Structural model performance and reinforced pavement technology in unstable location in the south of the Republic of Benin (West Africa)

Abstract

The main cities in West Africa have been characterized by the development of infrastructure in past decade. This paper examined the performance of the soil and of pavement in Benin (West Africa). In this research, four objectives have been adopted in-depth on the performance characteristics of West African soil and aim to (i) accessing characteristics of soil types in the region; (ii) assessing the performance of these soils with 3% of lime, with the combination of 3% lime and 3% cement; (iii) using geogrid to evaluate the performance of pavement on clayey soil; (iv) proposing a new pavement model strategy considering economic aspects of construction. The methods used to examine these objectives are experimental tests according to standard French test. Design of flexible pavement is largely based on empirical methods according to the transport research laboratory (TRL) Note 31 with WinJulea software and compared with a designed and evaluated pavement structure adopting the center experimental of building and public works (CEBTP) method. In addition, the research quantified the percentage of biaxial geogrid impacting the performance of pavement in a diminishing perspective. Flexible pavements (with and without geogrids) were built and subjected to 127.49 ​kN load applications. This paper firstly reveals the unstable and stable areas in southern Benin (West Africa) with the presence of clay soil, and secondly reveals that the use of 3% lime and the combination of 3% lime and 3% cement are limited in subgrade. In addition, the TRL Note 31 with WinJulea software is more economical while the one of CEBTP highly performs. More so, the paper confirms that the use of biaxial geogrid reinforcement in pavement structures highly reduces the construction cost. As conclusion, firstly, the pavement made from the recycled asphalt pavement materials with biaxial geogrid in subgrade is the best in the clayey area.