Year: 2024 | Month: January | Volume: 11 | Issue: 1 | Pages: 127-139
DOI: https://doi.org/10.52403/ijrr.20240114
Effects of Loading and Compaction Conditions on Permanent Strains of Unbound Lateritic Soils from Senegal and Burkina Faso
KI Bibalo Ida Josiane1, COULIBALY Mory2, GUEYE Rokhaya3, BA Makhaly4, HORNYCH Pierre5
1,3,4Laboratory of Mechanics and Modeling (L2M), Department of Geotechnical Engineering Sciences, Iba Der Thiam University of Thiès, Thiès, Senegal,
2Laboratory of Energy Materials, Electricity and Economic of IUT (LM3E), Department of civil Engineering Iba Der Thiam University of Thiès, Thiès, Senegal,
5Laboratory for auscultation, Modeling and experimentation of transport infrastructures (LAMES), University of Gustave Eiffel of Nantes, Materials and Structures Department (MAST), Nantes, France
Corresponding Author: Mory COULIBALY
ABSTRACT
Permanent strains of granular materials result from the repetitive passage of heavy trucks on the pavement. Pavement design relies mainly on permanent strains to predict rut depths. In order to contribute to the improvement of technical documents used for the design and modelling of pavements in tropical African countries, the researchers have focused on the determination of the permanent deformation parameters of laterites (axial (εp,1) and radial (εp,3) permanent strains). The Repeated Triaxial cyclic Loading (RTL) apparatus was used according to the European standard (EN 13286-7: 2004, Multistage method). Four sites of gravelly lateritic soils chosen, two from Burkina Faso (Badnogo2 and Dédougou) and two from Senegal (Sindia and Lam-Lam) were tested in this research. They are compacted to 95% and more of the optimum with a variation in water content of ±2% of the optimum. The permanents deformations are influenced by the water content, the compaction rate and the stress level. The axial permanent deformation ε1,p (max) decreases by 83.4% when the water content decreases from 12.10% to 7.59%. Moreover with a compactness rate that varies from 95.58% to 100.06%, respectively from a water content that varies from 10.04% to 9.36%, we observe a decrease in deformation ε_(1,p) from 224.340*10-4 to 148.150*10-4 from the 50,000 cycles, which shows the effect of the compactness rate and the stress level on the lateritic gravels materials soils. however, for a good control of permanent deformations on flexible pavements using gravel materials, it is necessary to compact at water contents lower than the optimum added to average compaction rates.
Keywords: permanent strains (p), lateritic soils, Repeated Triaxial cyclic Loading (RTL), Sindia, Badnogo2, Dedougou, Lam-lam.
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