1. Introduction
The Saudi Vision 2030 adopts comprehensive improvement standards across all areas of Saudi society, aiming to reduce carbon emissions resulting from the manufacturing of materials related to building construction [
1]. These emissions are expected to decrease by 30% and reach net-zero status by 2060. The urgency has arisen as countries worldwide gradually focus more on decarbonizing their economies [
2]. The annual growth rate of cement production is currently 4%, owing to the rapid increase in construction in developing countries [
3]. Sustainable development and construction are becoming increasingly important as environmental concerns grow. The building sector accounts for roughly 40% of global energy consumption and more than 30% of global greenhouse gas (GHG) emissions. For many years, concrete has been used to build long-lasting bridges, roads, building structures, medical facilities, housing, and commercial buildings to provide social infrastructure, promote prosperity, and aid in operational facility development. Concrete, as a widely used construction material, has a significant impact on sustainability [
4]. While environmental responsibility is undoubtedly important in construction, any method of construction must also be socially responsible and economically viable. To be truly sustainable, a building material must address all three of the aforementioned considerations [
5,
6].
The Kingdom of Saudi Arabia (KSA) has a large and rapidly growing building sector that heavily contributes to the country’s energy and environmental stresses [
7,
8]. However, the KSA has yet to adopt building sustainability standards and integrate life cycle assessment (LCA) into construction practices to address environmental challenges [
9]. The lack of adoption stems from the newness of the LCA concept in the Saudi construction industry. Furthermore, there is a clear gap in academic research regarding LCA studies in the building sector of the KSA [
10,
11,
12]. Among the G20 group of countries, the KSA now ranks as the fourth-fastest reducer of greenhouse gases (GHGs). Since 2010, the KSA’s historically rapid rate of emissions growth has been slowing, declining from an approximate 10% annual increase in 2010 to about 5% between 2011 and 2015. Saudi Arabia’s CO
2 emissions and percentage of annual change stabilized in 2016 and 2017, culminating in a 2.7% decrease in 2018 [
2].
The building construction sector globally, as well as in the KSA, accounts for approximately 40% of annual energy consumption. This sector is responsible for about 40% of global resource use, employs more than 10% of the workforce, and produces up to 40% of the solid waste worldwide. Additionally, it is a major contributor to CO
2 emissions, accounting for nearly 30% of all energy-related greenhouse gas (GHG) emissions. The production of concrete emits a substantial amount of CO
2, from material production to the manufacturing stage, primarily due to the cement manufacturing process. According to the Second Greenhouse Gas Emissions Report 1, in the KSA, each ton of cement releases about 0.3 tons of CO
2, contributing to 8.5% of the CO
2 emissions resulting from the calcination of raw materials and the burning of fossil fuels. Meanwhile, steel production is responsible for 28.9% of CO
2 emissions in the industrial processing and energy sectors [
13]. Despite steel being entirely recyclable, the steel remelting process consumes a significant amount of energy. However, there is considerable potential for reducing CO
2 emissions in the building construction sector, especially in both developed and developing countries [
14]. The volume of CO
2 emissions (and other GHGs) has been steadily increasing for several decades. Given that concrete is the most widely used man-made material globally, the construction of reinforced concrete structures significantly impacts the environment, primarily due to the use of cement as a binder for concrete and steel as reinforcement [
5].
To assess life cycle CO
2 emissions, concrete production operations were divided into three stages: raw material production, material transportation, and concrete manufacture. The environmental effect of each stage was thoroughly evaluated after estimating the energy spent and CO
2 released in each stage. Measures for enhancing environmental conditions were devised based on the assessment results.
Figure 1 depicts a flowchart of the concrete’s life cycle, from the building contractor placing an order for ready-mixed concrete to the reception of the concrete at the construction site [
5]. Based on the causes impacting the building environment in the KSA, this study studied a variety of specific variables, including compressive strength, EC, and cost. Not only does the construction sector consume a lot of energy and emit a lot of pollution, but it also accounts for a sizeable proportion of the total world CO
2 emissions [
15].
The simplified life cycle assessment (LCA) technique is a way of delivering a short yet informative study of the environmental consequences associated with a product, process, or service across its full life cycle [
16,
17,
18,
19]. Compared to typical complete LCAs, which may be resource-intensive and time-consuming, simplified LCAs shorten the assessment process by focusing on major impact categories and employing simplified models and data inputs. These simplified techniques frequently use tools like screening life cycle assessments or streamlined life cycle inventories to analyze environmental impacts, making them more accessible to small firms and projects with limited resources. While simplified approaches may not capture all of the intricacies of a thorough LCA, they nonetheless provide useful decision-making insights and can assist identify areas for improvement in environmental performance [
20]. It has been employed in a range of studies in different applications of building/construction engineering and is a widely accepted approach [
21]; for example, Hernández et al. [
22] used it for assessing a new structure system, Hou et al. [
23] used it for assessing cementitious composite materials (mixture design), and Eleftheriou et al. [
24] used it for assessing the use of cement bamboo frame technology.
Life cycle assessment (LCA), also referred to as life cycle analysis, serves as a tool for environmental impact assessment (EIA) to guide decisions in building design and construction. However, there is a scarcity of studies that compare various alternatives for the same construction project. In a prior study, the environmental impacts of three distinct four-pavement commercial office buildings were evaluated. These buildings were designed using C25, C50, and C75 concrete, respectively. The primary aim was to showcase the influence of concrete’s compressive strength on the service life and overall life cycle of structural solutions. The analysis of the results primarily focused on construction cost considerations [
25,
26].
Garcez et al. explored how the compressive strength of concrete affects the environmental impact, construction cost, service life, and durability of reinforced concrete (RC) structures [
5]. It demonstrated that C50 concrete showcased better environmental and economic performance compared to C75 while providing a balance between steel and concrete amounts [
5]. Goggins et al. investigated methods to manage energy consumption during reinforced concrete manufacturing, showcasing that using ground granulated blast furnace slag (GGBS) as a cement replacement significantly reduced energy consumption in RC structures [
27]. Zhang and Zhang utilized a multi-objective optimization approach to design sustainable RC members, emphasizing embodied emissions and costs, demonstrating that a slight cost increase could substantially reduce emissions [
6]. Zeinsek and Hajek analyzed strategies for designing RC structures with reduced carbon emissions, highlighting that using lower-strength concrete with a lower clinker content resulted in lower CO
2 emissions [
28]. Yoon et al. investigated sustainable design for RC columns, focusing on minimizing construction costs while considering energy consumption and CO
2 emissions, and found a potential 22% reduction in energy consumption and a 63% reduction in CO
2 emissions with a 10% increase in cost [
29]. Park et al. explored an assessment of CO
2 emissions based on the compressive strength of concrete mixtures used in construction in Korea, proposing methods for the quantitative assessment of CO
2 emissions at different production and transportation stages [
30]. Suhendro explored alternatives to reduce energy consumption and environmental impacts in cement manufacturing, suggesting the use of waste materials or alternative pozzolans to enhance concrete performance [
15]. Yeo and Gabbai focused on optimizing structural designs to reduce energy consumption, achieving a 10% reduction in the embodied energy through structural optimization techniques [
31]. Park et al. investigated optimizing building operations and designs to minimize CO
2 emissions, specifically concentrating on composite column designs in high-rise buildings, showcasing economical and environmentally efficient approaches [
32]. Fraile-Garcia et al. explored high-performance material use in RC column construction, emphasizing geometry, cement type, and concrete strength to reduce costs and emissions while highlighting the impact of execution methods on resource optimization [
33].
The relevance of building typology in influencing concrete compressive strength is critical to attaining a sustainable structural design. The building type affects the structural requirements, load-bearing capacity, and durability expectations. Understanding the unique requirements of the building type enables the development of concrete mixes with compressive strength designed to fulfil those demands. Building typologies need varied degrees of strength and resilience. The compressive strength is tailored to the exact needs of the building type, ensuring resource efficiency [
34]. This focused method reduces material consumption while retaining structural integrity, which contributes to sustainability objectives [
35]. The choice of compressive strength has a direct influence on the construction’s environmental imprint [
36]. By matching strength with building typology, the concrete mix may be optimized for a decreased environmental effect, considering aspects like embodied carbon and energy usage. Building typology influences the life cycle performance of buildings [
37]. The compressive strength must be carefully related to the building type’s expected lifetime, maintenance requirements, and general usefulness to ensure long-term sustainability [
38]. Finally, understanding the role of building typology in compressive strength allows for a more nuanced and sustainable approach to structural design. This acknowledgment guarantees that concrete compositions are customized to the individual demands of each building type, maximizing both performance and environmental effect [
5,
39].
The research focuses on a hotel building in the eastern region of Saudi Arabia, specifically Dammam. This hotel has 12 stories, 1280 inhabitants, and an average floor space of 2632 m
2. The structure is divided into four separate zones, from the basement to the top, each with twenty columns of three types: exterior, internal, and corner. This division sets the study’s goals, with a focus on safety and cost efficiency. The study is consistent with the Saudi Building Code (SBC) 301, 302, and 304 [
40,
41,
42], notably the concrete column design standards. Adherence to these criteria provides the foundation for guaranteeing structural integrity while efficiently controlling project expenses.
This study diverges by examining the environmental impact concerning concrete compressive strength in a larger-scale setting, specifically a hotel construction project situated in the eastern province of KSA [
43]. The primary objective of this study is to assess various concrete designs with differing compressive strengths, aiming to identify the most optimal design in terms of both environmental impact and cost effectiveness. It is critical to recognize the limits of depending exclusively on economic calculations [
44], particularly given that the present pricing of commodities often ignores the environmental implications of their production. While economic factors are important in decision-making, especially in building projects, the environmental consequences of material choices are just as important, if not more so, in terms of sustainability [
45]. The inclusion of cost considerations in sustainability materials research not only enhances the practical relevance and applicability of findings but also contributes to broader efforts aimed at mainstreaming sustainability principles in industry practices and policies. By demonstrating the cost viability of sustainable solutions, researchers can catalyze market uptake and incentivize investments in environmentally less-impact practices. Moreover, in the context of Saudi Arabia and similar regions experiencing rapid urbanization and infrastructure development, research that integrates both environmental and economic dimensions is particularly pertinent [
46,
47]. By addressing the dual imperatives of environmental stewardship and economic prosperity, such research endeavors can serve as catalysts for sustainable development pathways tailored to local contexts and priorities.
To accomplish the primary goal of this study, an exhaustive analysis will rigorously focus on measuring and refining concrete compressive strength, an essential process ensuring the precise calibration that is critical for upholding structural integrity and optimal performance within construction settings. Simultaneously, meticulous calculations will be applied to compile the bill of quantities (BOQ), delineating the required volumes of concrete (measured in cubic meters, m3) and steel (measured in tons) essential for strategic resource planning and facilitating seamless construction operations. Central to this endeavor is the evaluation of the embedded carbon coefficient (ECC) for each constituent ingredient incorporated in diverse concrete mixtures. This strategic calculation deeply examines the carbon footprint associated with individual components, offering invaluable insights into their environmental impact. In conjunction, the study will meticulously calculate the total embedded carbon (ECtotal) for each concrete mixture utilized, consolidating the collective environmental footprint of both concrete and steel components and providing a holistic perspective on their environmental impact. Moreover, an intricate and detailed cost analysis will be undertaken to thoroughly assess the financial implications of employing each concrete and steel mixture. This comprehensive evaluation aims to offer comprehensive insights into the financial viability and cost effectiveness of various formulation options available for construction materials. Finally, integrating the identified optimal compressive strength parameters, the study will ingeniously design a concrete mixture. This formulation aims to strike a delicate balance between economic feasibility and environmental sustainability, presenting a tailored solution specifically crafted for this building project.