1. Supervised by
Dr. Sami Hijjawi
Prepared by
Hamza Saifan
Abdul-Rahman Easa

2. Civil Engineering Department Soil Improvement and Design of Pavement
For
Sanour – Maythaloon Street – Jenin
Supervised by
Dr. Sami Hijjawi
Prepared by
Hamza Saifan
Abdul-Rahman Easa
2010– 2011

3. Project Outline Types of Pavement Study Area
Pavement Condition Description
Soil Improvement
Pavement Design Using AASHTO Method
Approximate Quantities and Costs
Conclusions and Recommendations

4. Typical stress distribution under a rigid and a flexible pavement.
Types of Pavement
Typical stress distribution under a rigid and a flexible pavement.

5. Flexible Pavement Asphalt concrete Surface Basecourse layer
Subbase layer (Rock Fill)
Subgrade

6. Study Area
Sanour –Maythaloon Street .

7. Pavement Distresses Description
1. Longitudinal Cracking
Cracks parallel to the pavement's centerline or lay down direction,
 usually a type of fatigue cracking.

8. Pavement Distresses Description

9. Pavement Distresses Description
2. Alligator Cracking
Series of interconnected cracks caused by fatigue failure of the Pavement surface under repeated traffic loading.

10. Pavement Distresses Description

11. Pavement Distresses Description

12. Pavement Distresses Description

13. Pavement Distresses Description
3. Raveling
The progressive disintegration of an Pavement layer from the surface downward as a result of
the dislodgement of aggregate
particles.

14. Pavement Distresses Description

15. Types of Soil Improvement
Lime Stabilization
Replacement
Subgrade
Geosynthetics
Cement Stabilization

16. 1. Lime Stabilization
Lime stabilization involves the use of burned lime products, quicklime, hydrated lime (oxides and hydroxides, respectively) and Codel.
Lime is a strong alkaline base which reacts chemically with clays, causing a base exchange Calcium ions displace sodium and hydrogen cations and combine with available silica and alumina in the soil to form complex silicates and aluminates .

17. 1. Lime Stabilization
The principal changes to a soil stabilized with lime include: reduction in plasticity index (PI) and volume change; increase in optimum moisture content, permitting compaction under wetter conditions and allowing the soils to dry out more rapidly; increase in strength and stability through a cementing action; and resistance to water absorption and capillary rise.

18. 2. Cement Stabilization
Portland cement is one of the older materials used for stabilization. The cement hardens the soil material and structural strength .
Soil cement is a mixture of Portland cement, water and soil compacted to a high density. When cured, the soil cement mixture becomes a hard, rigid base material.

19. 2. Cement Stabilization
Soil cement is used as a base course, a subbase course and a subgrade treatment for flexible and rigid pavements. Almost all types of soils can be used for cement stabilization except highly organic soils and heavy clay soils.
Four fundamental factors control the construction of soil cement : moisture content, curing duration, compaction, and cement content.

20. 3. Subgrade Replacement
A common approach taken where soft subgrade soils are encountered is to remove and replace the in situ soils with stronger, usually granular, materials.
This method can be practical and economical where soft deposits are shallow and are located above groundwater levels.

21. 4. Geosynthetics
Geosynthetics have been found to provide significant improvement in pavement construction and performance.
Geotextiles placed at the subgrade increase stability and improve performance of pavement constructed on high fines subgrade soils.

22. 4. Geosynthetics
Without using geosynthetics, these tensile stresses will cause tension cracks to develop within the bottom of the base course.
Due to dynamic traffic loads these cracks allow fines from the subgrade to migrate upward into the base course layer while base course aggregate simultaneously migrates downward into the subgrade.

23. PAVEMENT DESIGN USING AASHTO METHOD
1- Determine the type of
treatment: Reconstruction
2- Collect Traffic Data
5 - Determine thicknesses of pavement layers
3- Determine Average Annual Daily Traffic AADT
4- Calculate Equivalent Single Axial load ‘ESAL’

24. PAVEMENT DESIGN USING AASHTO METHOD
Flexible Pavement Design with 10 Years Design Period
So the ESAL = 0.451*106

25. PAVEMENT DESIGN USING AASHTO METHOD
Thicknesses

26. PAVEMENT DESIGN USING AASHTO METHOD
Costs
material
unit
quantity
unit cost
cost ($)
Excavation m3
18200 4
72800
Rock Fill
11200 35
392000
Base coarse m2
14000 5
70000
MC (prime coat )
9800 2
19600
Asphalt (2 layers ) 15
147000
701400
Total Cost = 701,400 $

27. PAVEMENT DESIGN USING AASHTO METHOD
Flexible Pavement Design with 20 Years Design Period
So the ESAL = 1.044*106

28. PAVEMENT DESIGN USING AASHTO METHOD
Thicknesses

29. PAVEMENT DESIGN USING AASHTO METHOD
Costs
material
unit
quantity
unit cost
cost ($)
Excavation m3
18200 4
72800
Rock Fill
11200 35
392000
Base coarse m2
14000 6
84000
MC (prime coat )
9800 2
19600
Asphalt (2 layers ) 20
196000
764400
Total Cost = 764,400 $

30. Conclusions and Recommendations
The subgrade layer consists mostly of silty clay materials with classification of A-7. The high plasticity of the encountered silty clays indicates a high possibility of soil volume change. This could be the sole explanation of the pavement condition.
Due to weak and swelling soil of subgrade layer , it is recommended to use soil improvement which is soil replacement with Rock Fill layer to reduce the effect of subgrade moisture content on the road layers .

31. Conclusions and Recommendations
It has been noticed that the difference in cost between two scenarios is too small so it is recommended to use 20 year Design period than 10 year Design period .
Visual inspection of the pavement surface reveals the existence of several types of distresses (longitudinal cracks, alligator cracks, …etc.) .
Upon to visual examination and record of distresses , it is recommended to reconstruct the pavement and its layers after removing the existing one .

32. Thank You!