roller compaction
Post on 16-Apr-2017
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Roller Compaction
Group 5 13-CE-05 13-CE-15 13-CE-26 13-CE-39
Department of Civil Engineering, MUST AJK
Purpose OF Compaction
• To increase the density
• To improve the shearing resistance
• To minimize the future settlement
• To reduce the permeability
Factors Affecting Compaction
• Compaction Energy
• Moisture Content
• Soil Type
• Layer Thickness
• Contact Pressure
• Number of Roller Passes
• Speed of Rolling
Methods of Compaction
• Kneading Compaction
• Static Compaction
• Dynamic Compaction
• Vibratory Compaction
Types of Compacting Equipment
Type of equipment required mainly depends on soil type:
• Smooth Wheel Rollers
• Sheepfoot Rollers
• Pneumatic Tyred Rollers
• Vibratory Rollers
• Grid Rollers
Smooth Wheel Roller
Smooth Wheel Roller
• One steel drum in Front and Two steel drum in Rear
• Area Coverage (100%)
• Gross weight (8 to 10 tonne)
• Adequate no. of passes (8 passes/20cm layer)
• Appropriate Speed (3 to 6 kmph)
• Contact Pressure (380 kPa Approx.)
• Suitable for compacting Gravels, Sand and Crushed Rock
• Performance depends on load per cm width
• Major Drawback: Non-reversibility of these tractor drawn rollers
Smooth Wheel Roller
Characteristics of 8-Tonne Smooth Wheel Roller
Sheepfoot Roller
Sheepfoot Roller • Many solid round or rectangular feet attached to steel drum
• Area Coverage (8 to 12%)
• Adequate no. of passes (12 to 20 passes)
• Appropriate Speed (6 to 10 kmph)
• Contact Pressure (1400 to 7000 kPa)
• Suitable for compacting heavy clays and silty clays
• Major Drawback: The loose top-lift material can act as a sponge
when it rains and slow the compaction process.
Sheepfoot Roller
General Characteristics of Sheepfoot Roller
Pneumatic Tyred Roller
Pneumatic Tyred Roller • 4 pneumatic smooth wheels on the Front axle whereas 5
wheels on the Rear axle to exert uniform pressure
• Area Coverage (80%)
• Adequate no. of passes (7 to 8 passes)
• Appropriate Speed (1.6 to 24 kmph)
• Contact Pressure (500 to 700 kPa)
• Used for both Earthwork and Bituminous Work
• Major Drawback: When stopped straight creates bulge which may not roll out
Vibratory Roller
Vibratory Roller
• Similar to smooth wheel rollers with the modification of
rotating drums
• Area Coverage (100%)
• Appropriate Speed
For Rock and Clay (1 to 2.5 kmph)
For Gravel and Sand (2 to 5 kmph)
• Very expansive but have high output and performance
Vibratory Roller
Several parameters influence compaction by vibratory roller:
• Frequency
• Amplitude
• Dead Load
• Dynamic Force
• Area of Contact
• Ratio between frame and drum weight
Vibratory Roller • For best compaction results frequency of roller should be
between 1 to 1.5 times the frequencies of soil
• Compaction effect is maximum between frequencies 25
and 50 Hz
Vibratory Roller
Vibratory Rollers have further following types:
• Towed Vibratory Rollers
• Self Propelled Rollers
• Vibratory Tandem Rollers
• Combination Rollers
• Double Drum Rollers
Vibratory Roller
Towed Vibratory Roller
• Weight (4 to 6 tonne)
• Heavy-duty rollers weigh up to 15 tonne so layer
thickness can be increased
• They cannot be reversed resulting into time loss
Vibratory Roller
Self Propelled Rollers
• Steel drum at the front and 2 pneumatic wheels at the rear
• Weight (8 to 12 tonne)
• Weight can be increased by ballasting
• For better performance at high static linear load, the
drum diameter must be large.
Vibratory Roller
Vibratory Tandem Roller
• Weight (7 to 17 tonne)
• Used mostly for bituminous work
Vibratory Roller
Combination Roller
• Vibrating drum on one axle and 3 to 5 pneumatic wheels
on the other axle
• Primarily used in bituminous work
Vibratory Roller
Double Drum Roller
• Useful for compacting soil in restricted areas, trenches etc.
• Improve elimination of internal friction between particles
• Improve pressure and shear stresses
Grid Rollers
Grid Rollers
• A cylindrical heavy steel surface consisting of a network
of steel bars forming a grid with squire holes
• Weight (5.5 to 15 tonne)
• Appropriate Speed (5 to 24 kmph)
• Weight can be increased by ballasting with concrete blocks
• Provide high contact pressure
• Suitable for coarse grained soils
Required Compaction Compaction test on particular soil in laboratory by:
• Standard Proctor Test
• Modified Proctor Test
To obtain compaction curve, OMC and MDD
Field densities are determined by:
• Sand Cone
• Nuclear Density Gauge
Results are compared. For 95% relative compaction, about 70% relative
density is specified.
Required Compaction
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