Physical and Mechanical Properties of Alkali-Slag Pervious Concrete

Alkali-activated pervious concrete was prepared using ground granulated blast furnace slag (GGBS) as a cementitious material substitute and sodium silicate as an alkali activator. This study investigated the effects of water-binder ratio, sodium silicate modulus, and alkali equivalent on the mechanical properties, permeability coefficient, and chloride ion resistance of the pervious concrete. The results showed that as the water-binder ratio increased from 0.27 to 0.31, the mechanical properties improved slightly, but the permeability coefficient decreased. The optimal mechanical performance was achieved at an alkali equivalent of 6%, while the highest porosity was observed at 0.3%. A sodium silicate modulus of 1.2 provided the best balance between mechanical strength and permeability. Then, regression analysis was used to confirm a linear correlation between porosity and permeability coefficient, while the Boltzmann model was used to establish a relationship between chloride ion content and penetration depth. Finally, a comparison with previous experimental results showed that GGBS contributed to improve the mechanical properties of pervious concrete.