The application of paper sludge ash to extermely stiff consistency concrete product

The main ingredients in paper sludge ash (PS ash), which is discharged by the paper industry, are SiO? and Al₂O₃. Therefore, the pozzolan reaction can be expected when it is added to concrete. However, its water absorptivity is so high that the plasticity of the resulting concrete is reduced. In this paper, the applicability of PS ash to extremely stiff concrete is evaluated by adding PS ash to cement and fine aggregate up to 300 kg/m³. A compressive strength of up to two times that of the original concrete was obtained.