Production and characterization of materials

Abstract

In the previous chapter, we have discussed the pressing need for a durable and green concrete. Use of recycled concrete aggregates as coarse aggregate replacement and other SCMs as partial cement substitute can become potential alternative constituents in concrete. Aggregates constitute 75–80% of the volume of concrete. In this chapter, we will mainly discuss the production of coarse recycled concrete aggregates which are obtained by recycling, sorting, and processing of the construction demolition wastes at the end-of-life of a concrete structure. Thus, waste collection, segregation, and processing methods to prepare them for use as coarse aggregates in concrete are discussed. While aggregates are mostly inert materials which do not participate actively in chemical reactions, their qualities can still impact the fresh and hardened properties of concrete. Thus, it is crucial to understand the properties of recycled aggregates in contrast to natural aggregates. When we fully substitute recycled coarse aggregates for natural coarse aggregates, it is interesting to see how the characteristics of the coarse aggregates impact the performance of concrete at macro-level. This chapter also discusses the properties of commonly available SCMs, like fly ash, slag, and silica fume, which can be utilized to positively modify the performance of RAC.