Research on wet physical properties of permeable concrete pavement with different porosity

Permeable concrete pavement has been widely used in building 'sponge cities'. Porosity has a great influence on wet physical properties such as permeability, water retention, and evaporative cooling performance of permeable concrete, and further research is needed. In this paper, permeable concrete specimens with target porosity of 20%, 24%, and 28% were made for indoor experimental research, including water permeability, water retention, and evaporation tests. The research results show that permeable concrete with a porosity of 28% has the best permeability among the three types of porosity. In the range of 20–28% porosity, as the porosity increases, the water retention performance of permeable concrete first strengthens and then weakens. The evaporative water loss of permeable concrete has the worst cooling performance on its surface temperature and the best cooling performance on its internal temperature. The air humidity above permeable concrete continues to decrease over time. The greater the porosity of the specimen, the later the air humidity above it becomes lower than the indoor ambient humidity. The work of this paper provides data support for permeable concrete pavement to improve outdoor thermal environment.