Current Knowledge and Research on the Design of Flexible Pavements in Senegal


Meïssa Fall

Dr Civil Eng., Earth Sciences Institute (IST), Faculty of Sciences and Techniques
University Cheikh Anta Diop of Dakar,
BP 15 685 Dakar-Fann, Senegal

Fala Faye

Dr Civil Eng., Polytechnic School of Thiès (ESP)
University Cheikh Anta Diop of Dakar, Senegal


Abdoulaye Mbodji

Civil Engineer, Jean Lefebvre-Senegal S.A., BP 106 Dakar, Senegal


In previous studies we had underlined the importance to have reliable characteristics to allow an optimal design of road structures. The research done in Senegal for the last ten years or so permits to pronounce now amply on the geotechnical reasons of the premature ruin of road tructures. The main problem of the weak life span of the road structures is due to an under-estimated design caused by an use of inappropriate characteristics with no control in the numerical codes of road design as Alize IIIŽ or EcorouteŽ of the LCPC. In situ investigation done since then with complementary experimental works permit to have reliable information on local subgrades, the most common gravel lateritic materials, roadmaking aggregates and finally the laterite-cement. This last material was the object of particular attention, bound to its specificity and especially by the fact that all base or sub-base layers in Senegal is prepared with. Finally, a fine analysis of the interrelationships between these features, their strength parameters and their modulus of elasticity permits to have now tools of choice to do reasonable road design. The done applied boards give satisfaction. It is then question now to define new norms/standards and specifications in road geotechnique. The present article is more amply about results gotten on the laterite-cement, essential element of the road construction in the whole african tropical zone. The results gotten on the surfacing materials as well as a methodology study of the subgrade will also be exposed.

Keywords: Laterite-cement, base, subgrade, gravel lateritic soil, Tropical, road design.

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