# Sustainability Enhancement and Evaluation of a Concrete Dam Using Recycling
## 1 Introduction  
Dams hold a significant role in the water resources management within nations, serving as pivotal structures that contribute not only to flood crisis management, but also fulfill various functions such as water supply, irrigation, and power generation [1, 2, 3]. Beyond the socioeconomic ramifications, dam deterioration carries the potential for profound environmental repercussions, encompassing both the immediate consequences of failure and the long-term impacts arising from the dam's presence and operations [4, 5]. Theseinclude alterations to downstream river ecosystems, habitat loss for aquatic species, and the disruption of animal migration patterns [6; 7]. The construction industry, encompassing various activities from raw material extraction to demolition waste recycling, constitutes a significant portion of Europe's environmental footprint [8; 9; 10; 11]. It represents half of the consumption of natural raw materials, accounts for 40% of total energy use (as the primary consumer), generates 46% of waste, and contributes to 36% of all greenhouse gas emissions. Within this sector, mineral materials, concrete, and other cement-based materials play a significant role in environmental impacts. The vast global production of concrete, reaching 25 billion tons annually, leads to the substantial utilization of natural resources and energy, primarily for cement and reinforcement steel production, as well as for transportation, construction, and demolition. This production also emits large amounts of greenhouse gases, primarily carbon dioxide (CO\({}_{2}\)) [12], primarily originating from cement production, along with emissions of SO\({}_{2}\) contributing to acidification, mainly from transportation. Additionally, it generates a considerable amount of construction and demolition waste, mostly being inert and non-dangerous [13]. The recycling process of materials from the structures' decommissioning phase has been evaluated, with a focus on concrete and steel. The concrete is crushed and processed to create recycled concrete aggregate (RCA), which can be reused in new concrete mixes for construction projects, reducing the demand for virgin aggregates. The steel is separated and melted down for reuse in various steel products, supporting circular economy principles by minimizing waste and conserving natural resources. These recycled materials not only help in reducing landfill waste, but also lower the environmental impact associated with the extraction and processing of raw materials. RCA, in particular, can be used in a variety of applications, including road base, foundations, and non-structural concrete, although further research is needed to fully evaluate its performance in high-stress structural applications such as dam construction. This recycling process contributes to the sustainability of large-scale projects by enabling the recovery and repurposing of valuable materials, thus reducing both the carbon footprint and life cycle costs of future construction [14]. Research on RCA has demonstrated that while RCA reduces landfill use and conserves virgin materials, it often results in reduced material strength. As a result, additional cement or raw materials may be required to meet performance standards, which introduces economic allocation complexities [15]. However, replacing primary aggregates with RCA does not inherently ensure improved environmental performance across the entire life cycle of a concrete structure. A comprehensive evaluation of sustainability should encompass social and economic dimensions alongside environmental considerations. Therefore, it is imperative to employ scientifically grounded approaches to assess all three aspects of sustainability. For environmental evaluation, the widely accepted and standardized method of life cycle Assessment (LCA) is commonly utilized, enabling the examination of environmental impacts across processes and product life cycles.