Executive summary
Engineers design geogrids as geosynthetic reinforcements in road construction. They transfer, distribute, and restrain loads. This happens through mechanical interlock with soil and total. Geogrids have several advantages over traditional reinforcement methods. They are lighter, resist corrosion, install quickly, and have a smaller carbon footprint. The Beijing–Shanghai high-speed rail project used 120 million m² of high-performance geogrids. This helped reduce embodied carbon by about 210,000 tCO₂. This white paper covers material types, performance metrics, application logic, and selection tips for pavement and subgrade engineers.
1. Geogrid types and core properties
1. Geogrid types and core propertiesSelection outcomes depend on matching material attributes to operational conditions. The principal geogrid families are summarized below.
| Type | Core material | Key performance metrics | Primary advantages | Limitations |
|---|---|---|---|---|
| Plastic geogrids | HDPE, PP | Tensile strength 15–120 kN/m; elongation ≤25% | Low cost, corrosion-resistant, lightweight | Limited high-temperature tolerance (≤140°C) |
| Glass-fibre geogrids | E-glass + PVC/asphalt coating | Tensile strength 25–120 kN/m; elongation ≤3% | High tensile strength, low creep, high-temperature durability | Brittle, poor flexural tolerance |
| Steel–polymer composite geogrids | High-strength steel wire + PE coating | Tensile strength ≥100 kN/m; node strength >300 N | Ultra-high strength; long service life (≥100 years) | Requires edge corrosion protection |
| Basalt-fibre geogrids | Basalt fibre | Temperature tolerance −260 to 700°C; tensile comparable to glass | Extreme-environment resistance; good toughness | Higher material cost |
| Polyester (PET) geogrids | PET yarns | Strong fatigue resistance; balanced biaxial strengths | Ductile, durable under sustained loads | Lower resistance to strong acids/alkalis |
Sources: material performance reviews and Tensar technical literature.
Note: The term geogrids in pavement construction is often used the same way as “geogrids in road construction.” This applies to overlay and surface layer reinforcement.
2. Application scenarios and selection logic
2.1 New embankment and soft ground reinforcement
Primary Issues:
Insufficient bearing capacity.
High embankment filled with lateral spreading.
Differential settlement.
Geogrids create a “snowshoe effect.” This spreads loads and can cut total settlement by 30% or more.
Soft coastal, tidal flat, marsh soils: Prefer uniaxial PP geogrids (e.g., TGDG35–TGDG50). At 2% strain, these products deliver ≥9 kN/m tensile force, enabling rapid strength gain. Cold-region implementations (e.g., Qinghai–Tibet applications at −45°C) confirm performance. Upgrade to steel–polymer composite geogrids (tensile ≥50 kN/m) for permanent, high-grade corridors. This helps limit differential settlement in karst zones.
High embankments (fill > 8 m): Use biaxial steel–polymer geogrids (80 kN/m spec). Make sure the node strength is over 300 N to control lateral deformation. Follow the construction sequence: “sides first, center last.” Also, ensure the geogrid wrap-back length is at least 1.5 m.
2.2 Surface-layer (pavement) crack mitigation
Early pavement distress often starts from reflective cracking and rutting. Geogrids help improve layer cohesion and delay failure.
Asphalt pavements, whether new or for maintenance, work best with glass-fiber geogrids. They have low elongation (≤3%) and fit well with asphalt. This choice usually adds 3 to 5 years to the service life against reflection cracking. In high-temperature paving (surface temps ≥60°C), use basalt-fiber geogrids. They can handle temperatures up to 700°C. Ensure full contact with the supporting layer and at least 300 mm of overlap.
Concrete overlays and slabs use polyester geogrids, like TGSG30-30. These geogrids provide strength, with at least 30 kN/m in both directions. They help reduce thermal cracking and are popular for airfield runway strengthening.
2.3 Transition zones, bridge approaches, and slope protection
Stress concentration at interfaces dictates specialized solutions.
Biaxial steel–polymer geogrids (50 kN/m) handle interface stresses well at fill–cut transitions and old–new embankment junctions. Create a 1:1.5 stepped excavation bench. Then, apply cement slurry to the bedding surface before placing the geogrid. This will enhance the bond. Implementation on high-speed rail corridors has reduced differential settlement to < 5 mm.
Bridge approach bump mitigation: Using high-modulus glass-fiber geogrids under approach slabs helps reduce foundation settlement. This can cut maintenance cycles by about 60%.
Slope protection (under 10 m height): Use uniaxial plastic geogrids (TGDG80) wrapped in vegetated erosion-control containers. They use a 40×40 mm mesh, which helps plants grow and boosts slope stability by about 40%. Slopes >10 m should use TGDG110+ and rock anchor or soil nail fixation.
2.4 Temporary and heavy-haul pavements
Balance the economy and structural demand for construction, roads, and mining routes.
Temporary access roads: Biaxial plastic geogrids (TGSG20-20) offer great cost and performance. They cut subbase thickness by about 30% and reduce construction costs by around 20%.
Extreme heavy-haul roads, like those for coal, use steel–polymer composite geogrids. These geogrids have a tensile strength of at least 100 kN/m. They resist creep well and can handle heavy truck traffic daily. This setup offers service lifetimes of over five years, even with constant heavy loads.
3. Procurement and specification guidance (FAQ highlights)
How do you select by road class and axle load?
Select materials based on design load demand:
Rural roads: biaxial plastic (TGSG15-15)
Expressways and primary highways: steel–polymer composite (50–80 kN/m)
Asphalt crack mitigation: glass fiber (GG40–GG80)
Ultra-heavy loads (axle load > 100 t): steel–polymer geogrids ≥ 120 kN/m
Always confirm parameters per GB/T 50290-2014 or project-specific standards.
Which auxiliary parameters matter besides tensile strength?
Key indices:
Elongation: ≤3% for surfacing geogrids; ≤15% for subgrade.
For high temperatures, choose basalt or glass.
Use PE-coated steel in saline or alkaline conditions.
Node strength: >300 N for steel–polymer composites.
Insist on third-party test certificates.
Must have at least 80% residual strength after 500 hours of UV exposure.
How do you balance cost and performance?
Follow the “fit-for-purpose” principle:
Focus on high performance for permanent infrastructure.
Emphasize cost-effectiveness for temporary work.
Example: for 1 km of secondary road subgrade, TGDG50 plastic geogrid (~¥8/m²) can save ~68% versus steel–polymer (~¥25/m²) while meeting design targets.
4. Conclusions and engineering recommendations
4. Conclusions and engineering recommendationsConclusions: Geogrids in road construction are now essential reinforcement systems, not just extras. Selection must consider three key areas: the specific needs of the scenario, the performance of materials, and managing life-cycle costs.
Recommendations
For soft-ground bearing improvement, focus on PP or steel–polymer geogrids.
For fixing pavement cracks, use glass-fiber or basalt-fiber geogrids. They help reduce creep and fit well with the surface.
Use biaxial steel–polymer geogrids in stress transfer and heavy-duty areas. Make sure they have verified node strength.
Need performance testing and third-party certification for each project.
Include UV, chemical, and long-term creep evaluations in procurement clauses.
Future manufacturing advances in high-performance geogrids will expand their role in low-carbon road construction and asset resilience. Proper specification and standardized application are decisive to realize the full technical and environmental benefits of geogrids in pavement construction and geogrids in road construction.
