Abstract
This paper assesses the use of water retentive pavement (WRP) made from fly ash as a mitigation strategy to urban heat island phenomenon. Our main objective is to develop a model using one-dimensional conservation equations to simulate the transport of heat and moisture in WRP. The evaporation efficiency, volumetric water content and matric potential were used as parameters. Under outdoor conditions, the thermal performance of WRP was compared with asphalt. Maximum surface temperature difference was from 10:00 JST to 15:00 JST, with asphalt being 9.1℃ warmer than WRP. Minimum surface temperature difference was from 22:00 to 06:00 JST, with asphalt 0.3℃ warmer than WRP. Calculation results show that the model can numerically evaluate the diurnal variation in surface temperature with 10.6% estimated error. Results of the temperature and water content profile imply that evaporation occurs first on the surface. The Average latent heat flux of WRP was 113.1 W/m2 and 41.6 W/m2 during the first and second day respectively. The reduction in daytime sensible heat flux by WRP compared with asphalt was 142.3 W/m2. Reduction in nighttime conductive heat flux by WRP compared with asphalt was 30.9 W/m2.
