Investigation on the properties of porous concrete as road base material

- Porous concrete is modified by suitable content of fine aggregate and fly ash.
- A linear interrelation between effective porosity and total porosity is matched.
- A power function between coefficient of permeability and effective porosity is fitted.
- The modified porous concrete has outstanding pavement performance.

As a kind of materials applied in road base course, porous concrete is required to have satisfactory strength, permeability, dynamic stability, scouring resistance and volume stability. In this paper, properties of porous concrete modified with fine aggregate and fly ash were investigated comparing with those of several ordinary road base materials. The results indicate that fine aggregate can improve compressive strength and durability of porous concrete as road base material. Porous concrete, especially modified porous concrete with additional fine aggregate, has advantages over other road base materials on erosion and shrinkage resistance. The image processing analysis also demonstrates that fine aggregate enhances the conjoint point between the aggregates in porous concrete. And fly ash can significantly improve compressive strength and dry shrinkage resistance of porous concrete. Furthermore, the results demonstrate that the total porosity of porous concrete shows a linear relation to effective porosity, and a power function relation exists between permeability and effective porosity. This modified porous concrete can be used as road base course for the sponge city project and also highway.