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Effective CBR and Elastic Modulus of Geogrid-Stabilized Prepared Subgrades Overlying Existing Soft Subgrades

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International Journal of Geosynthetics and Ground Engineering Aims and scope Submit manuscript


It is a common practice to stabilize soft subgrades by overlying a granular material stabilized with a layer of suitable geosynthetic. The present study proposes an approach to obtain the effective modulus of soft subgrades stabilized with locally available soil material in conjunction with geogrids. Relatively soft subgrades with California bearing ratio (CBR) equal to 2, 5, and 7% are simulated in the laboratory. Locally available soil material with CBR equal to 8, 14, and 20% stabilized with polypropylene (PP) and polyethylene terephthalate (PET) geogrids are prepared over soft subgrades. Geogrids considered in the study (PP30 and PET100) covers the low to high tensile stiffness range of available geosynthetics. In total, 30 large-scale model pavement experiments were carried out in large-size test chamber having inside dimensions equal to 1.5 m × 1.5 m × 1.0 m (length, width and height, respectively) under monotonic loading. The benefit is expressed in terms of modulus improvement factor (MIF) and improved subgrade CBRs, in accordance with mechanistic–empirical equations proposed in Indian Road Congress guidelines. The overall MIF values ranged between 1.2 and 2.8 for the test combinations considered in the study. Geogrid of high stiffness has excellent capability to improve the effective subgrade CBR to as high as 13% compared to unstabilized subgrade CBR equal to 5%. Results showed that improvement is significant for low CBR conditions and high stiffness of geogrid and vice versa. The cost-to-benefit analysis conducted within the study scope indicated that about a 48% reduction in the cost is observed for PP30 geogrid-stabilized subgrade compared to cement-stabilized subgrade.

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  1. Indian Road Congress (IRC:37) (2018) Guidelines for the design of flexible pavements, 4th Revision, Indian Road Congress. New Delhi, India

  2. Berg RR, Christopher BR, Perkins SW (2000) Geosynthetic reinforcement of the aggregate base/subbase courses of pavement structures. Geosynthetic Materials Association White Paper II. Geosynthetic Materials Association, Roseville, Minnesota, USA

  3. MoRTH Road statistics (2022) Annual report 2021–2022, Bharatmala road to prosperity, Ministry of Road Transport and Highways, Government of India, New Delhi. Sourced as on 17th Feb 2023

  4. Saride S, Avirneni D, Javvadi SCP (2016) Utilization of reclaimed asphalt pavements in Indian low-volume roads. J Mater Civ Eng 28(2):04015107.

    Article  Google Scholar 

  5. Kamel AM, Chandra S, Kumar P (2004) Behaviour of subgrade soil reinforced with geogrid. Int J Pavement Eng 5(4):201–209.

    Article  Google Scholar 

  6. Al-Qadi IL, Dessouky SH, Kwon J, Tutumluer E (2008) Geogrid in flexible pavements. Transp Res Rec J Transp Res Board 2045(1):102–109.

    Article  Google Scholar 

  7. Zornberg JG, Gupta R (2010) Geosynthetics in pavements: North American contributions. In: 9th international conference on geosynthetics, Brazil, pp 379–398

  8. Flutcher S, Jonathan WuTH (2013) A state-of-the-art review on geosynthetics in low-volume asphalt roadway pavements. Int J Geotech Eng 7(4):411–419.

    Article  Google Scholar 

  9. Abu-Farsakh MY, Akond I, Chen Q (2016) Evaluating the performance of geosynthetic-reinforced unpaved roads using plate load tests. Int J Pavement Eng 17(10):901–912.

    Article  Google Scholar 

  10. Saride S, Baadiga R, Balunaini U, Madhira RM (2022) Modulus improvement factor-based design coefficients for geogrid and geocell-reinforced bases. J Transp Eng Part B Pavements 148(3):04022037.

    Article  Google Scholar 

  11. Baadiga R, Balunaini U, Saride S, Madhira RM (2022) Behavior of geogrid- and geocell-stabilized unpaved pavements overlying different subgrade conditions under monotonic loading. Int J Geosynth Ground Eng.

    Article  Google Scholar 

  12. Perkins SW, Ismeik M (1997) A synthesis and evaluation of geosynthetic-reinforced base layers in flexible pavements: part I. Geosynth Int 4(6):549–604.

    Article  Google Scholar 

  13. Giroud JP, Han J (2004) Design method for geogrid-reinforced unpaved roads. I. Development of design method. J Geotech Geoenviron Eng 130(8):775–786.

    Article  Google Scholar 

  14. Ling HI, Liu Z (2001) Performance of geosynthetic-reinforced asphalt pavements. J Geotech Geoenviron Eng 127(2):177–184.

    Article  Google Scholar 

  15. Indian Road Congress (IRCSP59) (2019) Guidelines for use of geosynthetics in road pavements and associated works. In: The Indian Road Congress, New Delhi

  16. Balamaheswari M, Anitha B, Kanimozhi B, Prabhu N (2022) Improvement of California bearing ratio value in weak subgrade soil with the developed anchored geogrid. Mater Today Proc 49:1537–1542.

    Article  Google Scholar 

  17. Tiwari N, Satyam N (2022) An experimental study on strength improvement of expansive subgrades by polypropylene fibers and geogrid reinforcement. Sci Rep 12(1):6685.

    Article  Google Scholar 

  18. Jahandari S, Tao Z, Saberian M, Shariati M, Li J, Abolhasani M, Kazemi M, Rahmani A, Rashidi M (2021) Geotechnical properties of lime-geogrid improved clayey subgrade under various moisture conditions. Road Mater Pavement Des.

    Article  Google Scholar 

  19. Tang X, Stoffels SM, Palomino AM (2016) Mechanistic–empirical approach to characterizing permanent deformation of reinforced soft soil subgrade. Geotext Geomembr 44(3):429–441.

    Article  Google Scholar 

  20. American Association of State Highway and Transportation Officials (AASHTO-R50) (2013) Standard practice for geosynthetic reinforcement of the aggregate base course of flexible pavement structures, standard specifications for transportation materials and methods of sampling testing, thirty-fifth edition, Washington, DC

  21. ASTM D1883 (2021) Standard test method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils, ASTM International, West Conshohocken, PA.

  22. USCS (2011) Standard practice for classification of soils for engineering purposes (unified soil classification system). ASTM D2487, West Conshohocken, PA

  23. ASTM D698 (2021) Standard test methods for laboratory compaction characteristics of soil using standard effort (12,400 ft-lbf/ft3 (600 kN-m/m3)). ASTM International, West Conshohocken.

  24. Montanelli F, Zhao A, Rimoldi P (1997) Geosynthetic-reinforced pavement system: testing and design. In: Proceedings of the of Geosynthetics’97, vol (2), pp 619 – 632, Long Beach, California, USA, IFAI

  25. Baadiga R, Saride S, Balunaini U, Madhira RM (2021) Influence of tensile strength of geogrid and subgrade modulus on layer coefficients of granular bases. Transp Geotech 29:100557.

    Article  Google Scholar 

  26. ASTM D6637 (2011) Standard test method for determining tensile properties of geogrids by the single or multi-rib tensile method. ASTM International, West Conshohocken, PA.

  27. Ueshita K, Meyerhof GG (1967) Deflection of multilayer soil system. J Soil Mech Found Div ASCE 93(5):257–282.

    Article  Google Scholar 

  28. Baadiga R, Balunaini U, Saride S, Madhira RM (2021) Influence of geogrid properties on rutting and stress distribution in reinforced flexible pavements under repetitive wheel loading. J Mater Civ Eng.

    Article  Google Scholar 

  29. Al-Qadi IL, Dessouky S, Tutumluer E, Kwon J (2011) Geogrid mechanism in low-volume flexible pavements: accelerated testing of full-scale heavily instrumented pavement sections. Int J Pavement Eng 12(2):121–135.

    Article  Google Scholar 

  30. Al-Qadi IL, Dessouky SH, Kwon J, Tutumluer E (2012) Geogrid-reinforced low-volume flexible pavements: pavement response and geogrid optimal location. J Transp Eng 138(9):1083–1090.

    Article  Google Scholar 

  31. Rajesh U, Sajja S, Chakravarthi VK (2016) Studies on engineering performance of geogrid reinforced soft subgrade. Transp Res Proc 17:164–173.

    Article  Google Scholar 

  32. Saha Roy S, Deb K (2021) Modulus of subgrade reaction of unreinforced and geogrid-reinforced granular fill over soft clay. Int J Geomech 21(9):04021156.

    Article  Google Scholar 

  33. Sivapriya SV, Ganesh-Kumar S (2019) Functional and cost-benefits of geosynthetics as subgrade reinforcement in the design of flexible pavement. Rev Facult Ingenier 28(51):39–49.

    Article  Google Scholar 

  34. MoRTH (2013) Specifications for road and bridge works. 5th Revision. Ministry of Road Transport and Highways, New Delhi, India

  35. Liebenberg J, Visser A (2003) Stabilization and structural design of marginal materials for use in low-volume roads. Transp Res Rec J Transp Res Board, 1819, paper no. LVR8-1097, pp 166–172.

  36. Shah NS, George KP, Rao JS (1983) Promising marginal aggregates for low-volume roads. In: Low-volume roads: third international conference, 1983, vol 898, p 242. Transportation Research Board

  37. Mechanistic-Empirical Pavement Design Guide (MEPDG) (2015) Mechanistic–empirical pavement design guide—a manual of practice. American Association of State Highway and Transportation Officials, 2nd Edition. USA

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The authors are thankful to the National Highways Authority of India (NHAI) for funding this project (under Grant No. NHAI/TIC/R&D/108/2016). The authors also thank M/s TechFab India Pvt. Ltd. for providing geogrids.

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RB, UB, RB: concept, methodology, data collection, research monitoring, analysis, and original manuscript. UB: concept draft, project monitoring, methodology, manuscript writing, and editing.

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Correspondence to Umashankar Balunaini.

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Baadiga, R., Balunaini, U. Effective CBR and Elastic Modulus of Geogrid-Stabilized Prepared Subgrades Overlying Existing Soft Subgrades. Int. J. of Geosynth. and Ground Eng. 10, 41 (2024).

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