Study on evaporation rate of steel slag pervious concrete based on CT scanning

Pervious concrete can reduce the surface temperature and improve the outdoor environment through its own evaporation capacity. The unique pore structure makes pervious concrete different from ordinary concrete and has a great impact on its macro performance, such as mechanical, penetration, fatigue, durability, noise reduction performance. In this study, the correlation between water evaporation rate and pore structure parameters of steel slag pervious concrete (SPC) was analyzed, and an empirical model formula was proposed to characterize the water evaporation rate at different evaporation time. Evaporation experiments at different temperatures and different specimen heights were designed, and the evaporation of each specimen was obtained. The porosity and surface porosity of each specimen were determined by water replacement method and computed tomography (CT) scanning. The results show that the evaporation and initial evaporation rate of SPC increase with the increase of specimen height and temperature. The relationship between evaporation rate and evaporation time conforms to the exponential function distribution, showing a rapid decline stage and a gentle decline stage, with obvious inflection points. The pore size distribution and sphericity of SPC were analyzed, and its influence on evaporation rate was negligible. With the increase of height ratio, the tortuosity of SPC increases relatively, while the surface porosity decreases. The evaporation rate model of SPC considering the influence of specimen height, temperature, tortuosity and surface porosity is constructed. The research is helpful to improve the ecological design of SPC pavement and promote the application of SPC materials.