Selecting the appropriate road roller based on different compaction materials is crucial for ensuring engineering quality and efficiency. The core lies in matching the compaction principle and roller characteristics of the road roller with the physical properties of the material. Below is a selection guide for three typical materials: asphalt, subgrade soil, and crushed stone:

1. Compaction of Asphalt Mixtures

Asphalt mixture is a thermoplastic material, and its compaction effect directly affects the smoothness, density, and service life of the pavement.

Core Requirements:

• High-Temperature Rapid Compaction: Must be completed before the asphalt cools and hardens; otherwise, compaction will be difficult.

• Uniform Compaction: Avoid local over-compaction or under-compaction to prevent aggregate crushing.

• Surface Smoothness: The final pavement must be smooth with no wheel tracks.

Recommended Road Roller Types:

• Smooth Drum Static Road Roller:

• Function: Used only for finish rolling. When the asphalt temperature is low, static compaction is performed to finally eliminate wheel tracks and obtain a smooth surface.

• Advantages: The compaction process is gentle and does not damage the formed pavement.

• Pneumatic Tire Roller:

• Function: Used for intermediate and finish rolling. The kneading effect generated by its elastic tires can further improve density, allow the asphalt film to better coat the aggregate, and eliminate wheel tracks.

• Advantages: Uniform compaction effect, good surface quality, and effective prevention of early water damage to asphalt pavement.

• Double Drum Vibratory Road Roller:

• Function: Used for initial and intermediate rolling. Its high-frequency vibration can quickly rearrange asphalt particles to achieve high density.

• Advantages: High compaction efficiency and effective compaction of asphalt layers.

Selection Points:

• Usually adopt the combination of "double drum vibratory road roller + pneumatic tire roller".

• Avoid using heavy-duty, large-amplitude vibratory road rollers for long-term rolling at high temperatures to prevent aggregate crushing and pavement shoving.

2. Compaction of Subgrade Soil

Subgrade soil includes various types such as cohesive soil, sandy soil, and silty soil. The compaction goal is to improve strength and stability.

Core Requirements:

• Deep Compaction: Need to transmit compaction energy to the deep subgrade.

• Moisture Content Control: The compaction effect is closely related to soil moisture content and should be compacted near the optimal moisture content.

• Uniformity: Ensure consistent compaction degree in all parts of the subgrade.

Recommended Road Roller Types:

• Pneumatic Tire Roller:

• Function: Can be used for compaction of cohesive soil subgrades or as supplementary compaction after vibratory road roller compaction.

• Advantages: The kneading effect helps compact cohesive soil.

• Sheep's Foot Roller:

• Function: Specifically used for compaction of highly cohesive soils (e.g., clay).

• Advantages: The sheep's foot-shaped protrusions can penetrate deep into the soil layer, exert strong compaction on deep soil, and mix upper and lower soil layers evenly.

• Single Drum Vibratory Road Roller:

• Function: The main equipment for subgrade compaction.

• Advantages: Large exciting force, deep compaction depth, suitable for various types of subgrade soil, especially sandy soil and gravel soil.

Selection Points:

• For sandy soil and gravel soil, priority should be given to large-tonnage, high-exciting-force single drum vibratory road rollers.

• For cohesive soil, sheep's foot rollers or pneumatic tire rollers can be selected.

• Avoid compaction when soil moisture content is too high or too low.

3. Compaction of Crushed Stone / Graded Crushed Stone

Crushed stone and graded crushed stone are often used for pavement base or subbase, and their compaction goal is to form a stable skeleton structure.

Core Requirements:

• Particle Interlock: Need to make crushed stone particles interlock tightly to form strong internal friction.

• Reduction of Segregation: Minimize the separation of crushed stone particles during compaction.

• Smoothness: Provide a good foundation for subsequent surface paving.

Recommended Road Roller Types:

• Pneumatic Tire Roller:

• Function: Can be used as supplementary compaction equipment to improve density and uniformity.

• Advantages: The kneading effect helps interlock particles.

• Double Drum Vibratory Road Roller:

• Function: Can be used for compaction of graded crushed stone bases, especially in occasions with high smoothness requirements.

• Advantages: The surface after compaction is relatively smooth.

• Single Drum Vibratory Road Roller:

• Function: The main compaction equipment.

• Advantages: Vibration can effectively move and interlock crushed stone particles with high compaction efficiency.

Selection Points:

• Priority should be given to vibratory road rollers, and vibration parameters (frequency, amplitude) need to be adjusted according to crushed stone particle size and gradation.

• Avoid using excessive static load or too high amplitude to prevent crushed stone particle crushing.

Summary: Quick Overview of Material-Road Roller Matching

• Asphalt Mixture: Double Drum Vibratory Road Roller (initial/intermediate rolling) + Pneumatic Tire Roller (intermediate/finish rolling) + Smooth Drum Static Road Roller (finish rolling).

• Subgrade Soil (Sandy/Gravel): Single Drum Vibratory Road Roller.

• Subgrade Soil (Cohesive): Sheep's Foot Roller or Pneumatic Tire Roller.

• Crushed Stone / Graded Crushed Stone: Single Drum Vibratory Road Roller or Double Drum Vibratory Road Roller.

When selecting, factors such as project scale, operating environment, and cost budget should also be comprehensively considered to achieve the best compaction effect and economic benefits.