Comparison of Pavement Drainage Systems

Abstract

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. The drainage characteristics and pavement performance of four drainage systems under jointed portland cement concrete pavement are described and evaluated. Included are the Minnesota Department of Transportation (Mn/DOT) standard dense-graded base, two dense-graded base sections incorporating tranverse drains placed under the transverse joints, and permeable asphalt-stabilized base—a design that reflects current Mn/DOT drainable-base thinking. All sections contain longitudinal edge drains. Experiment variables include drainage flows, percent of rainfall drained, time to drain, base and subgrade moisture content, and pavement and joint durability. Two primary conclusions were reached. First, although all systems appear capable of removing drainable water from the pavement base, the permeable asphalt-stabilized base usually drained the most water within 2 hr after rainfall ended, while providing the driest pavement foundation and the least early pavement distress. Second, sealing the longitudinal and transverse joints temporarily reduced all rain inflow. After about 2 wk inflow resumed, although the joint sealants appeared to be intact.