Civil Construction Research Articles

Influence of Test Method on the Determination of Tensile Strength Perpendicular to Grain of Timber for Civil Construction.

Tensile perpendicular to grain is an important mechanical property in the design of joints in timber structures. However, according to the standards, this strength can be determined using at least two different methods: uniaxial tensile and three-point static bending. In this context, the present paper aims to investigate the influence of these test methods on the determination of tensile strength perpendicular to grain of wood used in civil construction timber. Three wood species from Brazilian planted forests (Pinus spp., Eucalyptus saligna, and Corymbia citriodora) were used in this investigation. Twelve specimens of each species were used for each test method investigated. Moreover, a statistical analysis was performed to propose an adjustment to the equation of the Code of International Organization for Standardization 13910:2014 for the three-point bending test. Tensile strength values perpendicular to grain obtained from the uniaxial tensile test were significantly higher than those determined by the three-point bending test. It is proposed that the tensile strength perpendicular to grain can be determined more precisely with adoption of coefficient 5.233 in the term [(3.75·Fult)/b·Lh] of the equation specified by the Code of International Organization for Standardization 13910:2014 for the three-point bending test.

CHARACTERIZATION OF CLT PANELS FOR CONSTRUCTION SYSTEMS

The civil construction market with wood in Brazil is growing and shows a promising future due to the availability of forests and technology. Wood offers advantages in the workability of prefabricated and semi-handcrafted components compared to masonry construction. Sustainability is an important goal for companies in the sector that invest in wood construction. It highlights the difficulty in executing wood construction in Brazil due to the lack of properly processed wood. The objective of this study was to compare the physical properties of Pinus elliottii and CLT panels. The results highlight that CLT panels significantly enhance mechanical strength compared to Pinus elliottii. Raw sawn wood is suitable for panel construction, with a C50 classification, and the elasticity results were superior to those found in the literature. The study emphasizes the importance of investing in technology and disseminating knowledge to advance in this market.

OCCUPATIONAL SAFETY IN CIVIL CONSTRUCTION OF THE STATE OF RORAIMA

This research highlights the safety of work in civil construction in the state of Roraima, with the objective of analyzing the safety practices adopted in the sector, identifying the main risks faced and assessing the effectiveness of implemented preventive measures. The methodology was based on the analysis of regulatory standards, local case studies and workers’ perception. The results showed that Roraima’s climate and geographical particularities impose additional security challenges, highlighting the importance of adapted practices and effective risk management. The conclusion points to the need to strengthen security culture in companies, with emphasis on workers’ education and training, as a way to reduce accidents and improve working conditions.

Proposed correction to the Gamma method for estimating the bending stiffness of CLT panels

Engineered wood products, such as Cross Laminated Timber (CLT), have been widely used in civil construction. Standard calculation methods, like the Gamma method commonly used in structural design, estimate the bending stiffness of elements. However, these methods are based on one-dimensional solids (bar elements), which can be limiting. This limitation may result in inaccurate estimates, especially when the panel's dimensions, measured in the median plane, significantly differ by an order of magnitude. In this research, a parametric study was carried out using the finite element method (three-dimensional approach), varying the panel's dimensions (width and length), the layers' thickness, and the number of layers (cross-section height), and adopting elastic properties considering either the wood's orthotropy or the rolling shear estimation (108 numerical simulations in all). Based on the parameterization, multiple variable regression models were used to establish a correction coefficient to be incorporated into the Gamma method to improve its accuracy in estimating bending stiffness. Therefore, the single adjusted equation (considering the wood's orthotropy) showed values closer to the numerical ones (MAPE = 0.95 %, RMSE = 2.96 × 1011 N⋅mm2, and CV = 1.60 %) than those obtained by the Gamma method (MAPE = 2.13 %, RMSE = 7.47 × 1011 N⋅mm2, and CV = 4.04 %).

Long-Term Performance of Mortars with Combined Incorporation of Ladle Furnace Slag and Metakaolin

Ladle furnace slag (LFS) is used as a supplementary cementitious material (SCM) due to its high calcium oxide (CaO) content. Its binding properties are enhanced in the presence of siliceous materials, such as metakaolin (MK), forming a ternary mixture that can directly replace ordinary Portland cement (OPC). However, despite this blend having already been evaluated in alkali-activated mixtures, knowledge about this mixture in situations of direct replacement of OPC by slag is still lacking. This study evaluates the synergistic effects of combining LFS and MK in cementitious mortars. Due to an insufficient hydration reaction observed in the short term, this study focuses on assessing the long-term performance of these mortars. Both the fresh and hardened states at 28 and 180 days are evaluated, and the resulting microstructural characteristics and constituent phases are also examined. After 180 days of curing, the mortar with MK exhibits superior binding activity compared to the results at 28 days. Although the nominal resistance does not show a clear advantage with the application of MK, a significant reduction in the porosity of the mortar is observed. Microstructural analysis indicates that the addition of MK increases the hydration compounds when mixed with LFS. Importantly, the sample containing MK and LFS showed a 42% reduction in cement consumption, highlighting the potential for resource efficiency. Thus, this study contributes to promoting a circular economy between the steelmaking and civil construction sectors.

GESTÃO DE RESIDUOS NA CONSTRUÇÃO CIVIL

The present article intends to address the importance of the waste management plan in works, aiming at the optimization of material and human resources. The civil construction sector is a great vector of social and economic development of the country, but is responsible for the growing generation of waste in the country and its inadequate disposal has caused numerous problems, promoted by the large volume generated tied the difficulties of final disposal and the risks Arising from disposal in irregular deposits. These wastes are generally generated by companies and service providers of engineering, public agencies and construction contractors. The present work sought to collect information about the losses of the lack of an RCC management plan in any construction sector. After all the research, there is a need for practices to mitigate the numerous problems, as well as the need to improve the waste management plan, presenting ways for sustainable development, such as reuse and recycling. These practices have the objectives of generating a significant economic advantage over the final destination of the deposits, reducing the amount of raw material used and consequently the generation of waste, contributing to a more rational consumption of the raw material.

MATERIALIZING THE LANDSCAPE: DRONES, GEODESY, AND 3D PRINTERS IN A VIABLE AND ECONOMIC SOLUTION FOR 3D MODELING: DRONES, GEODESY, AND 3D PRINTERS IN A VIABLE AND ECONOMIC SOLUTION FOR 3D MODELING

In recent years, environmental modeling has become increasingly crucial for understanding and mitigating the impacts of human activities on the environment. However, traditional methods for environmental mapping, primarily those of physical understanding, face challenges related to accuracy, time, and cost. In this sense, this work aimed to evaluate the technical feasibility of altimetric mapping and 3D model construction using drones, precision geodesy, and 3D printing as an extremely effective and low-cost alternative for environmental modeling. The study focused spatially on the boundaries of the IFRN/Campus Macau terrain. The study was conducted in five stages: I) Literature review; II) Geodetic survey (GNSS); III) Aerophotogrammetric survey; IV) Processing of geodetic and aerophotogrammetric data; and V) 3D printing. A protocol was obtained for the elaboration with high vertical and horizontal accuracy of the Digital Surface Model (DSM), orthomosaic, and 3D model (virtual and physical) of the mapped environment. Regarding the 3D model, its printing allowed for a perfect understanding of the geomorphology of the mapped environment and the existing physical structures. The applied technique could be useful in various areas, such as enhancing the planning stage in civil construction, architecture, and environmental studies. Also becoming a great ally in future geomorphological and tactile cartography studies.

Establishing professional accreditation pathways for Australian engineering geologists in the civil design and construction industry

Establishing professional accreditation pathways for Australian engineering geologists in the civil design and construction industry

Characterization of port dredging waste for potential used as incorporation on materials for civil construction: A case study in Brazil

Port operation activities have been expanding globally, driven by globalization and increased cargo handling. Developing countries, such as Brazil, China, and India, are experiencing a rise in the construction of modern ports. Recently, sustainability concepts have been integrated into maritime transportation, focusing on the construction and management of ports and exploring the reuse of waste generated during operations. The main objective of this study is to evaluate the potential application of the dredging material of port of açu (DMPA), sourced from a new private port in Rio de Janeiro State, Brazil, in developing sustainable construction materials. The dredged material, collected from the bottom of the shipping canal was physically, chemically, and morphologically characterized to compare its results with the processing and application requirements for alternative materials. A standard method for primary processing was developed, providing deeper insights into the material’s condition. Results indicate that the natural dredged material can be utilized as a filler in interlocking blocks or mortar. Additionally, an alternative processing route involving calcination can enhance the material's reactivity, presenting opportunities for higher-value applications, although the energy costs must be considered. The calcination of 650 °C resulted in a higher pozzolanic index, increasing its reactivity. The study concludes that port dredging waste from this case study has significant potential for use in sustainable building material development.

Feasibility study on the use of uçá crab waste in civil construction

The construction sector has undergone significant evolution in response to the needs generated by social transformations over time, experiencing various technological revolutions that have transformed the methods and materials used, from the rudimentary techniques of ancient civilizations to the technologies provided by scientific evolution. These transformations foment the demand for basic services, the search for technological and commercial innovation to continue meeting the needs of the population, which, consequently, has increased the production and accumulation of waste, especially organic waste and those from the food sector, such as the exoskeleton of the Uçá crab. The constant consumption of these crustaceans generates an abundance of waste improperly discarded in the environment, which can lead to negative impacts on fauna and flora. In short, as a form of mitigation, the partial use of Uçá crab shells in construction is proposed. Therefore, this study aims to investigate sustainability in the construction sector through the use of Uçá crab waste, through a bibliographic analysis of the topic addressed.

Waste glass as an eco-friendly substitute in plastering mortars: analyzing microstructure, thermal, and mechanical properties

This study investigates waste glass (WG) as an environmentally friendly substitute for natural sand in cement mixtures. Plastering mortars were fabricated by replacing sand with WG at proportions of 10%, 20%, and 30%. X-ray diffraction, Thermogravimetry, Scanning Electron Microscopy, and Energy-dispersive X-ray spectroscopy characterized the mortars. Compressive strength was measured at two ages (7 and 28 days) for WG-containing mortars. Results confirm the suitability of waste glass as a sand replacement in mortars, with the 20% WG sample showing optimal compressive strength, contributing to environmental and economic impact reduction. Thermogravimetric analysis of the 30% WG mortar shows a significant difference in mass loss percentages compared to the reference mortar, losing only 3.65% at 28 days versus 7.85%. Additionally, waste glass increased mortar density, reducing porosity and enhancing structural uniformity. Despite a decrease in compressive strength values, the results remain satisfactory for application in the Civil Construction industry. This comprehensive exploration underscores the potential of waste glass as a sustainable alternative, emphasizing its positive effects on both performance and environmental considerations.

Sustainability in the Efficiency of Water and Energy Use in Civil Construction: an Analysis of Vertical Residential Projects in the City of Maringá-PR

Sustainability in the Efficiency of Water and Energy Use in Civil Construction: an Analysis of Vertical Residential Projects in the City of Maringá-PR

Концепция экологической цивилизации в Конституции КНР

Since the 18th National Congress of the CPC in 2012, China has been actively promoting the construction of ecological civilization. In 2018, the concept of “ecological civilization” was enshrined in the Constitution of the PRC. At present, building “ecological civilization” has become the legislative goal of many laws in China, and China has also established special tribunals for environmental protection and conservation of ecological resources, which provide judicial specialization of environmental protection. The construction of “ecological civilization” is conducive to the protection of the earth’s three major ecosystems: wetlands, forests and oceans. Enshrining the concept of “ecological civilization” in the Constitution of the People’s Republic of China is of great significance to ensure China’s rule of law in the environmental field and presents China’s experience to the world.

The mechanism and path of pollution reduction and carbon reduction affecting high quality economic development - taking the Yangtze River Delta urban agglomeration as an example

In the wake of the COVID19 pandemic, what is crucial for the continued promotion of ecological civilization construction and sustainable green development in China is to achieve the dynamic and balanced development between pollution reduction, carbon emission reduction, and economic growth. Therefore, the indexes of CO2 emissions, pollution reduction intensity, and high-quality economic development are quantified in this study by using the panel data related to 26 cities in the Yangtze River Delta urban agglomeration(YRDUA) from 2010 to 2020. Furthermore, kernel density analysis, GIS spatial analysis, and other methods are employed to demonstrate the spatial and temporal patterns of pollution reduction intensity, CO2 emission levels, and the characteristics of high-quality economic development in the YRDUA. In order to reveal the dynamic relationship between pollution reduction, carbon emission reduction, and high-quality economic development, a panel vector autoregressive model (PAVR) was established and the system generalized method of moments was used to estimate the model coefficients. Additionally, Granger causality tests, impulse response analysis, and variance decomposition were conducted. There is a fluctuating upward trend shown by the overall level of CO2 emissions in the YRDUA, with significant spatial nonuniformity exhibited in carbon emissions. Despite the self-promotion mechanism playing a more significant role in the high-quality economic development in the YRDUA and its three regions, the impact of pollutant and carbon emissions on high-quality economic development is quite limited. A significant promoting effect is exhibited in those high and moderately high-quality economic development regions, while nonlinear effects are observed in those high and moderately high-quality economic development regions. As for the interactive relationships, the three factors are correlated with each other to a more significant extent in those high and moderately high-quality economic development regions, which contributes to mutual influence and causal relationship. However, there is no effective interactive mechanism observed among the three factors in the whole area and low-quality economic development regions, with high-quality economic development playing a major role in environmental pollution and carbon emission reduction.

Using crushed stone dust as a substitute for fine aggregates in concrete

Generation of waste from mining and high consumption of natural aggregates resulting from civil construction works have significant economic and environmental impacts. Aiming to use the stone dust residue from the rock crushing process, this study experimentally evaluates the use of crushed stone dust as a partial substitute for fine aggregates in concrete with a compressive strength of 30 MPa, thus providing an alternative in civil construction activities. Crushed stone dust was evaluated through physical, chemical, mineralogical, petrographic, and micromorphological characterization tests. The characterization results indicated that the material is classified as medium and fine sand, with 68.2% silicon dioxide and quartz peaks, i.e., similar to natural sand. Axial compression tests were performed on twenty cylindrical specimens with diameters of 100 mm and heights of 200 mm, broken at 28 days. Five of such specimens were made of reference concrete, without stone dust, while fifteen contained concretes with stone dust. In this approach, the percentage of stone dust in the concrete specimens ranged between 20%, 50%, and 100%, and compressive strength was kept constant at 30 MPa, with five cylinders with stone dust for each percentage of sand replacement. The results show the contribution of stone dust to the mechanical behavior of the concrete specimens, which corroborate the possibility of applying it as a substitute for fine aggregates, as compressive strength was higher in the concrete specimens with 20% and 50% stone dust compared to the reference concrete.

Coupling Relationship Between Rural Eco-Environment and Tourism Economic Development Based on Data

With the rapid development of economy, the contradiction between the ecological environment and economic development has become increasingly serious. The ecological environment is the foundation and prerequisite for the development of rural tourism, which promotes the rural ecological environment. The coordinated development of the two is of great significance to the sustainable development of rural tourism and the construction of rural ecological civilization. On the basis of combing the existing related research results, by constructing a rural tourism-ecological environment evaluation index system, using a coupling coordination degree evaluation model, this paper makes a comparative analysis of coupling degree and coordinated scheduling. The results show that there are obvious inter-annual differences in the coupling and coordination of rural tourism and the ecological environment in the county, and the overall development trend is positive. However, the coupling degree and coordination between the two is still at a relatively low level.

Spatial Correlation of Landscape Fragmentation and Ecological Sensitivity in China’s Giant Panda National Park and Surrounding Areas

The Giant Panda National Park (GPNP) and its surrounding areas constitute a comprehensive ecosystem aimed at protecting the natural habitat of giant pandas, maintaining biodiversity, and ensuring ecological balance. Investigating the spatial correlation between landscape pattern indices and ecological sensitivity (ES) in this area is a crucial step in the construction of ecological civilization and contributes significantly to ecological conservation, restoration, and environmental management. This study utilized Geographic Information Systems (GIS) and Fragstats software to select nine ecological evaluation factors and four landscape pattern indices to comprehensively evaluate the ES and landscape patterns of the GPNP and its surrounding areas. This study discovered that the ecological sensitivity of the GPNP is substantially higher than that of the neighboring areas, with the northern Qionglai Mountain area and the western Minshan area showing the highest concentrations of exceptionally high sensitivity. Highly sensitive areas account for 35.22% of the study region, concentrated in areas within the national park, except the Qinling area, as well as the western and southern surrounding areas. The distribution of moderately sensitive areas is more uniform, while low and insensitive areas are found primarily in the northern and eastern areas, along with the national park’s environs. Patch density (PD) within the GPNP is lower than in surrounding areas, with higher PD in the northern and central parts. The landscape division index (DIVISION) decreases from west to east, and the landscape disturbance index (LDI) is significantly lower within the national park than in surrounding areas, with small areas of high LDI in the entire study region. Moran’s index analysis of the GPNP and its surrounding areas shows that ecological sensitivity is positively correlated with landscape pattern indices (PD, SPLIT, DIVISION, and LDI), with the strongest correlation between DIVISION and ecological sensitivity. Spatially, the internal areas of the national park have lower landscape pattern indices but higher ecological sensitivity, while the eastern region exhibits severe landscape fragmentation. Major clusters of high and low values are found around the Qionglai-Daxiangling area, indicating that these areas of high ecological sensitivity have complex landscape structures, numerous habitat edges, and significant impacts on biodiversity and ecological processes. Overall, the areas surrounding the GPNP exhibit lower ecological sensitivity levels and higher landscape fragmentation, emphasizing the need for focused ecological protection in the northern part of the QLS region and the western part of the MS region. Additionally, attention should be given to the impact of landscape fragmentation in the surrounding areas in the interior of the GPNP. These results provide scientific evidence for the sustainable development of the GPNP and its surrounding areas.

James O 'Connor's Ecological Thought and its Practical Enlightenment

James O 'Connor's ecological thought was born in the middle and late 20th century. By using the unique theory of double contradiction and double crisis of capitalism, James O 'Connor revealed the global ecological crisis caused by the development of capitalism, outlined a new model of ecological socialism, and tried to find a feasible path to solve the global ecological crisis. To mitigate the adverse effects of the ecological crisis on the capitalist world. James O 'Connor's ecological thought has been widely discussed by the academic community since it was put forward. Subsequently, many scholars in the field of ecology have analyzed and studied James O 'Connor's thought. Through the organic combination with the current actual situation and practical experience, they began to apply James O 'Connor's ecological thought to the management of ecological problems. The construction of ecological civilization in our country is also developing continuously, and O 'Connor's ecological thought has a very positive enlightening and instructive significance to the construction of ecological civilization in our country.

Establishment of an Evaluation Indicator System and Evaluation Criteria for the Weihe River Ecological Watersheds

Ecological watersheds (eco-watersheds) are of great significance for boosting the construction of ecological civilization and realizing the ecological protection and high-quality development of watersheds. In order to establish a scientific eco-watershed evaluation index system, this paper refers to the river health evaluation index system, the water resources coupling evaluation index system, and the happy river evaluation index system, and reviews the development process of the ecological watershed evaluation index system. According to the eco-watershed theoretical system, combined with the relevant contents of policies and regulations, thousands of evaluation indicators that have been collected are screened using the theoretical analysis method and the frequency analysis method. Finally, a comprehensive evaluation index system of Weihe River eco-watersheds was constructed, including three first-level indicators: watershed water resources, socio-economic, and ecological. These were further subdivided into eight second-level indicators, namely water security, water resources, water economy, water management, water culture, water environment, water ecology, and water landscape. These second-level indicators were then further broken down into 60 third-level indicators. On the basis of determining the evaluation standards of Weihe River eco-watersheds, the evaluation weights were determined using the gray correlation method and the AHP-entropy comprehensive weight method (comprehensive weight), resulting in the establishment of an evaluation model and a coupling model for the eco-watersheds of the Weihe River. The results of the Weihe River eco-watershed evaluation model and the coupled coordination degree evaluation model show that, from 2019 to 2021, both the gray correlation analysis weights and comprehensive weight evaluation show a yearly increasing trend; the evaluation results are in the eligible status and below; and the evaluation grade is in the fourth-level eco-watersheds and below. Based on the evaluation results of each dimension, when comparing the gray correlation analysis weights with the evaluation of the comprehensive weights, the latter align more closely with the actual Weihe River Watershed. When comparing the evaluation results of the Henan Weihe River Watershed with those of the Handan Weihe River Watershed, the latter’s results, influenced by the scheduling of the Yuecheng Reservoir, are relatively better. Furthermore, in the evaluation of coupling coordination, the water resources subsystem is less coupled to other subsystems due to the 2021 flood. Therefore, in order to effectively improve the level of eco-watersheds, scientific and reasonable water resources scheduling programs should be developed.

Research on Carbon Emission Right Accounting Issues and Countermeasures

Against the backdrop of global climate change, China is actively promoting the construction of an ecological civilization and green and low-carbon development, and the accounting treatment of carbon emissions trading, as one of the important market mechanisms to achieve this goal, has become increasingly prominent. Although China has issued a number of accounting guidance documents on carbon emission rights trading, there are still a number of challenges and shortcomings, which limit the accuracy and comparability of accounting information and affect market participants' perception of the value of carbon emission rights. This paper firstly outlines the international accounting confirmation and measurement methods for carbon emission rights allowances, and comparatively analyzes China's current relevant regulations, pointing out the controversial points and deficiencies therein. In response to the above problems, this paper puts forward specific suggestions for improvement in the expectation that, to help the development of China's carbon emission right trading accounting system, to improve the quality of China's carbon emission right trading accounting system, to promote the healthy development of the entire carbon market, and to provide a solid accounting foundation for the realization of China's carbon neutrality goal.