Mechanical and physical properties of concrete containing FGD waste

The paper is part of a wide ranging research project on the optimum use of waste from the dry and semi dry flue gas desulphurisation (FGD) processes in concrete. It examines the influence of a typical simulated desulphurised waste (SDW) on the physical and mechanical and physical properties of concrete. SDW was chosen due to the wider variability in the composition of actual FGD waste. Two binder systems were investigated (i) cement and SDW (C-SDW) and (ii) cement, slag and SDW (C-SSDW). The SDW content ranged from 0-70% and the slag from 0-90% as partial replacement of the cement. The properties examined included compressive and flexural strength, water absorption, shrinkage and expansion. The results showed that replacing cement with SDW beyond 20% systematically reduce strength. An increase in SDW reduces shrinkage. The presence of small amounts of slag allows the use of high proportions of SDW. The use of desulphurised waste in concrete applications is possible as adequate strength can be achieved.