Effects of Glass Fiber Reinforced Polymer on Geotechnical Properties of Clayey Soil


1 Department of Geotechnical Engineering, Maraghe Branch, Islamic Azad University, Maraghe, Iran

2 bDepartment of Civil Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran


Soil reinforcement can be considered as the combination of two parts. One part is soil for compressive stress capacity and another part is some material such as geosynthetics such as steel belts and fibers for tensile stress capacity. Soil improvement is one of the useful methods to increase the strength parameters of the soil. The main goal of this study is to evaluate the effects of GFRP on the bearing capacity, shear strength, and permeability of clayey soil. For this purpose, the length of GFRP is selected 10 mm and amount of GFRP are 0.2, 0.4, 0.6, 0.8 and 1% that mixed randomly with clay. Mixture specimens prepared using the optimum water content. Bearing capacity of specimens measured by unconfined compressive test and direct shear test. Also, Permeability parameter assessed based on the falling head permeability test. Results of this study showed that with mixing GFRP up to 0.8% increases the clay bearing capacity and flexibility. Although with continuing to add GFRP the bearing capacity decrease, the clay permeability using GFRP is increased.


[1] Gray, D. H. and Ohashi, H., Mechanics of Fiber Reinforcement in Sand, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol.109, No. (3), 335-353, 1983.

[2] Dean, R. and Fretting, F., Soil Randomly Reinforced with Fibers. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 112, No.4, 823-827, 1986.

[3] Arenzic, R. M., and Chowdhury, R. N., Laboratory Investigation of Earth Walls Simultaneously Reinforced by Strips and Random Reinforcement, Geotechnical Testing Journal, ASTM, Vol.11, No.4, 241-247, 1988.

[4] Benson, C. H. and Kayer, M. V.,  Reinforcing Sand with Strips of Reclaimed High-Density Polyethylene, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol.120, No.5, 828-855, 1994.

[5] Ranjan, G., Vasan, R. M., and Charan, H. D. Probabilistic Analysis of Randomly Distributed Fiber Reinforced Soil, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol.122, No.6, 419 – 426, 1996.

[6] Michalowski, R. and Zoba, A., Failure of Fiber Reinforced Granular Soils, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol.122, No.3, 226-234, 1996.

[7] Andersland, O. B. and Khattac, A. S., Shear Strength of Kaolinite/Fiber Soil Mixtures. Proceeding International Conference on Soil Reinforcement, Paris, France, 20-26, 1997.

[8] Wang, Y., Frost, J. D. and Murray, J., Utilization of Recycled Fiber for Soil Stabilization, Proceedings of the Fiber Society Meeting, May 17-19, Guimaraes, Portugal, 59-62, 2000.

[9] Cai, Y., Shi, B., NG, C. W. W. and Tang, C., Effect of polypropylene fiber and lime admixture on engineering properties of clayed soil, Engineering Geology, Vol. 87, 230-240, 2006.

[10] Erdinciler, A., Ayhan, V., Influence of tire fiber inclusions on shear strength sand. Geosynthetic International journal, Vol. 17, 183-192, 2010.

[11] Sukantasokl, P., Jamsawang, P., Use of steel and polypropylene fibers to improve flexural performance of deep soil-cement column, Construction Building Material, Vol.29, No.1, 201-205, 2012.

[12] Cristelo, N., Cunha, M. C., Dias, M., Gomes, T. A., Miranda, T. and Araujo, N., Influence of discrete fiber reinforcement on the uniaxial compression response and seismic wave velocity of a cement-stabilized sandy-clay, Geotextiles and Geomembranes, Vol.43, 1-13, 2015.

[13] Sahebkaram, A and Dabiri, R., Effects of fiber type on improving the bearing capacity of clayey soils, International journal on technical and physical problems of engineering, Vol.9, No.30, 43-50, 2017. 

[14] ASTM D421-85, Dry Preparation of Soil Samples for Particle-Size Analysis and Determination of Soil Constants, Annual book of ASTM standards, (reapproved 1998), 1985.

[15] ASTM D422-63, Standard Test Method for article-Size Analysis of Soils, Annual book of ASTM standards (reapproved 1998), 1963.

[16] ASTM-D 4972, Standard test method for PH of soils, Annual book of ASTM standards, 1995.

[17] ASTM D 4318-95a, Standard test method for liquid limit, plastic limit an plasticity index for soils, Annual book of ASTM standards, 1995.

[18] ASTM-D 854-02, Standard test method for specific gravity of soil solids by water pycnometer, Annual book of ASTM standards, 2002.

[19] ASTM-D 698-00, Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft3 (600 kN-m/m3)), Annual book of ASTM standards, 2000.

[20] ASTM-D 3080-98, Standard test method for direct shear test of soils under consolidated drained condition, 1998.

[21] ASTM-D 2166/D2166M-13, Standard test method for unconfined compressive strength of cohesive soils, Annual book of ASTM standards, 2013.

[22] ASTM-D 5084-03, Standard test method for measurement of hydraulic conductivity of saturated porous materials using flexible wall permeameter, Annual book of ASTM standards, 2004.