Acta Univ. Agric. Silvic. Mendelianae Brun. 2026, 74(1-2), 27-37 | DOI: 10.11118/actaun.2026.003

EXPERIENCE WITH THE RESILIENT MODULUS DETERMINATION FOR FOREST ROADS DESIGN USING CYCLIC CBR TEST

Aleš Florian1, Lenka Ševelová2, Petra Machová1, Michal Kraus1, Luboš Podolka1
1 Department of Civil Engineering, Institute of Technology and Business in České Budějovice, Okružní 10, 370 01 České Budějovice, Czech Republic
2 Department of Landscape Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic

The design and assessment of road pavement structural layers made of natural and recycled materials requires careful determination of their physical-mechanical properties. The resilient modulus Mr , which characterizes the stiffness of the material under cyclic loading, is considered to be a fundamental parameter for characterizing material properties. The standard test for its determination is the cyclic triaxial test. An alternative solution is the cyclic CBR test, which uses a standard California Bearing Ratio device. The paper presents the experience and results obtained by its long-term use. Studies show that resilient modulus increases with increasing loading force and/or position of material in pavement construction, because the higher the layer of material is located, the greater the load acting on it. With increasing material moisture content or dry density resilient modulus is increasing up to the threshold level - optimum moisture content. Beyond this limit resilient modulus is decreasing. The larger is compacting level, the larger resilient modulus can be expected. But this compaction ability is strongly influenced by moisture content.

Keywords: resilient modulus, cyclic CBR, repeated CBR, low volume road, pavement, soil, moisture, subgrade, subsoil, compaction, soil density

Received: October 15, 2025; Revised: January 9, 2026; Accepted: February 4, 2026; Published: May 1, 2026  Show citation

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Florian, A., Ševelová, L., Machová, P., Kraus, M., & Podolka, L. (2026). EXPERIENCE WITH THE RESILIENT MODULUS DETERMINATION FOR FOREST ROADS DESIGN USING CYCLIC CBR TEST. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 74(1-2), 27-37. doi: 10.11118/actaun.2026.003
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    References

    1. AASHTO. 2001. Guidelines for Geometric Design of Very Low-Volume Local Roads (ADT 400). Washington, DC, USA: American Association of State Highway and Transportation Officials.
    2. AASHTO. 2008. Mechanistic-Empirical Pavement Design Guide (MEPDG). Washington, DC, USA: American Association of State Highway and Transportation Officials.
    3. ARAYA, A. A. 2011. Characterization of Unbound Granular materials for Pavements. Ph.D. Thesis. Delft, The Netherlands: Delft University of Technology.
    4. BRINCH HANSEN, J. A. 1961. General Formula for Bearing Capacity. Bulletin No. 11. Copenhagen, Denmark: Geoteknisk Institut, Institute Akademict for de Tekniske Videuskaber.
    5. CSN 736114. 1995. Road pavements. Basic requirements for design. Ministry of Transportation: Prague, Czech Republic.
    6. CSN EN ISO 13286-2. 2015. Unbound and Hydraulically Bound Mixtures-Part 2: Test Methods for the Determination of the Laboratory Reference Density and Water Content-Proctor Compaction. Institute for Technology Standardization, Metrology and State Testing: Prague, Czech Republic.
    7. CSN EN ISO 13286-7. 2004. Unbound and Hydraulically Bound Mixtures-Part 7: Cyclic Load Triaxial Test for Unbound Mixtures. Institute for Technology Standardization, Metrology and State Testing: Prague, Czech Republic.
    8. CSN EN ISO 13286-47. 2015. Unbound and Hydraulically Bound Mixtures-Part 47: Test Method for the Determination of California Bearing Ratio, Immediate Bearing Index and Linear Swelling. Prague, Czech Republic: Institute for Technology Standardization, Metrology and State Testing.
    9. CSN EN ISO 14688-2. 2005. Geotechnical Investigation and Testing-Identification and Classification of Soil-Part 2: Principles for a Classification. Prague, Czech Republic: Institute for Technology Standardization, Metrology and State Testing.
    10. CSN EN ISO 14689-1. 2004. Geotechnical Investigation and Testing-Dentification and Classification of Rock-Part 1: Identification and Description. Prague, Czech Republic: Institute for Technology Standardization, Metrology and State Testing.
    11. CSN EN ISO 17892-1. 2015. Geotechnical Investigation and Testing-Laboratory Testing of Soil-Part 1: Determination of Water Content. Prague, Czech Republic: Institute for Technology Standardization, Metrology and State Testing.
    12. CSN EN ISO 17892-4. 2017. Geotechnical Investigation and Testing-Laboratory Testing of Soil-Part 4: Determination of Particle Size Distribution. Prague, Czech Republic: Institute for Technology Standardization, Metrology and State Testing.
    13. CSN EN ISO 17892-12. 2018. Geotechnical Investigation and Testing- Laboratory Testing of Soil-Part 12: Determination of the Liquid and Plastic Limits. Prague, Czech Republic: Institute for Technology Standardization, Metrology and State Testing.
    14. DÍAZ, M. M., PERÉZ, I. 2015. Mechanistic-empirical pavement design guide: Features and distinctive elements. Rev. Construcción. 14, 32-40. Go to original source...
    15. FLORIAN, A., ŠEVELOVÁ, L. 2013. Computer Simulation of Low Volume Roads Made from Recycled Materials. Int. J. Civ. Environ. Eng. 10, 744-748.
    16. FLORIAN, A., ŠEVELOVÁ, L., ŽÁK, J. 2015. Influence of environmental humidity on mechanical properties of natural and recycled unbound materials. Acta Univ. Agric. Silvic. Mendelianae Brun. 63, 405-409. https://doi.org/10.11118/actaun201563020405 Go to original source...
    17. FLORIAN, A., ŠEVELOVÁ, L., ŽÁK, J. 2016. Reliability analysis of temperature influence on stresses in rigid pavement made from recycled materials. Acta Univ. Agric. Silvic. Mendelianae Brun. 64, 423-432. https://doi.org/10.11118/actaun201664020423 Go to original source...
    18. FLORIAN, A., ŠEVELOVÁ, L., ŽÁKOVÁ, K. et al. 2023. An Updated Cyclic CBR Test with Realistic Stress Values under the Plunger for Resilient Modulus Calculation. Forests. 14, 2425. https://doi.org/10.3390/f14122425 Go to original source...
    19. HAUSER, J., KOZUMPLÍKOVÁ, A., ŠEVELOVÁ, L. 2012. The Influence of the Soil Treatment on the CBR Test Values. In: Proceedings of the Int. Conf. on Ground Improvement and Ground Control: Transport Infrastructure Development and Natural Hazards Mitigation-ICGI. Singapore, 30 October-2 November 2012. pp. 1623-1628. Go to original source...
    20. HAUSER, J., ŠEVELOVÁ, L., MATULA, R. et al. 2018. Optimization of low volume road pavement design and construction. J. For. Sci. 64, 74-85. https://doi.org/10.17221/109/2017-jfs Go to original source...
    21. KULOGLU, T. F., LIEFFERS, V. J., ANDERSON, A. E. 2019. Impact of Shortened Winter Road Access on Costs of Forest Operations. Forests. 10, 1-20. https://doi.org/10.3390/f10050447 Go to original source...
    22. MEHRPAZHOUH, A., TAFRESHI, S. N. M., MIRZABABAEI, M. 2019. Impact of repeated loading on mechanical response of reinforced sand. J. Rock Mech. Geotech. Eng. 11, 804-814. https://doi.org/10.1016/j.jrmge.2018.12.013 Go to original source...
    23. MOLENAAR, A. A. A. 2008. Repeated Load CBR Testing, a Simple but Effective Tool for the Characterization of Fine Soils and Unbound Materials. Delft, The Netherlands: Delft University of Technology.
    24. NGUYEN, B. T., MOHAJERANI, A. 2016. Resilient modulus of fine-grained soil and a simple testing and calculation method for determining an average resilient modulus value for pavement design. J. Transp. Geotech. 7, 59-70. https://doi.org/10.1016/j.trgeo.2016.05.001 Go to original source...
    25. RAHMAN, M. M., GASSMAN, S. L., ISLAM, K. M. 2023. Effect of Moisture Content on Subgrade Soils Resilient Modulus for Predicting Pavement Rutting. Geosciences. 13, 103. https://doi.org/10.3390/geosciences13040103 Go to original source...
    26. RINCÓN-MORANTES, J., ALVAREZ, A., REYES-ORTIZ, O. 2022. Estimación de la rigidez de materiales granulares marginales no ligados mediante ensayo CBR dinámico. Ing. Desarro. 40, 92-113. https://doi.org/10.14482/inde.40.01.621.992 Go to original source...
    27. SAS, W., GLUCHOVSKI, A., MITURSKI, M. 2017. Studies on Resilient Modulus Value from Cyclic Loading Tests for Cohesive Soil. J. Ann. Wars. Univ. of Life Sci.-SGGW. Land Reclam. 49, 117-127, https://doi.org/10.1515/sggw-2017-0010. Go to original source...
    28. ŠEVELOVÁ, L., ARIAS, P. F., ŠLEZINGER, M. 2020. Influence of Improving Materials of Forest Roads on Surrounding Environment. Pol. J. Environ. Stud. 29, 3821-3830. https://doi.org/10.15244/pjoes/115272 Go to original source...
    29. ŠEVELOVÁ, L., FLORIAN, A. 2013. Comparison of Material Constitutive Models Used in FEA of Low Volume Roads. Int. J. Civ. Environ. Eng. 10, 421-425.
    30. ŠEVELOVÁ, L., FLORIAN, A., ŽÁK, J. 2021. Influence of Plunger Stress on Resilient Modulus of Forest Subgrade Soils Obtained from Cyclic CBR Test. Forests. 12, 1456. https://doi.org/10.3390/f12111456 Go to original source...
    31. ŠEVELOVÁ, L., KOZUMPLÍKOVÁ, A. et al. 2015. The Methodical Guide to the Design and Implementation of Pavement of Low Volume Roads [in Czech: Metodický průvodce návrhem a realizací vozovek nízkokapacitních komunikací]. Certified Methodology. Brno: Mendel University in Brno. 23327/2015-MZE-16222/M108.
    32. TP 170. 2023. Design of Pavement Structures. Prague, Czech Republic: Ministry of Transportation.
    33. YANG, S. H., LIN, H. D., KUNG, J. H. S. et al. 2008. Suction-Controlled Laboratory Test on Resilient Modulus of Unsaturated Compacted Subgrade Soils. J. Geotech. Geoenviron. Eng. 134, 1375-1384. https://doi.org/10.1061/(asce)1090-0241(2008)134:9(1375) Go to original source...

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