Field Testing of Porous Pavement Performance on Runoff and Temperature Control in Taipei City

Abstract

The Taipei University of Technology, under contract from the Taipei City Government, completed a study on porous asphalt (PA) and permeable interlocking concrete brick (PICB) pavement performance with respect to stormwater runoff reduction and surface temperature mitigation. Additionally, the variation of infiltration rates against time of these pavements was monitored. The results show the following: (a) Runoff peak reduction ranged from 16% for large, intense storms to 55% for small, long-duration storms. Rainfall volume reduction ranged from 16% to 77% with an average of 37.6%; (b) Infiltration rate: for PICB, it decreased by 25% to 50% over a 15-month monitoring period, but the rate at one location increased significantly after cleaning; for PA, the rate remained high at one location, but decreased by 70%–80% after 10 months at two other locations, due mainly to clogging problems; (c) Surface temperature: during storm events, porous concrete bricks had on average lower temperatures compared to regular concrete with a maximum difference of 6.6 °C; for porous asphalt the maximum drop was 3.9 °C. During dry days, both PA and PICB showed a tendency of faster temperature increase as the air temperature rose, but also faster temperature decreases as the air cooled when compared to regular pavements. On very hot days, much lower surface temperatures were observed for porous pavements (for PA: 17.0 °C and for PICB: 14.3 °C) than those for regular pavements. The results suggest that large-scale applications of porous pavements could help mitigate urban heat island impacts.