Road Pavement Design Under Tropical Climate

Abstract

Most pavement design methods used in tropical countries originated in European temperate climates, and direct application of these design methods have often led to expensive pavement failures, especially under increased traffic loads. The author describes a study of flexible pavements under Kenyan climatic conditions, and proposes a basis for development of sound pavement design for the tropics. He outlines the use of the Marshall stability and flow tests for asphalt under tropical conditions, and compares the advantages of the cement-stabilized murram base to the crushed stone base. When considering thin surfacing for flexible pavements which are particularly popular in tropical countries, reduction in horizontal tensile stresses can be achieved by using base materials with a high modulus of elasticity. While curbs and gutters are useful in reducing horizontal tensile stresses and strains in flexible pavements, their effect on pavement deflection is negligible, the author concludes.