Towards complete recycling of concrete using microwave heating

Abstract

Recycling of concrete into high quality products requires the separation of the cement matrix, sand and aggregate particles. Microwave heating stands as a strong candidate for selective liberation of these constituents, either directly or as a pre-treatment to a comminution step, as it takes advantage of the many contrasts in properties of the phases: thermal, mechanical, electrical and dielectric. Rapid microwave heating generates stresses within the concrete, which may lead to crack formation at phase boundaries, yielding liberated constituents. This work is a contribution to demonstrating the potential of microwave treatment for the selective liberation of concrete components.