Electrical fragmentation applied to the recycling of concrete waste – Effect on aggregate liberation

Abstract : This study presents an evaluation of an innovative technique for the treatment of concrete waste by electrical fragmentation. Scientific arguments are made, indicating that it is possible to strive for the recovery of waste by jointly recycling aggregates and the hydrated cement paste, in order to manufacture new concrete of the same mechanical quality as that produced using raw materials. The results of electrical fragmentation tests on concrete show that i) fragmentation level and selectivity are significantly enhanced when the size of the constituent aggregate in the concrete increases, which is a positive result because the largest proportion of most concrete mixes comprises coarse aggregate (45% of 5/20 mm aggregate); ii) the mineralogical nature of the aggregate has little impact on the electrical fragmentation level and has none on its selectivity, which are positive results demonstrating the robustness of the process in terms of its ability to process aggregate of different origins and iii) aggregate liberation degree depends on neither the energy level applied to the concrete, nor the quality of the process water, which are positive results for industrial applications. The results of this study show that electrical fragmentation has potential for integration as part of a recycling process for concrete waste on an industrial scale.