Quality Of Building Materials Research Articles

Fractal model of the strength of lightweight concrete based on volcanic tuff taking into account the scale effect

The study proposes a fractal model based on B. Mandelbrot's geometry. Mandelbrot geometry to describe the scale effect in concrete. It has been experimentally established that under-loading concrete undergoes degradation of its structure, which is expressed in the sequential destruction of fractals at different scale levels. It was found that the scale reduction leads to an increase in concrete strength: 20x20x20 mm specimens showed the highest strength among all four compositions (23.3-25.3 MPa). The average density of tuff concrete was also investigated: the smallest specimens had a density of 1961.3 kg/m³, while the largest specimens had a density of 1974.2 kg/m³, which is explained by the heterogeneity of the structure and pore distribution. The water permeability of concrete, evaluated through air permeability, showed that specimens with higher air permeability (30.2-30.5 s/cm³) had better water resistance (W14). These data indicate a correlation between air permeability and water resistance, which may be due to the denser structure and improved pore distribution. The study of air permeability makes it possible to predict the durability of concrete structures when exposed to moisture, as well as to improve the quality of building materials and reduce the cost of their operation.

Development of binders based on the СаО–Fe2O3 system

The object of research is the processes of structure formation and modeling of the properties of a specialized binder. The development of new binding materials based on production waste with high early strength indicators could make it possible to speed up construction period and is one of the urgent tasks at present. This study focused on the creation of binders based on the СаО–Fe2O3 system. The developed binder of the СаО–Fe2O3 system has the following composition: limestone – 26 %; red slime – 74 %, which has a dense fine-porous structure and high early strength indicators – 22.5 MPa with a density of 1960 kg/m3. There is also an increase in the average density of samples annealed at a temperature of 1200 ℃ for 60 minutes, ground and mixed with water, in comparison with samples fired at 1100 ℃ for 60 minutes, by 500 kg/m3, due to new formations. The prospect of using modified composite binders with special functional properties has been substantiated. The use of production waste based on the СаО-Fe2O3 system could make it possible to obtain materials with high physical and mechanical properties, which makes them promising for application in various areas of the construction industry. The development of such binders will help reduce the environmental impact of the construction industry, owing to the use of affordable and effective components. This approach will not only contribute to the improvement of the quality of building materials but also help reduce the ecological burden on the environment by using alternative resources and industrial waste. The developed binder could be used for the development of solutions for 3d printing, as well as repair of concrete coatings

Impedance Spectroscopy – comparison of experimental ceramic results with model parameters

Abstract Impedance spectroscopy is a non-destructive test method belonging to the group of electrical engineering measurements. The method is suitable for monitoring the quality of building materials even with low conductivity. Although the method focuses on the intrinsic conductivity of systems, most IS techniques, including data analysis methods, conceive of the material in terms of a lossy dielectric. In selecting the material for testing with the IS method, an attempt was made to bring the IS capabilities as close as possible to practical, real-world materials. This paper is devoted to a comparison of the impedance characteristics of ceramics with three types of dielectric models that are described in theory or referenced in the literature. The ceramic samples were fabricated using different material additions, such as bentonite, phosphoric acid, or sodium water glass. Experimental curves of the loss factor versus frequency for all samples are described and then approximations of selected samples are shown successively for all three models considered. Experimental results were obtained from more than 50 points in each characterization. Measurements were performed for frequencies from 40 Hz to 1 MHz.

The Rubassky architectural complex (Eastern Caucasus) of the VIII century : new data on excavations in 2023

The object of this study is a monumental hydraulic engineering structure of the late 8th century, discovered in 2014 in the lower reaches of the Rubas River, 20 km south of Derbent (Russia). Excavations have established the complex composition of this structure, which included 6 buildings of different types connected by building bundles. The functional purpose of 3 structures has been fully determined - wall No. 1, arched structure and main wall No. 2. The subject of this study is the analysis of new data on the design and functionality of 3 structures obtained during excavations in 2023 - step structure No. 6, walls No. 3 and structures No. 5 in the form of a platform.The full form of the structure No. 6 of the stepped structure has been established. Its length was 8.6 m. The methodology used by the author for substantiating chronology and functional orientation is: analysis of structural features; dating according to written sources. The study of the eastern section of wall No. 3, in the direction of the South-South was made. A preserved section with a length of 3.0 m and a thickness of 2.2 m was opened. The northern and southern facades of this section of wall No. 3 with a height of 1.4-1.5 m were constructed of large blocks installed according to the "poke-spoon" masonry system. The blockage consisted of a crushed stone. Within the excavation site of 2023, Wall No. 3 continues to the east. The length of the western and eastern sections of wall No. 3 in 2023 was 9.5 m. The southern section of structure No. 5 in the form of a platform has been studied to determine its length. A 1.5 m long section of this structure has been preserved on the new site. The total length of the facade of building No. 5 was 9.7 m, the rest of it was destroyed. Large and small fragments of stone blocks were recorded at the lower level of the excavation. Determining the functional purpose of the Rubassky architectural complex, based on its complex structure, layout, construction technology used, location in the valley of the Rubas River, as well as the high level of processing of stone blocks and the quality of building materials, is a difficult task.

Selection and application of building material suppliers based on the 2-tuple linguistic neutrosophic number combined grey relational analysis method

The quality of building materials will affect the implementation effect of construction projects. To ensure the service capacity of building materials, it is necessary to do a good job in selecting suppliers. In the specific evaluation of building material suppliers, after evaluation, suppliers with poor quality are excluded to ensure the quality of material supply, reasonably improve the construction effect of the building project, meet the construction needs of the building project, and improve the quality of the building project. The selection and application of building material suppliers (BMSs) is a multiple-attribute group decision-making (MAGDM) technique. In this study, the 2-tuple linguistic neutrosophic number combined grey relational analysis (2TLNN-CGRA) technique is constructed based on the classical grey relational analysis (GRA) and 2-tuple linguistic neutrosophic sets (2TLNNSs). Finally, a numerical example for building material supplier selection was constructed and some comparisons is constructed to illustrate the 2TLNN-CGRA technique. The main contribution of this study is constructed: (1) the 2TLNN-CGRA technique is implemented to cope with the MAGDM under 2TLNSs; (2) the 2TLNN-CGRA technique is implemented in line with the 2TLNN Hamming distance (2TLNNHD) and 2TLNN Euclidean distance (2TLNNED) simultaneously under 2TLNSs; (3) the numerical example for building material supplier selection is implemented to show the 2TLNN-CGRA technique; and (4) some efficient comparative studies are constructed with several existing decision techniques.

A geo-referenced micro-data set of real estate listings for Spain’s three largest cities

This article presents an open data product with large geo-referenced micro-data sets of 2018 real estate listings in Spain. These data were originally published on the idealista.com real estate website. The observations were obtained for the three largest cities in Spain: Madrid ( n = 94,815 observations), Barcelona ( n = 61,486 observations), and Valencia ( n = 33,622 observations). The data sets include the coordinates of properties (latitude and longitude), asking prices of each listed dwelling, and several variables of indoor characteristics. The listings were enriched with official information from the Spanish cadastre (e.g., building material quality) plus other relevant geographical features, such as distance to urban points of interest. Along with the real estate listings, the data product also includes neighborhood boundaries for each city. The data product is offered as a fully documented R package and is available for scientific and educational purposes, particularly for geo-spatial studies.

Social and seismic structural vulnerability in Zihuatanejo, Guerrero, Mexico

The spatial distribution of the social and seismic structural vulnerabilities in Zihuatanejo (ZIH), Guerrero, Mexico, was estimated. Social vulnerability was assessed considering twelve indicators, including parameters such as access to health services, education, housing, employment, and unfavorable family conditions. Seismic structural vulnerability was evaluated characterizing the structural features of local houses, assessing the type and age of construction, and the quality of building materials. Surveyed households were randomly selected from a statistically significant sample. Our findings indicate that in the western and eastern areas of ZIH the population has high and very high social vulnerability. The main factors that condition these levels of social vulnerability are low-income, female-headed families, and households with marginal access to information technology, such as internet and telephone. Although seismic ground amplification in ZIH is relatively low, the regions to the west and southwest of the city are zones where the impact of strong earthquakes to constructions may be greater than in other areas. In particular, the districts of Lázaro Cárdenas, Benito Juárez, Cuauhtémoc, Emiliano Zapata, Las Mesas, Buenos Aires, Lomas del Quebrachal, and Lomas del Riscal would be affected. In general, houses vulnerable to the impact of earthquakes are in regions where the population is socially more vulnerable. More than 50% of the population and 30% of the houses have high and very high level of social and structural vulnerability, respectively. Our results provide information to the local and federal authorities to strengthen their civil protection and mitigation plans.

Analysis of the Relationship of Domestic Sea Transportation to the Gross Regional Domestic Product of the Real Estate Sector in Indonesia

The economic slowdown due to the pandemic has negatively affected various sectors in Indonesia, including the real estate sector. Meanwhile, Java Island is still the center of the economy in Indonesia. This contrasts the conditions of regions outside Java, which are still experiencing development gaps. Despite being a minor contributor to GDP, areas outside Java, such as Maluku and Papua, have experienced rapid economic growth. This proves that, outside Java, there is still significant potential for growth and investment, although it is inevitable that it will face unique challenges and obstacles in the future. Some of the factors that cause this to happen are the lack of supporting infrastructure such as roads, limited skilled human resources, and connectivity and transportation mobilization in the area. Excellent and appropriate connectivity and mobilization are needed to support economic growth in an area. One option for mobilization tools for archipelagic countries like Indonesia is sea transportation. In meeting the needs of the property and real estate sector, sea transportation is one of the options of choice. Excellent and proper connectivity and mobilization can be a factor that supports economic growth as well as the real estate sector outside Java. In the real estate sector, maritime transportation is essential in the timely distribution of quality building materials and construction equipment to development sites. There is undoubtedly a link between marine transportation and property/real estate in Indonesia. The research method used in this study is a significant correlation analysis, namely Pearson Product Moment, to determine the relationship between two variables, namely Domestic Sea Transportation and Real Estate Sector GRDP. The results of the correlation data test in this study show that the Domestic Sea Transportation variable is positively correlated with the Real Estate GRDP variable. Indicated by the correlation coefficient value for each sea transportation variable of domestic ship visits (units) = 0.331, domestic ship visits (GT) = 0.504, the flow of Non-Crate and Container goods (unloading) = 0.251, the flow of Non-Crate and Container goods (loading) = 0.447. It can be interpreted that there is a positive relationship between the four sea transportation variables and Real Estate GRDP.

To Study the Partial Replacement of Cement by Eggshell, Chalk Powder with Addition of Basalt Fiber

Abstract: In concrete cement of Portland the aggregate are mixed with water and dry cement, they form a fluid of mass that mould easily into desired shape. The cement chemically react ingredient and water to form a matrix hard which the materials bind together into durable property stone that might use for many purpose. Use of chalk powder is also eco-friendly as the waste limestone or chalk material from industries as well as from schools and colleges, are effectively being used to form quality building materials. Basalt fiber is another solid strengthening material, which has wonderful mechanical properties and furthermore an eco-accommodating assembling process. Significantly number of examination has been directed on basalt fiber strengthened cement and has generally watched out for its mechanical properties. On the basis of previous researches which has been done we make a comparison of strength properties of concrete made with replacement and conventional concrete. Cement is replaced by Chalk, eggshell powder with addition of basalt fiber. Different specimens of the material are tested for strength. The result shows that concrete workability is fine and within limits after replacing cement with Chlak,eggshell powder with adding basalt fibers. However, workability gets reduced at higher replacement of materials. The strength parameters such as compressive strength, flexural strength, and split tensile strength also increase and show an optimum value at 8&8% cement replacement and 1.8% Addition of basalt fibers respectively. Test results are satisfactory up to 8&8% and 1.8% replacement. After this, there is a decrease in the strength of concrete. So, after this research work, we are able to find out that the replacement can be done to this extent but there may be chances of higher percentage of replacement by doing further investigations.

Structural damage observed in reinforced concrete buildings in Adiyaman during the 2023 Turkiye Kahramanmaras Earthquakes

Türkiye, located in a highly seismic region, has witnessed a history of devastating earthquakes, with unprecedented consequences noted in February 2023 when two powerful earthquakes near Pazarcik (Mw 7.7) and Elbistan (Mw 7.6) struck Southern Türkiye, resulting in extensive casualties, structural damage, and the compromised integrity of over 500,000 buildings. This study, centered on the Adiyaman region, scrutinizes the immediate structural damage to various reinforced concrete buildings, including both low-rise and tall structures. Many of the damages were attributed to structural deficiencies, including inadequate seismic reinforcement detailing, non-compliance with earthquake-resistant construction techniques, substandard concrete quality, and poor workmanship. The quality of building materials is considered a critical factor in structural resilience during earthquakes. Substandard materials or compromised quality can substantially impair a building's ability to withstand seismic forces. These key findings address a critical gap in understanding the vulnerabilities of reinforced concrete buildings in the aftermath of the 2023 Türkiye Kahramanmaraş Earthquakes. With professional rescue experience from the field, the authors bring unique insights.

Thermal performance evaluation of bio-bricks and conventional bricks in residential buildings in Aswan city, Egypt

From raw material extraction to final product disposal, the construction industry is integrally involved in every stage of the greenhouse gas emissions life cycle. One of the main causes of the climate catastrophe is the increasing use of polluting energy sources to power our homes and businesses. This massive problem of global warming has now forced countries to act. To further address sustainability, they seek to reduce energy consumption and CO2 emissions by adopting more sustainable materials. The current trend in scientific research is to use waste resources to improve the properties of various materials to exacerbate the problems of climate change because of the use of traditional building materials. Therefore, one of the most environmentally friendly alternatives to the standard procedure is the use of agricultural residues to improve the quality of building materials. This improvement will modify the thermal properties of building materials such as bricks, which will lead to an improvement in energy efficiency inside buildings, especially residential buildings. As a result, the research focused solely on simulating several bio-brick alternatives that had been discovered in earlier studies in order to test their viability in terms of increasing the energy efficiency of residential buildings in one of the hot cities. The study demonstrated that using bio-building materials can lower energy usage. In addition to saving energy in residential constructions, rice straw cement bricks and sugarcane bricks have operating efficiency rates of roughly 7% and 12%, respectively. All these advancements over conventional brick reduce greenhouse gas emissions and carbon dioxide.

Housing Satisfaction: A Comparison between Post-Second World War Large Housing Estates and Post-Socialist Multifamily Residential Neighbourhoods in Slovenia

As a reaction to the critical writings of urban sociologists regarding the quality of post-Second World War large housing estates (monotonous architectural design, cheap/poor quality building materials, high building density, minimum dwelling sizes, overcrowding, etc.), fewer problematic types of mass housing neighbourhoods started to emerge, first in Western European countries in the 1970s, and later in Eastern European countries after they abandoned the planned economy system of the communist era and adopted the market economy system. One of the major concerns often raised in this regard is that, due to a variety of negative aspects associated with post-WWII housing estates, these neighbourhoods may eventually end up as concentrations of low-income households, after the more affluent residents relocate to the more attractive, less problematic residential neighbourhoods. Such developments are, understandably, undesirable. This concern inherently assumes that the inhabitants of post-WWII housing estates are not satisfied with their housing and are, as a result, expected to move away, as soon as they can. This hypothesis presents the focus of discussion in this paper. We examine its validity with the help of the findings of a comparative study between post-WII large housing estates and post-socialist multifamily residential neighbourhoods that was conducted in Slovenia in 2021. Contrary to the hypothetical assumptions, our analyses of the research results reveal that the inhabitants of post-WWII large housing estates are (a) generally quite satisfied with their dwellings and residential neighbourhood and that (b) a large majority of them have no intention to move. Understanding people’s satisfaction with their housing circumstances requires a complex analysis of their attitudes that goes beyond surface-level observations and encompasses a broader range of psychological and social influences on housing choices, suggesting the need to incorporate these aspects into future research. The consideration of these aspects is essential in order to ensure the longer-term sustainability of post-WWII large housing estates.

Non-engineering house damage after the February 25th, 2022 West Pasaman Earthquake

The earthquake that occurred on February 25, 2022 with a magnitude of M6.2 in West Pasaman Regency, West Sumatera has resulted in many losses such as casualties and damages to infrastructure, especially residential buildings. To determine the level of damage to community houses due to the earthquake, a rapid visual assessment survey was conducted with the National Agency for Disaster Countermeasure (BNPB) and 100 Civil Engineering students. The Method used in this survey is based on the Public Work Minister Regulation, which categorizes the damaged houses into 3 categories, namely light, moderate and heavy damage. Based on the results of the assessment, the damage generally occurred on the walls and structural elements of the houses. The damages is caused by human error factors such as lack of planning, poor construction implementation, site selection and selection of quality building materials that were not in accordance with earthquake safe house building standards. One of the efforts to overcome the problem of the damage is to strengthen the house using a ferrocement layer. The level of buildings damage based on the distance from the earthquake center and the implementation of retrofitting on the damaged houses are also discussed in this paper.

Smart Material Test: Optimalisasi Pengujian Bahan Bangunan Berbasis Web

In designing material requirements, it is very important to do so that the use of materials becomes effective and efficient. Building materials are an important component in producing a reliable quality building structure. One of the efforts made to ensure the quality of building materials is to carry out material tests in the laboratory. The Palembang Aviation Polytechnic materials laboratory performs the testing procedure manually using a calculator or Microsoft Excel. Manual test calculations pose potential problems (error calculation) and must be well-documented. A materials testing calculation application is made for data processing to get better results and more efficient and effective calculations. The research aims to optimize the data processing of building materials testing using an application so that it is more efficient and effective and the data can be well documented. The material was used to calculate fine aggregate and coarse aggregate tests. The research has implemented a web-based Smart Material Test application using the programming language PHP Version 7, Laravel 8 Framework, and MySQL Database to optimize material testing that is more accurate and well-documented. The results show of testing the application, as many as 50 trials for each test found no application errors, and the average calculation difference was 0.0005 or 0.01744%. Thus, the application is very useful in assisting the calculation of building material testing.

ДОСЛІДЖЕННЯ ПЕРСПЕКТИВИ ВИКОРИСТАННЯ ЗОЛИ ВИНОСУ В БУДІВНИЦТВІ

The prospects of using fly ash, which occurs during the burning of coal in thermal power plants, in construction were studied. Fly ash is considered as a secondary product that can be effectively used to improve the quality of building materials and reduce the negative impact on the environment.The impact of ash on the strength of building materials, as well as their resistance to aggressive factors, is considered. In addition, the impact of using ash on the energy efficiency of building materials and reducing carbon dioxide emissions is considered.Ways of processing waste, which allow to significantly reduce the negative anthropogenic impact on the environment, are considered. It was found that gold and varnish waste can be used in construction, agriculture, and water treatment technologies. Ash and slag waste is most widely used in the construction industry as a ready aggregate and raw material. In particular, the use of thermal power plant slag for road construction is widespread.An overview of modern research and experience in the use of fly ash in construction is carried out, and examples of successful cases of its application are given.The research results show that the use of fly ash in construction has great potential. It allows to reduce the use of primary materials, improve the quality of construction materials and reduce the negative impact of the construction industry on the environment.In general, the use of fly ash in construction is a promising direction that contributes to sustainable development and reducing the negative impact of the construction industry on the environment. It allows efficient use of waste and ensures the creation of environmentally sustainable and energy-efficient building materials

“I have loved, O Lord, the beauty of thy house’: Magnificence and Catholic Architecture in Ireland, 1850–1900

Abstract This article explores the deliberate invocation and communication of ideas of ‘magnificence’ by Catholic building projects across Ireland between 1850 and 1900. Through an analysis of the rhetoric and discourse surrounding the construction of three case studies in Tipperary, Limerick, and Armagh, the article identifies shared concerns with articulating architectural magnificence through drawing attention to the site, on architectural detail and formal style, and the high quality of building materials. This emphasis on magnificence is examined in terms of the need to justify and legitimate expansive and expensive building and re-building projects, which often relied heavily on fundraising from communities already under financial pressure. The symbolic importance of magnificence is also explored in the context of the increased focus on the church as the central location of Catholic life and worship in the second half of the nineteenth century. Finally, the decision by Catholics to invest in magnificent architectural styles that referenced the medieval cathedrals of France and the classical grandeur of Catholic Rome is repositioned. Rather that framing this as a diffuse architectural eclecticism, the use of these diverse historical exemplars is considered as part of the need to rebuild a ruptured Catholic architectural traditional in Ireland, and to create an architectural identity that expressed triumph over past adversity, as well as confidence in Ireland’s role in spreading the Catholic faith around the world.

The impact of the ecological and climatic characteristics of the territory on the condition of the housing stock

The relevance of the subject of the work lies in the analysis of external environmental factors affecting the state of residential development. This analysis is carried out on the example of the territory of Primorsky Krai, in dynamics from 2002 to 2020. In the paper, a primary analysis of environmental factors affecting residential development is carried out and the quantitative dynamics of these factors in the aspect of Primorsky Krai is studied. In the process of research, analysis of data on temperature changes in dynamics from 2002 to 2020. indicates an increase in the deviation from the average temperature in the cold season, which has an extremely negative effect on the state of residential development due to the risk of an increase in freezing and thawing cycles, which is standard when studying the quality of building materials, in particular cement and concrete. The industrial complex is the most developed part of the economy of Primorye. Yes, according to the Federal State Statistics Service, the largest sectors of industrial production are the food industry, electric power, engineering and metalworking, which account for more than 70 percent of the total industrial production. No direct relationship was found in terms of industrial production and emissions. Therefore, here it is better to expand the number of criteria in the analysis of this trend, in particular, to supplement with such indicators as the hazard classes of emitted substances, the composition of emissions, measures taken in the field of environmental protection and their economic component. The purpose of this article is to analyze the environmental factors that affect the state of the housing stock, using the example of Primorsky Krai.

Inadequate Housing and Homelessness, With Specific Reference to South Africa and Australia

The main objective of this paper was to assess the phenomena of homelessness and inadequate housing in South Africa and Australia. The paper used a review of literature method. Findings show poor quality building materials, many people in need of housing, long waiting lists and slow delivery, and the challenges governments face in implementing and managing housing programmes effectively and efficiently are among the problems associated with the provision of adequate housing, according to the. All these factors have significantly contributed to both the proliferation of informal settlements and ever-increasing numbers of homeless population. Evidently, the successful implementation of housing programmes is hampered by a lack of political will and insufficient commitment on the part of governments to fulfil their obligations with respect to ensuring that all citizens have access to decent and adequate housing. There is a need for shifts in policy towards a more holistic approach that also includes measures to promote empowerment through self-employment and other income-related provisions.

Prevention of collapse: Analysis and Design

Throughout the ages men were engaged in construction activities besides other pursuits - to build their dwellings and shelter other activities. They willed to make these structures safe and free from collapse and hence employed various methods and designs. However in spite of all precautions it is impossible to guarantee the safety from collapse and destruction due to unforeseen causes. Some of the causes could be related to human errors like: poor design, faulty construction, foundation failures, extraordinary loads, compromising on quality of building materials, workmanship for economic reasons, negligence in enforcing building codes and their compliance laxity in supervision, inspection and approval by authorities etc. the other cause could be gas explosions, soil liquefaction, terrorist attacks, material degradations etc. It is admitted that it is uneconomical to design the structure for unforeseen events unless they have a reasonable chance of occurrence. The project study “Prevention of collapse: Analysis and design” ispresumedto help understand the collapse behavior of structure and accordingly design to prevent drastic, severe failures and save human lives and property. Secondly the practices employed to ensure safety and prevent collapse are to incorporate redundancies in structure in the form of detailing, ductile designs, tying of elements at particular locations, provision of hinges and their connections. However this study is limited to understand the outcome of failures for G+5 = buildings for column loss on different storeys, the adjacent beams, the increased loads on columns and footings studied and its resistances to failures and accordingly some measures are noted to prevent further collapse and danger.

Chemotaxonomic identification of Chamaecyparis formosensis Matsumura and Chamaecyparis obtusa var. formosana (Hayata) Rehder using characteristic compounds of wood essential oils

Chamaecyparis formosensis Matsumura and C. obtusa var. formosana (Hayata) Rehder are important, precious, and well-known species grown in Asia. Renowned for excellent natural durability, their wood logs are regularly used as quality building materials or furniture. However, these two species have similar appearances, e.g., leaf, twig, wood, hardly distinguishable by the naked eye. The purpose of the present study is to phytochemically differentiate these two species using volatile compounds from the woods. Wood essential oils were obtained by 6-h hydrodistillation. The chemical composition was identified by GC-MS, and semi-quantification was carried out to determine the content of each compound. Furthermore, compounds with a significantly higher content than those of the other species were screened by t-test and principal component analysis (PCA). Results from semi-quantification and t-test showed that C. formosensis contained higher content of cis-myrtanol (ratio 37.1 ± 19.8), chamaecynone (11.0 ± 6.7), and α-eudesmol (8.5 ± 7.9), while C. obtusa var. formosana comprised mainly of α-terpineol (30.2 ± 10.1) and borneol (24.0 ± 16.1). Moreover, PCA results showed that the representative compounds of C. formosensis were cis-myrtanol and chamaecynone, while those of C. obtusa var. formosana were α-terpineol, borneol, and α-cadinol. Taken together, the above-mentioned results suggested significant compositional differences between these two species. For distinguishing the two kinds of wood, C. formosensis should be easily identified by its two characteristic compounds: cis-myrtanol and chamaecynone; while C. obtusa var. formosana could also be distinguished by its characteristic compounds: α-terpineol and borneol.