Asphalt pavement pothole repair should follow principles such as "square patching for round holes, deep patching for shallow holes," and adopt a compaction sequence of "first the four sides, then the middle," filling in layers to ensure repair quality and make the pavement both safe and aesthetically pleasing.
Road Defects and Challenges
Over long-term use, asphalt roads face multiple challenges, including increased traffic volume, extended service life, and changes in natural conditions. These factors can lead to various road defects. Among them, potholes caused by localized aggregate loss are particularly prominent. They are not only widespread on asphalt pavements but also seriously affect driving safety and comfort, and damage the road's appearance. If maintenance is not carried out in a timely manner, it will not only pose a potential threat to driving safety but also lead to further increases in maintenance costs.
Currently, road maintenance organizations generally use cold asphalt patching materials to treat pavement potholes.

To ensure the quality and final aesthetics of pothole repairs, a series of maintenance technical requirements must be followed, and the following key principles must be adhered to during construction:
【"Round Potholes Repaired with Square Fillers, Slanted Potholes Repaired with Straight Fillers" Principle】 This principle requires that potholes, regardless of their shape (round, slanted, or other irregular forms), must be cut into right-angled rectangles. Simultaneously, ensure that the edges of the cut potholes are parallel or perpendicular to the road markings.
Following this principle results in smooth lines and an aesthetically pleasing appearance after repair, thus reducing driver visual fatigue.
【"Shallow Potholes Repaired with Deep Fillers" Principle】 Some potholes may appear shallow, with only the upper layer damaged; however, the damage may actually have penetrated to the lower layers or even the base layer. Therefore, when cleaning these potholes, we must look beyond the surface and ensure that each layer of damage is thoroughly treated. This not only improves the quality of pothole repairs but also reduces the frequency of maintenance, thereby lowering construction costs.
【"Continuous Potholes Repaired in Succession" Principle】 For severely damaged road surfaces, potholes often exhibit characteristics of continuity and connection. To ensure effective repair, these potholes need to be cut as a whole and repaired uniformly. This not only helps improve the overall strength of the repaired pavement but also effectively reduces construction complexity and prevents vehicles from bouncing.
【The "Appropriate Outward Shift of Tangent Line" Principle】 After delineating the repair interface and determining the repair area, we need to slightly extend the repair outline outward. This extension is typically based on the actual dimensions of the pothole surface, increasing by 5 to 10 centimeters in each direction to ensure the repair area forms a regular rectangle. This operation not only optimizes the connection between the old and new pavement but also helps improve the overall repair quality.
【Pothole Filling and Compaction Steps】 After completing the road surface trenching, all residues in the pothole must be thoroughly removed. Then, a bonding agent is applied, and asphalt cold patch material is filled and compacted. During this process, three principles must be strictly followed:
【The "Four Sides First, Then the Center" Compaction Principle】 During compaction, the principle of "four sides first, then the center" should be followed. This is because asphalt cold patch material has good ductility before compaction. Starting compaction from the center may push the asphalt mixture onto the old pavement, affecting the smoothness of the compaction. Compacting the edges first, then the center, effectively avoids this problem. Special attention should be paid to the joints between the new and old pavements; compaction should be applied across the joint to ensure a tight seal at the pothole edges, achieving a watertight seal.
【Compaction Sequence: Lateral Then Longitudinal】 When compacting asphalt patch material for large potholes, the sequence should be "lateral first, then longitudinal." Based on the road's direction, first use compaction tools for lateral compaction, then proceed with longitudinal compaction. This effectively prevents vehicles from bouncing due to improper compaction.
【Layered Filling, Layered Compaction】 When potholes exceed 5 cm in depth, a layered filling method should be used. Apply asphalt patch material in 3-5 cm thick layers, ensuring each layer is fully compacted. This ensures better density and higher repair quality after the repair.
In summary, the pothole repair process using cold patching compound on asphalt pavements requires adherence to several principles during the grooving stage, including "square patching for round potholes, straight patching for slanted potholes, and deep patching for shallow potholes," as well as merging and repairing consecutive potholes and appropriately shifting the tangent outwards. During the compaction of the filler, the order should be "four sides first, then the middle; transverse first, then longitudinal," ensuring layered compaction and thorough rolling to guarantee superior repair quality and a smooth, aesthetically pleasing final pavement.