Wood–Cement Composites: A Sustainable Approach for Mitigating Environmental Impact in Construction

Abstract

The construction industry’s environmental impact has become a growing concern, largely due to the energy-intensive production of conventional building materials. This paper explores the potential of wood–cement composites as a more sustainable alternative through a comprehensive literature review, including a bibliometric and scientometric analysis of research trends. Our analysis traces the evolution of wood–cement composites from early studies focused on mechanical properties, to recent investigations into their environmental benefits and practical applications. Key findings suggest that optimal performance can be achieved by treating wood with tetraethyl orthosilicate, incorporating additives like cellulose nanocrystals or wollastonite, and using wood from species such as Pinus. While partial cement replacement with wood waste and ash offers significant environmental advantages, precise formulations are needed to maintain structural integrity. This study also acknowledges certain methodological limitations, such as the reliance on keyword-based filtering, which may have excluded some relevant studies. Future research should address long-term durability, economic feasibility, and standardized testing methodologies to facilitate the adoption of wood–cement composites in the construction industry. These materials, particularly suitable for non-structural applications and insulation, hold promise as viable, eco-friendly building solutions capable of reducing the construction industry’s carbon footprint.

1. Introduction

The challenges facing our global society are becoming increasingly complicated as the world’s population continues to grow. According to the United Nations’ 2022 report [1], the global population has reached 8 billion and is projected to exceed approximately 8.5 billion by 2030, 9.7 billion by 2050, and a staggering 10.4 billion by 2100. Considering these predictions, it is expected that there will be more and more challenges in maintaining the balance between satisfying the increasingly numerous human needs and the requirements to protect the environment, including in achieving the goals of sustainable development [2].

One of the biggest challenges will be to ensure space for the development of human activities, so one of the sectors of activity that will feel this pressure is the construction industry [3]. The constraints on delivering these spaces extend beyond economic and technological factors; a significant limitation is given from the industry’s environmental footprint [4]. Current construction practices heavily rely on building materials, such as concrete and steel, which demand substantial energy inputs during their production [5]. Concrete is the most used building material worldwide, owing to its numerous advantages and ease of use [6]. However, the production of Portland cement, a critical component of concrete, requires considerable energy consumption [7]. With billions of metric tons of Portland cement produced globally, the associated carbon dioxide emissions from limestone degradation and coal combustion are harmful to the environment [8]. In these conditions, it becomes imperative to explore more ideas to mitigate the environmental impact of cement production.

From the wide range of available building materials, wood, renowned for its renewability, insulation properties, strength, workability, and aesthetic appeal, seems to be a good choice in construction [9]. Nonetheless, a complete substitution of concrete with wood is unfeasible, owing to wood’s susceptibility to rot, insects, and fire [9]. Wood also has a series of structural limitations imposed by the sizes of wood elements that can be directly harvested from trees and the presence of natural defects. A big part of these limitations can be overcome with the utilization of engineered wood products [10]. These constraints combined with a relatively limited awareness among civil engineers regarding wood as a building material, lead to the emerge of an intriguing concept—to develop a product that harnesses the eco-friendly qualities of wood while resembling the functionality of concrete [11].

The physical feasibility of blending wood with concrete is achievable, but not without challenges. At the core of concrete production lies the crucial process of cement hydration [12]. However, wood, being naturally porous and hygroscopic, can disrupt this hydration process [13]. Furthermore, the disparate coefficients of thermal expansion between wood and cement can induce stress, leading to cracks and damage as temperatures fluctuate [14]. The alkaline nature of cement can also trigger chemical reactions with cellulose fibers in wood, weakening its structural integrity over time [15], resulting in wood–cement composites with limited mechanical strength.

To overcome these difficulties, a series of studies [16,17,18,19,20] focused on identifying potential replacements for the Portland cement, maybe some cement that need lower energy to be produced and is not sensitive to the hydration process [21]. One of these solutions is represented by magnesium cement. The reduced environmental impact is given by the lower calcination temperature, somewhere around 700 to 1000 °C, compared to 1400 to 1450 °C in the case of Portland cement [22]. The main components of this cement are magnesium oxide and magnesium hydroxide, which react with water and have a low alkalinity and a quick setting time, so could be a good solution to be combined with wood [23]. The researchers pointed out that when used in combination with wood, magnesium cement acts as a binder that helps to strengthen and reinforce the wood structure [24]. Usually, this combination is used to produce buildings elements like walls, floors, panels, or even furniture [20]. Beside the structural consideration, the use of magnesium cement improves the proprieties of the wood, like increasing fire resistance and durability or improving the resistance to moisture and [21]. Another advantage is that the natural color of the MOC cement is yellowish, so it is close to the color of many natural wood species [25].

Despite existing technological solutions, key research questions remain unanswered, this study aims to address the following ones:

RQ1: What are the primary technical and operational barriers to optimizing the performance of wood–cement composites for widespread construction applications?

RQ2: What are the environmental benefits of using wood–cement composites, particularly in terms of sustainability and waste reduction?

RQ3: What types of construction applications are most suitable for wood–cement composites, considering their mechanical and environmental properties?

RQ4: What are the known limitations and future research needs regarding the durability and lifecycle performance of wood–cement composites?

These questions guide the investigation and highlight the potential impact of this study on advancing sustainable construction materials. As the global construction industry is struggling with the need for sustainable materials, addressing these research questions has the purpose of finding viable alternatives to traditional concrete. This study, by investigating the potential of wood–cement composites, directly aligns with global sustainability goals and the urgent need to reduce the construction sector’s carbon footprint.

Through a detailed keyword co-occurrence analysis, this study examines the thematic evolution of wood–cement composite research. By identifying key terms and their relationships, this analysis uncovers emerging trends, potential innovation gaps, and areas where further research could catalyze industry adoption of these sustainable materials. The practical applications of this study are that wood–cement composites offer potential as an eco-friendly alternative for a range of construction elements, including walls, panels, and flooring systems. By examining these materials’ performance, this study explores their potential to make sustainable construction more feasible and scalable.

To address the purpose of this study the methodology includes a rigorous research approach, comprehensive critical literature review methods, scientometric analysis, bibliometric analysis, and an in-depth examination of the literature. Data for this investigation were collected from the Clarivate Web of Science database, following the guidelines of the PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) technique. Two key software tools, Bibliometrix and VOSviewer, were used for comprehensive bibliometric analysis.

This manuscript adheres to the style guide for scientific and review papers. After this introductory section and the declaration of research goals, the subsequent sections of the paper present the research techniques and methodology, followed by the presentation of bibliometric analysis results and an in-depth exploration of the literature. While this study leverages keyword co-occurrence analysis for insight into research trends, it acknowledges the limitations of this methodology, such as potential biases in data selection and the exclusion of relevant but less-cited works. Acknowledging these limitations is essential to provide a balanced view of the findings. The paper ends in a concluding section summarizing major findings, and a comprehensive list of references integral to this study.

2. Materials and Methods

2.1. Data Collection

The data for this study were collected from the Clarivate Web of Science scientific database. This database was chosen due to its comprehensive coverage of scholarly articles and its relevance to the research topic. The data collection process commenced with an initial query using the keywords “wood and cement”. The initial interrogation revealed a total of 1403 papers. To refine the dataset for relevance to this study, key filters were applied, so the papers where the keywords appeared in the title, and the articles categorized as either “article” or “review” were chosen. By applying these filters, the number of articles was reduced to 277 papers.

In alignment with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 Statement, as proposed by Moher et al. [26] and updated by [27], the next phase of data selection followed the four-step PRISMA approach: identification, screening, eligibility, and inclusion, as illustrated in Figure 1.

The process of screening the 277 papers started by removing the duplicates, the papers with no information, books or books chapters. In this phase the number of papers reduced to 225 papers. In the screening phase, the titles of articles were analyzed and papers with titles outside the purpose of this study were eliminated. After this phase only 149 papers were further analyzed for eligibility by reading the abstract and searching the full text of the papers. In this phase the papers were filtered not only based on their title but also based on their content, so 16 papers were removed due to the content and research results outside the scope of this study. The final dataset comprises 133 papers.

The decision to choose these keywords and to consider only articles with these keywords in the title was aimed at ensuring that the selected papers focused primarily on wood–cement composites rather than addressing the topic tangentially. Using keywords in the title as a selection criterion assumes that if keywords appear in the title, the paper likely emphasizes those concepts as the main part of the research. This methodology, while it is effective in narrowing the dataset to highly relevant papers, may introduce bias by excluding valuable research that addresses wood–cement composites without explicitly mentioning “wood” and “cement” in the title.

This approach also has some limitations. By focusing only on the Web of Science database and restricting the search to English-language publications, we may have unintentionally excluded relevant studies from regional or non-English journals. Additionally, the reliance on specific keywords could have omitted studies that address similar topics but use different terminology. For example, research on “biocomposites” or “natural fiber composites” may be related to wood–cement composites but could be missed if those specific keywords were not included in the dataset. As a result, our dataset may underrepresent multidisciplinary studies that address wood–cement composites from a more general perspective. Another limitation is related to the terms “wood” and “cement”, which were chosen based on their relevance to the primary topic of this study. However, alternative terminology, such as “natural fiber composites”, “bio-based composites”, or “cellulosic materials in concrete” might be used by researchers from adjacent fields, such as material science or sustainable engineering. By focusing strictly on “wood and cement”, our dataset may have overlooked studies from these related fields that use different terms to describe similar materials or applications.

At the same time, the purpose of this study is to answer a more general question related to the suitability of wood waste to be used in a mixture with concrete and thus lead to the reduction of the negative effects of the construction industry on the environment, and it does not aim to deliver a complete review of all research in the field.

2.2. Data Extraction and Analysis

Journal articles retrieved from the scientific database were exported as plain text files, having essential data such as article titles, author keywords, author names, and citation information. The exported data underwent manual standardization to ensure compatibility with the requirements of the software tools used for analysis.

Data standardization was a critical step in preparing the dataset for analysis. Uniformity in the data format was essential to produce accurate results when employing software tools. The time invested in this manual process is very important for the study’s accuracy and reliability.

Software Tools

The primary tools and software used to process and analyze the data were Bibliometrix software (version 3.1), developed by Massimo Aria and Corrado Cuccurullo from the Department of Economics and Statistics at the University of Naples Federico II in Italy [28], and VOSviewer (version 1.6.17), created by Nees Jan van Eck and Ludo Waltman at the Centre for Science and Technology Studies, Leiden University, the Netherlands [29].

3. Results

3.1. The Evolution of the Annual Number of Published Articles

The annual publication trends provide valuable insights into the evolving interest in the field of wood–cement composites. Figure 2 illustrates the number of papers published annually, focusing on the research topic of “wood and cement”. On the horizontal line are represented the years of publication and on the vertical are presented the numbers of papers published each year. The graph was generated using the Bibliometrix 3.1 software.

The data presented in Figure 2 reveals an upward trend in research publications related to wood and cement composite materials. While the absolute numbers may appear relatively small, it can be observed that there is a growing interest in this subject matter, particularly in recent years. The year 2016, can be considered as the year when the interest for this topic started to increase, 10 papers were published. However, it’s important to notice that next year, in 2017, only 4 papers were published. From 2018, the number of publications rose to 19 and reached a peak of 21 papers in 2021 and up to July 2024 there were 16 papers published.

The upward trend in publication frequency indicates an increase in the importance of sustainable building materials in both academic and industrial settings. This increase can be seen as a response to the efforts of the construction industry to find alternatives to traditional concrete, which is known for its high environmental footprint. The peak in publications in 2019, 2020 or 2021 aligns with the global shift toward sustainable development goals and the increased urgency around climate change mitigation. However, the variability in publication numbers over the years may reflect fluctuations in funding availability, shifting research priorities, or technological challenges associated with wood–cement composite materials. This inconsistency suggests that while interest is growing, the field still faces hurdles that require sustained research investment and interdisciplinary collaboration to overcome.

3.2. The Trend Topic Analysis

To understand evolving themes in wood–cement composite research, a trend topic analysis was conducted. This analysis, based on data from the Web of Science database, highlights the keywords and concepts that have gained importance over time. Figure 3 provides a visual representation of this analysis, being formed by lines and bubbles to highlight the term frequency and temporal usage. The size of each bubble corresponds to the frequency of the associated term, with larger bubbles indicating more frequent usage.

Research on wood–cement composites has evolved over the years. Initial studies focused on examining mechanical properties, durability, and resistance to environmental factors like moisture, decay, and fire. As the field advanced, researchers began exploring innovative production methods and alternative raw materials to improve the performance of wood–cement composites. For instance, some studies experimented with magnesium-based cement and wood waste to enhance fire resistance and reduce carbon emissions. Recently, there has been a strong shift towards sustainability, with a focus on reducing the environmental impact of these materials. Researchers are now investigating production processes that incorporate waste materials and by-products, which not only lower carbon footprints but also improve recyclability and end-of-life management.

The trend topic analysis highlights a clear evolution in the field, where initial studies focused on establishing the foundational properties of wood–cement composites, while more recent research reflects a shift towards sustainability. The growing accent on terms such as “sustainability”, “recyclability”, and “waste incorporation” suggests that researchers are not only focused on improving the technical performance of these composites but are also increasingly aware of their lifecycle impacts. The exploration of alternative cement types, like magnesium-based cement, indicates an interest in finding binders that may offer lower emissions than Portland cement. This shift in focus towards eco-friendly materials is essential if wood–cement composites are to become viable competitors to traditional concrete on a larger scale. However, challenges remain, especially around ensuring these materials meet durability and strength requirements under real-world conditions.

3.3. The Keywords Co-Occurrence Analysis

Examining keyword co-occurrence provides a deeper understanding of the interconnected themes within wood–cement composite research. A keyword co-occurrence analysis, as explained in [30], reveals that the co-occurrence of words in several papers indicates a closely related meaning of the concepts of those words. This analysis can also be used to indicate trends and patterns in the topics studied. The analysis can be performed by using the keywords proposed by authors, the extra keywords or both. Usually, the editors of journals indexed in Clarivate Web of Science database propose extra related keywords for the papers, so they increase visibility in the searches. This analysis was performed using all keywords and only papers with a minimum of five occurrences were included.

Figure 4 shows the keyword co-occurrence network map, generated using VOSviewer software. In this map, keywords are represented by bubbles, with larger bubbles indicating higher frequency. Lines connecting keywords represent their co-occurrence in the same papers, while color-coded clusters group keywords with similar themes.

The dataset includes 708 keywords, with 39 meeting the minimum co-occurrence threshold of five. These 39 keywords are organized into five clusters, each with unique thematic focuses. The red cluster is the largest, with 10 keywords, followed by the green (9 keywords), blue (8 keywords), yellow (7 keywords), and purple (5 keywords) clusters.

The spatial arrangement of keywords on the map reflects their frequency in the analyzed papers, with frequently used keywords positioned centrally. For example, “composite” is situated at the center, with a link strength of 28.00 and an occurrence of 30, highlighting its importance in discussions of combining wood and cement into composite materials. Nearby, keywords such as “concrete” (link strength: 25.00, occurrence: 25) emphasize the development of wood–cement composites with concrete-like properties. Similarly, “strength” (link strength: 27.00, occurrence: 28) from the red cluster underscores the focus on mechanical strength in these materials.

In the green cluster, keywords like “hydration” (link strength: 23.00, occurrence: 24) and “mechanical properties” (link strength: 23.00, occurrence: 24) reflect research priorities around the cement hydration process and mechanical behavior in wood–cement composites. Additionally, “compatibility” (occurrence: 19, link strength: 19.00) highlights the importance of achieving compatibility between wood and cement. In the purple cluster, “durability” (occurrence: 19, link strength: 19.00) stands out as a significant research focus, emphasizing the need for long-term performance in wood–cement composites.

The clustering of keywords reveals distinct research directions. The red cluster, the largest on the map, primarily focuses on comparing wood–cement composites with traditional Portland cement concrete. Keywords such as “strength”, “composite”, and “concrete” suggest that a significant portion of research is dedicated to understanding the mechanical performance of these materials. This cluster highlights the challenge of ensuring that wood–cement composites can meet structural requirements, a critical factor for their adoption in the construction industry. The emphasis on “strength” reflects a research trend towards optimizing wood–cement composites to perform similarly to traditional concrete, with potential applications in areas that require moderate load-bearing capabilities. However, the lack of keywords related to “long-term durability” or “weather resistance” in this cluster suggests a gap in knowledge about how these composites will perform over extended periods.

In the green cluster, keywords like “hydration”, “mechanical properties”, and “compatibility” indicate a focus on the interactions between wood and cement. Research in this area addresses the technical challenge of compatibility, as wood’s organic nature can interfere with cement hydration, impacting bonding and strength. The presence of “compatibility” as a central theme suggests that this issue remains one of the primary barriers to widespread adoption. Addressing compatibility challenges is crucial not only for achieving strong, stable composites but also for enabling consistent performance across different wood types and environmental conditions.

The blue cluster explores the use of wood waste and wood ash in composites, highlighting the potential for wood–cement materials to contribute to sustainable construction. Keywords such as “wood waste” and “wood ash” reflect an industry trend towards reducing landfill waste by repurposing industrial byproducts. This focus on waste utilization aligns with broader sustainability goals, as it reduces reliance on traditional cement and supports a circular economy. The presence of sustainability-focused keywords highlights the potential of wood–cement composites to address environmental concerns in construction, particularly through the use of renewable or recycled materials. However, the relatively limited focus on “lifecycle assessment” in this cluster indicates a gap in understanding the full environmental impact of these composites over their lifespan.

In the purple cluster, keywords like “durability” and “compressive strength” emphasize the need for wood–cement composites to maintain performance over time. The focus on durability reflects a crucial aspect of research, as any material intended for construction use must demonstrate long-term reliability. The positioning of durability-related keywords suggests that researchers are actively investigating how wood–cement composites can withstand environmental stressors such as moisture, temperature fluctuations, and microbial activity. However, there is a noticeable absence of terms related to specific environmental conditions (e.g., “humidity” or “freeze-thaw cycles”), indicating an area for future research. Understanding the durability of wood–cement composites in different climates will be essential for expanding their applications in global markets.

The yellow cluster includes keywords related to the chemical properties and performance of wood and cement, such as “adsorption” and “organic compounds”. This area of research focuses on the effects of wood’s natural properties on cement behavior, including how organic compounds in wood may influence cement hydration and bonding. Keywords in this cluster also point to the exploration of chemical additives that could improve performance, such as silane coupling agents or nanocrystals. The emphasis on chemical interactions suggests that researchers are experimenting with various additives to mitigate compatibility issues and enhance mechanical strength, thus supporting broader applications of wood–cement composites.

The clustering of keywords reveals a clear trend toward specialization within the field, with distinct groups focusing on mechanical performance, compatibility, sustainability, durability, and chemical modifications. This specialization allows researchers to tackle specific challenges, such as improving fire resistance, optimizing mechanical properties, or increasing compatibility between wood and cement. It also highlights the need for collaborative efforts to integrate findings from different areas, creating cohesive solutions that address both technical and environmental requirements. Future breakthroughs in wood–cement composites may depend on interdisciplinary research that combines knowledge from these specialized clusters to develop materials that meet all industry standards for sustainable, durable construction.

3.4. The International Interest on the Subject

The field of wood and cement composites research continues to evolve, driven by the contributions of various authors and research teams. In this section, the focus is on an analysis of authors and their affiliations, shedding light on the prominent figures and the global distribution of research efforts. With the help of Bibliometrix software, a world map was generated highlighting the number of papers published in each country (Figure 5). The map was generated considering the authors’ corresponding countries as they appear in data exported from the Clarivate Web of Science database.

As can be seen in the map, the top countries exerting the biggest interest in this subject are Brazil with 43 papers published, China with 33 papers, Iran with 16 papers, and Canada with 14 papers.

The same situation regarding the distribution of international interest in the subject of wood and cement research can be observed if the correspondence author’s country is analyzed (Figure 6). The graph was also generated with the help of Bibliometrix software, and it presents on the horizontal line the number of documents and on the vertical line the author’s country. As a short note on the graph the notation “MCP” and “SCP” is used; this shows that the papers are having authors from multiple countries, MCP, or that the paper has authors from one country, SCP.

The data presented in Figure 6 reveal that the authors from China published 20 papers from a total of 133 papers selected in the ample database extracted from the WoS scientific database. Among these, only two papers were elaborated by an international research team, the rest of the 18 papers were written only by Chinese authors. In the second place, the authors from Brazil published 12 papers among which three papers were published having international authors. In the case of Iran, 8 papers were published only by local authors.

The data reveals that a substantial part of the research output in the field is done by authors within the same country. While international collaboration is essential for fostering diverse perspectives and advancing research, the current landscape indicates limited collaboration among researchers in this field. It is expected that in the future, given the increasing global interest in environmental protection and sustainable materials, the international research teams will play a more significant role.

4. A Comprehensive Examination of Literature

The literature on wood–cement composites reveal several key approaches that researchers have explored over the years. Although these approaches overlap, organizing them into main categories makes it easier to understand the development of the field. This examination of the research highlights the evolution of wood–cement composites, showing how the historical context shapes current directions in the field.

4.1. Early Investigations

The interest in exploring wood and cement composites dates back several decades. One of the earliest studies, titled “Preliminary Evaluation of a Wood-Cement Composite” [31] was published in Forest Products Journal. Although details of this early work are limited, the title reflects the emerging interest in wood–cement composites at the time.

In the next years, researchers began examining the feasibility of reinforcing cement composites with wood. Early studies, such as [32] identified the potential for improving the strength of wood fiber-cement composites with coupling agents. It became apparent that these composites are more suitable for low-water cement ratio applications, as discussed in [33]. These pioneering investigations played a crucial role in recognizing the challenges of integrating wood, a porous material, with cement composites, especially in terms of water–cement ratios.

An important aspect of wood–cement composites research is addressing the natural incompatibility between wood and cement. Researchers, as [34,35,36], highlighted the complexity of this issue, acknowledging that factors such as wood type, location within the tree trunk, and cutting time influence the compatibility. Understanding these factors has been crucial in developing ways to overcome compatibility issues.

While wood–cement composites offer environmental benefits, concerns about their long-term durability persist [35]. Research, including [36], has pointed to potential challenges, such as significant losses in physical and mechanical characteristics over time and accelerated aging [37]. These findings underscore the need for ongoing research to enhance the durability of wood–cement composites.

Recognizing these challenges, current research continues to focus on improving compatibility, improving mechanical properties, and addressing environmental concerns. Researchers build on earlier insights as they work toward solutions that balance sustainability with structural performance.

4.2. Treatment of Wood Fibers in Wood–Cement Composites

One way of improving the compatibility between wood and cement is to use various treatment methods and add additives to improve mechanical and physical proprieties.

Alkali Cooking Modification and Silane Coupling Agent. In [38], researchers achieved promising results by treating wood with alkali cooking modification and a silane coupling agent. This treatment enhanced the compatibility of wood waste with cementitious materials, resulting in improved mechanical strength [39]. The immersion of wood fibers in tetraethyl orthosilicate also resulted in positive outcomes when incorporated into cementitious matrices [40]. While the study indicated good properties for eucalyptus tree fibers after treatment, the optimal results within the cementitious matrix were obtained using pine wood fibers [41].

Cellulose Nanocrystal Particles. The addition of cellulose nanocrystal particles has demonstrated potential in improving the mechanical and physical properties of wood–cement composites [42]. Researchers found that the inclusion of 0.5% cellulose nanocrystal particles led to improved integrity within the microstructure of wood–cement panels. Additionally, a 9% substitution of cement with wollastonite presented favorable results in improving the properties of wood fiber-cement composites [43].

Sodium Hydroxide (NaOH) Treatment. The treatment of wood with sodium hydroxide (NaOH) led to mixed results. In one study [44], untreated pine strands exhibited superior compatibility with cement compared to treated samples. Another experiment [45] involving NaOH-treated wood fibers in cement mortars revealed that wood treatment influenced cement hydration, promoting the formation of more portlandite and calcium silicate gel.

Additives for Property Enhancement. Various additives, including phosphorus, boron, or magnesium compounds, have shown potential in improving the hygroscopic and mechanical properties of wood–cement composites [46]. Some of these additives can also serve as fire retardants for the incorporated wood [47].

Expanded Polystyrene and Paper Sludge. Researchers have explored innovative solutions such as incorporating expanded polystyrene, acting as an adhesive for composite boards [48]. Additionally, the combination of expanded polystyrene [49] and paper sludge with wood fibers in cement mortar exhibited promising results in optimizing performance [50]. Wood–crete building materials developed from sawdust and wastepaper also demonstrated compatibility and improved properties [51].

Approaches Based on Similarity Coefficient. In addressing wood and cement incompatibility, researchers in [52] introduced a similarity coefficient that measures the resemblance between wood–cement hydration temperature curves and those of simple cement. This approach provides insights into the degree of compatibility and may guide further developments.

The treatment of wood fibers in wood–cement composites continue to evolve, offering multiple ways for improving compatibility, durability, and environmental sustainability. Each approach presents unique findings and challenges, contributing to the ongoing development of wood–cement composite technology.

4.3. Diverse Materials and Their Impact on Wood–Cement Composites

Researchers have examined the effects of various materials—including different wood types, natural fibers, and wood waste—on the compatibility and properties of wood–cement composites.

While softwood species are commonly used in wood–cement composites, research has explored the potential of hardwood species as building materials. For instance, Leucaena leucocephala, a tropical hardwood species, was used to produce cement-bonded particleboards with encouraging results [53,54]. Similarly, soybean pods combined with eucalyptus wood were investigated, offering a novel composite possibility [55].

Studies have explored the use of poplar wood in cement mixtures [56,57]. However, the structure of the wood can act as an inhibitor of the cement hydration process [58]. To mitigate this, researchers have explored additives such as calcium chloride and sodium silicate to improve compatibility [59].

Ochroma pyramidale, a fast-growing wood type, has been used to create wood–cement composites suitable for nonstructural elements, even in moist environments [60]. Less common commercial species, such as Kelempayan wood, have also been investigated for their compatibility with cement [61].

Indian cedar wood is another type of wood used in the cement mixture [62]. The experimental results indicate that this type of wood can only be used in applications of sealing blocks or other light construction systems. Red ironwood (Lophira alata) sawdust and palm kernel shell were used in [63], while in [64], sawdust suitability from Tripiochiton scleroxylon, Entandrophragma cylindricum, and Klainedoxa gabonensis for the wood–cement composite was determined. Maple-wood sawdust addition in the cemented paste backfill improves its strength development, as shown in [65].

In [66], four Amazonian species, Eschweilera Coriaceae, Swartzia Recurva, Manilkara Amazonia, and Pouteria Guianensis, were investigated and the results indicate that all species are compatible with Portland cement, obtaining enough mechanical strength to be used for lightweight reinforced concrete. Amazonian species were investigated also in [67], where the authors observed that five studied species were classified as low inhibitory: Eschweilera coriacea, Inga paraensis, Inga alba, Pouteria guianensis, and Byrsonima crispa, while the wood from Swartzia recurva with arabinose content was directly correlated with the cement inhibition.

Incorporating natural fibers into wood–cement composites has yielded promising results. Seagrass fibers, coconut-husk fibers, and long sisal fibers have been explored as potential reinforcements [68]. Replacement of cement with banana fibers has shown potential for thermal insulation properties [69].

The utilization of wood waste, including Masson pine, in cement composites has demonstrated compatibility with Portland cement [70]. Researchers have examined the influence of wood particle size and found that larger particles can improve internal bond and mechanical properties.

Research in wood–cement composite studies has gone beyond the superficial and goes deeper into the complex properties of wood, primarily from the perspective of lignocellulose materials [71,72,73]. In [74], the examination extended to the pit torus and pit border, focusing on changes occurring after the casting of concrete and the subsequent heat release due to cement hydration. This research sheds light on the susceptibility of the torus membrane of wood within freshly poured concrete. It was observed that this membrane could be compromised within a matter of hours under increased temperature and alkaline conditions, potentially explaining the transport of alkaline ions into the wood’s inner structure.

Moreover, the influence of natural fibers [75] on the performance of wood–cement composites was explored in [76]. The findings emphasized the significant impact of wood’s hygroscopic behavior on cement hydration. Additionally, the particle size was identified as a critical factor affecting composite properties, as observed in [77]. A comparison between specimens with small and large wood particles revealed that larger particles exhibited superior internal bond strength and mechanical properties. The possibility of grinding wood into fine flour and incorporating it into cement mixtures was also evaluated in [78]. Surprisingly, this study revealed that the addition of a mere 2% of wood fiber flour resulted in an impressive over 40% increase in the compressive strength of the composite material. The same conclusions are drawn up, by the same authors, in [79], where they obtained an increase of the compressive strength by adding 1% of wood fibers to the mixture.

4.4. Exploring Wood Waste in Composite Production

Researchers have further explored the potential of wood waste to enhance the sustainability of construction materials. Several studies have addressed the use of wood waste as a cement replacement material, with compelling results. In [80], the researchers explored the utilization of wood waste ash as a cement replacement material for producing structural-grade concrete. This novel approach aligns with the principles of a circular economy.

The use of wood waste was investigated from the brick production point of view [81], obtaining good results in the replacement of cement. Studies like [82] demonstrated promising outcomes by incorporating wood waste from pallets and demolition activities, and even construction boards benefited from the integration of wood waste, as highlighted in [83]. Additionally, pruning waste from trees, if properly treated and added in small proportions to cement mixtures, was found to be a viable resource for wood–cement composite production [84].

One study [85] integrated wood waste in the form of powders and fibers into cement mortars. The results indicated that the most favorable outcomes were achieved when wood waste was used in modest quantities to replace sand in the mixture [77]. While a slight decrease in mechanical strength was observed due to the addition of wood waste, it was not significant enough to rule out its potential use, reinforcing the feasibility of wood waste as a supplementary cementitious material.

Wood–cement composite research has explored various innovations and adaptations. The development of wood–cement boards obtained promising results, as seen in [86] where wood waste particles from various Pinus species were used. Even with high wood content in the mixture, these boards exhibited favorable properties. Certain additions like silica fume or rice husk ash were found to enhance the performance of wood–cement boards, as revealed in [87]. Prolonged exposure revealed a significant loss in mechanical properties, emphasizing the importance of long-term behavior assessments.

Recycled and Alternative Aggregates in Cement Mixtures. Exploring recycled materials in cement mixtures, researchers in [88] utilized recycled wood fibers as an ecological aggregate in the cementitious matrix. This innovative approach aimed to improve indoor thermal comfort and support low-energy building design [89]. Additionally, the use of wood waste sawdust as a self-compacting cementation system was investigated in [90], resulting in a reduction in strength but a lower shrinkage strain. A similar study [91] compared the use of wood waste aggregates and sawdust as cement replants, with an optimum replacement ratio identified at 20%.

Curing processes played a significant role in enhancing the properties of wood–cement particleboards, as demonstrated in [92], where a 24-h CO₂ curing process substantially improved cement hydration. Moreover, novel technologies have been developed to recycle wood waste into noise and thermal insulating cement particle boards, as shown in [93].

Exploring Alternative Cement Types. Studies have not only focused on Portland cement but have tested alternative cement types to create wood–cement boards. For instance, magnesium oxychloride cement (MOC) was investigated in [21,26], resulting in lower thermal conductivity and higher mechanical properties. Magnesia-phosphate cement (MPC) was another alternative explored in [94], although challenges related to brittleness, strain capacity, and water resistance were identified.

In [95], the use of alumina and red mud was proposed to improve the resistance of MPC particleboards, particularly water resistance. Moreover, the role of hydration chemistry and reaction sequence in MPC cement was scrutinized in [96], with findings indicating that the ratio of magnesium to phosphate significantly influenced strength development. Furthermore, CO₂ curing processes also proved effective in magnesia cement, providing an avenue to transform contaminated wood waste into eco-friendly cement-bonded particleboards.

A distinct approach involved the development of particle boards using magnesium-based phosphate, as demonstrated in [97]. Besides wood waste, this study integrated other industrial residues like bagasse, hemp hurds, paper mill sludge [98], and wastepaper. The feasibility of creating eco-friendly construction materials from these materials was highlighted.

Wood waste can also be used to produce biochar. In the study of [99], biochar from food waste and wood waste was used as a carbon sequestering additive in mortar. In the case of wood waste, the researchers used mixed wood sawdust, and they obtained a carbon content of 87% of the weight, an increase of the compressive and tensile strength up to 20%, and the water penetration was reduced by 60% compared to a control sample. Using biochar with good results is also highlighted in [100]. In [101], utilized biochar from wood waste achieved increased compressive and tensile strength and reduced water penetration, reinforcing the value of wood waste as a building material.

These results are useful because they sustain the idea of continuing to use wood waste as a building material, in this case as a reinforcement to the mortar paste.

Incorporating Wood Waste Ash in Cement Mixtures. A big part of the research literature on the topic of using wood products to reduce the environmental footprint of concrete is focused on the use of wood ash. Most studies focused on wood ash obtained from the combustion of wood to generate heat. As a big part of the wood waste is currently used for this purpose, it is interesting to study if this is a good way of using the resulting wood waste. The researchers in [102] assessed the properties of ash obtained from wood chip combustion by grate combustion and circulating fluidized bed processes. While hydraulic properties were identified, no pozzolanic properties were detected in the former.

Wood bottom ash was proposed as a valuable solution, if used optimally, to sustainable development in [103,104]. Washed wood ash was also explored as a promising component for cement mixtures in [105]. Wood ash from pulp and paper mills was added in varying proportions, revealing a manageable reduction in compressive strength and elastic modulus, as seen in [106]. The authors of [107] identify that ash can be effectively used as a cement replacement material to produce structural grade concrete of acceptable strength and durability performances.

Unique insights were gained from examining the ash of exotic species like eucalyptus [108] and avocado, as reported in [109]. High levels of wood ash were found to reduce the composite’s strength, emphasizing the need for judicious proportions of wood ash [110].

In the study [111], the researchers indicate that the workability and the strength characteristics of a cement mortar having 10% wood ash can be improved by adding into the mix a small amount, 1 or 2%, of green-synthesized nano-TiO₂. The mixing of wood ash with metakaolin and chemical admixture was also investigated in [112].

To be used as raw material, wood ash must be properly stored. The study [113] highlights the importance of wood ash being stored in closed containers so to avoid faster ageing and to prevent pre-hydration and carbonatation. These results raise the problem of depositing raw components which must be investigated and considered in the development of a more ecological construction industry.

In the work [114], the researchers obtained an improvement of the compressive and bending strength in the case of adding up to 30% fly ash; similar results were also revealed by replacing the same percentage with biomass wood ash [115]. Improvement in the proprieties of the cementitious materials by adding wood biomass fly ash was obtained by the researchers in [116], they used 5, 10, and 15 wt.%. The results presented in [117] indicate that a percentage of 10% wood ash resulting from burning wood waste, used as a replacement for Portland cement, led to an improvement of the compressive strength.

Wood is also used intensely as a source of energy production; this leads to large amounts of ash. In [118], the authors performed a study on various sources of ashes used as supplementary cement material [119]. They indicate that the best source is the ash of wood chips from the whole tree and that the combustion method and the type of ash have a big influence on the characteristic of the composite material.

Wood biomass ash resulting from the brick industry was investigated as a component of white geopolymer cement with diatomite as the main ingredient [120] and proposed to be used as an alternative for Portland cement in decorative works. The wood ash resulting from the wood milling industry was used with good results as amending cement stabilization of expansive soil [121]. Their study revealed that adding 5% of sawdust ash into the cement stabilization mix led to an increase of up to 26% in early strength and 20% in delayed strength.

In this work [122], two peat–wood fluidized bed combustion fly ash samples—one with high calcium fly ash (24.9% Ca) and the other with low calcium fly ash (9.7% Ca)—were hardened and their hardening effects were investigated. A study was done on the reactive elements in the raw materials, the mineralogical makeups, and the compressive strengths of the mortars that were produced. The growth of strength was significantly improved. Portland cement must be added for low-Ca ash to harden at all.

4.5. Improving Wood–Cement Composite Characteristics

A critical review of research on wood–cement composites reveal valuable insights into their mechanical characteristics. Compressive tests, conducted in [123], illustrated an important decrease in Young’s modulus with increasing wood particle content. Similar findings were corroborated in [124], where a higher fiber content was associated with decreased bulk specific gravity and elevated water absorption capacity.

Reinforcing boards with microcrystalline cellulose, as proposed in [125], significantly improved the properties of wood–cement boards, particularly in the 5% to 10% range. Moreover, alternative compositions, like those involving steel netting and woven hemp strands, were found to enhance physical and mechanical properties, as observed in reference [99].

The effects of particle size and the wood-to-cement ratio on the physical and mechanical characteristics of vibro-compacted wood–cement composites, revealing an optimum ratio of 1:2.75 for denser, dimensionally stable composites, are detailed in [126]. Furthermore, the potential for the wider acceptance of wood–cement composites in the construction market as permanent formwork was explored in [127].

Enhancing Acoustic Properties and Predicting Moisture Content. Acoustic properties of wood composite boards were evaluated in [128], suggesting that variations in board density could improve sound absorption. The use of low-density wood–cement composites made using a novel technique was investigated in [129], showcasing favorable physical and mechanical qualities [89]. The vibro-dynamic technique was shown to be particularly effective, resulting in low-density, high-quality products [130].

The study outlined in [131] aimed to develop a model capable of calculating the moisture content of construction materials, including wood and untreated or hydrophobic mortar, at varying temperatures. Similarly, research into dielectric relaxation processes for mortar, as seen in [132], opened avenues to study the hierarchical water structures within complex materials.

Innovative Approaches and Reinforcements. An interesting approach in [133] involved reinforcing boards with steel netting and woven hemp strands while adding cement to the dry mass of wood. The results demonstrated that this approach enhanced every physical and mechanical property.

Assessing Long-Term Strength and Industrial Residues. Intriguing insights were gained by assessing the impact of long-term behavior on wood–cement composites, with accelerated and natural wear testing revealing distinct degradation patterns. This finding was reported in [87]. It was observed that the combination of different industrial residues, such as bagasse, hemp hurds, paper mill sludge, or wastepaper in wood–cement composites had notable potential, as demonstrated in [97].

Studies such as [118] delved into the usage of ashes from various sources as supplementary cement materials, highlighting the influence of combustion methods and ash types on composite characteristics.

5. Discussion

The growing interest in wood–cement composites, as observed in publication trends, reflects a shift in both academia and industry toward sustainable construction materials. This shift aligns with global efforts to reduce the environmental footprint of the construction sector, which is known for its high levels of resource consumption and CO₂ emissions. Our results indicate a steady increase in research publications focused on wood–cement composites, suggesting that this field is likely to expand as more stakeholders seek eco-friendly building alternatives. The keyword trends observed in our analysis, particularly around terms like “sustainability”, “durability”, and “compatibility”, indicate an industry shift toward environmentally responsible materials that maintain structural integrity. The focus on keywords such as “alternative binders” and “waste utilization” underscores an emerging trend in the construction industry to reduce reliance on traditional cement by exploring new materials and incorporating byproducts.

Across multiple studies, significant advances have been made in improving the compatibility and performance of wood–cement composites. Various treatment methods, such as alkali cooking, silane coupling, and the use of cellulose nanocrystals, have shown promising results in improving bonding strength and durability. These methods address challenges given by the natural incompatibility of wood and cement, specifically related to issues of water retention and poor bonding. For practitioners, this suggests that targeted treatments are essential to achieving high-performance composites that can withstand the demands of real-world applications.

The use of wood waste as a partial cement replacement has emerged as a major theme in recent research, motivated by the need for both resource efficiency and waste reduction. Studies have demonstrated that incorporating wood waste, sawdust, and wood ash can reduce cement usage, with a slight compromise in mechanical strength. When combined with specific curing processes, such as CO₂ curing, wood waste composites can achieve adequate strength for non-structural and even some structural applications. This finding highlights the potential of wood–cement composites not only as sustainable building materials but also as a means of reusing wood waste, which is often a byproduct of other industries.

Exploration into alternative binders to the Portland cement, such as magnesium oxychloride cement (MOC) and magnesia-phosphate cement (MPC), has shown that wood–cement composites can achieve specialized properties, including lower thermal conductivity and improved fire resistance. While these alternative binders have limitations—such as brittleness and sensitivity to water—future research may overcome these challenges, expanding the use of wood–cement composites in applications where fire safety and thermal insulation are critical. From a practical standpoint, alternative binders represent a promising direction for achieving more environmentally friendly composites.

Optimal proportions of wood in the mix are also crucial in determining composite properties. Lower wood-to-cement ratios generally achieve better mechanical performance, as specific ratios depend on the intended application. The size of wood particles and the use of natural fibers, such as coconut or sisal, can be adjusted to meet specific performance requirements, such as improved sound absorption or thermal insulation. This flexibility makes wood–cement composites a versatile option for various construction needs, from load-bearing walls to insulating panels.

Despite the progress in wood–cement composite research, several limitations remain. The reliance on short-term mechanical testing means that there is limited data on the long-term durability and lifecycle impacts of these materials. The variability in experimental methods across studies makes it difficult to directly compare results or establish standardized guidelines. One limitation of our study lies in the reliance on specific keywords and the use of the Web of Science database, which may have inadvertently excluded relevant studies, particularly those published in non-English languages or indexed in regional databases. Future studies should consider expanding keyword variations and including multiple databases to capture a broader and more diverse range of research. Furthermore, interdisciplinary collaboration will be essential to address the technical and logistical challenges associated with scaling up wood–cement composites for widespread use in the construction industry. By synthesizing recent advances in wood–cement composite treatments, material combinations, and sustainability implications, this study provides a comprehensive overview of current trends and critical barriers to adoption, serving as a roadmap for future research and industry practice.

6. Conclusions

Wood–cement composites show strong potential as a sustainable alternative to traditional concrete, offering both environmental benefits and functional versatility. This study, combined with an extensive literature review, highlights that key compatibility treatments—such as alkali treatment, silane coupling, and cellulose nanocrystal addition—are essential for improving the mechanical properties and durability of these materials. The partial replacement of cement with wood waste provides the dual benefit of reducing cement consumption while repurposing wood byproducts, which aligns with the broader trend toward sustainable and circular construction practices. Slight reductions in mechanical strength with wood content indicate a need for optimized curing processes and precise material proportions to ensure consistent performance.

To facilitate the adoption of wood–cement composites in the construction industry, several challenges must be addressed, including the need for long-term durability studies, standardized testing methodologies, and the development of alternative binders with improved environmental profiles. Interdisciplinary research is needed to explore the economic feasibility and lifecycle environmental impacts of these materials. By addressing these challenges, wood–cement composites could play a significant role in advancing sustainable construction practices, providing viable solutions for both non-structural and semi-structural applications in an increasingly resource-conscious world.