Neoloy Geocell

Last updated
Neoloy Geocells (Cellular Confinement System)
TypeRigid NPA Tough-Cell geocell
InventorPRS Geo-Technologies
Inception2006
ManufacturerPRS Geo-Technologies
Website https://www.prs-med.com
Notes
3D mechanical soil stabilization solution used in geotechnical & civil engineering, landscape architecture, infrastructure construction

The Neoloy Geocell (previously under the Neoweb trademark) is a Cellular Confinement System (geocell) developed and manufactured by PRS Geo-Technologies Ltd. Geocells are extruded in ultrasonically welded strips. The folded strips are opened on-site to form a 3D honeycomb matrix, which is then filled with granular material. The 3D confinement system is used to stabilize soft subgrade soil and reinforce the subbase and base layers in flexible pavements. Cellular confinement is also used for soil protection and erosion control for slopes, including channels, retention walls, reservoirs and landfills.

Contents

Material

Neoloy Geocells are manufactured from novel polymeric alloy (NPA). As stated in ASTM D8269-21:Standard Guide for Use of Geocells in Geotechnical and Roadway Projects: “It is important to note that geocells made from different types of materials, sizes, strengths, etc. may behave or perform differently from one another; therefore, it is important to understand and utilize proper material properties that relate to its performance…” [1] NPA has improved dynamic stiffness (elastic modulus), resistance to permanent deformation (creep) and tensile strength, compared to HDPE, a widely-used polymer used for geocells. [2] [3] [4] [5] Research has shown a rigid geocell material better retains the geocell geometry (dimensional stability) confinement and reinforcement. [6] [7] These geocell performance parameters are critical for the requirements of base-layer reinforcement of heavy-duty pavements and infrastructure. [8] Reinforcement with high modulus geocells also optimizes pavement design by enabling a longer design life and lower maintenance cycles/costs. [9]

History

The geocell concept was originally developed by the US Army Corps of Engineers in cooperation with Presto Products in the 1970s as "sand-grids" to improve the soft subgrades of unpaved roads for short-term use by heavy military vehicles (Webster and Alford, 1977). [10] PRS Geo-Technologies (est. 1996) began manufacture of Neoloy brand of geocells (aka Tough-Cells). A polymer alloy based on a polyolefin matrix reinforced by polyamide nano-fibers (NPA) was developed with improved stiffness and durability to extend its service life under low deformation levels. [11] [12] [13] [14] Geocells made from NPA have material properties to maximize the magnitude of mechanical stabilisation for the project design life in applications such as the structural pavements, embankments and high retention walls. [15] [16]

Research

Extensive research on exploring geocell reinforcement for roadway applications at the University of Kansas, [12] as well as at other geotechnical/civil engineering research institutes, such as the Indian Institute of Technology (Madras), ⁣ [17] University of Delaware, ⁣ [11] Clausthal University (Germany) [18] and Columbia University (NY). [19] The research described the mechanisms and influencing factors of geocell reinforcement, evaluated its effectiveness in improving roadway performance and developed design methods for roadway applications. The research [8] ⁣ included laboratory box tests, accelerated moving wheel tests, field demonstration, actual projects and development of design methods. [12] Comparative test results showed that Neoloy Geocells made from NPA improved stiffness, bearing capacity, stress distribution and reduced deformation considerably (Pokharel, et al. 2011 and 2009). [20] [21]

Applications

Neoloy Geocells are suitable for use in basal reinforcement of asphalt paved roads, due to high tensile strength, resistance to permanent deformation and dynamic (elastic) stiffness under cyclical load stresses. [12] Neoloy Geocells are typically used in soil stabilization and layer reinforcement of pavement types, such as highways, railways, ports, storage yards and unpaved haul, access and service roads. An example of an unpaved road project under difficult conditions in Afghanistan was undertaken by the UK Royal Engineering Corps Route Trident to create a secure patrol road for the benefit of troops and civilians alike. [22] [23]

Design methodologies

Research included the integration of Neoloy Geocells in existing road design methodologies. [24] Standard ISO/TR18228-5: Design Using Geosynthetics: Part 5: Stabilisation utilizes the concepts of serviceability and ultimate limit states to effectively withstand service loading, control deformation within service requirements, and over time. The design life of the project is proposed as a key design consideration, which means limiting the rate and level of deformation of the geosynthetic stabilisation accordingly. Geocells have shown to stiffen granular materials by 3D confinement, thereby increasing the modulus of the stabilized layer; this is the Modulus Improvement Factor (MIF). The stiffer the geocell, the higher the hoop tensile strength will be and thus the higher the MIF. [25] A reliable method for quantifying the Neoloy Geocell contribution to a pavement structure, the Modulus Improvement Factor (MIF) of 1.5-5 - dependent upon the material of infill, subgrade and location of reinforced layer - was obtained from field tests, laboratory tests and finite element studies. [17]


Sustainable transportation

Neoloy Geocells may be considered a sustainable road construction method. [26] By improving the structural properties of low strength materials, Neoloy Geocells can replace quarry aggregate with marginal, lower strength materials, such as locally-available sand; recycled and reclaimed construction materials (RAP and recycled concrete). Not only does the use of such materials in road construction conserve quarry resources and recycle waste. It also reduces quarry, haul and infill activities, which in turn decrease the amounts of fuel, pollution and the carbon footprint for projects. [27] A pavement reinforced with geosynthetics can also increase the lifespan of pavement structures, [12] which improves its sustainability by reducing repairs and maintenance.

How it works

When Neoloy Geocells are deployed and compacted with soil/aggregate, a composite structure is created from the geotechnical interaction of the material, soil and geometry. [28] Soil confinement retains infill materials in three dimensions providing high tensile strength on each axis. Under loading, Neoloy Geocells generate lateral confinement, while soil-to-cell wall friction reduces vertical movement. The high hoop strength of the cell walls, together with the passive earth and passive resistance of adjacent cells, also increases soil strength and stiffness. Aggregate abrasion is minimized by the cell confinement, thereby reducing attrition of the base material. [18] Vertical loading on Neoloy Geocells with compacted infill creates a semi-rigid slab or “beam effect” in the structure. [29] This distributes the load evenly and effectively over a wider area, thereby increasing bearing capacity and decreasing differential settlement. Research on the reinforcement mechanisms in geocells shows that the stiffness of the geocell material as well as geometry are the most important confinement parameters. [13] [30]

Environmental durability

NPA based Neoloy Geocells are an inert engineering thermoplastic, non-corrosive, non-leaching, and resistant to extreme environmental, weather and soil conditions, such as those in deserts, saturated peat bogs and arctic tundra. Additives provide retention of its engineering properties under long-term exposure to UV radiation and oxidation.

See also

Related Research Articles

<span class="mw-page-title-main">Geotechnical engineering</span> Scientific study of earth materials in engineering problems

Geotechnical engineering, also known as geotechnics, is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics to solve its engineering problems. It also relies on knowledge of geology, hydrology, geophysics, and other related sciences.

<span class="mw-page-title-main">Highway engineering</span> Civil engineering of roads, bridges, and tunnels

Highway engineering is a professional engineering discipline branching from the civil engineering subdiscipline of transportation engineering that involves the planning, design, construction, operation, and maintenance of roads, highways, streets, bridges, and tunnels to ensure safe and effective transportation of people and goods. Highway engineering became prominent towards the latter half of the 20th century after World War II. Standards of highway engineering are continuously being improved. Highway engineers must take into account future traffic flows, design of highway intersections/interchanges, geometric alignment and design, highway pavement materials and design, structural design of pavement thickness, and pavement maintenance.

<span class="mw-page-title-main">Road surface</span> Road covered with durable surface material

A road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, macadam, hoggin, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads or dirt roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.

<span class="mw-page-title-main">Railway track</span> Rail infrastructure

A railway track or railroad track, also known as a train track or permanent way, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties and ballast, plus the underlying subgrade. It enables trains to move by providing a dependable surface for their wheels to roll upon. Early tracks were constructed with wooden or cast iron rails, and wooden or stone sleepers; since the 1870s, rails have almost universally been made from steel.

<span class="mw-page-title-main">Asphalt concrete</span> Composite material used for paving

Asphalt concrete is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the beginning of the twentieth century. It consists of mineral aggregate bound together with bitumen, laid in layers, and compacted.

<span class="mw-page-title-main">Retaining wall</span> Artificial wall used for supporting soil between two different elevations

Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to. They are used to bound soils between two different elevations often in areas of inconveniently steep terrain in areas where the landscape needs to be shaped severely and engineered for more specific purposes like hillside farming or roadway overpasses. A retaining wall that retains soil on the backside and water on the frontside is called a seawall or a bulkhead.

<span class="mw-page-title-main">Permeable paving</span> Roads built with water-pervious materials

Permeable paving surfaces are made of either a porous material that enables stormwater to flow through it or nonporous blocks spaced so that water can flow between the gaps. Permeable paving can also include a variety of surfacing techniques for roads, parking lots, and pedestrian walkways. Permeable pavement surfaces may be composed of; pervious concrete, porous asphalt, paving stones, or interlocking pavers. Unlike traditional impervious paving materials such as concrete and asphalt, permeable paving systems allow stormwater to percolate and infiltrate through the pavement and into the aggregate layers and/or soil below. In addition to reducing surface runoff, permeable paving systems can trap suspended solids, thereby filtering pollutants from stormwater.

<span class="mw-page-title-main">Geosynthetics</span> Synthetic material used to stabilize terrain

Geosynthetics are synthetic products used to stabilize terrain. They are generally polymeric products used to solve civil engineering problems. This includes eight main product categories: geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells and geocomposites. The polymeric nature of the products makes them suitable for use in the ground where high levels of durability are required. They can also be used in exposed applications. Geosynthetics are available in a wide range of forms and materials. These products have a wide range of applications and are currently used in many civil, geotechnical, transportation, geoenvironmental, hydraulic, and private development applications including roads, airfields, railroads, embankments, retaining structures, reservoirs, canals, dams, erosion control, sediment control, landfill liners, landfill covers, mining, aquaculture and agriculture.

<span class="mw-page-title-main">Geotextile</span> Textile material used in ground stabilization and construction

Geotextiles are versatile permeable fabrics that, when used in conjunction with soil, can effectively perform multiple functions, including separation, filtration, reinforcement, protection, and drainage. Typically crafted from polypropylene or polyester, geotextile fabrics are available in two primary forms: woven, which resembles traditional mail bag sacking, and nonwoven, which resembles felt.

<span class="mw-page-title-main">Subbase (pavement)</span>

In highway engineering, subbase is the layer of aggregate material laid on the subgrade, on which the base course layer is located. It may be omitted when there will be only foot traffic on the pavement, but it is necessary for surfaces used by vehicles.

The California Bearing Ratio (CBR) is a measure of the strength of the subgrade of a road or other paved area, and of the materials used in its construction.

<span class="mw-page-title-main">Geocomposite</span> Materials to improve technical properties of soil or geotechnical structure

Geocomposites are combinations of two or more geosynthetic materials for civil engineering applications that perform multiple geosynthetic functions. Such composite materials may enhance technical properties of the soil or the geotechnical structure and minimize application costs.

<span class="mw-page-title-main">Geogrid</span> Synthetic material used to reinforce soils and similar materials

A geogrid is geosynthetic material used to reinforce soils and similar materials. Soils pull apart under tension. Compared to soil, geogrids are strong in tension. This fact allows them to transfer forces to a larger area of soil than would otherwise be the case.

<span class="mw-page-title-main">Mechanically stabilized earth</span> Soil constructed with artificial reinforcing

Mechanically stabilized earth is soil constructed with artificial reinforcing. It can be used for retaining walls, bridge abutments, seawalls, and dikes. Although the basic principles of MSE have been used throughout history, MSE was developed in its current form in the 1960s. The reinforcing elements used can vary but include steel and geosynthetics.

<span class="mw-page-title-main">Cellular confinement</span> Confinement system used in construction and geotechnical engineering

Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth retention. Typical cellular confinement systems are geosynthetics made with ultrasonically welded high-density polyethylene (HDPE) strips or novel polymeric alloy (NPA)—and expanded on-site to form a honeycomb-like structure—and filled with sand, soil, rock, gravel or concrete.

Novel polymeric alloy (NPA) is a polymeric alloy composed of polyolefin and thermoplastic engineering polymer with enhanced engineering properties. NPA was developed for use in geosynthetics. One of the first commercial NPA applications was in the manufacturer of polymeric strips used to form Neoloy® cellular confinement systems (geocells).

Soil stabilization is a general term for any physical, chemical, mechanical, biological, or combined method of changing a natural soil to meet an engineering purpose. Improvements include increasing the weight-bearing capabilities, tensile strength, and overall performance of unstable subsoils, sands, and waste materials in order to strengthen road pavements.

<span class="mw-page-title-main">Jean-Pierre Giroud</span>

Jean-Pierre Giroud is a French geotechnical engineer and a pioneer of geosynthetics since 1970. In 1977, he coined the words "geotextile" and "geomembrane", thus initiating the "geo-terminology". He is also a past president of the International Geosynthetics Society, member of the US National Academies, and Chevalier de la Légion d'Honneur.

Paradox Access Solutions is a construction company specializing in customized access solutions for companies who need temporary or permanent roadways built on unstable terrain, such as muskeg, permafrost or mud. The company is located in Acheson, Alberta with distribution access across Alberta and Saskatchewan.

<span class="mw-page-title-main">Analysis of controlled deformation in rocks and soils</span>

The Analysis of Controlled Deformation in Rocks and Soils, translated from Italian Analisi delle Deformazioni Controllate nelle Rocce e nei Suoli (ADECO-RS), also known as The New Italian Tunneling Method (NITM), is a modern tunnel design and construction approach. ADECO-RS was proposed by Pietro Lunardi in the 1980s on the basis of long in-depth research into the stress-strain behavior of more than 1,000 km of tunnel and more than 9,000 faces. In the past few decades, ADECO-RS has been widely used in Italian railway, highway and large underground construction projects and has been incorporated into Italian tunnel design and construction specifications.

References

  1. ↑ ASTM D8269-21. Standard Guide for use of Geocells in Geotechnical and Roadway Projects, ASTM International, West Conshohocken, PA, 2018, www.astm.org. https://doi.org/10.1520/D8269-21.
  2. ↑ Ruge, J.C., Gomez, J.G. and Moreno, C.A. (2019). Analysis of the Creep and the Influence on the Modulus Improvement Factor (MIF) in Polyolefin Geocells using the Stepped Isothermal Method. Geopolymers and Other Geosynthetics. Intech Open (www.intechopen.com). doi : 10.5772/intechopen.88518/
  3. ↑ Schary Y. (2020a) Neoloy—Developing a Novel Polymeric Alloy for Geocells. In: Sitharam T., Hegde A., Kolathayar S. (eds) Geocells. Springer Transactions in Civil and Environmental Engineering. Springer, Singapore. doi : 10.1007/978-981-15-6095-8_3
  4. ↑ Alexiew, D. and van Zyl, W. (2019). Cellular Confinement System Reinforcement – Innovation at the Base of Sustainable Pavements. 12th Conference on Asphalt Pavements for Southern Africa, Johannesburg.
  5. ↑ Pokharel, S.K. , Han J., Leshchinsky, D., Parsons, R.L., Halahmi, I. (2009). "Experimental Evaluation of Influence Factors for Single Geocell-Reinforced Sand," Transportation Research Board (TRB) Annual Meeting, Washington, D.C., January 11–15
  6. ↑ Vega, E., van Gurp, C., Kwast, E. (2018). Geokunststoffen als Funderingswapening in Ongebonden Funderingslagen (Geosynthetics for Reinforcement of Unbound Base and Subbase Pavement Layers), SBRCURnet (CROW), Netherlands.
  7. ↑ Pokharel, S.K., Han, J., Manandhar, C., Yang, X.M., Leshchinsky, D., Halahmi, I., and Parsons, R.L. (2011). "Accelerated Pavement Testing of Geocell-Reinforced Unpaved Roads over Weak Subgrade," Journal of Transportation Research Board, the 10th International Conference on Low-Volume Roads, July 24–27, Lake Buena Vista, Florida, USA"
  8. 1 2 Hegde, A., 2017. Geocell reinforced foundation beds-past findings, present trends and future prospects: A state-of-the-art review. Construction and Building Materials, 154, pp.658-674.
  9. ↑ Palese, J.W., Zarembski, A.M., Thompson, H., Pagano, W., and Ling, H.I. (2017). Life Cycle Benefits of Subgrade Reinforcement Using Geocell on a Highspeed Railway – a Case Study, AREMA Conference Proceedings (American Railway Engineering and Maintenance-of-Way Association). Indianapolis, Indiana, USA, September
  10. ↑ Webster, S.L. & Watkins J.E. 1977, Investigation of Construction Techniques for Tactical Bridge Approach Roads Across Soft Ground. Soils and Pavements Laboratory, U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, MS, Technical Report S771, September
  11. 1 2 Leshchinsky, D. (2009) "Research and Innovation: Seismic Performance of Various Geocell Earth-retention Systems," Geosysnthetics, No. 27, No. 4, 46-52
  12. 1 2 3 4 5 Han, J., Pokharel, S.K., Yang, X. and Thakur, J. (2011). "Unpaved Roads: Tough Cell – Geosynthetic Reinforcement Shows Strong Promise." Roads and Bridges. July, 49 (7), 40-43
  13. 1 2 Yang, X., Han, J., Pokharel, S.K., Manandhar, C., Parsons, R.L., Leshchinsky, D., and Halahmi, I. (2011)." Accelerated Pavement Testing of Unpaved Roads with Geocell-Reinforced Sand Bases", Transportation Research Board (TRB) Annual Meeting, Washington, D.C., January 23–27
  14. ↑ Pokharel, S.K., J. Han, R.L. Parsons, Qian, Y., D. Leshchinsky, and I. Halahmi (2009). "Experimental Study on Bearing Capacity of Geocell-Reinforced Bases," 8th International Conference on Bearing Capacity of Roads, Railways and Airfields, Champaign, Illinois, June 29 - July 2,
  15. ↑ Kief, O. (2015b). “Structural Pavement Design with Geocells made of Novel Polymeric Alloy.” Geosynthetics 2015 Conference Proceedings. Portland, Oregon, February.
  16. ↑ Leshchinsky, B., (2011) “Enhancing Ballast Performance using Geocell Confinement,” Advances in Geotechnical Engineering, publication of Geo-Frontiers 2011 conference, Dallas, Texas, USA, March 13-16.
  17. 1 2 23. Kief, O., and Rajagopal, K. (2011) "Modulus Improvement Factor for Geocell-Reinforced Bases." Geosynthetics India 2011, Chennai, India
  18. 1 2 Emersleben A., Meyer M. (2010). The influence of Hoop Stresses and Earth Resistance on the Reinforcement Mechanism of Single and Multiple Geocells, 9th International Conference on Geosynthetics, Brazil, May 23 – 27
  19. ↑ Leshchinsky, B., (2011) "Enhancing Ballast Performance using Geocell Confinement," Advances in Geotechnical Engineering, publication of Geo-Frontiers 2011, Dallas, Texas, USA, March 13–16, 4693-4702
  20. ↑ Pokharel, S.K. , Han J., Leshchinsky, D., Parsons, R.L., Halahmi, I. (2009). "Experimental Evaluation of Influence Factors for Single Geocell-Reinforced Sand," Transportation Research Board (TRB) Annual Meeting, Washington, D.C., January 11–15
  21. ↑ Pokharel, S.K., Han, J., Manandhar, C., Yang, X.M., Leshchinsky, D., Halahmi, I., and Parsons, R.L. (2011). "Accelerated Pavement Testing of Geocell-Reinforced Unpaved Roads over Weak Subgrade." Journal of Transportation Research Board, the 10th International Conference on Low-Volume Roads, July 24–27, Lake Buena Vista, Florida, USA
  22. ↑ Pannell, Ian (28 January 2010). "Progress slow and messy in Afghanistan". BBC News.
  23. ↑ Harding, Thomas (2009). "Afghanistan: Glimmers of hope in Helmand". Daily Telegraph. Archived from the original on 2015-09-25.
  24. ↑ Kief, O. (2015b). “Structural Pavement Design with Geocells made of Novel Polymeric Alloy.” Geosynthetics 2015 Conference Proceedings. Portland, Oregon, February.
  25. ↑ ISO Standard WD TR 18228-5. (2018). Design using Geosynthetics – Part 5: Stabilization. International Organization for Standardization. Geneva, Switzerland. Unpublished.
  26. ↑ Pokharel, S.K., Norouzi, M., Martin, I. and Breault, M. (2016). Sustainable road construction for heavy traffic using high strength polymeric geocells. Canadian Society of Civil Engineers annual conference on Resilient Infrastructure June 1-4, 2016 London Ontario.
  27. ↑ Norouzi, M., Pokharel, S.K., Breault, M., and Breault, D. (2017). Innovative Solution for Sustainable Road Construction. Leadership in Sustainable Infrastructure Conference Proceedings. May 31-June 3, Vancouver, Canada.
  28. ↑ Alexiew, D. and van Zyl, W. (2019). Cellular Confinement System Reinforcement – Innovation at the Base of Sustainable Pavements. 12th Conference on Asphalt Pavements for Southern Africa, Johannesburg.
  29. ↑ Vega, E., van Gurp, C., Kwast, E. (2018). Geokunststoffen als Funderingswapening in Ongebonden Funderingslagen (Geosynthetics for Reinforcement of Unbound Base and Subbase Pavement Layers), SBRCURnet (CROW), Netherlands.
  30. ↑ Emersleben A., Meyer M. (2009). Interaction Between Hoop Stresses and Passive Earth Resistance in Single and Multiple Geocell Structures, GIGSA GeoAfrica 2009 Conference, Cape Town, South Africa, September 2–5
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