Geosynthetics in Road Pavement Design and Construction in Kenya

Abstract

In the past two decades, Kenya has been investing heavily towards infrastructure development. Infrastructure is at the heart of the country’s goal of attaining its Vision 2030 of accelerating transformation into a rapidly industrializing middle-income nation by the year 2030. Road construction costs, among other infrastructural development’s costs, have been increasing rapidly. This can be attributed, partly, to the fast depletion of natural construction materials, and the increase in population density, which in turn shrinks the available land on which to place proposed infrastructural projects. The cost of land acquisition has skyrocketed. The design engineer is so often constrained to follow the available route alignment, despite the existing conditions, which are unsuitable at times. The traffic loading on Kenyan roads has also increased. There has been the need to build roads that can accommodate higher axle loading, for long periods. At this point in time, alternative construction materials that guarantee a reduction in costs of construction and life-cycle costs, and at the same time accommodate the increased loading on our roads, are highly welcome. Geosynthetics provide varied possibilities. The applicability of geosynthetics in road pavements, considering the cost approach, was addressed in this research. Geosynthetic reinforcement of the base, or subbase courses, was looked into, and the recommended practice introduced. The cost savings that are derived by using geosynthetics was also addressed, and also the sustainability of using geosynthetics in road pavement design and construction. It was established that there are geosynthetic materials in the Kenyan market that can be used to reinforce road pavements. Analysis of the reinforcement possibility showed that placing a geotextile below the subbase or base of the pavement will yield substantive savings in costs of construction and eventual life-cycle costs. This is in addition to other associated savings in reduced pollution and shortened construction period.