The vibration mode (frequency, amplitude, vibration direction) of a roller directly affects compaction results. Different materials (e.g., asphalt, soil, gravel) require specific vibration parameter combinations. Below is a detailed adjustment guide:

I. Core Vibration Parameters

Roller vibration systems are adjusted through three key parameters:

1. Vibration Frequency (Hz/rpm)

• High (40-50 Hz): Surface compaction (e.g., asphalt).

• Low (25-35 Hz): Deep compaction (e.g., subgrades).

2. Amplitude (mm)

• Low (0.4-0.8 mm): Fine compaction, prevents aggregate breakage.

• High (1.5-2.0 mm): Impacts deep, loose materials.

3. Vibration Direction

• Vertical (Standard): General-purpose compaction.

• Oscillation (Horizontal): Reduces vibration impact on nearby structures.

II. Vibration Mode Adjustments for Different Materials

1. Asphalt Mix Compaction

• Initial Compaction (Stabilization):

• Frequency: 30-35 Hz (low)

• Amplitude: 0.8-1.2 mm (medium-low)

• Purpose: Stabilizes mix, prevents displacement.

• Intermediate Compaction (Densification):

• Frequency: 40-45 Hz (high)

• Amplitude: 0.4-0.6 mm (low)

• Purpose: Maximizes density, avoids aggregate crushing.

• Final Compaction (Smoothing):

• Turn off vibration, use static mode or pneumatic tire roller kneading.

2. Soil/Gravel Subgrade Compaction

• Thick Layers (30 cm+):

• Frequency: 25-30 Hz (low)

• Amplitude: 1.8-2.0 mm (high)

• Purpose: Deep compaction for load-bearing capacity.

• Thin Layers (<20 cm):

• Frequency: 35-40 Hz (medium)

• Amplitude: 1.0-1.5 mm (medium).

3. Cement-Stabilized Aggregate (Base Layers)

• Initial Compaction: Low freq. + high amp. (28 Hz/1.5 mm) for stability.

• Final Compaction: High freq. + low amp. (42 Hz/0.6 mm) for surface strength.

4. Special Scenarios

• Confined Areas/Near Structures:
  Use oscillation mode (horizontal vibration) to minimize resonance.

• Slope Compaction:
  Roll uphill with medium freq. + medium amp. to prevent slippage.

III. Operational Steps (Example: Double-Drum Roller)

1. Identify material type and thickness (e.g., 5 cm asphalt layer).

2. Select vibration mode:

• Asphalt: High freq. + low amp. (e.g., 45 Hz/0.6 mm).

• Subgrade: Low freq. + high amp. (e.g., 28 Hz/1.8 mm).

3. Test compaction:

• Verify density with a nuclear gauge after trial section.

• If under-compacted → Increase amplitude or reduce speed.

4. Dynamic adjustments:

• For wet materials, slightly increase frequency (e.g., damp soil needs higher impact).

IV. Key Precautions

• Asphalt Surfaces: Avoid high freq. + high amp. to prevent aggregate damage.

• Cohesive Soils: Excessive amplitude causes "springy soil" (hard surface, loose sublayer).

• Vibration Start/Stop: Activate only when the drum fully contacts material to avoid surface marks.

V. Example Settings by Roller Type

VI. Summary

• Asphalt: High frequency + low amplitude; finish with static mode.

• Soil/Gravel: Low frequency + high amplitude; compact in layers.

• Oscillation Mode: Use near vibration-sensitive structures.

• Always conduct test sections to determine optimal settings!