This course will introduce you to principles of pavement drainage. Water has a detrimental effect on pavement performance, primarily by either weakening subsurface materials or erosion of material by free water movement. For flexible pavements the weakening of the base, subbase or subgrade when saturated with water is one of the main causes of pavement failures. In rigid pavement free water, trapped between the rigid concrete surface and an impermeable layer directly beneath the concrete, moves due to pressure caused by loadings. This movement of water (referred to as pumping) erodes the subsurface material creating voids under the concrete surface. In frost areas subsurface water will contribute to frost damage by heaving during freezing and loss of subgrade support during thawing. Poor subsurface drainage can also contribute to secondary damage such as 'D' cracking or swelling of subsurface materials. This course will give you professional tools that will allow you to move forward in learning how to design for drainage of pavements.

Learning Objectives

• Learn the effects of subsurface water;
• Learn about the effects of infiltration and subterranean water;
• Learn how subdrainage facilities can be categorized into two functional categories, one to control infiltration, and one to control groundwater;
• Learn how flow of water through soils is expressed by Darcy's empirical law;
• Learn how the value of permeability depends on the characteristics of the permeable materials and the properties of the fluid;
• Learn how permeability is a function of a complex relationship with grain size;
• Learn about the void ratio or porosity of soils, and its influence on permeability;
• Learn why the type and condition of the pavement surface will have considerable influence on the volume of water entering the pavement structure; and
• Learn about pavement drainage in frost susceptible soils..