Sustainable Reactive Powder Concrete Comprising Waste Materials: A Review

The escalating environmental cost incurred in the production of cement has further increased demand for high performance cement-based materials that combine excellent mechanical properties with lower environmental effect. This RPC presents a dense microstructure, superior performance and advantages in structure and durability but it is limited to well characterized by its extremely high volume of cement, use of silica fume engineered quartz powders, high embodied energy/carbon and material cost so far. To address these issues, increased attention has been paid to the utilization of waste resources and industrial by-products in RPC blends as partial replacements of cement, silica fume or fine aggregates. The present review is an extensive and critical analysis of sustainable RPC produced with waste materials. The method is developed through a systematic review and synthesis of available experimental and analytical research results dealing with alternative binders, fillers, and aggregates applied in RPCs. The characteristics and material properties of waste materials such as fly ash, ground granulated blast-furnace slag, waste glass powder and agricultural ashes, recycled concrete fines are being systematically reviewed. Their effects on the properties of fresh concrete, mechanical properties, durability, microstructure/crack development and high-temperature behavior are critically reviewed. Concurrently, such a strategy is explored for its environmental and economic performance via embodied energy, embodied carbon and cost–performance indicators to measure sustainability paybacks. The evidence examined shows that suitably formulated waste-based RPC can attain compressive strengths in the range of (120–200 MPa) with cement savings of the order of 20–30% with associated embodied carbon and energy reductions up to approximately 15–25%, and 10–20%, respectively. In addition, partial replacement of expensive ingredients by waste materials which are locally available greatly enhances the cost efficiency without much compromising other properties.