, plugs the voids, and forms a watertight surface
- 13. SURFACE COURSE Surface course isthe layer directly in contact with traffic loads and generally contains superior quality materials. a. It provides friction, smoothness, drainage, b. It must be tough to resist the distortion under traffic and provide a smooth and skid- resistant riding surface, c. It must be waterproof .
- 14. TACK COAT Tack coatis a very light application of asphalt, usually asphalt emulsion diluted with water. It provides proper bonding between two layer of binder course and must be thin, uniformly cover the entire surface, and set very fast
- 15. Seal coat Thin asphaltsurface treatment used to— 1.waterproof or seal the surface 2.no non-skid slippery surface 3.improve night visibility 4.revaitalize old bituminous wearing surface
- 16. BINDER COURSE • Thislayer provides the bulk of the asphalt concrete structure.
- 17. TYPES OF FLEXIBLE PAVEMENT Densegrade Open grade Gap grade
- 18.
- 19. BASIC PRINCIPLE IRC (37-2012) •Vertical stress or strain on sub-grade • Tensile stress or strain on surface course
- 20. FACTOR FOR DESIGN OF PAVEMENT Designwheel load • Static load on wheels • Contact Pressure • Load Repetition Subgrade soil • Thickness of pavement required • Stress- strain behaviour under load • Moisture variation Climatic factors Pavement component materials Environment factors Traffic Characteristics Required Cross sectional elements of the alignment
- 21. FAILURES OF FLEXIBLE PAVEMENTS . Alligator cracking orMap cracking (Fatigue) Consolidation of pavement layers (Rutting) Shear failure cracking Longitudinal cracking Frost heaving Lack of binding to the lower course Reflection cracking Formation of waves and corrugation Bleeding Pumping
- 22. DESIGN LIFE National Highways– 15 Years Expressways and Urban Roads – 20 Years Other Category Roads – 10 – 15 Years
- 23. COMPUTATION OF TRAFFICFOR USE OF PAVEMENT THICKNESS DESIGN CHART 365 xA[(1+r)n – 1] N = --------------------------- x D x F r N = Cumulative No. of standard axles to be catered for the design in terms of msa D = Lane distribution factor A = Initial traffic, in the year of completion of construction, in terms of number of commercial vehicles per day F = Vehicle Damage Factor n = Design life in years r = Annual growth rate of commercial vehicles
- 24. TESTS OF BITUMEN Ductility test Flashand Fire point test Float test Loss on heating test Penetration test Softening point test Specific gravity test Viscosity test Water content test
- 25. THE ADVANTAGES OF FLEXIBLE PAVEMENTS » Adaptabilityto stage construction » Availability of low-cost types that can be easily built » Ability to be easily opened and patched » Easy to repair frost heave and settlement » Resistance to the formation of ice glaze
- 26. The disadvantages » Higher maintenancecosts » Shorter life span under heavy use » Damage by oils and certain chemicals » Weak edges that may require curbs or edge devices
- 27. references 2. IS: 20:2007Codes for the rural roads & standard designing of a pavement. • 3. Khanna & Justo, Highway Engineering Provisions & general data obtained for soil tests, designing of flexible pavement & traffic survey study. • 4. B.N Dutta, Cost Estimation, Estimation procedures & format obtained by this book. • 5. K R Arora, Soil Mechanics & Foundation Engineering Soil tests & their details are obtained. • 6. B.C Punmia, Soil Mechanics, Soil tests & their applications are preferred from this book. • 7. www.wikipedia.org • 8. www.civil.org • 9. www.civilworks.org • 10. www.nptel.co.in
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