**1. Introduction**

The construction industry is the single largest energy consumer in the European Union (EU), as well as one of the largest carbon dioxide (CO2) emitters (mainly from construction, demolition, and renovation) [1]. Over the past two decades, countless studies have been conducted on ways to improve the current situation. One of the researched areas relates to the development of alternatives for traditional concrete, which is a widely used material for construction. Demand for ordinary Portland cement-based concrete (hereafter referred to as OPC-based concrete) is continuously increasing [2]. Unfortunately, OPC-based concrete requires a considerable amount of ingredients and resources which are acquired through mining and exhaustive processing, causing immense quantities of greenhouse gas emissions to be sent into the atmosphere [3,4]. This review examines geopolymer as a promising alternative because it not only allows for a reduction in CO2 emissions and water consumption in comparison with OPC-based concrete production (the former by 80% [5]), but it can also be produced effectively using various waste materials [6]. A majority of studies about geopolymer concrete focus on using high amorphous precursors, such as fly ash, silica fume, and ground granulated blast-furnace slag [2,7], which are industrial byproducts. These are abundantly available in some countries. However, in many, they are either unavailable or available only in small, limited quantities [8]; therefore, it is always useful to search for new, suitable, and preferably local materials for geopolymer production. By analyzing the literature, regulatory acts, and studies, it was found that there is a large amount of construction waste in the European Union (and also in Latvia) which is currently being disposed of in landfills or reused only in small quantities. Therefore,

**Citation:** Radina, L.; Sprince, A.; Pakrastins, L.; Gailitis, R.; Sakale, G. Potential Use of Construction Waste for the Production of Geopolymers: A Review. *Mater. Proc.* **2023**, *13*, 2. https://doi.org/10.3390/ materproc2023013002

Academic Editors: Katarzyna Mróz, Tomasz Tracz, Tomasz Zdeb and Izabela Hager

Published: 13 February 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

within the framework of this review, much attention is paid to widely available and local construction waste (clay brick waste and aerated concrete waste) in order to evaluate the possibilities of their use for the production of geopolymers.
