This document summarizes several research papers on the use of recycled concrete aggregates and other supplementary cementitious materials in concrete mixes. Specifically, it discusses studies that investigated replacing natural aggregates with recycled concrete aggregates and fly ash, as well as adding metakaolin or glass fibers, to create concrete mixes with sufficient strength and workability. The objectives and findings of each study are briefly described. Overall, the document reviews recent work on developing more sustainable concrete mixes using recycled materials to reduce construction waste.