Geotechnical Performance and Pavement Potential of Kouria Lateritic Gravel in Guinea

Djidoula TAKO^{1, 2,} , Fatoumata Yarie SYLLA², Fode Bangaly KEITA¹, Mamadou KOULEMOU² and Maimouna BARRY²

¹Institut Polytechnique, Université Gamal Abdel Nasser de Conakry, Conakry, Guinea

²Université Mercure International, Conakry, Guinea

Cite this paper:
Djidoula TAKO, Fatoumata Yarie SYLLA, Fode Bangaly KEITA, Mamadou KOULEMOU and Maimouna BARRY. Geotechnical Performance and Pavement Potential of Kouria Lateritic Gravel in Guinea. American Journal of Civil Engineering and Architecture. 2026; 14(5):215-220. doi: 10.12691/ajcea-14-5-5

Abstract

Lateritic gravels offer a valuable local resource for road construction in Guinea. This study evaluates the pavement potential of Kouria gravel through complementary physical and mechanical indicators. The programme combined eight field sampling locations, laboratory identification, compaction, bearing-capacity and particle-resistance tests, with complementary direct-shear and oedometer investigations. Cross-analysis quantified moisture windows, effort-normalised bearing gains and wet-abrasion variability while retaining separate test batches. The material exhibited a plasticity index of 5.7 percentage points. The complementary compaction series reached a maximum dry density of 1.82 Mg/m³. Interpolated moisture intervals were 18.8–25.6% and 21.1–24.5% at 95% and 98% of that reference density, respectively, corresponding to a 51% contraction in window width. Between 10 and 56 blows per layer, the two recorded bearing-ratio columns increased by factors of 4.89 and 6.71, with diminishing incremental gains. Mean Micro-Deval loss was 11.49%, with a coefficient of variation of 3.7%. Direct shear yielded apparent parameters of 54.8 kPa and 32.8°, while compression increased with applied stress. Kouria gravel presents favourable characteristics for pavement subbase development and promising base-course potential. The combined evidence identifies coordinated moisture, compaction and drainage control as practical priorities for mobilising this resource, with application-specific qualification defining its final use.

Keywords:
lateritic gravel pavement materials compaction bearing capacity Guinea

This work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

References:

[1]	Paige-Green P, Pinard M, Netterberg F, “A review of specifications for lateritic materials for low volume roads,” Transp Geotech. 5, 86–98, 2015.
[2]	Toll DG, “California Bearing Ratio tests on a lateritic gravel from Kenya,” Transp Geotech. 5, 59–67, 2015.
[3]	Tatsuoka F, Gomes Correia A, “Importance of controlling the degree of saturation in soil compaction linked to soil structure design,” Transp Geotech. 17, 3–23, 2018.
[4]	Konaté A, Rosin S, Sidibé D, Mechling JM, “Evolution de la portance de sols d’assise latéritiques de chaussées soumis à des sollicitations climatiques cycliques [Evolution of the bearing capacity of lateritic pavement foundation soils subjected to cyclic climatic loading],” Acad J Civ Eng. 43(1), 431–443, 2025.
[5]	Gansonré Y, Breul P, Bacconnet C, Benz M, Gourvès R, “Estimation of lateritic soils elastic modulus from CBR index for pavement engineering in Burkina Faso,” Int J Pavement Res Technol. 14, 348–356, 2021.
[6]	Mbengue MTM, Lawane Gana A, Messan A, Pantet A, “Geotechnical and mechanical characterization of lateritic soil improved with crushed granite,” Civ Eng J. 8(5), 843–862, 2022.
[7]	Nzabakurikiza A, Onana VL, Ngo’o Ze A, Ndzié Mvindi AT, Ekodeck GE, “Geological, geotechnical, and mechanical characterization of lateritic gravels from Eastern Cameroon for road construction purposes,” Bull Eng Geol Environ. 76, 1549–1562, 2017.
[8]	International Organization for Standardization. ISO 17892-1:2014. Geotechnical investigation and testing — Laboratory testing of soil — Part 1: Determination of water content. Geneva: ISO; 2014. Amendment 1:2022.
[9]	International Organization for Standardization. ISO 17892-4:2016. Geotechnical investigation and testing — Laboratory testing of soil — Part 4: Determination of particle size distribution. Geneva: ISO; 2016.
[10]	International Organization for Standardization. ISO 17892-12:2018. Geotechnical investigation and testing — Laboratory testing of soil — Part 12: Determination of liquid and plastic limits. Geneva: ISO; 2018. Amendments 1:2021 and 2:2022.
[11]	Association française de normalisation. NF P94-093. Sols: reconnaissance et essais — Détermination des références de compactage d’un matériau — Essai Proctor normal — Essai Proctor modifié [Soils: determination of compaction reference values; standard and modified Proctor tests]. La Plaine Saint-Denis: AFNOR; 2014.
[12]	Association française de normalisation. NF P94-078. Sols : reconnaissance et essais — Indice CBR après immersion — Indice CBR immédiat — Indice Portant Immédiat — Mesure sur échantillon compacté dans le moule CBR [Soils: soaked CBR, immediate CBR and immediate bearing index on samples compacted in a CBR mould]. Paris: AFNOR; 1997.
[13]	European Committee for Standardization. EN 1097-1:2023. Tests for mechanical and physical properties of aggregates — Part 1: Determination of the resistance to wear (micro-Deval). Brussels: CEN; 2023.
[14]	European Committee for Standardization. EN 1097-2:2020. Tests for mechanical and physical properties of aggregates — Part 2: Methods for the determination of resistance to fragmentation. Brussels: CEN; 2020.
[15]	European Committee for Standardization. EN 933-8:2012+A1:2015. Tests for geometrical properties of aggregates — Part 8: Assessment of fines — Sand equivalent test. Brussels: CEN; 2015.
[16]	International Organization for Standardization. ISO 17892-10:2018. Geotechnical investigation and testing — Laboratory testing of soil — Part 10: Direct shear tests. Geneva: ISO; 2018.
[17]	International Organization for Standardization. ISO 17892-5:2017. Geotechnical investigation and testing — Laboratory testing of soil — Part 5: Incremental loading oedometer test. Geneva: ISO; 2017.
[18]	Fredlund DG, Morgenstern NR, Widger RA, “The shear strength of unsaturated soils,” Can Geotech J. 15(3), 313–321, 1978.