The following details the process from four aspects: construction preparation, material selection, operation steps, and precautions.
I. Pre-construction Preparation
Site Survey: A comprehensive assessment of the damaged pavement is necessary to determine the width of cracks (e.g., narrow cracks <5mm, medium cracks 5-15mm, wide cracks >15mm), pothole depth (generally ≤10cm is shallow, >10cm is deep), and area range, thus determining the repair plan. For example, narrow cracks can be treated with crack filling, while potholes require layered filling.
Tools and Equipment Preparation: A cutting machine (for cutting crack edges), a high-pressure air compressor (for cleaning cracks), a blower (for removing dust), heating equipment (e.g., a hot melt kettle to heat the repair material to 160-180℃), paving tools (e.g., scraper, roller), and safety protective equipment (e.g., reflective vest, goggles) are required. **Environmental Conditions Check:** The construction temperature must be above 5℃. Construction is strictly prohibited in rainy weather or when the road surface is wet, otherwise it will affect the material's adhesion. If construction is carried out in low-temperature environments (such as northern winters), low-temperature repair materials must be selected or antifreeze agents must be added.

II. Material Selection and Proportioning: Asphalt pavement repair materials should be selected according to the type of damage:
Crack Repair: High-viscosity, highly elastic sealant (such as rubberized asphalt) should be preferred. Its viscosity must meet industry standards (e.g., the "Technical Specification for Highway Asphalt Pavement Maintenance" requires a viscosity ≥ 2000 Pa·s) to ensure a tight bond with the original pavement after filling and prevent secondary cracking.
Pothole Repair: Cold-mix asphalt or hot-mix asphalt mixtures with a gradation similar to the original pavement should be used. Cold-mix asphalt is suitable for emergency repairs and can be directly laid and compacted; hot-mix asphalt needs to be heated on-site to 160-180℃, and its asphalt-aggregate ratio (the ratio of asphalt to aggregate) is usually controlled at 4.5%-6.5% to ensure strength and durability.
III. Step-by-Step Construction Process
1. Crack Repair (Taking Crack Filling as an Example)
Grooving: Use a cutting machine to cut a V-shaped groove 5-10cm wide and 3-5cm deep along the crack direction, and remove debris from the groove.
Cleaning: Use a high-pressure air compressor or blower to blow away dust from the groove, ensuring no loose dust remains.
Heating and Filling: Heat the crack filler to 180-200℃ and pour it into the groove. The filling height should be 2-3mm higher than the road surface to prevent shrinkage and sinking.
Compacting: After the material cools to below 60℃, compact it with a strip or small road roller to ensure it is flush with the original road surface.
2. Pothole Repair (Taking Hot Mix as an Example)
Cutting and Cleaning: Use a cutting machine to remove the damaged parts of the pothole edge, forming a regular rectangle, down to the hard base layer, and remove loose particles from the bottom.
Tack Coating: Apply 0.3-0.5 L/m² of emulsified asphalt to the bottom and sides of the pothole to enhance adhesion between the new and old materials.
Layered Filling: Fill the pothole with hot-mix asphalt in 2-3 layers, each layer not exceeding 5 cm in thickness. Compact with a plate vibrator or small roller, achieving a compaction degree of ≥95%.
Surface Treatment: After the final layer, smooth the surface with a scraper and apply sealant to the joints with the existing pavement to prevent water seepage.
IV. Construction Precautions
Safety Protection: Construction personnel must wear reflective vests and safety helmets. Warning signs must be set up on site. Heating equipment must be kept away from flammable materials to prevent fire.
Material Temperature Control: Hot-mix asphalt must be used within 2 hours to prevent temperature drops from reducing adhesion. Cold-mix asphalt must be stored in a dry, well-ventilated place to prevent moisture absorption and clumping.
Traffic Control: The construction area must be closed off. Traffic should only be allowed after the material has fully cured (usually 2-4 hours) to prevent deformation caused by vehicle traffic. V. Adjustment Plans for Different Scenarios
Highway Repair: Construction should be carried out at night when traffic is low, using fast-curing repair materials to shorten the sealing time.
Bridge Expansion Joint Repair: Materials with an elastic modulus similar to the original structure should be selected to avoid cracking due to temperature changes.
Low-Temperature Environment Construction: Antifreeze agents can be added or repair materials with good low-temperature flexibility can be selected to ensure that flexibility is maintained even at low temperatures.