*Article* **Circular Economy of Construction and Demolition Waste: A Case Study of Colombia**

**Henry A. Colorado 1,\* , Andrea Muñoz <sup>1</sup> and Sergio Neves Monteiro <sup>2</sup>**


**Abstract:** This paper presents the results of research into construction and demolition (C&D) waste in Colombia. The data and analyses are shown in a local and Latin American context. As the situation in Colombia is quite similar to that in many developing countries worldwide, this research and its findings are potentially applicable to similar economies. Several factors were calculated and compared in order to evaluate which best fit the data from Colombia. We also included an experimental characterization and analysis of several key types of C&D waste from important infrastructure projects in Colombia, specifically by using the X-ray diffraction and scanning electron microscopy techniques. For the quantification of CDW, a calculation was performed based on the area and four factors of volume and density, followed by an econometric analysis of the detailed information using the Hodrick–Prescott filter, which revealed the CDW trends. Our results revealed that there are limitations regarding the availability of information and effective treatments for this waste, as well as shortcomings in education and other issues, not only for Colombia but also for other countries in Latin America.

**Keywords:** solid waste; construction and demolition; circular economy

**1. Introduction**

Global warming is a very serious threat that could cause a devastating worldwide disaster if actions are not taken by all countries to reduce the excessive consumption of materials [1], develop sustainable agriculture [2], and, most importantly, apply politics to find real solutions [3]. Due to the urgency of this situation, it is necessary to increase corrective measures in all areas of solid waste management and recycle as much as possible, particularly in sectors that produce large amounts of waste that consists of metallurgical slags [4,5], rubber tires [6–8], organics [9], and construction and demolition waste (CDW) [10]. Moreover, preventive strategies such as improved economic models must be developed. The popular circular economy model [11,12] has been implemented in many sectors, e.g., by modifying manufacturing and design processes so that products last longer and can be used in other applications after their lifecycles (upcycling). For this reason, many sectors that involve materials and electronic devices are now experiencing a revolution, with processes being redesigned to fit the circular economy model [13], for example, in additive manufacturing [14], construction and building materials [15], smart materials [16], thermoelectric modules [17], and the transportation industry [18]. Furthermore, models have been developed for the sustainable design of solid-waste management on a city [19] and country scale [20].

Construction, demolition, and renovation activities generate a large amount of waste which harms the environment and can have a significant impact on global warming if it is not managed properly [21]. It is estimated that around 35% of construction and demolition waste (CDW) ends up in landfills without any type of treatment [22]. Therefore, new

**Citation:** Colorado, H.A.; Muñoz, A.; Neves Monteiro, S. Circular Economy of Construction and Demolition Waste: A Case Study of Colombia. *Sustainability* **2022**, *14*, 7225. https:// doi.org/10.3390/su14127225

Academic Editor: Ming-Lang Tseng

Received: 23 April 2022 Accepted: 30 May 2022 Published: 13 June 2022

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solutions, technology, and approaches are required for the management of CDW. The European Commission proposed that by 2020, a minimum of 70% of construction and demolition waste should be recycled. However, there were some member states of the European Union in which recycling rates already exceeded 70% [23]. This has been achieved through good waste management practices that essentially implement circular economy principles in the construction and demolition sector and beyond. The most effective practices are aimed at maximizing the reuse of items by facilitating recycling, material recovery, and the secondary use of materials through quality assurance schemes for wastederived materials. This involves considering the entire value chain of the construction sector and implementing these principles throughout [24].

To establish a construction and demolition waste management system, an appropriate CDW quantification must be determined that can help the government make realistic decisions and policies and determine the places wherein disposal can be granted (e.g., end of waste disposal [25]). The globally adopted methodologies for quantifying CDW can be summarized into six categories: the method of visiting the site, the method of calculating the generation rate, the method of life analysis, the method of classifying the accumulation system, the method of modeling variables, and other assorted methods [26]. The site visit method (SV) requires that investigators go to the construction or demolition site. The generation rate calculation method (GRC) seeks to obtain the waste generation rate and estimate certain alternative parameters such as the financial value based on the area. The life analysis method is mainly used to quantify demolition waste based on mass balance, assuming that every building will at some point be demolished and therefore the amount of demolition residue must be equal to the mass of the built structure. The accumulation system classification method (CSA) is based on the generation rate calculation method but involves a quantification system for different special materials. The variable modeling method uses the modeling of variables to simulate the generation of waste, taking into account five factors (specific activity, type of work and equipment, type of material and storage, site and weather conditions, and company policy). The other methods include estimating waste production as a percentage of the purchase of materials and calculating the amount of residue for some materials based on their chemical characteristics.

In this article, the amount of construction and demolition waste generated in Colombia was quantified using innovative methods involving the area of construction and the volume and density factors of the materials. Additionally, a case study from Colombia was considered and the composition of the waste was characterized. Subsequently, an econometric study was carried out to better understand the behavior and factors that influence the generation of CDW in Colombia. Finally, the CDW situation in Colombia and other countries was evaluated and compared.
