This report presents a new method for analysis of the drainage of a saturated base. Starting from basic principles of water retention and flow in porous media, this analysis leads to some new methods for the estimation of minimum degrees of saturation, drainable porosities and drainage times. This study found that current practices in the FHWA subdrainage design manual tend to overestimate the amount of drainage from fine-grained bases and greatly underestimate the amount of drainage from coarse-grained bases. Also of importance is the ability to estimate the lowest degree of saturation that can be achieved through gravity drainage. The new methods for the analysis of pavement subdrainage are implemented in two computer programs: (1) SUBDRAIN - simulates the drainage of water from a pavement base that is initially saturated and provides estimates of the minimum degree of saturation in the field and key drainage times; and (2) SUBDRAIN-C - simulates the flow of water into and out of the base over a period of years - the inputs include a long-term record of 15-minute rainfall data and the output shows how often the base is likely to be saturated or nearly saturated.

The purpose of this manual is to provide clear and helpful information for maintaining gravel roads. Very little technical help is available to small agencies that are responsible for managing these roads. Gravel road maintenance has traditionally been "more of an art than a science" and very few formal standards exist. This manual contains guidelines to help answer the questions that arise concerning gravel road maintenance such as: What is enough surface crown? What is too much? What causes corrugation? The information is as nontechnical as possible without sacrificing clear guidelines and instructions on how to do the job right.

Presents a complete coverage of all aspects of the theory and practice of pavement design including the latest concepts.

Only book world-wide addressing this topic. The principal output of the European co-operative Action on "Water Movements in Road Pavements & Embankments". Provides unique guidance on assessing water condition and its affects on road performance. Provides unique guidance on assessing and ameliorating contaminant movement in pavement groundwater. Written by leading experts in Europe.