Study On The Clogging Behavior Of Porous Asphalt Mixture

Porous asphalt pavement arouses world’s attention because its good pavement performance:it can effectively reduce the moisture and glare caused by water accumulated in the surface, andit also can reduce traffic noise. It has been widely applied in foreign countries. But the cloggingof the pavement’s voids reduces its service life and limits its application in China. Rare researchon anti-clogging ability of porous asphalts has been worked out interiorly. Based in this situation,a long-period clogging behavior on porous asphalts has been created in the laboratory.This paper made single layer and double layers porous asphalt mixtures with different kindsof structure parameters (porosity, maximum aggregate size and categories of asphalts) by thedesign of graduation composition, tested specimens’ performances and analyzed the influencefactors on them. Two kinds of permeability setups are used for measuring the permeability of thespecimens which are respectively a falling-head permeameter and a constant-head one. Thesetwo permeameters can respectively get two kinds of permeability coefficient: Cw and k which areused to evaluate the change history of the specimens’ permeability during the period of theclogging behavior. Studied how the structure parameters affect the permeability andanti-clogging ability of porous asphalts.The analysis of test results shows that the greater the porosity is, the greater the permeabilityand anti-clogging ability will be, but a high porosity will lead the drop of the porous asphalts’structure stability. The porosity and the permeability have a good correlation and the correlationequation between porosity and the permeability coefficient: k is achieved. The theoreticalformulation on permeability coefficient: k after been clogged is deduced. The specimens’anti-clogging ability will get improved when the maximum aggregate size is greater. The highviscosity modified asphalt has a significant improved effective on the stability and anti-fatigueperformance of porous asphalts, but little impact on anti-clogging ability.Otherwise, the clogging behavior research on double-layers porous asphalts shows that thepermeability and anti-clogging ability will get better if the porosity of the first layer is higher orthickness is smaller. Flush and brush double-layer specimens with a high pressure washer inorder to evaluate the easiness of the specimens to be cleaned. It turns out that the specimens willbe easier to be cleaned if it has a higher porosity and a thinner first layer. The double-layerporous asphalts are easier to be cleaned than the single-layer ones.