Eco-efficient concrete in the circular economy of the precast industry: an example of sustainability

Abstract

The circular economy is an economic model of production and consumption that involves reusing, repairing, restoring, and recycling materials after their useful life. The use of waste as raw materials is one of the actions to establish this model in companies to achieve emissions at zero or neutral cost. The European prefabricated directives promote the implementation of a series of voluntary sustainability actions such as: the reduction of waste to be sent to landfill, the increase of additions to cement of at least 25%, an increase of 25% in the proportion of recycled aggregates to be used and reduction or recycling of water consumption, all for the benefit of reducing CO2.This work exposes a real example of a company of prefabricated structural elements of construction applying the previous actions, incorporating a waste centre for its own and external use, where the waste materials are given a second life generating a new concrete. This new recycled concrete is designed with the substitution of natural aggregates for recycled aggregates in different proportions, even up to 100%, using recycled additions to the cement, using recycled water from the concreting plant itself in its process. The sustainable eco-concrete resulting from HR-30 and HR-45 resistance, self-compacting, is mechanically characterized and incorporated into the prefabricated elements tested also in prototypes against bending, shear and deformation stresses.