Road Maintenance And Repair Solutions

I. Conservation Classification and Applicable Scenarios

II. Key technologies and techniques

1. Preventive maintenance technology

● Fog sealing layer (Fog Seal)

i.Technique: use high pressure equipment to spray emulsified asphalt or asphalt rejuvenation agent (dosage 0.8-1.2kg/m²), close the micro-cracks of the pavement, and restore the viscosity of asphalt. 

ii. Effect: Delay aging for 5-8 years, the cost is only 1/5-1/3 of milling and resurfacing.

● Micro-Surfacing

i. Material: Polymer modified emulsified asphalt + aggregate (3-5mm) + filler, thickness 5-10mm. ii.

ii. Application: Repair rutting (depth ≤15mm), improve skid resistance, open to traffic 2 hours after construction.

● Crack Filling

i.Material: Silicone sealant, rubberized asphalt adhesive (temperature -20℃ to 70℃).

ii.Technique: clean the cracks (compressed air blowing) → heating the groove wall → filling sealant → cooling molding.

2. Corrective maintenance technology

Hot regeneration repair

● Hot regeneration on site:

Heat the old pavement (100-130℃) → rake loose → add regeneration agent → re-paving and rolling.

Advantage: 100% utilization of original pavement material, environmental protection and high efficiency, suitable for continuous disease repair.

● Factory mixed hot regeneration:

The old material is transported back to the factory and mixed with new material (the proportion of regenerated material ≤ 30%), used in the surface layer or grass-roots level.

Cold Patch Repair

● Materials: Finished cold patch asphalt mixture (with additives, can be constructed at - 10℃ to 40℃).

● Scenario: emergency repair, winter construction, no heating equipment, can be opened to traffic after compaction.

3. Structural maintenance technology

● Roadbed grouting reinforcement

Process: drill holes to the roadbed disease layer (e.g. soft base, hollow) → inject cement slurry or polyurethane foam → fill and compact.

Inspection: Geo-radar comparison is used before and after grouting to ensure that the compactness is improved by ≥20%.

● RUBBLE PAVEMENT (RUBBLE REFORMATION)

Applicable: the overall strength of the old cement concrete pavement is insufficient and needs to be changed to asphalt pavement.

Process: Multi-hammer head crusher crushes the old slab into 3-10cm particles → crushing and stabilization → paving stress absorption layer → asphalt surface layer.

● Advantage: preserving the original roadbed structure, shortening the construction period by 50%, and reducing the emission of construction waste.

4. Emergency Maintenance Technology

quick repair material

● Fast-hardening cement: strength reaches 20MPa in 1 hour, used for pothole and broken plate emergency repair.

● Polymer composite materials: e.g. MMA (methyl methacrylate) coating, curing in 20 minutes, used for emergency repair of airport runways.

Temporary drainage systems

● Mobile pump trucks (flow rate ≥500m³/h) are deployed during heavy rainfall, combined with sandbags to seal the water-prone points, and access is restored within 4 hours.

III. Intelligent maintenance management system

1. Detection and assessment technology

non-destructive testing equipment

● Ground Penetrating Radar (GPR): detects the layered thickness, voids and water content of roadbed with an accuracy of ±5cm.

● Laser Leveling Instrument: Quickly measure IRI (International Leveling Index) and determine the driving quality of road surface (IRI≤2.5m/km is excellent).

● Falling Hammer Bending Depth (FWD) Instrument: Determine the structural bearing capacity of the pavement, and guide structural maintenance decisions.

Digitalized assessment platform

● establishes road “health records”, analyzes disease development trends through AI algorithms, and automatically generates a list of maintenance priorities (e.g., prioritizing road sections with RQI (road surface driving quality index) <60).

2. Intelligent Scheduling and Monitoring

GPS management for maintenance vehicles

● Real-time tracking of equipment location and operation trajectory to optimize route planning (e.g. when multiple pavers are working together, the spacing is controlled at 5-8m).

Remote Monitoring System

● Deployment of strain gauges and inclination sensors in key bridges and tunnels, with automatic alarms for abnormal data (e.g. crack expansion rate > 0.2mm / month).

3. Big data decision support

Analyze historical maintenance data and establish “Disease - Climate - Traffic” correlation model, for example:

● Prior to the rainy season, focus on checking the drainage system of water-prone road sections;

● Encrypt rutting resistance testing on heavy traffic sections.

IV. Environmental Protection and Sustainable Practices

1. Material recycling

● The recycling rate of old asphalt is ≥95%, and the recycled material is used for grass-roots level or low-grade road surface layer;

● Concrete waste is processed into recycled aggregate (utilization rate ≥80%), which is used for temporary right-of-way or park roads.

2. Low-carbon process promotion

● Increase the proportion of warm-mix asphalt construction to more than 30%, reducing CO₂ emission by about 20kg/ton asphalt;

● Electric maintenance equipment (e.g. electric rollers, sweepers) gradually replaces fuel equipment, reducing noise by 10-15dB.

3. Ecological restoration

● Slope maintenance adopts vegetative concrete (including grass seed and water retaining agent), with 90% coverage rate within 6 months;

● adopt drought-tolerant plants (e.g. Sedum) for the central divider, reducing irrigation water by more than 50%.

V. Examples of typical maintenance programs

1. Preventive maintenance package for highways

● Applicable road conditions: 5-8 years after the commissioning of the highway, no structural diseases on the road surface, slight cracks and aging.

● Program:

i. Filling and sealing of cracks along the whole line (for cracks with width >3mm). ii;

ii.Carriageway micro-surface (thickness 8mm), hard shoulder fog sealing layer. iii;

Periodicity: 1 time per year, 3 years in a row, total cost reduced by 40% compared with post-disease restoration.

2. Emergency Repair of Urban Trunk Roads

● Scenario: pothole found in the early morning (depth 15cm, area 10㎡), need to be repaired within 6 hours.

● program:

i. Cut the pothole (expand to regular shape) → clean up the loose debris. ii;

ii.Pave cold patching asphalt mixture (compaction in two layers, each layer thickness ≤7cm);

iii.Spreading stone chips to prevent sticking wheels and setting temporary warning signs before opening to traffic.

3. Low-cost maintenance of rural roads

● technology:

● adopts “Mud-caking gravel + Emulsified asphalt cover” technology to fill the abrasion layer before the rainy season every year;

● mobilize villagers to participate in daily inspections and report any disease promptly (incentive mechanism).

VI .Indicators for assessing conservation effectiveness

Summary

The road maintenance and repair solution realizes the change from “passive repair” to “active prevention” through the whole chain management of “accurate detection - scientific decision - efficient implementation - recycling”. “ to “active prevention”. The future development direction focuses on intelligence (AI disease identification, unmanned maintenance machinery), greening (fully recycled materials, low-carbon processes) and intensification (multi-service collaborative scheduling), ultimately realizing the optimal allocation of maintenance resources and preserving and increasing the value of road assets.