Asphalt cold patching is a road repair material that can be applied at room temperature, requiring no heating. It is suitable for quickly repairing localized defects such as potholes and cracks. The following are detailed application steps:
1. Pre-Application Preparation
Material and Tool Preparation
Materials: Asphalt cold patching material (including base asphalt, aggregate, and additives).
Tools: Shovel, scraper, plate compactor, roller (optional), broom, dust screen, and safety warning signs.
Defect Detection and Marking
Detection: Use ground-penetrating radar or visual inspection to determine the depth, extent, and condition of the pothole.
Marking: Mark the patch area with chalk or spray paint, following the "round hole, square patch" principle and ensuring neat cut edges.
Safety Measures: Post safety warning signs and cordon off the construction area to prevent pedestrians and vehicles from entering.
Applicants must wear protective equipment (gloves, masks, and hard hats).

2. Base Preparation
Pothole Cleaning
Debris Removal: Use a shovel or broom to remove debris, such as gravel, mud, and ice, from the pothole. Depth Check: If the pit depth is greater than 5cm, excavate in layers, with each layer ≤5cm thick.
Trimming and Milling
Trimming: Use a cutter or milling machine to make vertical cuts along the pit edge to ensure a regular repair area.
Milling: If the base layer is loose or damaged, mill it down to a solid base.
Primer Application
Primer Options: Use emulsified asphalt or modified emulsified asphalt.
Application Method: Apply evenly to the bottom and sides of the pit to enhance adhesion.
III. Cold Patch Filling
Material Mixing and Preparation
Mixing: If the cold patch material has been stored for an extended period, mix it for 1-2 minutes in advance to ensure uniformity.
Filling Amount: The fill material should be 1-2 cm (thin layer) or 3-5 cm (thick layer) above the road surface, with the center slightly higher than the surrounding areas.
Filling Method
Manual Filling: Use a shovel to fill the cold patch material into the pothole and level it with a scraper.
Mechanical Filling: For large-scale repairs, use a paver. Keep the thickness uniform to ≤±3 mm.
Layered Filling
If the pothole depth is greater than 5 cm, fill the pothole in layers, compacting each layer immediately after filling.
IV. Compaction and Forming
Compaction Tool Selection
Thin layers (≤ 3 cm): Vibratory plate compactor, tire roller, or manual compaction.
Thick layers (> 3 cm): Steel wheel roller or vibratory roller.
Compaction Steps
Initial Compaction: 1-2 passes at a speed of 1.5-2.5 km/h to initially stabilize the material. Recompacting: 2-3 passes at a speed of 3-5 km/h to ensure density.
Final Compacting: 1 pass to eliminate wheel marks and smooth the surface.
Compacting Standards: Compacting degree ≥ 93% for ordinary roads, ≥ 95% for highways.
The surface should be smooth and free of wheel marks, and edges and corners should be compacted without loose patches.
V. Surface Treatment and Maintenance
Surface Treatment
Spreading Stone Dust: Fill surface gaps and improve wear resistance.
Removing Excess Material: Use a broom to remove excess stone dust and keep the surface clean.
Initial Maintenance
Covering and Protection: Cover the repaired area with dust screens or plastic sheeting to prevent rainwater from washing away the surface.
Load Avoidance: No vehicles are allowed to pass within 2-4 hours after construction, and heavy vehicles should be avoided for 72 hours.
Long-Term Maintenance
Regular Inspection: Check the repaired area quarterly for flatness, adhesion, and cracks.
Waterproofing: Apply a waterproofing agent to areas prone to water accumulation to extend the service life. VI. Construction Precautions
Environmental Conditions
During rainy days or high humidity, suspend construction or provide shelter from the rain.
In low-temperature environments (below -10°C), add an anti-cold agent to ensure material fluidity.
Material Storage
Cold patch material should be stored in a dry, ventilated warehouse, away from direct sunlight and rain. The storage period should not exceed 6 months.
Safe Construction
Construction personnel must follow safety operating procedures and avoid direct contact with chemical additives.
Construction Flowchart
plaintext Copy Code Pre-construction Preparation → Base Preparation → Cold Patch Material Filling → Compaction and Forming → Surface Treatment and Maintenance
Construction Results and Advantages
Quick Traffic Opening: Light vehicles can pass 2-4 hours after construction, and the road is fully open 24 hours later.
Environmental Protection and Energy Saving: No heating is required, reducing harmful gas emissions and meeting green construction requirements.
Cost Savings: Short construction period, minimal machinery usage, and reduced overall costs.
Through these steps, the asphalt cold patch repair area will have stable strength and good durability, extending the service life of the road.