Lightweight composite aggregates as a dual end-of-waste product from PET and anthropogenic materials

Abstract

This article describes the course and results of experiments related to the development of thermal technology for the synthesis of waste materials, therefore, stabilized. The product of such a reaction, while maintaining the specific conditions of the process, acquires an attribute of a lightweight composite aggregate. Two production technologies case studies based on various synthesis mechanisms and reaction centers, as well as different temperature regimes were adopted to design the most optimal method. As a matrix in the created composite the flakes from recycling of a post-consumer thermoplastic polymer PET (polyethylene terephthalate) were used. The composite filler’s role was fulfilled by several fine-grained anthropogenic raw materials. As a result of the experiments, various lightweight aggregates product lines were manufactured and their physical-chemical basic properties examined and mutually contrasted. The created products differed in performance in function of the adopted method and filler material. The obtained granulate is a specific and a unique type of lightweight aggregates denominated, for this purpose, as a composite lightweight aggregate - CLA. The main advantage of the proposed technology implies less heat energy to be supplied in comparison with the existing methods for obtaining such building materials from the waste resources. The other benefit is related to the aspect of its sustainable development performed by using exclusively waste materials for its production. As shown by the research results obtained of the basic characteristics of the aggregate, the produced material can be a full-fledged replacement of a natural aggregate. Some features of this material, such as a lower density or a reduced water demand of the resultant mix, are additional avails, when applied for cementitious building materials. Thanks to this, it is possible to manufacture lighter elements with a lower cement content and also without declining the main mechanical properties.