roller compaction

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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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