CE403 Construction Methodology

1. CE403Construction Methodology Compaction & Finishing

2. The Compaction Process Increasing density of a soil by mechanically forcing the soil particles closer together, expelling air in the void spaces of the soil. Can be accomplished in a few hours.

3. The Consolidation Process Increasing density of cohesive soils resulting from the expulsion of water from the void spaces in the soil. May take as long as months, or years.

4. Factors Affecting The Degree of Compaction • The Soil’s Physical & Chemical Properties • The Soil’s Moisture Content • The Compaction Method • The Thickness of the Soil Layer (Lift)

5. The Four Basic Compaction Forces • Static Weight (Pressure) • Manipulation (Kneading) • Most Effective on Plastic Soils • Impact • Low Frequency for Plastic Soils (10 Hz) • Vibration • Higher Frequency (80 Hz) • Effective on cohesionless soils ~ Sand & Gravel

6. Optimum Moisture Content • Very Important Factor ~ the moisture at which maximum density can occur. • Proctor Test: ASTM & AASHTO • Standard Proctor Test • ASTM D 698, AASHTO T-99 • Modified Proctor Test • ASTM D 1557, AASHTO T-180

7. Proctor Compaction Tests

8. Typical Compaction Test Modified Proctor Line Of Optimums Zero Air Voids Dry Density lb/cu ft Standard Proctor Water Content (% Dry Weight)

9. Modified Proctor Test Results for Various Soils

10. Compaction Specifications • From 90 to 95% of the maximum density as determined by either the Standard or Modified Proctor Test. • For Example: • 95% of Standard Proctor for Embankments, Dams, and Backfills. • 90% of Modified Proctor for floor slabs on-grade. • 95% (to 100%) for pavements with high wheel loads.

11. Typical Compaction Test Modified Proctor Line Of Optimums Zero Air Voids Dry Density lb/cu ft 100% of Standard Proctor Standard Proctor 95% of Standard Proctor Water Content (% Dry Weight)

12. Types of Compaction Equipment • Tamping Foot Rollers • Grid/Mesh Rollers • Vibratory Compactors • Steel Wheel/Smooth Drum Rollers • Rubber Tired/Pneumatic Rollers • Segmented Pad Rollers • Rammers/Tampers

13. Vibratory Compactors Hand-Operated

14. Smooth & Padded Rollers

15. Pneumatic/Tired Compactor

16. Vibratory

17. Water Trucks

18. Equipment Selection

19. Number of Pass Effect Number of Passes

20. Number of Passes

21. P = Number of Passes Required W = Width Compacted per Pass, ft S = Compactor Speed, mi/h L = Compacted Thickness, “Lift”, in E = Job Efficiency Estimating Compactor Production

22. Job Management • Lifts should be kept as thin as possible for the most efficient compaction. • Typical Lift Specifications • 5-8” for Rollers, except for Vibro’s & Pneum’s • 12” for Heavy Pneumatic Rollers. • 8 to 48” for Vibratory Rollers. • 7” for Vibratory Rollers compacting Rock.

23. Grading & Finishing

26. Shoulder Traffic Lanes Shoulder PAVEMENT BASE SUB BASE SUBGRADE Compacted or Stabilized Typical Roadway Components

27. Blade Positions

28. Articulated Grader Positions

29. Estimating Production

30. Grading Example • 15.0 miles of gravel road requires reshaping & leveling. • Six passes of a motor grader will be required. • Job efficiency is 0.80 • Based on operator skill, machine characteristics and job characteristics, you estimate two passes at 4 mi/h, two passes at 5 mi/h, and two passes at 6 mi/h for this job.