Neoloy Geocells Increase Resistance With Reduced Thickness

Neoloy® Geocells provide greater reinforcement than geogrids, while using inferior soil and reducing the required pavement thickness.

There are numerous advantages to using Neoloy Geocells, in comparison to geogrids. Neoloy is more durable and resistant. At the same time, there are significant cost savings using Neoloy, which reduces pavement thickness and can deploy inferior soil.

Comparison Table

Resistance and Dimensional Stability

TOPICNeoloy GeocellsGEOGRID
Resistance-deformationHighly elastic behavior (resistance) before reaching high deformationSmall resistance at small deformation
Durability under cyclic dynamic loadsVertical loads are translated to radial loads that are translated to hoop stress in geocell walls for very high dimensional stability and structural integrityHigh level of deformation
Resistance zoneResistance is achieved in a the three-dimensional “plane”The resistance is limited to a thin plane, in one or two directions
Bending moment resistanceDepth of layer provides an increased bending moment resistance effective to at least the height of cell walls. Additionally the structural resistance and integrity of the Neoloy solution provides a better performance under concentrated or ”point” loadsAlmost no resistance. Geogrids require a minimum of two layers to create a planer composite before gaining minor Bending Moment Resistance
Vertical soil interface frictionLarge interface area of highly textured and perforated cell wallsSmall height of active area
Lateral deformationLateral stresses on the cell walls are confined by stiff cell walls, while the passive earth resistance of adjacent cells provides additional resistance against the loaded cell. The result is a stiff beam with high bearing capacity.The limitation of the lateral expansion is restricted to a very small section (unless the Geogrid can be used in a “wrap-around” fashion).
Stress and settlement Neoloy distributes the surface load though the three-dimensional beam or semi-rigid slab as a unit, reducing stresses transferred to the subgrade by up to 50%. Also as the stress is more uniformly distributed in the mattress, total and differential settlements are greatly reduced.Geogrids only respond to loading within a small effective radius. The load is distributed over a smaller area, and thus, the stress increases as does the possibility of total or differential settlements

Infill Soil Types, Soil Retention, Drainage

TOPICNeoloy GeocellsGEOGRID
Reinforced/retained soilsAccepts a wide variety of soils, even inferior or poorly graded granular materialsRequires specific quality (and high-cost) aggregate fill type
Retained soil improvementImproves the apparent cohesion of the soil, which significantly increases its resistance to imposed loading.The improved area has a limited vertical range
Performance with abraded soilsThree-dimensional confinement reduces aggregate abrasion and attritionReduces attrition only if used with specific granular and graded soil
Drainage performanceRetains soil particles in a multi-axial range, thus allowing the natural passage of liquid flows in any direction while preventing those flows from leaching away the retained soil particles.Retains soil particles in only thin layer consistent with its planer dimension. Liquid flows can easily leach soil particles away in all other directions.

A key difference between the Neoloy Geocell and geogrid reinforcement in road construction is the thickness of the confined layer. The Neoloy 3D vertical zones of influence (full confinement) is at least 20 mm, whereas the geogrid reinforcement zone (interlock, not full confinement) is limited to 1-2 times the size of the granular material. Neoloy Geocell 3D confinement also minimizes lateral movement of soil better than geogrids.

Moreover, geogrid road reinforcement require specific and relatively expensive granular materials (ballast, crushed stone and gravel). They cannot reinforce fine grain “inferior” non-cohesive materials as there is no interlocking. Neoloy 3D confinement transforms the modulus of inferior (fine grained) fill to that of higher quality granular fill, such that they can be used for structural infill. This includes lower cost native soil, quarry waste, sand, and recycled construction waste.

Neoloy Geocells also create a reinforced mattress with a beam effect with unbounded base material. Comparative tests of Neoloy vs. geogrids in road construction demonstrated that the Neoloy Geocell improvement factor was higher than any of the seven leading geogrids tested.

Neoloy’s dramatic impact on the thickness of structural pavements was demonstrated in field trials conducted by KOAC–NPC (Netherlands). Neoloy was the only geocell tested against 7 leading geogrids and the only product tested with inferior aggregate infill.

 

Benefits of Neoloy Geocells vs. Geogrid Reinforcement

  • 3D larger fully and partially confined zones of influence – more reinforcement
  • 3D confinement better minimizes movement of soil in 3 directions
  • Neoloy creates a beam effect that greatly increases bearing capacity
  • Neoloy confinement enables use of range of inferior and recycled infill materials
  • Can utilize granular materials with average particle size from less than 20 to10 mm or less
  • Save infill costs by utilizing less-expensive, available granular infill
  • More sustainable solution than geogrids
  • Economically advantageous

The mean road-base thickness reduction factor (CBR =1.5) for Neoloy was 0.73, using the CROW design methodology (see chart). This value exceeded all previously known values for geogrid reinforcement. Even after truncating the test limits to 0.5 (the highest known values for geogrids) Neoloy achieved the highest reduction factors of all tested geogrids.