Upcycling Arundo donax Biomass: A Systematic Review of Applications, Materials, and Environmental Benefits for Greener Construction

Abstract

This study presents a systematic literature review on the reuse of Arundo donax as a secondary renewable raw material for sustainable construction. Originally classified as a dangerously invasive species by the International Union for Conservation of Nature (IUCN), Arundo donax has recently gained recognition as a non-conventional promising biomass resource, particularly in the context of green innovation and circular economy strategies in light of the European Green Deal and the New European Bauhaus initiatives. This review combines bibliometric mapping and full-text analysis, leading to the selection of 20 peer-reviewed studies, thematically clustered into two main application areas: the development of panels and composites with improved mechanical, thermal, and acoustic performance; and the use of this species in geotechnical or low-tech solutions, such as earth construction and erosion control. While most contributions are recent and technically oriented, this review highlights several critical gaps, such as the lack of standardized testing protocols, the limited number of environmental assessments, and the absence of long-term performance evaluations. Despite these limitations, the considered biomass shows significant potential to support regenerative design strategies for the built environment. Future research should prioritize comparative LCA studies, industrial scalability, and the formulation of guidelines to integrate Arundo donax-based materials into sustainable construction practices.

1. Introduction

The pursuit of sustainable development entails meeting current societal needs without compromising the ability of future generations to meet theirs [1]. Within this well-acknowledged framework, the construction sector emerges as one of the most resource-intensive and environmentally impactful industries worldwide. In 2020, construction activities were responsible for approximately 75% of sectoral carbon emissions, equivalent to 8.7 gigatons of CO₂, while the production of building materials accounted for an additional 25% [2,3]. According to the Global Buildings Tracker by the International Energy Agency, the building sector alone generated 37% of total global CO₂ emissions in 2022 [4,5]. In response to that, international policy frameworks and academic research have increasingly prioritized the development of low-impact, resource-efficient, and environmentally sustainable building materials as novel non-conventional materials. Among the various strategies under investigation, plant-based resources, particularly those derived from agricultural residues and fast-growing and invasive species, stand out for their renewability, biodegradability, and compatibility with existing structures in light of circular economy principles [6,7].

In this context, invasive plant species represent a unique opportunity: their environmental threat can be mitigated through appropriate strategies of valorization that convert biomass into new valuable construction resources. Arundo donax L. (hereafter referred to as AD), commonly known as Giant reed or Marsh reed, is recognized by the International Union for Conservation of Nature (IUCN) as one of the 100 most invasive plant species globally [8], as better discussed in the next section. Native to Asia and now widespread across the whole Mediterranean basin and large part of the continents in various sub-species, AD proliferates along riverbanks and wetlands, where it disrupts native ecosystems, obstructs waterways, and spreads aggressively [9]. Due to its invasive nature, AD is characterized by rapid growth, high biomass yield, and favorable reed mechanical properties, features that make it a promising candidate for eco-friendly construction applications [10]. Notably, the intensification of scientific studies over the last decade has recently led the EU to reconsider its classification since 2020: AD is no longer regarded merely as an invasive alien species, but increasingly acknowledged as a potential renewable resource for biomass production [11].

In fact, despite AD being historically exploited in traditional architecture worldwide [12,13,14], it has recently regained attention in experimental studies exploring its integration as a bio-aggregate into composites, binders, and fiber reinforcement applications. However, the scientific literature still remains fragmented, sector-specific, and often lacking in holistic or comparative approaches. Hence, this novel study addresses this great gap by presenting a systematic literature review of the recent research published in the last decade, exclusively focusing on the reuse of AD parts in construction-related materials and components. This review aims to classify existing applications, assess material innovations, and highlight emerging experimental trends. The originality of this review lies in its combined use of bibliometric filtering, full-text qualitative analysis, and thematic clustering, all applied to a single plant species viewed simultaneously as an ecological atavistic challenge and a novel strategic resource. Unlike previous reviews that focus either on general biomass reuse or on specific construction materials, this work provides an integrated perspective centered on AD as a novel sustainable input for green innovation in construction.

To this end, this study seeks to answer the following research questions:

RQ1: What are the main applications of AD in construction materials to date?

RQ2: What types of building and construction materials and components (e.g., composites, mortars, panels, etc.) have been developed?

RQ3: What challenges, benefits, and environmental implications are identified in the literature?

This review is structured as follows: Section 2 provides an overview of AD’s botanical characteristics and its potential as a residual biomass source, by also enumerating the multiple issues related to its invasiveness. Section 3 outlines the methodological framework used to identify, filter, and categorize the relevant literature in the sector. Section 4 presents the core analysis, organizing the selected studies into thematic clusters based on material applications and technological strategies. Finally, Section 5 offers a critical discussion of the key findings, addressing existing knowledge gaps and outlining possible directions for future research before this paper is concluded.

2. Arundo donax Overview

2.1. Botanical and Residual Biomass

To assess the potential of AD as a viable secondary renewable raw material for greener applications in construction, it is essential to first understand its botanical features and the types of biomasses it generates. Commonly known as Giant or Marsh reed, AD is a tall, robust, and perennial rhizomatous grass, resembling bamboo, belonging to the Poaceae family [15]. Although likely native to Asia, Arundo donax has spread rapidly through subtropical and temperate zones worldwide and is now widely naturalized across the Mediterranean region, particularly in the Iberian Peninsula and the South of Italy, where it poses significant ecological, economic, and hydrological concerns [16,17,18,19]. Based on available studies [8,19], Figure 1A illustrates its global distribution, highlighting the continents where it is considered either native or alien (main species and sub-species), while Figure 1B details its spread in the Mediterranean context.

A particular focus on the Mediterranea environments is presented as AD is there exceptionally invasive due to the combination of mild, wet winters and hot, dry summers, which mimic its native climatic conditions and allow it to outcompete native vegetation. This aggressive growth alters river hydrology, increases erosion, reduces biodiversity, and threatens endemic plant communities. Moreover, its high biomass and flammability increase wildfire risk, while its dense stands can damage infrastructure, obstruct irrigation canals, and affect agricultural productivity [20]. In specific areas such as the bay of Barcelona and the Pyrenees foothills (Spain) or in Sicily (Italy), the combination of topography and wind patterns facilitates the dispersal of plant fragments, accelerating colonization along waterways and disturbed lands [21]. Recognizing the difficulty of eradicating the species, several EU research initiatives shifted focus toward valorization strategies, seeking to transform AD from a purely invasive threat into a potential resource for bioenergy, biomaterials, and other sustainable applications [8,22,23]. Moreover, a recent biological control program targeting AD was initiated from Portugal through the introduction of specialist herbivorous insects native to Europe [24,25]. These voracious agents target the shoots, rhizomes, and developing buds of AD, weakening the plants, reducing stem height and diameter, and impairing leaf development. Such insects, partially native of south Europe, are widespread in the Mediterranean and particularly common in southern Italy and Sicily, where are causing substantial plant decline. Furthermore, the suitability of these Mediterranean-origin agents has been evaluated in North American contexts showing some efficacy but limited effectiveness in controlling dense AD stands under field conditions [24].

AD is characterized by a standard (C3) photosynthetic pathway [26] and a remarkable ability to adapt to diverse soil types, from coarse sands to highly compact clays, contributing to its high invasiveness. Nevertheless, AD thrives particularly in well-drained areas near freshwater ecosystems [27]. Its growth is supported by a thick and knobby rhizome system which, once established, produces resilient and extensive, clonal root systems that can cover several acres, exceed 1 m in thickness, and reach depths of up to 5 m [28]. Above the ground, the plant develops dense clumps of thick cylindrical culms, hollow and segmented by nodes, ranging from 2–8 m in height and up to 4 cm in diameter. These stems grow rapidly, elongating by 30–70 cm during the vegetative phase [29]. The culms are flanked by long, lanceolate leaves arranged in two opposite rows, typically 30–50 cm long and 2–6 cm wide [30]. The leaf margins are sharp and can cause cuts if handled carelessly, representing another critical issue for its management. At the top, AD produces a purplish plumed inflorescence 30–60 cm long in late summer; however, its reproduction is almost entirely vegetative via rhizomes, as fertile seed production is extremely rare [29].

During harvesting or control operations, AD yields several distinct biomass fractions, summarized in

Table 1. AD: biomass fractions description and key properties.

Biomass Fraction	Description	Key Properties
Culms (stalks)	Tall, hollow cylindrical stems (up to 8 m)	Lightweight, rigid, segmented; high structural integrity
Leaves	Long, narrow leaf blades (30 ÷ 50 cm)	Fibrous, flexible; high surface area
Rhizomes	Deep, woody underground roots	Dense lignocellulosic material; difficult to extract
Mixed biomass	Whole-plant residues from cutting/removal	Heterogeneous composition; variable fiber and moisture content

and visually presented in Figure 2.

2.2. Issues of Alien Species Diffusion

As stated previously, AD is recognized by the IUCN’s Invasive Species Specialist Group as one of the 100 of the World’s Worst Invasive Species [8,31], due to its ecological aggressiveness and global spread. As any other alien species’ uncontrolled proliferation, AD poses significant environmental risks in the territory it colonizes as it alters soil pH and salinity, disrupts hydrological dynamics, outcompetes native flora, and increases fire hazards due to the accumulation of standing dry biomass [32]. Furthermore, its limited commercial value and high removal costs, along with the sharp leaf margins, make its management particularly challenging [33].

In recent decades, there has been a significant increase in both the number and diversity of identified invasive alien species (IAS) worldwide [34]. This expansion is primarily attributed to the disruption of natural ecological barriers and the resulting imbalance within affected ecosystems. IAS encompasses a broad range of organisms, spanning from prokaryotic microorganisms to multicellular eukaryotes, and impacting both aquatic and terrestrial environments [35].

The dispersal of these species occurs through natural mechanisms but is predominantly accelerated by human activities. Some IAS naturally expand their range when geographic or ecological barriers are removed (i.e., during flooding events connecting previously isolated lakes or the emergence of land linking islands) thereby facilitating dispersal into ecologically compatible habitats [36]. However, anthropogenic activities have greatly accelerated and broadened their spread, notably through globalization, international trade, and travel. These factors enable the long-distance translocation of non-native species, which, once introduced, often establish populations in ecosystems lacking natural predators or regulatory pressures [37].

The movement of goods and species across continents, whether intentional, such as pets, crops, or biological control agents, or accidental, has significantly exacerbated the spread of IAS. Concurrently, terrestrial transport networks and the construction of artificial infrastructures such as offshore wind farms, dams, and urban developments further facilitate their diffusion. Agricultural practices, especially monocultures and watershed modifications, degrade habitats and create conditions favorable to biological invasions [38]. Climate change compounds these effects by altering temperature, humidity, and hydrological patterns, often benefiting more resilient and adaptable invasive species [39].

The environmental impacts of IAS are complex and multifaceted. They can alter habitats chemically, by modifying turbidity and organic content in aquatic systems, and physically, by transforming landscape morphology and dynamics. Such drastic changes often result in biodiversity loss, genetic homogenization, and reduced ecosystem resilience. This process can lead to irreversible shifts termed “invasive meltdown” where successive invasions mutually reinforce one another via positive feedback loops [40]. Although predominantly negative, some studies report neutral or even beneficial effects, including providing habitat or food sources for threatened species, substituting extinct species in food webs, or regulating other IAS. IAS also pose public health risks by acting as vectors for pathogens, parasites, and allergens, thereby endangering human well-being. Finally, from an economic point of view, IAS impose substantial costs for prevention, control, mitigation, and loss of ecosystem services, as well as degradation of recreational and agricultural landscapes.

2.3. Arundo donax: A Terrestrial Invasive Alien Species

Among the invasive alien plant species (IAPS), AD is particularly critical due to its rapid colonization ability foster by its propagation mechanisms and ecological adaptability. In fact, AD primarily reproduces asexually via rhizomes and lateral shoots, spreading through soil, water, wind, and agricultural activities [16]. Even under drought conditions, AD can regenerate roots upon rehydration. Rhizome growth occurs horizontally at a rate of approximately half a meter per year, enabling continuous and rapid territorial expansion [41]. When lignified culms meet soil, subsequently nodal buds produce new roots and shoots, which give rise to additional rhizomes, thereby accelerating clonal spread [42]. This regenerative mechanism complicates control efforts as the rhizomes left in the soil after mechanical removal can easily regrow [43,44]. Moreover, AD can thrive in moist soils and flooded areas, exhibiting low sensitivity to substrate quality and notable resistance to high temperatures, specific pathogens, and some diseases [45]. All of that facilitates its presence in wetlands and riparian zones also [46].

Occurrence data from the Global Biodiversity Information Facility (GBIF) reveal its propagation even in geographically distant areas, often resulting from colonial introductions or agricultural propagation [41,46,47]. For example, in Ecuador, AD was introduced during the colonial period as its culms were exploited for the manufacture of musical instruments, fiber production, energy, and building construction. Current populations largely stem from escaped cultivations or horticultural dispersal [47]. The ecological consequences of such uncontrolled diffusion are manifold: the species’ high flammability promotes wildfires, after which it regrows even more vigorously. It suppresses native vegetation growth, reduces suitable nesting habitats for birds due to dense foliage, and alters river ecosystems by diminishing shading. This leads to increased water temperatures and algal blooms, which reduce aquatic biodiversity. Moreover, it modifies river hydrology and geomorphology, concentrating flows, causing erosion, weakening riverbanks, and increasing flood risks. Accumulated detached culms and rhizomes cause blockages that exacerbate these issues. Its water high consumption significantly contributes to water loss in river systems [44]. As an example of the disruptive consequences of its diffusion, the storm DANA that impacted the Mediterranean area in autumn 2024, causing, i.e., extreme floods in Spain and the death of about 232 people, highlighted the exacerbating role of AD biomass accumulation in obstructing waterways and infrastructure, intensifying flood damage [48]. Although debates persist regarding the extent to which the species worsens flooding events, it is widely acknowledged that AD presence can amplify the destructive effects of natural disasters, especially in anthropogenically altered landscapes [47].

2.4. Control Strategies and Management Challenges

Managing AD still remains a complex challenge. Control strategies usually include the application of chemical herbicides, which pose several risks to native flora and fauna and may contaminate water sources. Physical removal is resource-intensive, requiring substantial labour and materials to treat extensive areas. Mechanical methods, i.e., employing heavy machinery, risk further ecosystem disturbance. Less invasive alternatives involve promoting interspecific competition to limit access to soil nutrients, yet these approaches demand specialized skills and ongoing monitoring. A critical consideration is that all interventions must commence with cutting the reed stands, and the harvested biomass is classified as waste, presenting additional logistical and economic burdens. Finally, the species’ extraordinary regenerative capacity from even small rhizome fragments renders eradication efforts particularly difficult [44].

Because of such extreme spread globally, the last decade has witnessed a growing scientific interest in AD potential as a renewable lignocellulosic feedstock, leading to a shift in its perception at the policy level. In 2020, the European Union officially ceased to classify AD as merely an invasive alien species, recognizing instead its potential as a biomass source for energy and material production [11]. Paradoxically, the very characteristics that have contributed to its ecological dominance, rapid growth, high biomass yield, and robust structure, are also the ones that make AD a promising renewable raw material for sustainable resource recovery and green building technologies.

Having that in mind, as already mentioned, this comprehensive review aims to collect, analyze, and critically discuss the existing literature and research findings related to AD possible reuses as innovative solutions for a greener construction.

3. Methodology

To explore the scientific domain AD reuse in sustainable construction, a structured and multi-step methodology was implemented based on a study by [49]. This approach aimed to ensure thematic precision, reproducibility, and alignment with current standards in biomass reuse research. The full workflow, summarized in Figure 3, comprises seven steps: database selection, subject area filtering, keyword refinement, journal quartile filtering, full-text screening, bibliometric mapping, and qualitative clustering.

The initial literature search was conducted using the Scopus database, chosen for its comprehensive coverage of peer-reviewed scientific publications. The first step consisted in selecting the keyword Arundo donax, queried in the title, abstract, and keyword fields and the temporal limitation of 2014 ÷ 2024, to uncover the relevant most recent studies. That process limited to the English language, returned 1105 documents complying with the selected criteria.

To further refine the dataset and focus only on the research related to materials and environmental applications, the results were additionally filtered by subject area (considering the classification resulting from the previous queries (cf. next Section 4. “Results and discussion”). Hence, only articles classified under Environmental Science, Energy, Chemical Engineering, Engineering, and Materials Science were retained, reducing the aforementioned total to 710 records.

Subsequently, another keyword-based refinement was applied aimed at identifying those contributions that were explicitly related to construction and associated areas. Therefore, a combination of the previous Arundo donax with terms such as cement, mortar, concrete, clay, gypsum, lime, panel, composite, binder, and bioplastic were used.

After DOI-based deduplication, this step yielded 235 unique documents. Afterwards, articles published in Q1 journals only, according to the Scimago Journal Rank (SJR) for the corresponding year, were retained. Journals indexed under high-impact categories such as Architecture, Civil Engineering, Building Materials, Waste Management, and Polymers and Plastics were prioritized. This step resulted in a shortlist of 112 articles. It is important to acknowledge that lower-ranked journals (Q2, Q3, …, conference papers, etc.) also contribute scientifically valuable research, and publication outside Q1 venues should not be interpreted as a measure of inadequacy. The complexities and challenges inherent in the peer-review and publication process, especially for high-impact journals, are well recognized. The decision to limit this review to Q1 publications was a deliberate methodological choice, intended to maintain a consistent and rigorous standard across the dataset. Given that the objective was not to provide an exhaustive inventory of all existing studies on AD, but rather to critically analyze a focused selection of high-quality, directly relevant works within a clearly defined methodological framework, the current selection is considered both adequate and representative. Moreover, the studies excluded at this stage remain valuable and will serve as the foundation for future research efforts.

All 112 research articles were then subjected to full-text screening to verify their relevance to the research objective, namely, the reuse, transformation, or valorization of AD biomass in the context of construction areas for the development of materials, products, elements and system. In this context, the manuscript adopts a hierarchical classification: AD fractions are referred to as “materials” when considered individually; when AD is combined with other constituents, such as binders and/or aggregates, the resulting mixture is defined as a “product”; the integration of materials or products into a functional unit constitutes a building “element”; the assembly of multiple elements, along with their interconnections, defines a construction “system”. Consequently, studies focusing on unrelated applications (e.g., pharmacology, bioenergy, or environmental remediation) were excluded. After this evaluation, 22 articles were finally deemed directly relevant and selected for deep analysis.

Bibliographic data from the selected 22 articles were compiled into a structured spreadsheet and imported into VOSviewer (version 1.6.20) for bibliometric analysis [49,50,51]. The software was used to generate the following:

• A Keyword Co-occurrence Map, to identify dominant research themes;
• A Source Co-Citation Map, to analyze relationships between journals;
• A Country Co-Authorship Map, to visualize international collaboration patterns.

Thresholds for visualization were applied based on occurrence and citation frequency. To identify cross-cutting themes, a hybrid clustering approach was adopted. More particularly, abstracts from the 22 studies were analyzed using ChatGPT-4 through a series of structured prompts aimed at categorizing each paper’s material type, treatment strategy, and intended application. Example prompts included the following:

• “Based on this abstract, which material category best describes the study?”;
• “Summarize the main contribution using 3–5 technical keywords.”

The output from the AI-assisted analysis served as a preliminary classification tool and, in particular, ChatGPT-4 AI use was limited to the preliminary phase of thematic clustering. Nonetheless, the limitations of AI-assisted interpretation, such as ambiguity in abstract language or dependency on prompt design, were fully acknowledged and addressed through this rigorous manual validation step. In fact, all the AI-results obtained were then completely manually reviewed and validated by the authors through full-text analysis, ensuring consistency with the scope and research questions of this review.

The complete methodological process is visually summarized in Figure 3, which outlines the analytical steps and decisional criteria adopted in this review.

4. Results and Discussion

4.1. Scientific Production Trends and Thematic Distribution

This section provides an overview of the evolution of the scientific output associated with AD, whose first selection returned 1105 documents as shown in Figure 4A. From that, it resulted that the first publication ever on the topic was [52], dating back to 1935, that dealt with the study of the alkaloids present in AD biomass. Following this, based on a curated dataset of 710 documents retrieved from the Scopus database, the initial query was performed using the term Arundo donax in titles, abstracts, and keywords, restricted to English as used language of publications edited in the last decade (2014–2024). To ensure thematic consistency with the scope of this review, only records classified under Environmental Science, Energy, Chemical Engineering, Engineering, and Materials Science were retained. In fact, these subject areas reflect the interdisciplinary nexus between biomass reuse, sustainable construction, and materials science & innovation.

Figure 4B illustrates the annual distribution of publications on AD across the selected last decade. While the trend reveals year-to-year variability, an overall upward trajectory is clearly observable. Notable peaks are recorded in 2020 and 2023, with 73 documents each, alongside an early increase in 2017 (69 publications). Despite a temporary dip in 2018 (56 publications), the long-term pattern indicates a sustained and growing scientific interest in AD as a renewable and multifunctional biomass source.

These dynamics align with broader trends in biomass valorization research, such as those observed in the case of general wood waste [49], where peaks in academic output often coincide with international sustainability agendas, evolving regulatory frameworks, and increasing investments in low-carbon technologies. In this context, the scientific community’s expanding attention to AD reflects its emerging recognition as both an ecological concern and a promising contributor to circular material strategies.

Figure 5 illustrates the geographical distribution of publications on AD. Italy emerges as the most prolific contributor, with 258 publications, followed by China (125), the United States (76), Spain (67), and Portugal (46). Italy’s leading position is likely attributed to both the widespread diffusion and invasiveness of AD across the Mediterranean basin, and in particular on the Italian territory, and a robust national interest in leveraging invasive species for innovative, eco-compatible solutions. The presence of China and the United States in the top five underscores a more globalized research engagement, suggesting that the worldwide scientific community is beginning to explore AD beyond its regional context.

Figure 6 presents the distribution of the same 710 documents by subject area, as a result of that first enquiry. It is observed that the largest share of publications falls under the topic Environmental Science (30.0%), followed by Energy (17.3%), and Agricultural and Biological Sciences (14.6%). These results align with the predominant use of AD in contexts such as bioenergy production, phytoremediation, and ecological restoration. Interestingly, although Engineering (6.8%) and Materials Science (5.2%) remain less represented, their presence points to an emerging interest in repositioning AD as a viable technical input in the development of novel and sustainable construction materials, bio-based composites, and innovative building solutions. This thematic gap reinforces the timeliness and added value of the present study, which shifts the focus toward material-oriented applications of AD residues in sustainable construction.

4.2. Bibliometric Analysis

The co-occurrence map, shown in Figure 7, was designed with VOSviewer. Here, a minimum threshold of 3 co-occurrences per keyword was set, with a manual reduction to 22 keywords after removing some detected 4 duplicates. From a temporal perspective, the colour gradient (ranging from blue to yellow) reflects the average publication year associated with each keyword, offering additional insight into the evolution of scientific focus over time. Earlier studies (2017–2019, marked in blue) concentrated on mechanical testing, thermal analysis, and fiber characterization, confirming an initial emphasis on understanding the fundamental performance of AD as a reinforcing secondary (renewable) raw material in bio-composites. As the timeline progresses into 2020–2021 (green spectrum), the literature begins to highlight broader concepts such as environmental impact, natural materials, and bio-based, suggesting a shift toward the sustainability potential of AD in eco-friendly formulations. More recent publications (2022, yellow tones) introduce terms such as sustainability, building materials, and adhesives, indicating a consolidated interest in construction applications and in integrating AD parts into industrially scalable, low-impact solutions. The timeline embedded in the co-occurrence map thus reflects not only the thematic diversity of AD related research but also its maturation toward more holistic, application-driven perspectives.

Figure 8 illustrates the co-citation network of journals referenced within the 20 selected documents. The analysis was conducted by setting a minimum threshold of 5 citations per source, resulting in a total of 27 journals and 169 co-citation links. Among them, Construction and Building Materials stands out as the most central node, with 14 links and 22 citations, confirming its pivotal role in research concerning innovative construction materials derived from biomass. Bioresources follows with 20 links and 20 citations, while Polymers records the highest connectivity with 25 links, despite a lower citation count (13), suggesting its transversal relevance in studies dealing with bio-composites and material formulation. This network not only highlights the leading journals in the domain of AD valorization but also reveals the interdisciplinary nature of the topic, bridging materials science, polymer chemistry, and sustainable construction. The presence of strongly linked journals from adjacent fields reflects the convergence of multiple research agendas around the exploitation of renewable resources for material innovation.

In Figure 9 the co-authorship network derived from the selected Q1 publications reveals a limited pattern of international collaboration. Applying a minimum threshold of two documents per country, only three countries met the inclusion criteria, namely Italy, Spain, and Portugal, resulting in a sparse network with just two co-authorship connections. This configuration confirms the strong involvement of the Southern European countries in the scientific investigation on AD; yet also highlights a lack of broader cross-national cooperation. Compared to the wider geographical landscape outlined in Figure 5, where nations like China and the United States played major roles, the narrowing effect of the Q1 journal filter significantly reduced geographical diversity. These findings point to the need for broader collaborative frameworks and more inclusive research networks capable of capturing the full potential of AD valorization across diverse contexts.

4.3. Literature Review

The selected 22 documents, built upon the findings of the bibliometric analysis presented in Section 4.2, were examined in-depth to cluster the main topics of research and evaluate the principal outcomes achieved to date.

Generally speaking, collected papers deal with the manufacture of innovative materials and products where AD is differently grinded and sieved to obtain particles or fibers of various dimensions. Moreover, chemical treatments, mainly based on alkaline baths, are studied to improve the adherence of the AD to the material matrix and evaluate possible performance improvements. All the documents were entirely read and subsequently clustered according to the main research topic. In addition, results were collected and briefly described.

From that analysis, two main clusters were identified, as shown in

Table 2. Classification of the identified articles into thematic clusters (listed from the most recent).

Cluster	Cluster Description	n° Documents	Reference
Cluster 1	Development of novel materials	11	Manzi et al., 2024 [53] Tabkit et al., 2024 [54] Ortega et al., 2021 [32] Suárez et al., 2021 [9] Badagliacco et al., 2020 [55] Stanzione et al., 2018 [54] Sargin Karahancer et al., 2016 [56] Scalici et al., 2016 [57] Fiore et al., 2014 (a) [33] Fiore et al., 2014 (b) [58] Fiore et al., 2014 (c) [59]
Cluster 2	Development and performance analysis of innovative technical elements	11	Cintura et al., 2024 [60] Mora-Ruiz et al., 2024 [61] Malheiro et al., 2023 [10] Ferrandez-García et al., 2022 [7] Vitrone et al., 2022 [62] Malheiro et al., 2021 [63] Molari et al., 2021 [64] Ferrandez-García et al., 2020 [65] Ferrandez-Villena et al., 2020 [66] Barreca et al., 2019 [6] Martínez Gabarrón et al., 2014 [67]

:

• Development of novel materials;
• Development and performance analysis of innovative technical elements.

To complement the frequency-based analysis, an additional evaluation was performed to explore the scientific visibility of each thematic cluster. For this purpose, the total number of citations for each reviewed article was retrieved from Scopus, along with the Scimago Journal Rank (SJR) impact factor of the journals in which the papers were published. These values were aggregated by cluster, enabling the computation of two indicators for each group: (a) the average number of citations per article and (b) the average journal impact factor.

Figure 10 presents these two metrics side by side for each cluster, with values independently normalized on a 0–1 scale to ensure comparability. Absolute values are also reported in parentheses above each bar to support interpretation. Results show that Cluster 1 clearly stands out in both dimensions, reflecting high academic visibility and journal prestige. In contrast, Cluster 2, while still valuable, demonstrates lower citation averages and a slightly less prominent journal impact, suggesting that it may reflect a more practice-oriented or emerging research stream with potential for future growth in impact.

A comparative analysis of the identified clusters follows.

4.3.1. Cluster 1: Development of Novel Materials

In the first cluster (1—Development of novel materials), 11 documents are grouped, all addressing the use of AD as reinforcement in innovative and sustainable mixes. Two sub-groups can be distinguished within this cluster. The first (subcluster 1A) focuses on the development of mortars with inorganic binders, such as lime or geopolymers, while the second (subcluster 1B) includes studies employing plastic-based binders.

In the sub-cluster 1A, it is noted that AD is used in different ways to manufacture natural fiber composites. In the study by Sargin Karahancer et al. [56], AD is used in the form of fibers derived from rhizomes, whereas in the studies by Badagliacco et al. [55] and Manzi et al. [53], the fibers are obtained from the processing of culms. In the latter two studies, the fibers underwent various chemical treatments. In particular, in [56] fibers, obtained from the processing of AD rhizomes and cut 3 cm long, were employed to produce bio-composite asphalts. Specimens were prepared by incorporating different mass percentages of AD fibers (e.g., 0.25, 0.50, 0.75, and 1.00%) to assess their influence on the performance of the resulting materials. Main results showed that a fiber content above 0.75% reduced moisture susceptibility, while the optimal performance was achieved with 0.25%. This is explainable for the highly hydrophilic nature of AD fibers, which leads to excessive water absorption, adversely affecting mechanical performance. Ref. [55] investigated the flexural strength improvement in lime-based mortar through the addition of AD fibers, for potential applications in construction. In this case, the fibers were obtained from the peeled culms of AD and cut to lengths of 4, 8, and 12 cm. Two different pre-treatments, by linseed oil and polyethylene glycol (PEG), were evaluated to examine their effects on the final mechanical properties and the adhesion between fiber and matrix. In general, the linseed oil treatment resulted in poor adhesion between fibers and matrix, whereas the application of PEG led to improved bonding. Moreover, lower fiber content and shorter fiber lengths were associated with better workability of the bio-composites. While a slight reduction in compressive strength was observed, a significant increase in flexural strength was also measured. In [53] the AD fibers were extracted from AD culms, cut to lengths of 1–5 mm, and pre-treated in a NaOH solution. These fibers were incorporated into waste-based alkali-activated green cement (geopolymers) mixtures that used porcelain stoneware industry waste, specifically polishing and grinding residues, as a partial replacement for metakaolin. The produced geopolymeric mortars exhibited an overall increase in flexural strength of approximately 18%, with minimal impact on the workability of the fresh mix.

To conclude, the selected studies showed that AD fibers are promising sustainable reinforcements for various composites, making them bio-based, more sustainable, and circular. Fiber content and treatments like NaOH, PEG, and plasma improve the adhesion between fiber and matrix, improving mechanical strength and thermal stability. Optimal fiber length and dosage balance workability and performance, as an excessive quantity may reduce durability due to fibers’ hydrophilicity. AD fibers generally tolerate processing temperatures up to 230 ÷ 275 °C leaving a higher lignin content that contributes to their robustness and, in turn, to the resulting bio-composite overall mechanical performance. Additionally, it is noted that AD fibers may offer eco-friendly alternatives for construction and advanced materials with tunable properties.

In the second sub-cluster 1B, 8 documents are grouped that specifically employed AD parts (waste) in natural fiber plastic-based binders’ composite. Scalici et al. [57] and Fiore et al. [33,58,59] analyzed and investigated AD natural fibers used as reinforcement in resins, albeit through different approaches. Specifically, in [57] the fibers were derived from AD leaves and plasma-treated with the aim to the enhance the interfacial adhesion with the matrix. Compression-molded specimens were produced using fiber contents of 2.5 wt.% and 5 wt.%, with lengths of 1 and 3 cm, randomly distributed. The results demonstrated that the used plasma pre-treatment improved mechanical performance of the bio-composite regardless of the fiber content and length, due to enhanced fiber–matrix adhesion. The authors also compared the thermal behaviour of treated and untreated fibers, revealing comparable results, indicating that the plasma treatment did not compromise the thermal stability of AD fibers. [33] differs from the previous one as fibers are generated from AD culms rather than leaves. Here, the feasibility of using untreated fibers, mechanically processed and shredded, was explored. Three compositions were studied, differing in fiber mass content (5%, 10%, and 15%), and length (<150 μm, 150–300 μm, 300–500 μm, and 500 μm–2 μm). The effect of the AD fiber incorporation was assessed through mechanical characterization, comparing the results with an epoxy resin reference. Main findings revealed that the addition of AD fibers contributed to improved tensile resistance, indicating an effective reinforcement in the matrix. The reduced adhesion between the hydrophobic epoxy matrix and the hydrophilic fibers, mainly attributed to the absence of any fiber surface treatment, limited the interfacial bond. Additionally, the variation in fiber length and content resulted in differing strength values, which the authors linked to the presence of voids in the specimens. In [59] the incorporation of AD fibers (150–500 mm) into polylactic acid (PLA)-based biocomposites was examined. Samples containing 10% and 20% fiber by mass were compared with pure PLA reference. Results showed that the inclusion of AD fibers led to increased tensile and flexural moduli. The morphology and physico-chemical characteristics of AD fibers was also investigated in [58]. In this study, the fibers, ranging from 100 to 160 mm in length, were obtained from culm processing. The cellulose, hemicellulose, and lignin contents were determined, with the latter being higher than that of other, less common natural fibers. The mechanical strength tests showed a brittle failure behaviour with an abrupt drop in mechanical stress at break. Thermogravimetric analysis indicated thermal stability up to approximately 275 °C, suggesting that these fibers can be exploited as reinforcement in composite materials as long as the polymer matrix processing temperature (whether thermosetting or thermoplastic) does not exceed that limit. The results were consistent with those reported for other natural fiber types and confirmed the potential of AD fibers for polymer reinforcement. Surface impurities typical of natural fibers may be removed through chemical pre-treatments to improve interfacial adhesion with polymer matrices, as per another study by the same authors.

The chemical treatment of AD fibers with NaOH to enhance thermal stability and mechanical properties was further explored by Suárez et al. [9], Ortega et al. [32], Tabkit et al. [54], and Stanzione et al. [68]. In [9] an experimental method to extract fibers from AD culms was developed; fibers—with fiber contents up to 40% by mass—were then used to produce thermoplastic bio-composites based on polyethylene (PE) and polypropylene (PP). Mechanical tests revealed good composite performance, with increased tensile and flexural stiffness and elastic modulus, although a reduction in ultimate strength and poor compressive behaviour were observed. Thermogravimetric analysis showed a degradation temperature of approximately 230 °C, different from the value reported by in [58], and demonstrated that thermal stability improved with NaOH treatment, although mechanical performance did not. The mechanical behaviour of various PE-based composites was studied in [32], where 20% fiber content was used, comparing the AD fibers (2 mm length, from culms) with those from Pennisetum setaceum and Ricinus communis, common alien plants whose fibers may be used to manufacture bio-composite materials. AD fibers were also NaOH-treated to study eventual effects on mechanical performance. Results indicated that AD incorporation yielded composites with lower density than PE reference. Furthermore, fiber treatment led to increased density compared to untreated fibers. Mechanical properties were found to be dependent on fiber length, with NaOH-treated fibers generally outperforming untreated ones. AD fibers as a reinforcement agent for 3D printing filaments, based on PLA and PP waste-based blends, were investigated in [54]. To improve fiber–polymer compatibility, fibers were pre-treated with NaOH. Several specimens were produced with varying fiber contents, all of which showed melt flow indices suitable for 3D printing. The NaOH pre-treatment significantly enhanced fiber–matrix adhesion compared to untreated fibers. Mechanical performance increased with the addition of AD fibers and was further improved when the treatment of fibers was conducted. The use of unrefined bio-based polyols derived from the fermentation of AD biomass was evaluated in [68] for the synthesis of polyurethane (PU) and polyurethane acrylate (PUA) foams. Three types of polyols were synthesized via esterification and polycondensation reactions involving succinic acid (SA) and 1,4-butanediol (BDO). One polyol was produced via fermentation of lignocellulosic AD biomass, while another was synthesized by hydrogenation of SA in aqueous medium. The results indicated that the morphological structure and mechanical performance of the foams were influenced by the polyol content. The best-performing foams in terms of fine, homogeneous cellular structure and high compressive modules were those containing polyol derived from 50 wt.% AD fibers. At 50 wt.% SA content, the compressive modulus increased by approximately 140%, associated with increased foam density. At higher concentrations, a reduction in compressive modulus was observed, due to SA’s effects on the thermal and structural properties. Overall, these foams showed potentials for many applications, from packaging to absorbent materials.

In general, it can be concluded that the incorporation of AD fibers improves the mechanical strength of bio-composite materials, particularly tensile and flexural strength. The fibers act as a reinforcing phase within the polymer matrices, improving the material’s capacity to withstand mechanical loads by enabling load transfer from the matrix to the typically stiffer and stronger fibers. The improvement in tensile strength is especially notable, as the fibers effectively resist crack propagation, while in flexural applications they help the composite absorb deformation without breaking. However, reinforcement effectiveness depends on factors such as fiber type, orientation, length, volume content, and fiber–matrix adhesion. The last one may be improved by treatments based on chemical baths. In fact, discussed studies demonstrated that pre-treatments on AD fibers, such as NaOH bath, can significantly increase the interfacial adhesion and, thereby, lead to improved mechanical performance.

4.3.2. Cluster 2: Development and Performance Analysis of Innovative Technical Elements

The second cluster (2—Development and performance analysis of innovative technical elements) includes 11 studies addressing the use of AD, either in bulk form or opportunely ground and sieved, as processed fibers or particles, for the manufacture of construction materials for innovative building components, primarily panels for both structural and non-structural applications.

Within this cluster, it is possible to identify several sub-groups, as follows.

Barreca et al. [6] and Martínez Gabarrón et al. [67] focused their studies on structural applications in traditional architecture. In [6] a construction system was reinterpreted from traditional architecture involving AD culms to develop a load-bearing vertical partition. The solution consists of a panel with an internal air cavity of approximately 20 cm, built with a wooden frame supporting two double layers of AD culms, finished on both sides with 1 cm-thick cementitious plaster. Thermal analyses were conducted on the panel, simulating the application in a residential building in a Mediterranean climate. Results, compared to a conventional load-bearing masonry wall, revealed a total annual energy demand for heating and cooling of 4.154 kWh for the masonry structure against 1.807 kWh for the panel incorporating AD. This corresponds not only to significant economic savings but also to a reduction in environmental impact, with estimated annual CO₂-equivalent emissions of 2.517 kg for brick walls against 1.905 kg for AD walls. In [67] efforts were made to improve the adhesion between AD culms used in traditional floor slabs and gypsum plasters. Starting from the analysis of vernacular construction methods, the authors aimed to enhance technical knowledge of these technological systems by reinterpreting traditional techniques to increase resistance and adhesion between materials and layers. The AD culms were tested in different configurations and diameters. Among all tested prototypes, the best results were obtained from the configuration with longitudinal grooves carved into the contact surface with plaster, increasing surface roughness. That configuration improved the flexural strength of the traditional structural element by approximately 116%.

The works by Ferrandez-Villena et al. [66], Vitrone et al. [62], and Cintura et al. [60] explored, albeit through different approaches, the development of panels using AD processed into fibers or particles. In [66] the production of panels, made from chopped and sieved AD rhizomes, is proposed. The boards were manufactured with different particle sizes and using a thermo-press mould. Various panel types were tested for performance, with results compared to relevant European standards. A key finding was the correlation between production parameters and performance: longer pressing times generally improved mechanical properties. Particle size also significantly affected performance, with the best results obtained for particles between 0.25 and 1 mm. The aim of [62] was to investigate the possibility of reducing dependence on wood products by using alternative materials such as AD. After treating AD fibers with steam at different temperatures, panels measuring 150 × 50 × 3 mm were produced. The highest performance was achieved with a pre-treatment temperature of 200 °C. Unlike the previous studies, in [60] sodium silicate solution was incorporated during panel fabrication. AD was used in combination with hazelnut shells as bio-aggregate. The pre-treatment resulted in a significant improvement of the panels performance, also enhancing fire resistance, and reducing smoke emissions.

Panels made by assembling entire AD culms were studied in Malheiro et al. [10] and Malheiro et al. [63]. In the latter study, the culms were bound together using steel wire. Thermal properties, including thermal resistance, transmittance, and conductivity were evaluated. The results showed that the manufactured panels complied with legal requirements for thermal insulation materials. Additionally, the resistance of AD to mold was assessed. These analyses were further expanded in [10], where AD culms, deriving from different climatic regions, were used to investigate the eventual influence of the geographical origin on performance. The study included tests on physical properties and durability against mold. All the panels performed effectively as thermal insulation solutions, regardless of origin, meeting relevant standards for insulation materials in terms of thermal resistance and conductivity. That study is particularly interesting as showed that AD features, if used as material reinforcement, are completely independent from the climatic origin of the plant, enlarging possible applications to all those areas where AD lives.

Thermo-pressed particleboards made from AD particles are investigated by Ferrandez-García et al. [65] and Ferrandez-García et al. [7]. The former [65] focused on evaluating the performance of thermo-pressed panels made from resins and AD particles with different size ranges (0.25–1 mm, 1–2 mm, and 2–4 mm). The results highlighted how particle size affects panel density, with larger particles yielding lower density and better acoustic performance. This is due to increased porosity caused by greater particle size. While these negatively impacted mechanical properties, sound absorption was significantly enhanced. All panels outperformed conventional wood-based panels used in construction, and increasing panel thickness further improved acoustic properties. Based on that study, in [7] particleboards were produced by using thin AD particles (<0.25 mm) in 10–20 wt.% proportions, while Portland cement was employed as binder, and potato starch (0.5–10 wt.%) as plasticizer. The manufacturing process involved hot pressing at 2 MPa and 100 °C for 1 to 4 h to prepare panels’ samples that were subsequently characterized. Results indicated that higher starch content improved mechanical strength, while increased cement content enhanced water resistance. The AD particles did not degrade upon contact with water, due to the presence of potato starch, which facilitated proper cement hydration, as in cement without vegetable fibers. As a result, high-performance sustainable particleboards were produced under European standards.

Finally, the integration of AD with materials for light structural applications has been explored as a sustainable construction approaches in Mora-Ruiz et al. [61] and Molari et al. [64]. The inclusion of AD in earthen-material was investigated in [61]. Earth offers excellent thermal mass and moisture buffering, while the addition of waste-based biomass can enhance workability and contribute organic binding agents. More particularly, the study investigates the seismic performance of rammed earth walls reinforced with AD fibers, as a traditional constructive technique in Colombia. The study involves material characterization and cyclic load testing under lateral drift (0.2–1.4%) and vertical load. Results showed that while AD inclusion slightly reduced the compressive and flexural strength, however, it significantly impaired better energy absorption by improving hysteretic performance and energy dissipation. Also, in [64] it was explored the performance of an earth-based composite material reinforced with AD fibers investigating the mechanical behaviour (compressive, tensile, and flexural strength), thermal conductivity, and water absorption of the produced specimens. The experimental results showed that fiber reinforcement improved tensile and flexural strength, as AD acted as reinforcing agent in the matrix, while slightly reducing compressive strength. The bio-composite also demonstrated low thermal conductivity and moderate water absorption, making it suitable for energy-efficient buildings. These studies also highlight the potential of AD as a natural, renewable reinforcement to improve the mechanical and thermal performance of earthen materials. However, the overall structural integrity could be compromised, and further investigation into vertical reinforcement strategies for enhanced seismic performance is necessary. Challenges remain regarding long-term durability, biological stability, and—most of all—standardization. Further research is needed to fully assess the environmental and mechanical performance of these hybrid materials for greener construction.

To conclude, the studies within this cluster emphasized AD as a highly versatile building material, effective both in its natural culm form and processed into fibers, particles, or rhizomes. Indeed, AD enables the production of various construction components, including structural panels and thermal or acoustic insulators. Through physical modifications and chemical or thermal treatments, significant improvements in strength, durability, and fire resistance are achievable. Notably, components based on AD parts offer superior thermal performance compared to traditional masonry, resulting in energy savings and reduced CO₂ emissions. The products’ properties can be tailored by adjusting processing parameters and additives, allowing optimization for acoustic, mechanical, or moisture resistance. Importantly, the integration of traditional techniques with modern scientific methods fosters sustainable, high-performance, and culturally respectful building solutions. Overall, AD emerges as a promising bio-based material for an innovative, circular, and sustainable construction.

5. Conclusions

This review systematically analyzed 22 scientific publications on AD for construction-related applications, from an original larger number of documents, combining bibliometric mapping, thematic clustering, and full-text screening to provide a structured and reproducible synthesis. The final corpus was categorized into two distinct thematic clusters, revealing both the current state and the transformative potential of AD as viable material in sustainable construction. More particularly, cluster 1 aggregates studies focusing on the development of innovative green materials for applications in construction incorporating AD residues. These works highlight promising mechanical performance, reduced environmental impact, and compatibility with existing construction systems. The high average citation rate and journal impact factor of this group reflect its academic maturity and alignment with current sustainability frameworks. Cluster 2, in contrast, encompasses research exploring novel technological solutions for innovative construction often at earlier stages of experimentation or recalling more traditional constructive technologies. Despite lower visibility metrics, this cluster is particularly rich in innovation, introducing new treatment techniques and hybrid composites that position AD as a competitive alternative raw material to synthetic reinforcements.

Overall, the literature confirms a growing scientific interest in repositioning AD from invasive alien species to valuable raw material as a renewable source. This trend is supported by recent policy shifts, including the European Union’s 2020 reclassification of AD as a potential biomass resource rather than an invasive threat. However, important gaps still persist, and more scientific and technological research is needed. These include the absence of harmonized characterization methods for AD materials, limited standardization across case studies, and a lack of comparative life cycle assessments to quantify environmental benefits.

Based on these findings, future research should include the following:

• Develop shared testing protocols for mechanical, thermal, and environmental properties of bio-materials incorporating AD;
• Investigate the effects of different pre-treatments on performance, especially for polymer–fiber composites;
• Quantify environmental impacts through LCA and carbon footprint analysis, supporting data-driven decisions;
• Expand experimental work on structural applications, upscaling from lab-scale to pilot or real-world demonstrators;
• Critically explore socio-environmental trade-offs, especially in relation to the dual status of AD as both a resource and a species with ecological risks.

By combining ecological mitigation with material innovation, AD offers a strategic opportunity to contribute to the decarbonization of the built environment and boost sustainability and circularity in construction. To conclude, this review provides a consolidated basis for advancing that potential, helping guide future research toward technically sound, ecologically aware, and policy aligned innovation trajectories.