Progress and Prospect of Solid Waste Utilization in Construction Industry: A Bibliometric Analysis Based on CiteSpace and VOSviewer

Abstract

The high-value-added and resourceful reuse of solid waste is regarded as a promising technological approach within the construction industry, playing a vital role in advancing sustainable development and ecological civilization. In this study, VOSviewer and CiteSpace were utilized to systematically perform a bibliometric analysis of research related to the reutilization of solid waste in the construction sector, using data from the Web of Science Core Collection and Scopus databases. The analysis focused on publication volume over the last decade, global collaboration networks, thematic journals, keyword co-occurrence, and timeline clustering. The results reveal that: (1) The number of publications related to solid waste in construction has steadily increased over the last decade; (2) Significant research contributions have been observed from China. However, a cohesive core of contributing authors has yet to emerge, and broader, more equitable international collaboration remains necessary; (3) Research foundations span disciplines such as environmental science, materials science, physics, and chemistry, indicating a clear trend of interdisciplinary integration; (4) Current research primarily explores the performance and environmental impacts of concrete and waste-derived materials. Over time, topics have expanded from early explorations to include environmental assessments, waste management, and the circular economy, increasingly advanced technologies to investigate high-performance and diverse material applications. In the future, the energy efficiency and green sustainability of solid waste are expected to draw continued attention, with emerging technologies such as 3D printing and artificial intelligence likely to foster more interdisciplinary research in optimizing material performance.

1. Introduction

In the global context of economic recycling and environmental protection, addressing the issue of solid waste has become imperative. According to the World Bank’s report [1], the generation of municipal solid waste (MSW) has exhibited a significant upward trend. Driven by accelerated urbanization and shifting consumption patterns, global MSW production increased from 2.01 billion tons in 2016 to 2.24 billion tons in 2020, with an average annual growth rate of 2.3%. Notably, the growth was particularly pronounced in low- and middle-income countries. Among these, the proportion of construction solid waste has risen steadily, accounting for 1.3 billion tons (64.7% of total MSW) in 2016 and reaching 1.6 billion tons (71.4%) by 2020. Projections indicate that this figure will exceed 2 billion tons by 2025. Furthermore, significant regional disparities exist in the resource utilization rates of MSW. High-income countries, such as Germany and South Korea, achieve recycling rates exceeding 50% through well-developed sorting systems and policy incentives. In contrast, low- and middle-income countries struggle with recycling rates typically below 10% [2]. As a leading emerging economy, China generates more than 1 billion tons of construction solid waste annually, representing over half of the global total. However, the resource utilization rate in China remains low, fluctuating between 5% and 10% [3]. Analysis of construction waste composition reveals that inert materials, such as concrete and masonry, constitute over 70% of the output. The low degradability of such materials poses significant ecological challenges for landfill disposal. Empirical research [4] predicts that by 2050, the global MSW volume will increase by 70% relative to the 2020 baseline, with low-income countries experiencing a three-fold increase. This exponential growth underscores the urgency for systematic management of construction solid waste. To address this challenge, developing a comprehensive life cycle assessment (LCA) framework is critical. By applying material flow analysis, a closed-loop system encompassing the generation, collection, treatment, and reuse of waste can be optimized. Such an approach is essential to surmount current technical bottlenecks and institutional barriers, enabling more effective resource utilization in the construction sector.

With the continuous increase in solid waste generation and the growing demand for non-renewable raw materials, significant weaknesses in existing solid waste management systems have become apparent. Traditional treatment methods are increasingly inadequate to meet the requirements of sustainable development. A large proportion of municipal solid waste is either directly landfilled or openly dumped without proper treatment. This situation underscores the urgency and necessity of promoting the reutilization of solid waste. Within this framework, the issues of concrete production and usage are particularly prominent. Although concrete is widely used for its excellent mechanical and physical properties, its production process exerts significant environmental pressure. Billions of tons of concrete are produced annually, with CO₂ emissions from the manufacturing of its raw materials causing irreversible damage to the global ecological environment. Furthermore, concerns about CO₂ emissions, energy consumption, high aggregate demand, concrete demolition waste, and filler requirements raise doubts about the sustainability of concrete production. Consequently, researchers are striving to identify low-carbon materials that can substitute for cement, leveraging the resource potential of solid waste. Solid waste, characterized by large reserves, a low carbon footprint, and easy accessibility, can be applied as supplementary cementitious materials (SCMs) in construction to harness its secondary value. Studies suggest that solid waste, as novel construction materials, not only reduces concrete usage but also enhances its performance. Driven by international green building initiatives, the construction industry has increasingly incorporated the recycling and utilization of solid waste. Among these, industrial byproducts (e.g., fly ash [5], blast furnace slag [6], bottom ash [7], red mud [8], rice husk ash [9], mine tailings [10]) exhibit the highest recycling rates and are frequently employed as supplementary cementitious materials (SCMs) in the development of sustainable building materials. Construction and demolition waste, including discarded concrete [11], bricks [12], wood [13], metals [14], glass [15], and gypsum board [16], is often repurposed as recycled aggregates for concrete and brick production. Agricultural waste, such as rice husk ash [17], straw [18], and coconut shells [19], is utilized in the preparation of lightweight aggregates or as biomass fuels. Additionally, hazardous solid wastes, such as heavy-metal-stabilized bottom ash [20] and sludge residues [21], can be recycled as road base materials after undergoing stabilization using techniques like cementation or geopolymerization. These common types of solid waste, once processed through appropriate technological treatments, can effectively replace or enhance traditional construction materials.

However, research on the reutilization of solid waste in the construction sector largely remains at the experimental stage [22], with key indicators such as the long-term performance of materials, lifecycle assessment, and extent of application still requiring further investigation. Numerous researchers have analyzed the role of solid waste from the perspectives of material systems and performance [23,24,25]. For instance, Das Dipankar et al. [26] reviewed recent advances in developing sustainable and environmentally friendly geopolymer bricks from industrial solid waste, demonstrating through testing that these bricks exhibit excellent mechanical strength (compressive and flexural) and durability in harsh environments. Sun Qi et al. [27] successfully prepared an optimal composite material from magnesium sulfate cement and multi-source industrial solid waste under specific conditions, exploring its economic and environmental benefits and potential applications. Liu Jianlei et al. [28] utilized traditional sintering methods to develop an eco-friendly, fully solid waste-based permeable material using water-quenched slag and silica sand tailings, which shows significant application potential in sidewalk construction. Sun Yu et al. [29] investigated the performance variations of solid waste aggregates mixed with porous asphalt, providing valuable insights for road engineering. Guo Xuan et al. [30] comprehensively examined the research progress of inorganic industrial solid waste (IISW) in building material preparation, water/air treatment, and soil improvement, indicating that large-scale integrated utilization of IISW in the construction industry appears promising. These studies collectively highlight the broad development prospects for solid waste in the construction field.

Despite solid waste reutilization becoming a research hotspot in the construction sector and a substantial body of literature being published in related fields, there remains a lack of clear understanding regarding the construction of these knowledge systems. Bibliometric methods have been widely applied in fields like environmental science and materials science to assess research impact, identify emerging trends, and reveal features and hotspots in specific domains [31]. Moreover, few scholars have systematically reviewed the progress of solid waste utilization in construction using a combination of qualitative and quantitative methods; most reviews exhibit subjective bias and lack quantitative bibliometric analysis. Therefore, this study aims to explore the evolutionary process of knowledge related to solid waste utilization in the construction field. Research articles from 2014 to 2024 in the Web of Science Core Collection and Scopus databases were selected as the data sample. Visualization analysis was conducted using CiteSpace and VOSviewer bibliometric tools to identify the most influential researchers and institutions, research hotspots, emerging trends, knowledge gaps, and future research directions in this area. This study offers a clear picture of the current state of solid waste research, serving as a reference for future research direction clarification.

2. Methodology and Data Resource

2.1. Methodology

Scientometrics, with its quantitative analysis advantages in fields such as science, scientific communication, and science policy, has been widely applied to quantitatively assess scientific contributions, monitor scientific development, identify emerging trends, and reveal internal structures within knowledge domains [32]. The recycling of solid waste, as a hot topic in sustainable development, has garnered significant attention from scholars. This paper employs two bibliometric visualization tools, CiteSpace 6.3.R3 and VOSviewer 1.6.19, to construct knowledge maps and perform a visual analysis of literature on the reuse of solid waste in the construction field over the past decade.

To select appropriate tools for bibliometric analysis, a comparative evaluation was conducted among widely used scientometric software, including CiteSpace 6.3.R3, VOSviewer 1.6.19, RefViz 2.1, and HistCite Pro 2.1 [33,34]. While RefViz and HistCite excel in keyword frequency counting and thematic clustering, they lack the deep co-citation analysis capabilities and cannot generate timeline maps of research themes. In contrast, CiteSpace is noted for its robust network analysis and time-series analysis features, making it suitable for constructing large knowledge network maps. This capability allows researchers to discern the development trends within a discipline and comprehend the knowledge structure and dynamics within literature databases [35]. VOSviewer is renowned for its intuitive and clear visualization effects, which can vividly present the dynamic collaborative relationships between subgroups in a research domain through variations in node size, color, shape, and dynamic network structures [36]. Therefore, CiteSpace and VOSviewer were selected as the analysis tools for this study to minimize subjectivity and bias.

Through these tools, an analysis of the frequency of annual publications, countries, institutions, authors, and keywords related to the reuse of solid waste in the construction field was conducted, clarifying the publication distribution characteristics domestically and internationally. Core authors, journals, and keywords were identified, and co-occurrence networks and visual knowledge maps of authors, countries, keywords, and journals were constructed, elucidating the distribution and collaborative relationships of research teams worldwide. By analyzing keyword timeline maps, the thematic evolution process across different time and space contexts was revealed, providing a quantitative basis for accurately grasping research hotspots and frontier dynamics.

2.2. Data Resources

To establish a comprehensive literature database for research on the reutilization of solid waste in the construction field and to conduct a more objective and thorough bibliometric analysis, the Web of Science (WOS) Core Collection and Scopus databases were selected for thematic literature screening. The Web of Science Core Collection is a globally authoritative academic information retrieval platform developed and maintained by Clarivate Analytics, encompassing important databases such as SCI, SSCI, and A&HCI, and is widely recognized by the academic community. Scopus, maintained by Elsevier, is the world’s largest abstract and citation database of peer-reviewed literature, including scientific journals, books, and conference proceedings [37,38]. Both databases are commonly used data sources for bibliometric research, providing comprehensive and reliable data support for this study. Each literature entry includes information such as title, authors, publication date, journal, abstract, and references. Due to the broad inclusion of research topics, some overlap exists between the WOS and Scopus databases [39]. Therefore, deduplication was conducted using software during the data selection process. Given the aim of this paper to review the progress in solid waste reutilization in the construction sector, key terms such as “solid waste”, “building”, “construction”, “architecture”, and “civil engineering” were used as the core search terms, with a time span set from 2014 to 2024. Ultimately, following a series of screening processes, a sample of 2357 qualified documents was identified. The detailed screening process and bibliometric analysis process are illustrated in Figure 1.

3. Results Analysis

3.1. Annual Publications and Trends

The annual publication volume serves as a crucial indicator for assessing progress within a research field. This metric quantifies the development of existing research outcomes over time, thereby clarifying the current state of research. Furthermore, by fitting the annual publication data, a more objective prediction of future development speed and trends can be achieved. The distribution of the annual and cumulative number of publications is shown in Figure 2.

Over the past decade, the number of publications related to solid waste utilization in the construction industry has shown a steady upward trend, indicating growing scholarly interest in this field. Based on the trend in publication volume, the research in this area can be divided into three distinct phases: The first phase (2014–2017) represents the initial exploratory stage, with publications constituting 16.04% of the total, reaching 130 papers in 2017. This stage’s research outcomes were significantly influenced by the global concepts of the circular economy. For instance, in 2014, the European Commission released “Towards a Circular Economy: A Zero Waste Programme for Europe” [40], which systematically introduced the requirements of the circular economy. In 2016, the United Nations launched the 2030 Agenda for Sustainable Development, implementing a circular economy action plan that included production, consumption, waste management, and resource recycling [41]. Research during this period primarily focused on urban solid waste management and preliminary exploration of solid waste applications, laying a policy and management foundation for subsequent research [42,43]. The themes involved at this stage were relatively fundamental, as the research was still in its infancy. The second phase (2018–2020) is characterized by sustained growth, with publications accounting for 24.14% of the total, reaching 238 papers by 2020. In March 2020, the European Commission adopted “A New Circular Economy Action Plan” [44]. During this period, increased attention was directed towards the sustainable development of construction and demolition waste, as well as the use of recycled solid waste as building materials. The third phase (2021–2024) marks a period of rapid development, with more than 250 papers published annually on average, constituting 59.82% of the total, and peaking at 424 papers in 2024. This phase’s rapid growth may be driven by China’s 14th Five-Year Plan and the global energy crisis [45]. The intensifying energy crisis has prompted researchers in the construction field to enhance the resource utilization of solid waste, conduct research on green building materials, and seek low-carbon, environmentally friendly materials to mitigate material consumption and carbon emissions in the construction industry, thereby contributing to green development and the comprehensive utilization of solid waste.

3.2. Types of Solid Wastes Used in Construction

Statistical analysis of annual publication trends has confirmed the rapid growth of research on the reutilization of solid waste within the construction industry, underscoring the significant research value of this field. Based on authoritative reports such as the Global Construction Waste Management Report and extensive literature studies, a comprehensive classification and statistical analysis of solid waste types utilized in construction were conducted. This analysis encompassed their sources, recycling technologies, and utilization potential. Solid waste used in construction has been categorized into five primary types: industrial solid waste, construction solid waste, domestic solid waste, agricultural solid waste, and hazardous waste. The proportions of different types of solid waste utilized in global construction are illustrated in Figure 3.

The large-scale accumulation of solid waste has caused severe environmental pollution, making the resource utilization and large-scale application of these materials an effective strategy for addressing the global issue of solid waste buildup. Recycling and processing solid waste for use as construction materials represents a key approach to its application in the construction industry, highlighting the potential for solid waste utilization in this sector. Among various types of solid waste, industrial solid waste, construction solid waste, and domestic solid waste constitute the majority. Industrial solid waste, originating from industrial activities such as metallurgy, chemical production, and power generation, includes materials such as fly ash, coal gangue, steel slag, red mud, tailings, and smelting furnace slag. While industrial development has contributed significantly to economic growth, it has also generated substantial quantities of waste, which can release harmful substances such as heavy metals during collection, transportation, and processing, posing risks to both the environment and public health [46,47]. Consequently, extensive research has focused on the resource utilization of industrial solid waste, with fly ash serving as a prime example. Due to its spherical glass bead morphology and pozzolanic activity, the active SiO₂/Al₂O₃ in fly ash reacts effectively with cement hydration byproducts, such as Ca(OH)₂, making it widely used in the construction industry as a low-carbon mineral admixture for material preparation or concrete performance enhancement [48]. Steel slag and red mud, due to their favorable structural properties, have been developed for use in road base materials [49]. Tailings and coal gangue, benefiting from mineral synergy effects, have been utilized in the production of recycled aggregates and lightweight aggregates, reducing the need for natural aggregate extraction [50,51]. Additionally, coal gangue has been adopted as an alkaline activator in geopolymer studies, contributing to innovations in emerging materials within the construction industry [52]. The resource utilization of industrial solid waste has thus become a crucial pathway for achieving green and low-carbon development in modern construction practices.

Construction solid waste primarily originates from activities such as construction, demolition, and residential renovation and represents a critical focus in global solid waste management. During construction processes, significant quantities of waste materials, including discarded wood, surplus mortar, and excavated soil, are generated. Discarded wood, due to its porous structure, has been reclaimed for the development of functional building materials [53]. Surplus mortar and excavated soil, with their cohesive properties, can be stabilized with cement or lime and repurposed as recycled cementitious materials or ground stabilization substances [54]. Solid waste produced from demolition activities, such as concrete debris and waste bricks and tiles, has been recycled as lightweight building materials. Waste concrete, in particular, has been repurposed for the production of pervious concrete or further processed for use as mortar aggregates [55,56]. These measures facilitate resource-efficient treatment and reduce the accumulation of waste materials. In residential renovation activities, waste ceramic tiles and gypsum boards are the primary types of construction waste generated. Waste ceramic tiles, due to their low water absorption characteristics, have been recycled for the production of functional aggregates such as skid-resistant pervious bricks or lightweight aggregate concrete, significantly enhancing the frost resistance of construction aggregates [57]. Similarly, waste gypsum boards have been utilized as recycled construction materials, with experimental findings demonstrating their suitability as effective mineral expansion agents. These agents not only improve the chemical stability of lightweight materials but also reduce the leachability of metals [58]. Consequently, the recycling and reuse of construction solid waste provide a sustainable solution in terms of technical, environmental, and economic perspectives, offering substantial potential for the development of green, lightweight building materials in construction projects.

Domestic solid waste is generated from daily activities in residential, commercial, and public institutions (e.g., schools and hospitals), including food waste, discarded plastic packaging, paper waste, glass waste, and rubber waste. Although waste classification systems have been widely implemented to enhance processing efficiency [59], traditional methods of managing municipal solid waste—such as sanitary landfill, incineration, composting, anaerobic digestion, and stabilization—remain the predominant approaches [60]. In the construction industry, waste glass is commonly recycled through aggregate substitution techniques for use in concrete materials [61]. Additionally, its reflective properties can be utilized in the development of architectural coatings. Discarded rubber is repurposed in composite cement materials to reduce reliance on natural resources in construction applications [62]. This utilization not only promotes sustainable practices but also underscores the potential of municipal solid waste as a resource in the development of environmentally friendly building materials.

Although agricultural solid waste and hazardous waste constitute a relatively small proportion of overall solid waste, their research prominence within the construction industry has been steadily increasing. Agricultural solid waste refers to discarded materials generated from agricultural production processes and rural households, such as rice husk ash, straw, waste bamboo, wood shavings, rice straw, wheat straw, bagasse, and discarded agricultural films. These biomass wastes have attracted significant attention from researchers due to their short reaction times and high utilization efficiency. Rice husk ash and straw, in particular, are widely applied as concrete modifiers in construction, where they partially replace cement to improve concrete strength, durability, and thermal properties while mitigating environmental impact. Rice husk ash, which is rich in silica, enhances the hydration process of concrete and interacts synergistically with steel slag to achieve sustainable cement substitution [63,64]. Charred straw can be used to produce lightweight aggregate concrete [65], while waste bamboo and wood shavings are utilized for the fabrication of structured composite construction materials [66]. Additionally, bagasse fibers have been found to significantly enhance the microstructural properties of cement-based composites [67], demonstrating the expanding scope of agricultural solid waste recycling in the construction sector.

Hazardous waste primarily includes materials that contain heavy metals or fibrous substances, such as lead-based paint, electroplating sludge, and mineral wool dust. Despite its relatively small proportion of total solid waste, hazardous waste is considered the most dangerous category. Its improper management can lead to catastrophic consequences, necessitating the development of high-value recycling technologies to ensure broader sustainable utilization [68,69]. Through stabilization techniques, lead-based paint can be combined with cementitious materials to produce radiation-shielding concrete [70]. The SiO₂ and Al₂O₃ components in electroplating sludge can be alkali-activated for the development of geopolymers, which are used as stabilizing materials for road bases [71]. Mineral wool dust, on the other hand, can partially substitute cement to positively impact concrete performance [72]. Current research employs various technologies for the remediation of heavy metal-containing solid waste, including cement-based solidification [73], chemical stabilization [74], and high-temperature thermal treatment [75]. As research advances, innovative technologies are expected to further contribute to the safe and efficient handling of hazardous waste, drawing more attention to the recycling and reuse of heavy metal-containing materials.

The utilization of the five major categories of solid waste in construction has been comprehensively summarized above. The application of solid waste in the construction industry is not limited by their proportion or size but is centered on exploring their potential and optimizing their material properties. Through substitution and innovation, solid waste can be repurposed for high-value applications. A bibliometric analysis of various indicators has objectively revealed the advancements and future prospects of solid waste recycling in construction, aiming to promote its resource-efficient utilization and development.

3.3. Global Distribution Collaborations Analysis

3.3.1. Analysis of Author Collaboration Network

In a specific research field, highly cited authors serve as the backbone for facilitating academic innovation and pioneering development. Additionally, these authors play a critical role in enhancing the educational impact and competitiveness of journals. Consequently, “author” was utilized as a node, and VOSviewer was employed to visualize and analyze the authorship and collaboration network within the selected literature. As illustrated in Figure 4, this approach effectively identifies the current scholars’ assessments of their research directions and illustrates the collaborative relationships among different researchers and teams. This visualization aids in comprehending the overall research trajectory more effectively. The size of the nodes reflects the frequency of the authors’ appearances, while the connecting lines signify collaborative relationships between the authors of the papers; thicker lines denote close cooperation. Within this study, 8667 authors were cataloged from the selected literature spanning the years 2014 to 2024, with 85 authors publishing more than five papers. The statistics pertaining to the top 10 authors, in terms of publications, are presented in

Table 1. The top 10 authors in terms of published articles.

Rank	Author	Count	H-index
1	Poon, ChiSun	42	116
2	Arulrajah, Arul	35	66
3	Horpibulsuk, Suksun	31	74
4	Xuan, Dongxing	24	42
5	Liu,Jun	19	42
6	Ling, Tung-Chai	18	58
7	Wang,Wenlong	16	39
8	Lu,Weisheng	14	47
9	Townsend, Timothy G.	14	52
10	Lisak,Grzegorz	12	50

.

Quantitative analysis of authors assists in identifying the core contributors in the field of solid waste reutilization in the construction industry, highlighting the scholarly exchange and collaboration among researchers. As depicted in Figure 4, although the authors are somewhat dispersed, the network diagram is divided into several tightly-knit research teams, ranging in size from 3 to 7 members. Among the top 10 authors, over 50% are Chinese scholars, indicating their active participation in this field and underscoring their international influence and significant research capabilities. Poon, ChiSun recorded the highest number of publications at 42, closely followed by Arulrajah, Arul, and Horpibulsuk, Suksun, with 35 and 31 publications, respectively. Regarding the H-index, Poon and ChiSun achieved a remarkable score of 116, reflecting a substantial academic impact. Additionally, the core authors collectively published 225 papers, accounting for 9.55% of the total publications, suggesting that a stable core authorship group has yet to be established. Research areas covered by these core authors are diverse, including solid waste recycling, carbonation technology, the development of new construction materials, life cycle assessment, and environmental impact analysis. These efforts are all directed towards promoting sustainable development and the integration of eco-friendly technologies in the construction materials industry. The collaborative team led by Poon, Chi-Sun, in collaboration with Ling, Tung-Chai, has achieved significant advancements in the areas of carbonation methods for concrete waste and related improvement technologies [76], as well as the performance of recycled concrete aggregates [77,78]. Their research has demonstrated that carbonation treatment can effectively enhance the quality of recycled concrete aggregates. The research team led by Arulrajah, Arul, and Horpibulsuk, Suksun, was among the early entrants in exploring the use of solid waste within the construction industry. Efforts have been made to synthesize innovative solid waste materials, such as geopolymers, from recycled waste [79,80]. Additionally, the team has focused on investigating the performance of pavement subbase demolition waste, aiming to identify sustainable applications for road construction [81]. Additionally, emerging researchers have entered the field. For example, Townsend, Timothy G has concentrated on studying materials like municipal solid waste incineration (MSWI) bottom ash (BA) [82].

Overall, the development of solid waste initiatives in the construction sector is gaining momentum, with an increasing number of researchers becoming involved. Nonetheless, academic collaboration remains limited, pointing to the necessity for stronger connections between related research areas at the academic level in the future to encourage more interdisciplinary cooperation. This enhanced collaboration could lead to the production of higher-quality research outcomes through closer teamwork.

3.3.2. Analysis of Institution Collaboration Network

The network of research institution partnerships serves as a crucial indicator for the visualization analysis of academic literature. In this study, VOSviewer’s institution analysis function was employed to visualize and analyze the publishing institutions featured in the literature. This network not only objectively presents the academic partnerships among the institutions involved in this research area but also quantitatively evaluates each institution’s contribution to the literature. The collaboration network of research institutions is illustrated in Figure 5. Each node represents a contributing organization, with the size of the node proportional to the number of documents produced by that organization. The lines connecting the nodes depict the cooperative relationships between organizations; thicker lines signify closer collaboration. From the selected literature spanning 2014 to 2024, 2440 institutions were recorded, with 66 of them publishing over ten papers. The top 10 institutions, based on the number of publications, are detailed in

Table 2. The top 10 institutions in terms of publication articles.

Rank	Institution	Count	Citations
1	Tongji University	57	1761
2	Chinese Acad Sci	55	1598
3	Hong Kong Polytech University	46	2389
4	Southeast University	43	536
5	Wuhan University of Technology	43	1550
6	Zhejiang University	35	840
7	Shanghai Jiao Tong Univ	30	1178
8	Univ sci & technol Beijing	29	745
9	Harbin Inst Technol	28	1033
10	Cent south Univ	28	938

.

Table 2 indicates that research on solid waste in the construction field is primarily concentrated in higher education institutions and key laboratories, with Chinese universities playing a dominant role. This distribution reflects the significant engagement of China’s universities and research institutions in this area. The institutional collaboration network diagram in Figure 5 exhibits a multi-centered and broad-themed characteristic. Leading research institutions by publication volume include Tongji University (57 publications), the Chinese Academy of Sciences (55 publications), and Hong Kong Polytechnic University (46 publications). The size of the nodes indicates these institutions’ substantial international influence and prolific publication output. Research teams centered around Tongji University focus primarily on studying the application scenarios of solid waste materials through model design [83] and experimental analysis [84]. They have achieved certain advancements in emerging green pavement engineering [85,86] and 3D printing smart construction [87,88,89]. The Chinese Academy of Sciences has conducted extensive research on low-carbon processing and green sustainable building materials [90,91]. In contrast, the research team at Hong Kong Polytechnic University emphasizes the mechanical properties of solid waste materials such as fly ash and silica fume, as well as life cycle assessments of waste reuse [92]. Additionally, the Chinese Academy of Sciences has established a dense collaborative network with institutions such as Hong Kong Polytechnic University, the University of Chinese Academy of Sciences, and Tongji University, facilitating close research cooperation. However, it is evident that the collaborative scope of Chinese research institutions remains relatively closed, with insufficient partnerships with international universities. Therefore, future research on solid waste in the construction industry should place greater emphasis on international collaboration to strengthen academic exchange between domestic and global entities.

3.3.3. Analysis of Country Collaboration Network

The Country Cooperation Network Map serves as an indicator of a nation’s overall research and development level in a specific field while also visualizing the degree of international collaboration. The included literature was analyzed based on the country of publication, with “Country” serving as a node. Each node represents a country, and the size of the node is proportional to the number of publications emanating from that country. The lines connecting the nodes indicate international cooperation; thicker lines denote stronger collaborative ties. In this study, 106 countries were identified from the selected literature spanning 2014 to 2024, with 63 of them publishing more than five papers. The main countries and their cooperation networks are shown in Figure 6. The top 10 countries, ranked by the number of publications, are presented in

Table 3. The top 10 countries in terms of publication articles.

Rank	Country	Count	Citations
1	China	872	26,527
2	USA	273	7251
3	India	182	4512
4	Australia	146	6364
5	Brazil	102	4096
6	England	98	4395
7	Italy	96	2794
8	Spain	74	2220
9	Malaysia	73	4358
10	Canada	68	3361

.

Analysis of the data in Table 3 reveals that China has published the most research on the utilization of solid waste in the construction field, totaling 872 publications, which accounts for 37% of the overall output. Following China are the United States (273 publications), India (182), and Australia (146). Figure 6 further illustrates China’s central role in the international collaboration network within this domain, with a larger node size indicating not only a high volume of publications but also significant international influence. This prominence may be closely linked to policies such as the World Green Building Council’s “Net Zero Carbon Buildings Commitment” [93] and China’s “14th Five-Year Plan for Circular Economy Development” [94]. Moreover, the thicker lines connecting China with countries like the United States, Australia, the United Kingdom, and India signify more frequent and robust collaboration in this field. The relatively larger nodes of these countries also reflect their active research involvement and their importance in international collaborations. However, the distribution of the collaboration network may be uneven, with some countries positioned at the network’s periphery. This positioning could limit the global sharing of knowledge and the efficiency of technological innovation. Smaller nodes and thinner lines in the figure potentially represent countries with less research activity or emerging research presence, as well as nascent collaborative relationships with major research nations.

In conclusion, while the collaboration network diagram reveals the current state of international cooperation in solid waste utilization research within the construction sector, it also highlights issues such as excessive concentration, uneven distribution, and a lack of diversity. Future research and policymaking should aim to promote broader and more balanced international collaboration to drive sustained development and innovation in the field.

3.4. Subject and Journal Analysis

To investigate the flow of information and the trajectory of knowledge development within specific disciplines, a domain-level citation pattern analysis was conducted using CiteSpace. This method aims to reveal the distribution of literature and citation pathways across various academic disciplines [95]. A dual-map overlay analysis of journals related to solid waste in the construction sector is presented in Figure 7. Additionally, the “co-citation” analysis function in VOSviewer was employed to perform density visualization of cited journals, further highlighting research hotspots. The density visualization map, showing the prominent journals in solid waste research within the construction field, is displayed in Figure 8. The 10 journals with the highest publication volume are summarized in

Table 4. Top 10 journals with the most cited publications.

Rank	Journal	Citations
1	Construction and Building Materials	13,326
2	Journal of Cleaner Production	8088
3	Waste Management	6978
4	Cement and Concrete Research	3593
5	Resources, Conservation and Recycling	2996
6	Journal of Hazardous Materials	2614
7	Cement and Concrete Composites	2599
8	Bioresource Technology	1615
9	Journal of Environmental Management	1516
10	Science of The Total Environment	1498

. By integrating the complementary functionalities of these two bibliometric tools, the journal distribution and the developmental trajectory of this research domain were examined more objectively, providing valuable insights into the scholarly landscape of solid waste research in the construction sector.

Figure 7 presents the dual-map overlay analysis of research on solid waste in the construction sector, with Figure 7A,B representing different analytical perspectives and temporal dimensions. Figure 7A represents the citing journals subject areas and frontier research fields, while Figure 7B represents the subject areas of cited literature (references) and the basic research fields. This analysis reveals clear macrostructural patterns, including significant citation clustering from “Chemistry, Materials, Physics” and “Environment, Toxicology, Nutrition” toward “Veterinary Science, Animal Science”. The enlarged vertical and horizontal ellipses in the figure indicate the dominance of certain journals and authors in these fields within influential academic journals. The dual-map overlay analysis underscores the highly interdisciplinary nature of this research field, which integrates materials science, chemistry, environmental science, zoology, toxicology, and biology. Furthermore, cross-disciplinary connections are evident, such as from “Mathematics, Mechanics” to “Physics, Materials, Chemistry”, and from “Systems Science, Computing Science, Computer Science” to “Economics, Political Science”. These patterns indicate the exchange of knowledge and mutual influence among diverse disciplines. This signifies that research on solid waste in the construction industry is not only rooted in fundamental disciplines such as environmental science, materials science, physics, and chemistry but is also expanding into broader scientific domains, highlighting the considerable potential for continuous growth in this area.

In the study of academic journals, density heatmaps are primarily used to reveal the relationships and co-occurrence patterns among journals within a given research field. Each circle in the figure represents a journal, with the size of the circle reflecting its significance or frequency within the research and the color potentially indicating intensity or time periods of research activity. According to Figure 8 and Table 4, journals such as Construction and Building Materials, Journal of Cleaner Production, and Waste Management occupy critical positions in this field, demonstrating their high relevance and impact. Additionally, journals such as Bioresource Technology and Renewable and Sustainable Energy Reviews appear with brighter colors, indicating their current prominence and research intensity. Cross-disciplinary connections are also prominent; for example, journals like Science of The Total Environment and Energy highlight the integration of multiple disciplines. This trend reflects a high concentration of research activity in thematic journals within the field of construction materials, further underscoring the growing interdisciplinarity of modern scientific inquiry.

In summary, the above analysis provides valuable insights into the multidisciplinary perspectives and journal development trends in research related to the utilization of solid waste in the construction industry. Looking ahead, future research efforts should focus on fostering diversified innovation within foundational research fields and expanding multidimensional studies on solid waste applications in construction on a global scale. Such endeavors are expected to significantly advance the sustainable development of the construction sector.

3.5. Theme Analysis of Research Hotspots

3.5.1. Analysis of Keyword Network

This study aims to visualize research hotspots and trends in the utilization of solid waste in the construction sector from 2014 to 2024 through a keyword co-occurrence analysis conducted using CiteSpace. Keyword co-occurrence analysis investigates the frequency with which keywords appear in the literature to reveal relationships between different topics within the field. A co-occurrence relationship is established when two sets of keywords appear in the same document, and a higher frequency of co-occurrence indicates a stronger association between them [96]. The CiteSpace software was utilized in this study, with “keywords” selected as the analytical focus. The selection criteria for nodes were set to include the top 50 most-cited or frequently occurring items within each time slice. This configuration ensures the inclusion of the most highly cited keywords, while the Minimum Spanning Tree (MST) pruning method was employed to streamline keyword nodes and highlight key elements within the network. The keyword co-occurrence knowledge map associated with solid waste research in the construction sector is illustrated in Figure 9. The map comprises 188 keyword nodes (represented by N = 188). The size of each node corresponds to its frequency of occurrence, and the inner ring’s color reflects the year of keyword emergence. The progression of colors from cooler to warmer shades illustrates the temporal evolution of each keyword’s prominence. The purple rings enclosing certain nodes indicate their centrality, with thicker purple circles denoting higher levels of centrality. A total of 1426 connections (E = 1426) are observed between the keyword nodes, where the thickness of a connection reflects the strength of the co-occurrence relationship. The network density is 0.0811, which signifies the relative interconnectedness of the nodes. A higher density implies closer relationships between nodes and stronger overall network connectivity. Statistical analyses reveal that the top 15 keywords ranked by occurrence frequency are listed in

Table 5. The top 15 keywords (Sorted by frequency).

Rank	Keyword	Count
1	fly ash	442
2	concrete	378
3	municipal solid waste	362
4	performance	308
5	mechanical property	282
6	construction	265
7	strength	220
8	life cycle assessment	206
9	compressive strength	186
10	behavior	157
11	heavy metals	133
12	durability	109
13	hydration	104
14	circular economy	98
15	aggregate	80

, while the top 15 keywords ranked by centrality are listed in

Table 6. The top 15 keywords (Sorted by centrality).

Rank	Keyword	Centrality
1	concrete	0.20
2	fly ash	0.15
3	life cycle assessment	0.15
4	mechanical property	0.12
5	behavior	0.10
6	municipal solid waste	0.08
7	aggregate	0.08
8	construction	0.08
9	heavy metals	0.07
10	waste management	0.06
11	bottom ash	0.06
12	demolition waste	0.05
13	sewage sludge	0.05
14	anaerobic digestion	0.04
15	3d printing	0.03

. These keywords collectively summarize the primary research hotspots in the field of solid waste utilization in construction over the past decade.

As illustrated in Table 5 and Table 6, considering that the database of papers analyzed primarily focuses on the utilization of solid waste in the construction industry, it is unsurprising that keywords directly associated with “solid waste” and “construction” appear with high frequency. Consequently, explicitly related terms such as “municipal solid waste” (362) and “construction” (265) were excluded from further analysis. Based on frequency, the top ten high-frequency keywords were identified as follows: “fly ash” (442), “concrete” (378), “performance” (308), “mechanical property” (282), “strength” (220), “life cycle assessment” (206), “compressive strength” (186), “behavior” (157), “heavy metals” (133), and “durability” (109). Ranked by centrality, the top ten keywords were identified as “concrete” (0.20), “fly ash” (0.15), “life cycle assessment” (0.15), “mechanical property” (0.12), “behavior” (0.10), “aggregate” (0.08), “heavy metals” (0.07), “waste management” (0.06), “bottom ash” (0.06), and “demolition waste” (0.05). These results indicate that keyword frequency and keyword centrality are not necessarily proportional. An intricate and complex network of co-occurrence relationships among keywords was observed in the co-occurrence diagram (Figure 8). The overall distribution exhibits a “supercore, polycentric, pan-thematic” pattern, which signifies the presence of a dominant central theme surrounded by multiple interrelated subtopics. Furthermore, the outer rings of most keyword nodes are depicted in darker colors, signifying that these keywords have been increasingly studied over the past decade. This trend highlights the sustained research interest in these topics.

Over the past decade, increasing attention has been devoted by researchers to the application of solid waste in the construction sector. Materials such as fly ash, silica fume, rice husk ash, ground granulated blast-furnace slag, and tailings have been successfully used as partial or complete replacements for supplementary cementitious materials (SCMs) in concrete, thereby finding widespread application in construction [97,98]. Among these materials, fly ash, owing to its high SiO₂ and Al₂O₃ content, has attracted the most extensive research as a high-performing mineral binder [99,100]. Furthermore, increasing interest has also been observed in studies investigating bottom ash, heavy metal recovery, demolition waste, sludge, and geopolymer applications. Research has demonstrated that cement-based or geopolymer solidification techniques can efficiently recover heavy metals from solid waste, enabling large-scale utilization of these materials. For instance, Teerawattanasuk et al. [101] investigated the lead immobilization properties of cement-treated clay using atomic absorption spectroscopy and reported significant improvements in heavy metal fixation, contributing to reduced industrial waste pollution. Similarly, Sun et al. [102] prepared geopolymers using sludge residue through wet alkaline pretreatment and found that this approach yielded effective heavy metal immobilization as well as high compressive strength. Tang, Qiang et al. [103] studied the stabilization and solidification of metal-containing incineration fly ash using Portland cement, evaluating the mechanical properties, leaching behavior, and environmental impacts of the resulting road material. Additionally, Yu, Hao et al. [104] utilized carbon dioxide mineralization technology to carbonate the inherent heat and water vapor in industrial solid waste flue gas into CO₂-cured cementitious materials. Their results demonstrated enhanced mechanical strength with increasing curing temperature and relative humidity, offering promising pathways for low-carbon solid waste treatment and sustainable building material production.

Researchers have also widely adopted experimental design techniques alongside machine learning and deep learning models to validate the mechanical performance and strength (particularly compressive strength) of solid waste materials and investigate the underlying mechanisms. Hou, Jiaojiao et al. [105] attempted to manufacture 100% solid waste-based cementitious materials and employed mechanical performance evaluation models, demonstrating the feasibility of incineration fly ash-based materials for construction. Hassani, Abolfazl et al. [106] and Bai, Yueji et al. [107] designed geopolymer composites by integrating industrial waste with geopolymer mortar and validated their feasibility through experimental testing and carbon footprint assessment, advancing the development of sustainable road base construction materials. The prominence of “life cycle assessment” (LCA) as a keyword in Table 5 and Table 6 underscores the significant focus in research on analyzing the environmental impacts of reusing solid waste in the construction sector. By conducting lifecycle environmental evaluations, researchers seek to better understand the current state of environmental performance associated with solid waste materials. For example, Wang, J. et al. [108] objectively assessed the energy consumption and carbon emission changes before and after integrating bottom ash into the road construction process, demonstrating that this application significantly aids carbon reduction. Similarly, Bansal, Deepesh et al. [109], through an LCA framework, evaluated the environmental impact of substituting natural aggregates with incineration bottom ash (IBA) in pavement layers, presenting a more comprehensive framework for IBA reuse in road construction.

In conclusion, researchers worldwide have made substantial progress in the reuse of solid waste in the construction sector, continually identifying innovative applications. These efforts encompass the multifaceted utilization of fly ash, solidification technologies for heavy metal-contaminated solid waste, recycling of construction and demolition waste, and the diverse applications of other types of solid waste. Objective experimental studies on the mechanical properties of solid waste materials have provided robust technical support and theoretical foundations for achieving resource-efficient and hazard-free solid waste utilization, as well as for the development of sustainable building materials.

3.5.2. Analysis of Keyword Cluster

To visualize the research hotspots and trends related to solid waste in the construction sector from 2014 to 2024, a multivariate statistical analysis was conducted based on keyword similarity, following the principles of hierarchical clustering to clearly illustrate the relationships between publications and thematic hotspots [110]. Using the Timeline View functionality of the CiteSpace software, a timeline clustering visualization of keywords was generated, as shown in Figure 10. In this timeline, each circle represents a keyword, with multiple related keyword nodes grouped under each thematic cluster. The position of each circle is fixed in the year of the keyword’s first occurrence, and if the same keyword appears in subsequent years, its occurrence frequency is incrementally added to its initial position. Connections between nodes are represented by lines, with line colors corresponding to the thematic cluster colors, illustrating the relationships and developmental trends of different keywords over time. The clustering results yielded a modularity value (Q) of 0.4726 (greater than 0.3), indicating that the clustering structure is statistically significant. The weighted mean silhouette value (S) was calculated as 0.7446 (greater than 0.7), suggesting that the clustering results are reasonable and reliable. A total of 10 clusters were identified within this research area, labeled as follows: #0 life cycle assessment, #1 mechanical properties, #2 municipal solid waste, #3 circular economy, #4 anaerobic digestion, #5 3d printing, #6 artificial aggregate, #7 microstructural evaluation, #8 demolition wastes, #9 cementitious material.

By analyzing the distribution of lines and nodes corresponding to thematic clusters along the timeline, several conclusions can be drawn. During the early research phase (2014–2016), studies were primarily focused on foundational topics such as the mechanical properties (#1) of municipal solid waste (#2). These areas continued to receive sustained attention in subsequent years. Within the “life cycle assessment (#0)” theme, early keywords such as “system” and “China” indicate that significant contributions to environmental evaluation in the solid waste field were made by researchers in China. Over time, terms related to environmental impacts and resource management, such as “optimization”, “energy consumption”, “landfill”, and “carbon dioxide”, emerged more frequently. This suggests an increasingly in-depth focus on the environmental factors affecting all stages of the life cycle, with particular emphasis on studies related to carbon emissions and energy utilization [111,112]. Under the “mechanical properties (#1)” cluster, research primarily explored material attributes such as strength [113], durability [114], and microstructural performance [115], with the greatest attention paid to “compressive strength”. Investigations into keywords like “fly ash”, “Portland cement”, and “high-performance concrete” reflect the evolution and intensification of research from traditional cementitious materials to high-performance concrete and the utilization of industrial by-products such as fly ash. These trends highlight the construction materials field’s commitment to performance optimization and sustainability. For instance, Wiranata, Didi Yuda et al. [116] investigated the use of fly ash and bottom ash as road base materials, analyzing their performance and structural design parameters for pavement applications. Similarly, Sikder, Rakesh et al. [117] examined the application of cupola furnace slag (CFS) in the construction sector, assessing the mechanical and durability properties of CFS-based concrete and proposing a novel approach to solid waste management. In the “municipal solid waste (#2)” cluster, keywords such as “incineration fly ash”, “immobilization”, “heavy metals”, “aluminum”, and “solidification” underscore the emphasis on the comprehensive utilization of fly ash and the immobilization of heavy metals as key areas of urban solid waste treatment and resource recovery. Moreover, the processes of collecting, recycling, and disposing of solid waste have been shown to exert significant environmental impacts, making solid waste management an important global issue. Incineration has also been extensively studied as a common treatment method for municipal solid waste, with research efforts directed toward improving energy recovery efficiency and addressing the treatment and utilization of incineration residues [118].

In summary, during this phase, research directions on solid waste were relatively fragmented, with limited collaboration between research groups. Each research hotspot remained in its early development stage. The findings primarily revolved around exploring the characteristics and material properties of different types of solid waste and assessing their life cycle carbon emission impacts. These studies laid the groundwork for advancing solid waste management and its sustainable integration into the construction sector.

During the mid-phase of research (2017–2020), emerging fields such as the circular economy (#3), anaerobic digestion (#4), and 3D printing (#5) gained prominence as research hotspots. Within the “circular economy (#3)” theme, early studies primarily focused on introducing and elaborating theoretical concepts, including principles, frameworks, and theoretical models. Over time, research shifted toward practical applications, particularly those emphasizing the circular utilization of materials in construction. For instance, the integration of “building materials” with the circular economy highlights efforts to reuse and recycle construction waste and to develop novel, environmentally friendly building materials. The connection between “behavior” and the circular economy suggests that researchers have also investigated the behaviors of various stakeholders involved in implementing circular economy initiatives and their impact on its development. The visual network analysis reveals clear links between the circular economy and keywords like “policy” and “implementation”, indicating an increasing emphasis on the integration of theoretical research, policy development, and practical application. Attention has been directed toward operationalizing circular economy principles to address real-world challenges in resource recycling and waste management within the construction sector. Additionally, interconnected nodes with themes such as “life cycle assessment (#0)”, “municipal solid waste (#2)”, and “mechanical properties (#1)” underscore the cross-disciplinary nature of circular economy research. Evaluating the environmental impacts of solid waste over its entire life cycle has been identified as an essential theme in the development of the circular economy, with municipal solid waste management occupying a central role [119]. This research points to promising applications of circular economy principles in advancing solid waste management and materials development. In the “anaerobic digestion (#4)” theme, relevant keywords include “sewage sludge”, “food waste”, “biomass”, and “renewable energy”. These keywords reveal the significant applications of anaerobic digestion technology in the context of solid waste research in the construction domain. “Sewage sludge” and “food waste” represent common feedstocks for anaerobic digestion, underscoring the focus on resource recovery from organic waste through this technique. Research has sought to optimize the conversion of these wastes into bioenergy or reusable materials. Furthermore, the association of “anaerobic digestion (#4)” with other research themes signifies the multifaceted nature of this technology in solid waste studies. Its connection with the “circular economy (#3)” indicates its role as a key technological avenue for achieving circular resource utilization [120]. The linkage with “municipal solid waste (#2)” highlights anaerobic digestion’s ability to complement other waste treatment methods, such as incineration and landfilling, in creating integrated urban waste management systems. Cross-references with “life cycle assessment (#0)” emphasize the sustainability and environmental benefits of anaerobic digestion technology. For the “3D printing (#5)” theme, increasing linkages and node sizes have been observed since 2018, accompanied by keywords such as “design”, “extraction”, and “degradation”. These terms suggest a focus on material development, process optimization, and performance evaluation of printed products. The intensification of research into this theme is closely tied to the rise of intelligent construction technologies, with 3D printing representing an innovative technological breakthrough in the construction industry. An increasing number of studies have investigated the development of sustainable cementitious composites using 3D printing [121,122,123].

In summary, this research phase highlights the growing importance of technological innovation in advancing circular economy principles. Anaerobic digestion has emerged as an effective organic waste treatment and energy recovery technology, poised to become a focal point for technological enhancement and application expansion within circular economy frameworks. Meanwhile, 3D printing presents new opportunities for the circular economy by reducing reliance on virgin materials and unlocking novel applications for solid waste. Future research is likely to focus on material compatibility, process optimization, and extending waste-derived material applications within the scope of 3D printing and other technological advancements.

In the recent research phase (2021–2024), growing attention has been directed toward themes such as artificial aggregates (#6), microstructural evaluation (#7), demolition waste (#8), and cementitious materials (#9). These topics reflect a continuing emphasis on the performance and applications of recycled materials derived from solid waste. Clear interconnections between these themes are evident. Keywords such as “partial replacement” and “implementation” indicate the increasing importance of managing “demolition waste (#8)” as urban areas undergo sustainable renewal and as older structures are demolished. “Artificial aggregates (#6)” have emerged as one of the primary pathways for repurposing demolition waste in construction materials. Terms such as “fly ash” and “slag” highlight the utilization of these solid wastes as raw materials for the production of artificial aggregates. This approach not only promotes the resource recovery of solid wastes but also reduces dependence on natural aggregates. “Accelerated carbonation”, a sustainable technology, has been shown to enhance the mechanical properties of artificial aggregates while achieving permanent CO₂ sequestration [124]. Additionally, artificial aggregates treated via carbonation demonstrate remarkable efficacy in stabilizing heavy metal ions present in raw materials. “Microstructural evaluation (#7)” is not only gaining wider application in the study of artificial aggregates but is also recognized as a pivotal tool for optimizing the properties of materials derived from solid waste. Techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) are frequently employed to analyze the microstructural characteristics of recycled materials. The integration of microstructural evaluation with mechanical performance analysis has become increasingly prevalent, facilitating the development of novel, high-performance construction materials. Within the theme of “cementitious materials (#9)”, strong links to the “circular economy (#3)” have been observed, indicating a growing alignment between research on cement-based materials and circular economy principles aimed at efficient resource utilization and reduced environmental impact. Recyclable construction materials, such as clay bricks, have been identified as potential aggregates or additives in cement-based composites. These materials exhibit the ability to improve concrete properties, such as reducing thermal conductivity and enhancing insulation performance [125]. Keywords like “prediction” suggest ongoing research utilizing mathematical models, machine learning algorithms, or other methods to forecast the mechanical and durability properties of cementitious and related materials. The linkage between “cementitious materials (#9)” and “microstructural evaluation (#7)” underscores researchers’ focus on the microstructural evolution of cement-based or solid waste-derived materials.

In summary, during this research phase, the focus on sustainable building materials, such as artificial aggregates and cementitious composites, has intensified. The integration of microstructural evaluation techniques into material performance studies has accelerated innovation, while alignment with circular economy principles has emphasized environmental impact reduction and resource efficiency.

3.5.3. Keywords with Citation Bursts

Keywords exhibiting citation bursts indicate periods during which their citation frequency increased significantly. The emergence of different keywords across various time periods reflects the dynamic evolution of research hotspots in the field of solid waste utilization within the construction sector [126]. By employing the “Burstness” module in the keyword co-occurrence analysis, a visualization of keyword bursts was generated, as shown in Figure 11. In this figure, thick red lines indicate the specific years during which bursts occurred. Burst intensity serves as an indicator of the sudden rise in keyword frequency within a given time interval. Higher burst intensity values signify that the corresponding keyword experienced heightened research activity and interest during that period. This analysis provides valuable insights into the shifting focus of research in the field and reveals emerging trends over time.

In the research on solid waste utilization within the construction sector, the keyword “sustainability” exhibited a burst intensity of 7.72, maintaining exceptionally high research interest from 2014 to 2020. This sustained high level of attention has established sustainability as a priority research direction for scholars in this field, reflecting global concerns regarding environmental, economic, and social sustainability. Between 2014 and 2019, keywords such as “residues”, “road construction”, “municipal solid waste”, “system”, “life cycle assessment”, “environmental impact”, “city”, “collection”, “disposal”, and “challenges” displayed significant burst intensity and gradually emerged as research hotspots. In particular, the keyword “city” demonstrated a burst intensity of 7.12, indicating growing interest in urban solid waste management, including the collection, disposal, and valorization of solid waste, as well as the sustainable development of urban construction. From 2020 to 2024, keywords such as “reduction”, “optimization”, “landfill”, “powder”, “degradation”, and “microstructure” began to show prominence. Notably, the keyword “optimization”, although initially appearing in 2017, exhibited a sharp research focus during 2020–2021, with a burst intensity of 7.11. This trend reflects the recognition that optimization is a critical strategy for enhancing efficiency, reducing costs, and improving performance. Research has centered on the optimization of various aspects of solid waste reuse, including material properties, production processes, process parameters, and system configurations. Furthermore, “powder” emerged as a key research focus between 2022 and 2024, reaching a burst intensity of 7.68. This highlights the rise of novel construction technologies and materials in the context of solid waste utilization. Research interests in “powder” include the study of its performance in specific applications (e.g., powder coatings, 3D-printing powders), the development of new materials (e.g., nano-powders, functional powders), and the relationship between the microstructure and performance of powder-based materials.

In summary, the research focus has shifted from foundational topics such as residue reuse and road construction to more specific environmental concerns, including urban solid waste management, greenhouse gas emission control, and environmental impact assessment. In recent years, there has been growing interest in topics such as waste reduction, resource optimization, landfill technology advancements, and microstructural analysis of materials. This shift reflects the field’s increasing emphasis on enhancing resource efficiency, minimizing environmental impacts, and advancing the circular economy. Most importantly, sustainability remains the central theme of solid waste research in the construction sector, permeating the entire research timeline. This is evidenced by the prominence of keywords such as “sustainability”, “environmental impact”, “reduction”, and “optimization”.

4. Discussion

This study employs bibliometric analysis to systematically and visually examine research hotspots and developmental trends in the reutilization of solid waste within the construction sector. The analysis focuses on key themes, including fly ash, bottom ash, heavy metals, geopolymers, and life cycle assessment, alongside their evolutionary trends. The findings highlight the reciprocal relationship between solid waste reutilization and sustainable development in the construction industry.

Fly ash, an industrial by-product, is widely used as a supplementary cementitious material in the construction sector and has consistently attracted significant research attention, particularly in the development of high-performance concrete and sustainable building materials. Bibliometric analysis demonstrates that fly ash can partially or fully replace Portland cement, with extensive applications in improving concrete workability and compressive strength. To promote its utilization, several countries have implemented policies encouraging the use of industrial by-products. For instance, China issued the Guidelines for Comprehensive Utilization of Industrial Solid Waste to advance the integration of fly ash and slag into various applications [127], while the Indian government, through the Fly Ash Utilization Notification, mandated coal-fired power plants to use fly ash in the production of construction materials such as bricks and cement [128]. These policy measures have facilitated the standardization and large-scale application of fly ash in construction, aligning with the principles of a circular economy and supporting the sustainable advancement of the construction industry.

Heavy metal contamination remains a critical challenge in managing solid waste within the construction sector. Bibliometric analysis indicates that the stabilization, solidification, and resource utilization of heavy metals are key areas of research and are considered effective strategies for reducing solid waste volumes. By immobilizing heavy metals within materials such as cement or geopolymer, they can be converted into stable building materials [129,130]. This not only represents an innovative avenue for developing construction materials but also provides a novel pathway for neutralizing hazardous industrial waste in construction applications. The rising prominence of geopolymer research further reinforces the principles of the circular economy. Its applications have expanded beyond simple material substitution to high-performance construction solutions meeting stringent structural and environmental standards.

Moreover, bibliometric analysis highlights the growing significance of LCA as a structured framework for quantifying the environmental impacts of innovative materials. LCA is extensively applied to evaluate the carbon footprint and energy consumption of materials such as fly ash, bottom ash, geopolymers, and recycled aggregates [131,132,133]. Findings suggest that integrating comprehensive LCAs into real-world construction projects can assist decision-makers in assessing the long-term benefits of incorporating solid waste into the green building paradigm. This approach provides valuable insights into the environmental sustainability and economic viability of solid waste-based construction materials, fostering their application in future sustainable development initiatives.

Through bibliometric trend analysis, research and applications of solid waste in the construction sector have evolved from fundamental studies to advanced solutions aligned with green and low-carbon frameworks. This progression has enabled the effective integration of environmental sustainability principles into construction practices. Early studies primarily focused on characterizing solid waste materials and identifying viable substitutes for traditional construction materials. These efforts provided the theoretical foundation for establishing regulatory frameworks and initiating waste reduction strategies. Subsequently, with the advancement of circular economy concepts and the emergence of new technologies, research priorities shifted toward optimization and validation of solid waste materials. This shift has driven innovative developments in high-performance construction materials. Presently, research in this field demonstrates a growing integration of sustainable development goals with automation and digital technologies. For example, automated processes and intelligent modeling tools are increasingly employed to design solid waste-based materials that exhibit enhanced mechanical properties and multifunctional characteristics [134,135,136]. In addition, findings from sustainability and low-carbon research have provided a scientific basis for the formulation of stricter environmental policies. These advancements underscore the pivotal role of solid waste research in addressing global environmental challenges and advancing the sustainable transformation of the construction industry.

5. Research Needs and Future Directions

Using bibliometric analysis, this study reviews the themes of existing research on the reuse of solid waste in the construction sector, identifies current trends, and predicts future research directions based on emerging demands in the field:

(1)

In-Depth Exploration of the Synergistic Effects of Solid Waste

The potential synergistic and complementary effects among different types of solid waste require further investigation. From a material performance perspective, various solid wastes possess unique chemical reactivity, making it essential to study their optimal proportions and the chemical synergy between them. Synergistic reactions among solid wastes represent a critical aspect of reutilization research, with significant implications for the microstructure and long-term performance of resulting materials. In terms of processing techniques, there are substantial differences in the energy consumption required for the treatment and utilization of distinct solid wastes. Furthermore, the incorporation of certain solid wastes may exert either positive or negative effects on specific stages of the production process. Therefore, systematic research that comprehensively considers the environmental impacts of different materials is urgently needed. However, the synergistic effects among different types of solid waste remain an underexplored area, which should be prioritized in future research. Additionally, current studies primarily focus on the short-term properties and characterization of solid waste products, with relatively limited attention paid to their long-term performance. Consequently, when investigating the synergistic effects of solid waste, priority should be given to understanding long-term effects, such as the durability of materials.

(2)

High-Performance and Diversified Applications of Solid Waste

Currently, solid waste, particularly fly ash, is primarily utilized to improve workability and reduce costs. However, its overall utilization efficiency remains insufficient. Future research should focus on optimizing particle size distribution, activating reactivity, and employing emerging modification technologies to investigate the underlying mechanisms of solid waste. This will enable its large-scale application in high-end construction materials, such as those used in high-rise buildings and hydraulic structures. Furthermore, research should transcend traditional applications like recycled aggregates and brick production, aiming instead to develop high-value-added and diversified construction products. By combining different types of solid materials, multifunctional building composites can be engineered, effectively leveraging the resource advantages of solid waste while meeting the diverse needs of various construction scenarios. Of particular note, geopolymer materials, as a novel class of inorganic non-metallic materials, represent a promising direction. Future efforts should prioritize the utilization of a broader range of solid waste types for the development of environmentally friendly products. Regarding raw material selection, further exploration is needed into more sustainable alkaline activators and additives to minimize or eliminate the use of hazardous substances. This approach could reduce potential environmental risks while enhancing the natural degradation or recyclability of geopolymers after their lifecycle ends.

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Emerging Intelligent and Automated Technologies Steering the Future of Solid Waste Reutilization

The application of emerging intelligent and automated technologies in solid waste management is anticipated to further advance, enabling an integrated development of smart and automated systems. In solid waste management, advanced sensor technologies and data analytics will be increasingly employed to monitor and control material performance and quality in real time, thereby facilitating the establishment of intelligent waste management models. In terms of production processes, automated equipment and robotic technologies will be adopted to enhance efficiency, while advanced separation techniques will be developed to improve the purity and quality of recycled solid waste materials. Additionally, the exploration and promotion of green, low-carbon processing technologies will enable the efficient conversion of solid waste into valuable resources. On the materials innovation front, intelligent tools such as big data, machine learning, and artificial intelligence algorithms will be leveraged to simulate the microstructural evolution and performance of solid waste in building materials, thereby reducing the need for extensive experimental trials and lowering costs. Furthermore, emerging technologies from other industries, such as microencapsulation, can be adapted to develop self-healing building materials, enhancing structural durability and safety. The rapid growth of 3D printing technology offers fresh avenues for the reutilization of solid waste, with particular focus on exploring its feasibility as 3D printing material, which is expected to become a key research direction in this field. The integration of intelligent and automated technologies represents not only a transformative step for the construction industry but also a driving force for achieving broader and more efficient recycling and reuse of solid waste in construction.

In summary, the future development of solid waste reutilization in the construction sector encompasses multiple dimensions, highlighting its significant potential for recovery and application. Achieving this goal will require a collaborative effort involving advancements in materials science, the integration of emerging technologies, interdisciplinary research, and the establishment of standardized regulations alongside market development. These combined efforts are essential for driving the sustainable development of the construction industry.

6. Conclusions

This study draws from relevant literature on the reuse of solid waste in the construction sector, sourced from the Web of Science (WOS) Core Collection and Scopus databases. Using two bibliometric visualization tools, CiteSpace (6.3.R3) and VOSviewer (1.6.19), a series of knowledge maps were constructed to evaluate trends in annual publication volume, global collaboration networks, thematic journals, research hotspots, and evolutionary trajectories. The findings reveal advancements in the reuse of solid waste in construction, offering a comprehensive overview of emerging research trends and the interconnections among the literature. This provides valuable insights and references for future studies in the field.

(1)

Growth of Research Output

Over the past decade, research on solid waste reuse in construction has exhibited steady growth, indicating increasing recognition of its academic and practical value. This trend suggests that the field is likely to continue gaining attention from researchers worldwide.

(2)

Global Collaboration and Network Analysis

In the analysis of knowledge graphs on global collaboration, research on solid waste in the construction sector has been predominantly conducted through partnerships among universities and research institutions across different countries. Chinese researchers have been found to play an active role in this field; however, their teams are relatively small, and stable core groups of authors have not yet been established. Additionally, the level of international collaboration among Chinese universities and research institutions remains limited, resulting in relatively isolated research networks. International cooperation in this area exhibits a concentrated and imbalanced pattern, further reducing the efficiency of global knowledge exchange. Solid waste reutilization represents a multidisciplinary issue, and its progress in the construction sector is closely interconnected with research from other industries and fields. To address these limitations, it is imperative to enhance global collaboration among academic communities and research institutions, particularly in terms of research themes, methodological approaches, and technological innovation. Researchers from diverse disciplines, including materials science, environmental science, civil engineering, and economics, should be encouraged to engage in cross-disciplinary cooperation to jointly develop innovative reuse technologies and strategies. This growing trend of interdisciplinary collaboration is expected to break down disciplinary barriers, offering new opportunities and challenges for scientific research.

(3)

Journal and Thematic Analysis

Through a combined analysis of journal overlay maps and density visualization, it is evident that research on solid waste reuse in construction primarily draws on disciplines such as environmental science, materials science, physics, and chemistry. This scope is now expanding into broader scientific domains, reflecting the growing trend of interdisciplinary research in modern science. Journals such as Construction and Building Materials, Journal of Cleaner Production, and Waste Management hold significant influence in this field. Highly dynamic journals like Bioresource Technology and Renewable and Sustainable Energy Reviews also capture considerable attention. Future studies should emphasize diverse and multidisciplinary innovations in foundational research, advancing toward themes such as environmental sustainability and green building practices, both of which represent the focal points of solid waste reuse and broader societal development trends.

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Research Hotspots and Evolutionary Trends

Hotspot and trend analysis reveals that fly ash garners the highest research frequency, while studies on bottom ash, heavy metal recovery, demolition waste, sludge, and geopolymer applications have also seen growing interest. Researchers have extensively studied properties of solid waste materials and their environmental sustainability through life cycle assessments. The research trajectory over the past decade can be divided into three phases: Initial Phase: Focus on solid waste properties and environmental impacts. Intermediate Phase: Exploration of themes such as the circular economy and emerging technologies. Current Phase: Investigations aligning with a green and low-carbon framework, integrating automation and digitalization to develop high-performance and diversified solid waste applications in construction. It is noteworthy that sustainable development remains the core theme underpinning the reuse of solid waste in construction, persisting as a central focus throughout the research timeline.

This bibliometric analysis provides a comprehensive summary of advancements in solid waste reutilization within the construction sector, highlighting the academic significance of this research area and its considerable potential for further exploration and development. Despite notable achievements, the realization of truly sustainable applications requires sustained efforts and validation from governments, researchers, industry stakeholders, and policymakers. Such collaboration is critical for transforming bibliometric insights into practical and actionable solutions.