Eco-cement Cobblestones with Polyurethane Wastes

Abstract

With the aim of implementing a circular economy in all manufacturing processes, by reducing the use of raw materials, while minimizing the use of natural resources and valuing several industrial wastes, efforts are focused on the development of new techniques that allow the use of wastes in the construction sector, in order to turn them into raw materials for the development of new materials, thus achieving all the processes towards a sustainable environment. With this purpose, different precast cement cobble has been manufactured using recovered polyurethane waste from complete vehicle roofs generated in the automotive industry, turning them into a raw material. Depending on the amount of waste used, with progressive substitutions of sand of 20%, 40% and 60% of polymer waste, the final properties are achieved according to the application requirements, both in the fresh and hardened state, reaching the values required by current standards. As well as water properties and microstructure, accelerated aging tests in freeze-thaw cycles and crystallization of salts have been tested, stablishing the compressive strength before and after, guaranteeing the properties in outdoor environments in which these materials can be placed. The characterization has been completed with tests on the generation of volatile organic compounds (VOCs), fire resistance and Life Cycle Assessment (LCA). In this way, the development of innovating solutions is achieved, valorizing waste that is generated in significant quantities, being able to be used in prefabricated products to be used in the building sector. © The Author(s) 2025.