Sludge Ash as Filler for Portland Cement Concrete

Sludge is an unavoidable by‐product of wastewater treatment. For highly urbanized cities, incineration of sludge might be a viable means of sludge disposal; however, a substantial amount of ash is produced by the burning process and must be disposed of by other means. The feasibility of using sludge ash as filler in concrete is studied, and the effects of sludge ash on the properties of fresh and hardened concrete are investigated. The results indicate that the sludge ash could be used as a partial replacement for cement in concrete.