Modification of Ordinary Concrete Using Fly Ash from Combustion of Municipal Sewage Sludge

This article focuses on the impact of fly ash from the combustion of municipal sewage sludge (FAMSS) as a cement additive in the amounts of 5%, 10%, 15%, 20% and 25% (by mass) on selected concrete properties. In the course of the experimental work, water penetration depth and compressive strength measurements were made at various periods of curing (from 2 to 365 days). In addition, the potential impact of FAMSS on the natural environment was examined by determining the leachability of heavy metals. FAMSS-modified concretes showed small values of water penetration depth (lower than 50 mm), as well as good compressive strength (reaching minimum class C30/37 after 130 days of maturing)-similar to the compressive strength obtained for conventional concrete. In addition, the partial replacement of cement with FAMSS has environmental benefits, expressed as a reduction in CO₂ emissions. In addition, study has shown that compliance with environmental requirements is associated with heavy metal leaching.