Design Guidelines for Subsurface Roadway Drainage Systems


Book Description

Poor drainage of asphalt pavements causes the pavement to undergo several types of distress, such as stripping, potholes, and others. The aim of this book is the development of guidelines to select proper design parameters of subsurface roadway drainage systems. This comprised the investigation of a variety of roadway cross-section configurations using computer modelling. The investigation started with evaluating the hydraulic situation under a selected roadway with many cross-section configurations in a water-logged area, in both cases of the presence and absence of many design alternatives of a subsurface drainage system. Then, the optimum parameters of each design alternative of the drainage system were determined to lower the groundwater table to a safe level under each configuration of the roadway cross-section. A microscopic groundwater flow model was created in Processing Modflow to simulate the hydraulic situation under the roadway cross-section in both cases of the drainage conditions. A cost analysis was performed in both cases of un-drained and drained roadway cross-sections including all configurations of the roadway cross-section and the roadway drainage system.










Report No. FHWA-RD.


Book Description







Pavement Subsurface Drainage Systems


Book Description

This synthesis will be of interest to geologists; hydrologists; geotechnical, pavement, construction, and maintenance engineers; and researchers. State department of transportation (DOT) program managers and administrators will also find it of interest. The synthesis describes the current state of the practice for the design, construction, and maintenance of pavement subsurface drainage systems. It provides information on the positive effects of good subsurface drainage and the negative effects of poor subsurface drainage on pavement surfaces. This report of the Transportation Research Board presents data obtained from a review of the literature and a survey of the state DOTs. It is a supplemental update to NCHRP Synthesis of Highway Practice 96, Pavement Subsurface Drainage Systems (1982). The synthesis provides a supplement to design issues not found in Synthesis 96, but faced by current designers, e.g., type and quality of aggregate, compaction requirements for open-graded aggregates, asphalt and cement binders, and use of geosynthetics. In addition, it describes the effects of design, construction, and maintenance decisions on the performance of pavement subsurface drainage systems.