Clogging Mechanism of Permeable Concrete: a Review

Urbanization results in the conversion of pervious spaces to areas of impervious (paved) surface which creates numerous problems such as erosion, flash floods, pollution of rivers and hot island in city. A sustainable solution to this problem is to use permeable pavements which only began to find application in Australia recently. Permeable pavements can facilitate biodegradation of oils from cars and trucks, help rainwater infiltrate into soil, replenish groundwater, allow tree roots to breathe, and reduce flash flooding, but they have not been widely adopted in Australia due to concerns mainly over reduced structural capabilities and clogging. A research project is being carried out at USQ aiming at understanding the influence of pore structures features and particle deposition on clogging resistance and permeability reduction. Clogging is perceived as a major problem for any type of permeable pavement. Even with vigorous maintenance clogging is common. In the paper, some common types of clogging are discussed first, followed by the clogging effect on the performance of porous concrete mainly related to the change of the porosity and the pore structure properties. Testing methods for measuring porosity and hydraulic conductivity which include both physical testing and image analysis are reviewed in detail.