Using a modified jaw crusher for improved concrete recycling: energy consumption and separation efficiency

Closing the material loop of the concrete industry will reduce material consumption, waste generation, and lower CO 2 emissions. Although the use of recycled concrete aggregates (RCA) in new concrete mixtures has been demonstrated, little research has been published on techniques improving the liberation of hydrated cement paste (HCP) during concrete recycling. Using a modified crusher designed for HCP liberation, this paper investigates the impact of material feed, crushing frequency, and width of the closed-side settings on the material output and energy consumption. It was shown that factors increasing friction and abrasion promote HCP liberation and generate cleaner aggregates, but also increase the energy consumption compared to a conventional jaw crusher. When accounting for the increase in surface area, the energy consumption of the modified crusher and the conventional jaw crusher became comparable.