| 1. |
- Al-Shami, Qahtan, et al.
(författare)
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Efficient numerical simulations on the forest barrier for seismic wave attenuation: engineering safe constructions
- 2024
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Ingår i: Frontiers in Built Environment. - : Frontiers Media S.A.. - 2297-3362. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims to elucidate the clear visibility of attenuating seismic waves (SWs) with forest trees as natural metamaterials known as forest metamaterials (FMs) arranged in a periodic pattern around the protected area. In analyzing the changeability of the FM models, five distinct cases of “metawall” configurations were considered. Numerical simulations were conducted to study the characteristics of bandgaps (BGs) and vibration modes for each model. The finite element method (FEM) was used to illustrate the generation of BGs in low frequency ranges. The commercial finite element code COMSOL Multiphysics 5.4a was adopted to carry out the numerical analysis, utilizing the sound cone method and the strain energy method. Wide BGs were generated for the Bragg scattering BGs and local resonance BGs owing to the gradual variations in tree height and the addition of a vertical load in the form of mass to simulate the tree foliage. The results were promising and confirmed the applicability of FEM based on the parametric design language ANSYS 17.2 software to apply the boundary conditions of the proposed models at frequencies below 100 Hz. The effects of the mechanical properties of the six layers of soil and the geometric parameters of FMs were studied intensively. Unit cell layouts and an engineered configuration for arranging FMs based on periodic theory to achieve significant results in controlling ground vibrations, which are valuable for protecting a large number of structures or an entire city, are recommended. Prior to construction, protecting a region and exerting control over FM characteristics are advantageous. The results exhibited the effect of the ‘trees’ upper portion (e.g., leaves, crown, and lateral bulky branches) and the gradual change in tree height on the width and position of BGs, which refers to the attenuation mechanism. Low frequency ranges of less than 100 Hz were particularly well suited for attenuating SWs with FMs. However, an engineering method for a safe city construction should be proposed on the basis of the arrangement of urban trees to allow for the shielding of SWs in specific frequency ranges.
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| 2. |
- Abdulhameed, Ali A., et al.
(författare)
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Experimental and environmental investigations of the impacts of wood sawdust on the performance of reinforced concrete composite beams
- 2023
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Ingår i: Case Studies in Construction Materials. - : Elsevier Ltd. - 2214-5095. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- It has been established that using recycled materials to replace some of the fine aggregates is a viable solution. Most researchers focused on the durability aspect of wood sawdust concrete, while less information is available on its structural performance. Therefore, this article aimed to investigate the performance of reinforced concrete beams fabricated from concrete with a partially replaced fine aggregate (FA) by wood sawdust (WS) in the range of 5–45 % (by weight). Six beams underwent 4-point bending tests till collapse. The beams' slump, density, compressive strength, cracking and failure mode, energy absorption, and economic and environmental aspects were studied. The findings showed that the failure region of sawdust concrete was more significant than the reference samples. Despite the compressive strength of the concrete containing different ratios of sawdust being reduced by about 7–30 %, the target compressive strength still has a limit of low to normal concrete grade. The results show that the increase in sawdust percentages decreased the acquired absorbed energy of the subjected load to reach failure. A cost reduction of 9 % and a cost index of 61 % is achieved using wooden sawdust-based concrete. By substituting sawdust for fine aggregate, the sustainability of sawdust concrete in terms of cost and environmental advantages may be improved. In addition, it is well-known that harnessing the transformative potential of industrial waste in concrete production not only minimizes landfill usage, but also promotes resource efficiency, reduces carbon emissions, and advances the circular economy, propelling designers, engineering and builders towards a greener and more sustainable future in the construction industry. According to the test findings, wood sawdust may be utilized to produce normal and low-strength structural concrete.
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| 3. |
- Agrawal, Dhiraj, et al.
(författare)
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Optimization of eco-friendly concrete with recycled coarse aggregates and rubber particles as sustainable industrial byproducts for construction practices
- 2024
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Ingår i: Heliyon. - : Elsevier. - 2405-8440. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- In this technology era, sustainable construction practices have become quite imperative. The exploration of alternative materials to reduce the environmental footprint is of paramount importance. This research paper delves into an exhaustive investigation concerning the utilization of recycled coarse aggregates (RCA) and rubber particles (RP) in concrete. It contributes to the growing body of knowledge aimed at fostering sustainable development in the construction industry by reducing waste, promoting recycling, and mitigating the environmental footprint of building materials. The objective of the study is to evaluate the potential benefits and limitations associated with incorporating these materials, thereby providing a sustainable alternative to conventional concrete. In this research, construction and demolition waste were recycled and used as RCA as a fractional switch of natural coarse aggregate (NCA) from 0% to 100%, with an increment of 20% replacement of NCA in concrete. The RP received from discarded tires generated as automobile industry waste were used as a volumetric fractional substitution of sand in concrete from 0% to 20%, with a 5% increment. No pre-treatment for RCA and RP was carried out before their utilization in concrete. A total of 26 mixes, including control concrete without NCA and RP, with a design strength of 40 MPa, were prepared and tested. Concrete mixes were examined for workability, density, mechanical, and durability properties. It was found that the concrete with 60% RCA and 10% RP showed satisfactory results in evaluation with the strength parameters of control concrete, as the compressive strength obtained for this concrete mix is 40.18 MPa, similar to the control mix. The optimization for RCA and RP was conducted using Response Surface Methodology (RSM). The major concern observed was a rise in water absorption with an increase in the percentage replacement of NCA and natural sand by RCA and RP. Findings from the investigation illustrate a promising prospect for the use of RCA and RP in concrete applications, displaying competent mechanical properties and enhanced durability under certain conditions, offering a viable option for environmentally friendly construction practices. However, the research also sheds light on some constraints and challenges, such as the variability in the quality of RCA and the necessity for meticulous quality control to ensure the reliability and consistency of the end product. It is discerned that further refinement in processing techniques and quality assurance measures is pivotal for mainstream adoption of RCA and RP in concrete construction.
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| 4. |
- Alshaeer, Honin Ali Yahya, et al.
(författare)
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Optimisation of compressive strength of foamed concrete with a novel Aspergillus iizukae EAN605 fungus
- 2023
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Ingår i: Case Studies in Construction Materials. - : Elsevier. - 2214-5095. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- The production of concrete by incorporating a microorganism has emerged as a promising research area, offering potential benefits such as reduce carbon footprint, enhance durability and increased strength. The present study reported for the first time using a fungal strain (Aspergillus iizukae EAN605) in biocementation. The study aims to investigate the effectiveness of incorporating Aspergillus iizukae EAN 605 into foam concrete to improve its performance, particularly its strength. The study employs the response surface methodology (RSM) to explore the relationship between density, microorganism concentration and water /cement ratio (w/c) and their effects on compressive strength. Through a series of experiments,the highest recorded compressive strength was achieved with a density of 1800kg/m3, w/c ratio of 0.5, and Aspergillus iizukae EAN605 concentration of 0.5g/l, resulting in a remarkable 37.5% increase compared to foam concrete (FC). The variables of density, A. iizukae EAN 605 and their interaction density*fungi (D*F) significantly impacted compressive strength, with p-values of 0.000, 0.016, and 0.010, respectively.X-ray diffraction (XRD) analysis was employed to identify the crystalline composition of the precipitates formed on the fungal hyphae, providing insights into the mineralogical transformations occurring during the biocementation process. Additionally, scanning electron microscope (SEM) imaging was utilised to visualise the morphology and distribution of the calcite crystals, further supporting the evidence of fungal-mediated mineral precipitation in foam concrete. The findings of this study hold significant implications for the concrete industry, as the incorporation of Aspergillus iizukae EAN605 in foam concrete offers a sustainable solution to enhance compressive strength and contribute to environmental friendly construction practices. This study provides valuable insights for future research and practical applications in the field of bio-foamed concrete (B-FC).
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| 5. |
- Amran, Mugahed, et al.
(författare)
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Shrinkage mitigation in alkali-activated composites: A comprehensive insight into the potential applications for sustainable construction
- 2023
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Ingår i: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 20
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Forskningsöversikt (refereegranskat)abstract
- The extant body of literature articulates a noticeable disparity in the susceptibility to cracking and concomitant material degradation between alkali-activated composites (AAC) and ordinary Portland cement (OPC), predominantly attributable to shrinkage and subsequent drying phenomena. This divergence derives from the nanoscopic porosity of AAC binders, which is substantially finer than their OPC counterparts. However, experimental research validates that the judicious incorporation of alternative cementitious materials and fibrous reinforcements enriches the shrinkage characteristics of AAC, thereby enhancing its overall structural performance. Given the crucial role of shrinkage in defining the material integrity of AAC, especially under constrained environmental conditions, an in-depth understanding of shrinkage mechanisms materializes as a necessity for conceiving efficient shrinkage-mitigating strategies. In light of the growing interest in optimizing AAC through various material integrations and methodological innovations aimed at shrinkage diminution, this scholarly review undertakes an extensive synthesis of the laboratorial investigations focused on AAC shrinkage behavior and mitigation. However, this article critically evaluates widespread strategies for shrinkage mitigation, explicating their operative mechanisms. Moreover, it is outlined gaps in the existing research paradigm, promoting for targeted scholarly endeavors to yield a more clear understanding of shrinkage dynamics and to facilitate the advancement of environmentally sustainable AAC composites. Meanwhile, this study intended to consolidate existing research on developing trends in order to gain a comprehensive understanding of the possible uses of AACs and identify viable strategies for addressing AAC shrinkages. By addressing the challenges related to micro-cracking and shrinkage, the long-term durability of AACs may be improved, leading to increased adoption of these materials as sustainable building options in the construction industry today.
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| 6. |
- Iftikhar, Bawar, et al.
(författare)
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Experimental study on the eco-friendly plastic-sand paver blocks by utilising plastic waste and basalt fibers
- 2023
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Ingår i: Heliyon. - : Elsevier. - 2405-8440. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- Plastic waste poses a significant hazard to the environment as a result of its high production rates, which endanger both the environment and its inhabitants. Similarly, another concern is the production of cement, which accounts for roughly 8% of global CO2 emissions. Thus, recycling plastic waste as a replacement for cementitious materials may be a more effective strategy for waste minimisation and cement elimination. Therefore, in this study, plastic waste (low-density polyethylene) is utilised in the production of plastic sand paver blocks without the use of cement. In addition to this, basalt fibers which is a green industrial material is also added in the production of eco-friendly plastic sand paver blocks to satisfy the standard of ASTM C902-15 of 20 N/mm2 for the light traffic. In order to make the paver blocks, the LDPE waste plastic was melted outside in the open air and then combined with sand. Variations were made to the ratio of LDPE to sand, the proportion of basalt fibers, and sand particle size. Paver blocks were evaluated for their compressive strength, water absorption, and at different temperatures. Including 0.5% percent basalt fiber of length 4 mm gives us the best result by enhancing compressive strength by 20.5% and decreasing water absorption by 50.5%. The best results were obtained with a ratio of 30:70 LDPE to sand, while the finest sand provides the greatest compressive strength. Moreover, the temperature effect was also studied from 0 to 60 °C, and the basalt fibers incorporated in plastic paver blocks showed only a 20% decrease in compressive strength at 60 °C. This research has produced eco-friendly paver blocks by removing cement and replacing it with plastic waste, which will benefit the environment, save money, reduce carbon dioxide emissions, and be suitable for low-traffic areas, all of which contribute to sustainable development.
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| 7. |
- Sewar, Yousef, et al.
(författare)
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Bonding strength performance of bamboo-based composite materials: An in-depth insight for sustainable construction applications
- 2024
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Ingår i: Heliyon. - : Elsevier Ltd. - 2405-8440. ; 10:13
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Forskningsöversikt (refereegranskat)abstract
- This review systematically examines the multitude of factors influencing bonding strength in bamboo-based composite materials, given the rising prominence of bamboo as a green building material. With bamboo's inherent variability in mechanical properties and structure, engineered bamboo products have emerged to address challenges related to connections and joints. Such advancements have necessitated a detailed exploration of adhesive systems, a significant cost determinant in bamboo production. The adhesive bonding mechanism in bamboo, akin to wood, involves intricate processes including adhesive spreading, penetration, and solidification, influenced by the unique chemical composition of bamboo. The interfacial bond quality plays a pivotal role in determining the durability and performance of the final products, with numerous factors such as bamboo species, layered structure, adhesive type, and treatment types impacting the mechanical properties. Particular attention is given to the disparities in physical and mechanical properties between the bamboo culm's core and shell layers, attributing complexities to the gluing process. Examining shear failure strength reveals its criticality in mechanical investigations, with variations in bonding strength affecting the outcome. The review underscores the need for consistent quality control and adept manipulation of these influential factors for the successful manufacture of bamboo-based products. A comprehensive discussion ensues on the variables controlling the bonding properties of the developed bamboo products, aiming to evaluate and highlight the optimal parameters and procedures essential for enhancing the quality and reliability of bamboo-based composite materials for sustainable construction applications.
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| 8. |
- Waghe, Uday, et al.
(författare)
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Enhancing eco-concrete performance through synergistic integration of sugarcane, metakaolin, and crumb rubber : Experimental investigation and response surface optimization
- 2023
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Ingår i: Journal of Engineering Research. - : Elsevier. - 2307-1877.
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable construction has gained paramount importance due to the consideration of the devastating effects of construction activities on the environment. Researchers are exploring innovative approaches to mitigate the carbon footprint and enhance the durability of concrete. In order to regulate the demand and cost of concrete constituents, such as cement and sand, there is a need to invent alternative materials and utilize various industrial and agricultural wastes instead of concrete ingredients, either partially or completely. The experimental investigation and optimization of eco-concrete composites by integrating sugarcane bagasse ash (SCBA), metakaolin (MK), and crumb rubber (CR) are cutting-edge research areas that aim to develop environmentally friendly and high-performance concrete materials. The present research work has attempted to utilize SCBA up to 15% by weight of cement with an increment of 5%, MK as a fractional exchange of cement up to 15% with 5% intervals, and CR was utilized as fractional volumetric substitution of sand from 0% to 15% in concrete. Different sets of combinations were evaluated to identify effects on density, workability, compressive strength, split tensile strength, flexural strength, and microstructural properties. This study has obtained satisfactory results when compared to the control concrete for 10% substitution of cement with MK and 10% substitution of cement with SCBA, along with a 10% replacement of fine aggregate (i.e., sand) with CR. The results were analyzed and optimized using Response Surface Methodology (RSM), which illuminated a strong correlation between experimental findings and RSM models, with an R squared (R2) value of 0.9580. The experimental findings and RSM models showed a significant correlation. The increment in the substitution of sand with CR resulted in a decline in strength, and it can be controlled by adopting different effective pretreatment techniques for CR.
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