| Summary: | Increased sealing of soil due to urbanization produces higher runoff volumes, less infiltration and thus less recharge of groundwater. Terms e. g. “Low Impact Development”, “Sustainable Urban Drainage Systems” introduce management practices for a sustainable handling of stormwater. A tool of this technique is porous pavement which may support infiltration, reduce runoff and guarantee good roundwater qualities. Constructions with porous asphalt were built 1986/87 in Haparanda and 1993/94 in Luleå with given porosities of 15 to 20 %. First measured infiltration capacity were 6 mm/min in Haparanda. During the first 5 years of operation the infiltration capacity declined from 290 mm/min (1995) to 19 mm/min (2000) in Luleå. Since those years no more investigations were employed thus it is of interest how the long-term performance of the asphalt may be after years of performance. Investigations were made on porosity, infiltration capacity and the influence of vacuum-cleaning on both variables. Furthermore the differences in winter gritting, maintenance of both streets were introduced to the evaluation of the results. Porosity was tested in a laboratory by Pycnometer tests and modified double ring infiltrometer tests were conducted determining the infiltration capacity. Results showed porosity lying still in a range from 14 to 20 % while infiltration capacity declined rapidly. Vacuum-cleaning increased infiltration capacity in Luleå while the pores in Haparanda seemed completely clogged. Based on the results of this study regular maintenance and conformed winter gritting may support life-span and ability of infiltration. Validerat; 20110713 (anonymous)
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