Seems like the "big if feasible" part is reducing concrete to hydrated cement paste. From actual paper: https://www.nature.com/articles/s41586-024-07338-8 http

Seems like the "big if feasible" part is reducing concrete to hydrated cement paste. From actual paper: https://www.nature.com/articles/s41586-024-07338-8 https://www.nature.com/articles/s41586-024-07338-8 Recovered cement paste (RCP) is not commercially available at scale at present. . . . The value of the improved recovered aggregates is not at present high enough to cover the extra cost of processing, so RCP is currently landfilled. However, the know-how and the technologies required to produce RCP at scale exist. [22] 22. Thermomechanical beneficiation of recycled concrete aggregates (RCA): https://www.sciencedirect.com/science/article/pii/S0950061821029445?via%3Dihub https://www.sciencedirect.com/science/article/pii/S095006182... The cited paper does not support the assertion that tech to recycle concrete into RCP exists. The paper discusses removing adhered mortar (AM) from recycled concrete aggregate (RCA).