COMPARATIVE FIELD PERFORMANCE OF SUBDRAINAGE SYSTEMS

Long-term pavement performance in wet climates is directly related to the amount, extent, and duration of internal moisture. Retention of mo isture in base/subbase layers can lead to damage and premature failure of the pavement structure. A positive subdrainage system can mitigate moisture retention. Two types of subdrainage collector systems are co mmonly used for removing subsurface moisture from pavement systems. Th ese are the conventional perforated pipe edge drains and the prefabric ated edge drains (PFEDs) or geotextile fin drains. Significant researc h was conducted in Indiana on in-place asphalt, concrete, and overlaid pavement sections incorporating these two types of subdrainage system s. Data collected from instrumented sites show varying response rates and time of outflow with respect to precipitation for pavement and col lector types. Pavement-shoulder joints were found to be the major sour ce of surface infiltration. Statistical analysis has shown significant influence of base permeability in addition to pavement and drain type s on outflow volumes.