Investigating Wash Off of Fines from Aggregate Used in Permeable Pavement Construction: Implications for Long-Term Function
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Date
2025-05
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The Ohio State University
Abstract
Permeable pavements are a widely implemented green infrastructure (GI) practice used to reduce urban runoff and filter pollutants. While research has shown permeable pavements improve water quality, little attention has been given to the effects of construction materials used in these systems and their effects on effluent quality. A few studies have noted potential sediment wash off from aggregates immediately following construction (i.e., a start-up effect), which this study assessed using a controlled laboratory study with 12 PVC columns. Each column contained layered limestone aggregate and a concrete paver to model typical permeable interlocking concrete pavement (PICP) systems, one type of permeable pavement. Four treatments were evaluated in triplicate: two flow rates (high [37.85 liters per hour] and low [3.785 liters per hour]) and aggregate sourced from two different quarries. Effluent from simulated storm events was analyzed for total suspended solids (TSS) and particle size distribution (PSD). For the first simulated storm event, effluent TSS concentrations ranged from 941.43-2402.94 mg/L. A sharp decline in effluent TSS was observed within the first 6 storm events for every treatment, with initial decay trending toward a final horizontal asymptote for TSS concentrations. After nearly the equivalent of one year of rainfall, TSS concentrations in three of the four treatments remained above the average PICP effluent concentration of 22 mg/L from a database of field studies of permeable pavements, suggesting extensive, continued sediment wash-off. PSD did not change significantly over time and exhibited few differences across treatments. These findings underscore the importance of refining aggregate preparation techniques to reduce sediment wash off following permeable pavement construction, thereby reducing effluent TSS concentrations, limiting clogging at the underlying soil interface, and improving long-term infiltration capacity. This research provides valuable insights to optimizing PICP design and construction practices for urban stormwater management.
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Keywords
Permeable Interlocking Concrete Pavements, PICP, Green Infrastructure, Construction Materials, Water Quality, Sediment