Treatment Of Lateritic Pavements By Adding Cement And Bitumen Emulsion:Application To The Rural Roads

The sustainability of a road is obtained by an optimized design that responds directly to the needs defined by its context.The heterogeneity of the soils,the climatic conditions,the use by the user and the immediate environment are all an integral part of the specific context of a pavement.The technical,financial and environmental performance will then be guaranteed by a global vision of the system.Thus,the material at the heart of a road is just as essential as the ramifications of the road network covering the whole of a country.This research project aims to study the technology of lateritic soil with combination of bitumen emulsion and cement,applied in the road context.This is motivated by the lack of knowledge of the technology and previous recommendations to explore an auscultation approach on a new method of earth road design.To do this,a review of the literature is carried out in order to associate the typical Cameroonian design needs with the international design methods,the influencing factors and the experimental means.Soil samples were obtained from borrow pits located in Tsinga village Area Council in Yaoundé/Cameroon.Three percentages of additives were considered: 4%,6% and 8%.The bitumen emulsion and cement contents were combined in percentages: 75/25,50/50,25/75 to form three additives.The geotechnical properties such as Unconfined Compressive Strength(UCS)test and California Bearing Ration(CBR)test were determined on the treated soil sample and on the untreated soil sample.The UCS and CBR for soil samples A and B were 0.62 MPa and 42%,0.70 MPa and 49%,respectively.The CBR of soil sample A at 4% additives of mix proportions 75/25,50/50 and 25/75 were 51%,67% and 70%,respectively.The corresponding values for UCS were 0.60,0.85 and 1.35.While for 8% additives the CBR for soil sample B were 74%,96%,103%,and UCS were 0.71,1.50 and,2,05,respectively.It was observed that both the UCS and CBR values increased as the cement component increased for both soil samples.Stabilising laterite with mixture of bitumen emulsion and cement improved the strength of the soil.