Physicochemical charactezation through Granulometric, Geochemical and Mineralogical studies (Laser granulometry, XRF, XRD) of soils from the city of Mbanza-Ngungu for use in a composite ecomaterial
Keywords:
Raw soils, raw earth, Ecocomposite material, Fiber-reinforced adobes, XRF, XRD, Physico-chemical, mineralogical characterizationAbstract
In the face of the challenges posed by climate change and rapid urbanisation in the DRC, construction on raw soils (unbaked earth) reinforced with plant fibres appears as a sustainable ecological solution, reducing energy consumption, deforestation, and CO₂ emissions. Soils T1, T6, and T7 (with clay and silt content up to 24% and 72%) would ensure plasticity and cohesion conducive to fibre adhesion and crack limitation, while T4, T5, and T8, containing up to 57% medium and coarse sand, would provide better mechanical resistance and dimensional stability. The XRF results identify two axes explaining 69.3% of the variance. The first contrasts the dominant silica (up to 84.6% at T1) with aluminium and iron oxides, and the second distinguishes the variability of potassic minerals (K₂O) and ferric minerals (Fe₂O₃). The XRD results reveal the presence of minerals that directly influence plasticity, elasticity, strength, and durability, such as kaolinite (up to 56.7% at T5), illite (12.97% at T7), quartz (47.9% at T1), feldspars, hematite, and goethite. These findings, combined with the soil classification according to USCS, AASHTO, EN ISO 14688, and WRB standards, show that T3, T4, T5, and T7, classified as CL (clayey silts), rich in kaolinite and illite, can be recommended for cohesion needs and crack limitation, whereas T1, of the ML type (sandy silt or SC, clayey sand), or also quartzitic, requires fibre reinforcement to compensate for its low plasticity. This study, which integrates granulometric, mineralogical, and geochemical approaches with statistical analyses (PCA and Pearson correlations), and whose future perspectives include formulation and experimental mechanical validation, provides a solid scientific basis for the development of local, sustainable, high-performance, and environmentally friendly biosourced eco-materials.
Downloads
References
Abdi, H., et Williams, L. J. (2010). Principal component analysis. Wiley Interdisciplinary Reviews: Computational Statistics, 2(4), 433–459. https://doi.org/10.1002/wics.101
Abdi, H., et Williams, L. J. (2010). Principal component analysis. Wiley Interdisciplinary Reviews: Computational Statistics, 2(4), 433–459. https://doi.org/10.1002/wics.101
Alene, T. E., Mohammed, T. A., et Gualu, A. G. (2022). Use of sisal fiber and cement to improve load bearing capacity of mud blocks. Materials Today Communications, 33, 104557. https://doi.org/10.1016/j.mtcomm.2022.104557
Alhassnawi, N., Azmi, M., Fattah, M. Y., et Ahmad, F. (2025). Physical, chemical, and mechanical characterization of coated date palm leaf fiber from the Middle Region of Iraq for potential in civil engineering application. Jurnal Kejuruteraan, 37(1), 37–48. https://doi.org/10.17576/jkukm-2025-37(1)-04
Al-Massri, G. M., Ghanem, H., Khatib, J. M., et Elkordi, A. (2025, February). Influence of adding banana fibers on the mechanical properties and volume stability of mortar for paving block applications. Journal of Natural Fibers, 22(1). https://doi.org/10.1080/15440478.2025.2464152
Anger, R. (2011). Approche granulaire et colloïdale du matériau terre pour la construction (Thèse de doctorat, Institut National des Sciences Appliquées de Lyon). Lyon, France: INSA de Lyon. https://tel.archives-ouvertes.fr/tel-00735722
Aouiche, I., Daoudi, L., Ihbach, F.-Z., et Ouahmane, B. (2016). Caractérisation minéralogique et granulométrique des sédiments littoraux de la baie d’Agadir (Maroc atlantique): Dynamique sédimentaire et sources des matériaux. Journal of Materials and Environmental Sciences, 7(1), 123–132.
Bailly, G. C., El Mendili, Y., Konin, A., et Khoury, E. (2024). Advancing earth-based construction: A comprehensive review of stabilization and reinforcement techniques for adobe and compressed earth blocks. Eng, 5(2), 750–783. https://doi.org/10.3390/eng5020041
Bau, M., et Dulski, P. (1996). Distribution of yttrium and rare-earth elements in the Penge and Kuruman iron-formations, Transvaal Supergroup, South Africa. Precambrian Research, 79(1–2), 37–55. https://doi.org/10.1016/0301-9268(95)00087-9
Castro, G. M., Park, J., et Santamarina, J. C. (2023, November). Revised soil classification system: Implementation and engineering implications. Journal of Geotechnical and Geoenvironmental Engineering, 149(11), 04023109. https://doi.org/10.1061/JGGEFK.GTENG-10447
Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale, NJ: Lawrence Erlbaum Associates. ISBN 978-0805802832
Danso, H., Martinson, D. B., Ali, M., et Williams, J. B. (2015). Physical, mechanical and durability properties of soil building blocks reinforced with natural fibres. Construction and Building Materials, 101, 797–809. https://doi.org/10.1016/j.conbuildmat.2015.10.069
Daryati, D., Widiasanti, I., Septiandini, E., Ramadhan, M. A., Sambowo, K. A., et Purnomo, A. (2019). Soil characteristics analysis based on the unified soil classification system. Journal of Physics: Conference Series, 1402(2), 022028. https://doi.org/10.1088/1742-6596/1402/2/022028
Dejeant, F., Garnier, P., et Joffroy, T. (2021). Local materials, materials of the future: Local resources for sustainable cities and territories in Africa. Villefontaine, France: CRAterre. https://doi.org/10.58079/najm
Dethier, J. (2019). Habiter la terre: L’art de bâtir en terre crue. Traditions, modernité et avenir. Paris, France: Flammarion. ISBN 978-2081442818
Duong, N. T., Satomi, T., et Takahashi, H. (2021). Potential of corn husk fiber for reinforcing cemented soil with high water content. Construction and Building Materials, 271, 121848. https://doi.org/10.1016/j.conbuildmat.2020.121848
Filzmoser, P., Hron, K., et Templ, M. (2018). Applied compositional data analysis. Springer. https://doi.org/10.1007/978-3-319-96422-5
Fournier, J., Bonnot-Courtois, C., Paris, R., Voldoire, O., et Le Vot, M. (2012). Analyses granulométriques : Principes et méthodes. Dinard, France: CNRS. https://doi.org/10.5281/zenodo.13920079 (doi.org in Bing)
Gauzin Müller, D., Sémon, P. (ill.), Doat, P., Fontaine, L., et Guillaud, H. (2016). Architecture en terre d’aujourd’hui : Les techniques de la terre crue. Paris, France: Museo. https://doi.org/10.58079/naga
Guerreiro, S., Arsénio, P. M. R., Florentino, V., et Madeira, M. (2026). Land evaluation following updated World Reference Base (WRB) soil mapping: A tool for sustainable land planning in Mediterranean environments. Land, 15(3), 383. https://doi.org/10.3390/land15030383
Gyasi, E. K., et Purushotham, S. (2023, November). Advancements in soil classification: An in-depth analysis of current deep learning techniques and emerging trends. Air, Soil and Water Research, 16(3), 11786221231214069. https://doi.org/10.1177/11786221231214069
Hunter, J. D. (2007). Matplotlib: A 2D graphics environment. Computing in Science & Engineering, 9(3), 90–95. https://doi.org/10.1109/MCSE.2007.55
International Organization for Standardization. (2017). ISO 14688-1:2017 Geotechnical investigation and testing – Identification and classification of soil – Part 1: Identification and description. Geneva: ISO.
Jolliffe, I. T., et Cadima, J. (2016). Principal component analysis: A review and recent developments. Philosophical Transactions of the Royal Society A, 374(2065), 20150202. https://doi.org/10.1098/rsta.2015.0202
Kafodya, I., et Okonta, F. (2018). Effect of fibre surface coating on the mechanical properties of natural fibre-reinforced soil. International Journal of Geotechnical Engineering, 15(3), 338–348. https://doi.org/10.1080/19386362.2018.1542557
Kaiser, H. F. (1960). The application of electronic computers to factor analysis. Educational and Psychological Measurement, 20(1), 141–151. https://doi.org/10.1177/001316446002000116
Kasinikota, P., et Tripura, D. D. (2023). Effects of coir fibres and cement addition on properties of hollow interlocking compressed earth blocks. Innovative Infrastructure Solutions, 8(10). https://doi.org/10.1007/s41062-023-01240-4
Kovacevic, M. S., et Jurić Kaćunić, D. (2014). European soil classification system for engineering purposes. Građevinar, 66, 801–810. https://doi.org/10.14256/JCE.1077.2014
Kovacevic, M. S., Jurić-Kaćunić, D., Libric, L., et Ivoš, G. (2018). Engineering classification of soil according to EN ISO 14688-2:2018. Građevinar, 70(10), 873–879. https://doi.org/10.14256/JCE.2437.2018
Laborel-Préneron, A., Aubert, J.-E., Magniont, C., Tribout, C., et Bertron, A. (2016). Plant aggregates and fibers in earth construction materials: A review. Construction and Building Materials, 111, 719–734. https://doi.org/10.1016/j.conbuildmat.2016.02.119
Lê, S., Josse, J., et Husson, F. (2008). FactoMineR: An R package for multivariate analysis. Journal of Statistical Software, 25(1), 1–18. https://doi.org/10.18637/jss.v025.i01
Li, C., Wang, K., Li, S., Gao, Y., et Cao, Y. (2026). Coupled hydro-mechanical processes in rainfall-triggered mudstone landslides revealed by 3D laser scanning and model testing. PLoS ONE, 21(4), e0345165. https://doi.org/10.1371/journal.pone.0345165
Lin, Y., Mu, G., Xu, L., et Zhao, X. (2016). The origin of bimodal grain-size distribution for aeolian deposits. Aeolian Research, 20, 80–88. https://doi.org/10.1016/j.aeolia.2015.12.001
Liveneau, P., et Marin, P. (2012). Matérialités contemporaines – Materiality in its contemporary forms: Architecture, perception, fabrication, conception. MC 2012 Symposium, Villefontaine, novembre 2012. Villefontaine: Les Grands Ateliers. ISBN 978-2-913962-14-9
McKinney, W. (2010). Data structures for statistical computing in Python. In Proceedings of the 9th Python in Science Conference (SciPy 2010) (pp. 56–61). https://doi.org/10.25080/Majora-92bf1922-00a
Ouedraogo, M., Dao, K., Millogo, Y., Aubert, J. E., Messan, A., Seynou, M., Zerbo, L., et Gomina, M. (2019). Physical, thermal and mechanical properties of adobes stabilized with fonio (Digitaria exilis) straw. Journal of Building Engineering, 23, 250–258. https://doi.org/10.1016/j.jobe.2019.02.005
Pawlowsky-Glahn, V., Egozcue, J. J., et Tolosana-Delgado, R. (2015). Modeling and analysis of compositional data. Wiley. https://doi.org/10.1002/9781119003144
Pedregosa, F., Varoquaux, G., Gramfort, A., et al. (2011). Scikit-learn: Machine learning in Python. Journal of Machine Learning Research, 12, 2825–2830.
Reimann, C., Filzmoser, P., Garrett, R. G., et Dutter, R. (2008). Statistical data analysis explained: Applied environmental statistics with R. Wiley. https://doi.org/10.1002/9780470987605
Riffia, S., Ghorbel, E., Schmidt, F., et Cuccagna, F. (2026). Review of Natural Fiber-Reinforced Compressed Earth Blocks: Toward Enhanced Performance and Environmental Sustainability. Journal of Natural Fibers, 23(1), 2619017. https://doi.org/10.1080/15440478.2026.2619017
Sally, N., Pemberton, J., et Awe, O. O. (2024, April). A comparative study of soil classification machine learning models for construction management. International Journal of Construction Management, 25(4), 1–10. https://doi.org/10.1080/15623599.2024.2341500
Schober, P., Boer, C., et Schwarte, L. A. (2018). Correlation coefficients: Appropriate use and interpretation. Anesthesia & Analgesia, 126(5), 1763–1768. https://doi.org/10.1213/ANE.0000000000002864
Serratrice, J.-F. (2016). Mesures des propriétés cycliques des sols limoneux ou argileux au laboratoire. Revue Française de Géotechnique, 148, 1–13. https://doi.org/10.1051/geotech/2016009
Sridharan, A., et Prakash, K. (2000). Classification procedures for expansive soils. ICE Proceedings – Geotechnical Engineering, 143(4), 235–240. https://doi.org/10.1680/geng.2000.143.4.235
Thanushan, K., et Sathiparan, N. (2022). Mechanical performance and durability of banana fibre and coconut coir reinforced cement stabilized soil blocks. Materialia, 21, 101309. https://doi.org/10.1016/j.mtla.2021.101309
Tourtelot, J., Bourgès, A., et Keita, E. (2021). Influence of biopolymers on the mechanical behavior of earth-based building materials. Recent Progress in Materials, 3(3), Article 31. https://doi.org/10.21926/rpm.2103031
Van den Boogaart, K. G., et Tolosana-Delgado, R. (2013). Analyzing compositional data with R. Springer. https://doi.org/10.1007/978-3-642-36809-7
Vissac, A., Bourgès, A., Gandreau, D., Anger, R., et Fontaine, L. (2017). Argiles et biopolymères: Les stabilisants naturels pour la construction en terre. Villefontaine, France: CRAterre. ISBN 978-2-906901-88-9
Xiao, Y., Tong, L., Che, H., Guo, Q., et Pan, H. (2022). Experimental studies on compressive and tensile strength of cement-stabilized soil reinforced with rice husks and polypropylene fibers. Construction and Building Materials, 344, 128242. https://doi.org/10.1016/j.conbuildmat.2022.128242
Yang, Y., Wang, L., Wendroth, O., Liu, B., Cheng, C., Huang, T., et Shi, Y. (2019). Is the laser diffraction method reliable for soil particle size distribution analysis? Soil Science Society of America Journal, 83(2), 291–305. https://doi.org/10.2136/sssaj2018.07.0252
Yazıcı, M. F., et Keskin, N. (2024). Experimental investigation of the mechanical properties of polypropylene fiber-reinforced clay soil and development of predictive models: Effects of fiber length and fiber content. Arabian Journal for Science and Engineering, 49(10). https://doi.org/10.1007/s13369-023-08688-7
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Lukuama et al.
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
