This presentation explores the use of waste materials as aggregates in concrete, including unused concrete, bricks, blocks, gypsum, plastics, and glass. The waste hierarchy and methods for managing waste are discussed, along with the benefits and limitations of using recycled materials in concrete. The presentation also covers the utility of using glass, plastic, and recycled cement as substitutes for natural aggregates, and the effects on the strength and workability of the resulting concrete. References from relevant studies are provided.