Aplicação da análise multicritério à decisão na avaliação da sustentabilidade dos resíduos de concreto pré-fabricado.

Abstract

The growing concern for the environment and the severe consequences of its excessive use caused by human activity have driven the development of research and new technologies aimed at mitigating the impacts on the planet. In Brazil, the construction industry is responsible for generating a large volume of waste with a low recycling rate. Among these, construction and demolition waste (CDW) and precast concrete waste (PCW) stand out. In the context of construction systems, the prefabrication of concrete elements offers sustainability advantages. In this regard, the industrialization process of the construction industry contributes to reducing waste generated on construction sites. However, like any construction system, prefabrication also generates waste. This waste can originate from leftover fresh concrete during the manufacturing process or from the disposal of elements that do not meet quality criteria. The management of PCW is extremely important, and tools that assist in decision-making can be used to optimize this process. This research proposes the application of the Analytic Hierarchy Process (AHP) method as a decision-support tool for the disposal or reuse of PCW. To this end, a pilot study was conducted in which the main criteria addressed and the current disposal method used were identified. Data for this research were collected through an online questionnaire, which was answered by thirteen experts involved in the production process of precast concrete elements and the management of works in the segment, and these data were applied in the AHP method matrices. The AHP method demonstrates applicability in both individual and group judgment cases. Through the aggregation of individual judgments (AIJ), a single result can be obtained that reflects the opinions of various judges. Through the application of the method, it was possible to identify that, in the opinion of most experts, the implementation of a transformation center for PCW into recycled aggregates would be considered the most important alternative. The absence of measures to encourage the use of recycled aggregates from PCW in recycled concrete has led companies to dispose of them in landfills. Another possibility would be to establish partnerships with CDW recycling companies. Given this scenario, this research sought to raise awareness among experts in the precast sector and companies in the segment that there are different alternatives for the disposal of PCW, thus enhancing the sustainability aspects of this construction system.