Drainage

Pervious pavement provides a solution for many highly developed urban areas where an excessive amount of contaminated water is diverted into storm and sewer systems and left untreated before entering natural water sources such as rivers and streams. By allowing water to flow through the pavement surface and infiltrate the underlying soil, pervious pavements can reduce the amount of this pollution. Test cells were constructed at MnROAD to be monitored for drainability to evaluate the possibility of using pervious pavements to mitigate this problem. Other important criteria influencing the performance of pervious concrete in pavements will also be monitored, including mechanical and structural properties, surface characteristics, noise, and durability. This document summarizes the research that went into Report 2011-23, "Pervious Concrete Test Cells on MnROAD Low-Volume Road.."

The Minnesota Department of Transportation and many municipalities in Minnesota have built sidewalks city streets, low volume roads, boat ramps and parking lots with pervious concrete. Since 2005 when the first pervious concrete initiative was constructed at the MnROAD facility, three test cells have been constructed, monitored and maintained. Paradoxically, non pervious pavements are similar to pervious pavements in their requirements for drainability for durability. However pervious concrete requires that the voids should be connected and free of clogging agents for durability of conductive and acoustic properties. The effect of clogging and the characteristics of pervious concrete, clogged with various agents are examined. Desirable acoustic absorption and hydraulic conductivity are reduced when pervious concrete is clogged and may be restored with adequate maintenance practices.

This report presents the literature relating to design of thermoplastic pipe, describes the development and implementation of field tests conducted for this project, extends the findings of the field tests through calibration of two- and three-dimensional computer models and parametric studies, and makes recommendations for design and installation of thermoplastic pipe under shallow cover and highway live loads.

This paper summarizes current subsurface pavement drainage used by various state and local agencies. The paper starts with a brief introduction on moisture in a pavement and the damage it can cause. Following the introduction, the relative effectiveness of subsurface drainage is estimated based on environmental conditions, traffic levels, and physical characteristics of the pavement structure. The next three sections of the paper discuss various components used in subsurface drainage, combinations of drainage components to perform specific drainage tasks, and maintenance required to keep drainage components functioning. Next, results from a survey sent to Minnesota city and county agencies are given summarizing current drainage practices used on lower volume roads. Finally, the last part of the paper gives cost and performance data on drainage systems used by various states.

The MnDOT Bridge Office sought out information on best practices regarding the use of drainage systems on bridges. Minnesota regulations strongly discourage the discharge of runoff directly into waterways; however, bridge drainage systems can lead to accelerated deterioration in bridge elements. MnDOT requested a synthesis to gather information to assist them in future development of guidance on design, detailing, specifications, construction, and maintenance procedures for bridge needs, focusing specifically on agencies with similar northern climates to the greatest extent possible.

This Tool serves as a guide to assist agencies in understanding drainage problems and options to consider for mitigating structural damage to pavements due to moisture. The weather and soil conditions vary drastically across Minnesota. Engineers should use their engineering judgment and seek expert guidance when necessary.

Pavement drainage systems have become a common addition to construction and reconstruction plans. Several types of transverse and longitudinal drains that vary in shape, size and cost are often included in designs although little is known about their performance. This study describes and evaluates the drainage characteristics and pavement performance of four drainage systems under jointed portland cement concrete pavement. Included are the Minnesota Department of Transportation (Mn/DOT) standard dense graded base. two dense graded base sections incorporating transverse drains placed under the transverse joints, and permeable asphalt stabilized base, a design which reflects current Mn/DOT drainable base thinking. All sections include longitudinal edge drains. Construction of the test sections was done during 1989. Monitoring of rainfall and drainage began in 1990 and continued through 1994. Experiment variables include drainage flows, percent of rainfall drained, time to drain, base and subgrade moisture content, and pavement and joint durability. Pavement performance evaluations will continue over the next several years. This paper presents an overview of the study, examines the data, and summarizes the findings. The study is expected to lead to improvements in the design of positive pavement drainage systems.

With typical road construction, relatively impermeable materials may surround the pavement structure and create bathtub sections that retain infiltration and spring-thaw seepage for extended periods of time. However, if this water is removed, the base and subgrade can provide better pavement support, pumping of fines can be minimized, and aggregate freeze-thaw performance can be enhanced. Subsurface drains are one of the most commonly used techniques to help remove moisture from both old and new pavement structures. The Minnesota Department of Transportation (Mn/DOT) defines three types of subsurface drains: (1) pavement edge drain type, (2) permeable aggregate base type, and (3) subcut drain type. In addition, (4) special application transverse type subsurface drains are used for isolated drainage problems.

The time individual engineers, administrators and their staff invest in researching drainage law and defining the best approach to solving drainage issues can be considerable. This document provides quick access to information needed to solve those problems and discover legal solutions to recurring drainage issues and the time saved could be invested in other pressing public responsibilities. This study also contains information which might be useful to local elected officials, private property owners and other interested parties as it offers concise educational materials that simplify and inform them on drainage issues and laws related to regional watershed protection, county road/highway ditches, city street/storm sewers and related drainage infrastructure.

This Technical Summary pertains to report 2019-27, Iron-Enhanced Swale Ditch Checks for Phosphorus Retention.