Vol.5,No.1,2025-Table of Contents

 

  • Experimental and numerical study on the flexural performance of reinforced laminated bamboo lumber beams with prestressed GFRP bars
  • Abstract This paper presents a new method to strengthen laminated bamboo lumber (LBL) beam by embedding prestressed glass fiber reinforced polymer (GFRP) bars at the bottom of LBL beams. The bending test of 30 LBL beams with a size of 2000 mm × 100 mm × 150 mm was carried out with the prestress level and reinforcement ratio as the influencing factors. The test result shows that the failure mode of prestressed LBL beams is mainly the fracture of bamboo fibers at the bottom of the beams. Embedding prestressed GFRP bars in the specimens is a good way to enhance the mechanical properties of LBL beams, including flexural capacity and stiffness. The ultimate bearing capacity of prestressed GFRP bars composited beams are increased to 40.6%, and the bending stiffness are increased by 22.5% comparing with ordinary beams. Based on the test results, a theoretical calculation model for the bearing capacity of the LBL beam was finally proposed, and the calculation results were basically consistent with the experimental results. Finite element modelling (FEM) using continuum damage mechanics was also adopted to verify the failure pattern and the strengthening mechanism of strengthened LBL beams.… More
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  • High performance synthetic fiber-reinforced concrete mixed with nanoparticles: A proof-of-concept green railway sleeper product
  • Abstract This paper investigates the effects of nanoparticles and fibers on the durability and microstructural properties of mortar and concrete, aiming to create a high-performance railway sleeper product as an alternative sustainable material in the market. In the Phase 1, the main objective is to evaluate the effectiveness of nanoparticles, such as nano alumina (NA) and nano silica (NS), at 1%, 3%, and 5% additions, along with rice husk ash (RHA) and ground granulated blast furnace slag (GGBFS) in terms of strength and durability performance. To further enhance structural integrity, the study incorporates fibers such as polypropylene fiber (PPF) and polyvinyl alcohol fiber (PVA) at a constant volume fraction of 0.5%. The hybridization of NA and NS with PPF and PVA fibers was developed and analyzed through scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) analysis. The mechanical property tests revealed that hybrid nanoparticles enhanced compressive strength by 15% compared to control and mono nanoparticle composites. Durability tests, including water absorption, rapid chloride penetration, and water penetration, showed that adding 5% hybrid nanoparticles and 0.5% fibers resulted in high strength (17.81%) and significant pre refinement. In Phase 2, a proof-of-concept green railway sleeper was developed using 100% recycled aggregate concrete (RAC), reinforced with glass fiber-reinforced polymer (GFRP) and the hybrid fibers from Phase 1, demonstrating enhanced mechanical properties and durability. Additionally, finite element crack analysis using Abaqus® software provided an in-depth understanding of sleeper performance, revealing improved crack resistance under operational fatigue loading and reduced maintenance costs. This innovative approach showcases a sustainable product with superior performance, addressing both environmental and structural challenges in railway infrastructure.… More
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  • Optimizing fly ash and rice husk ash as cement replacements on the mechani-cal characteristics of pervious concrete
  • Abstract Replacing cement with fillers while being environment-friendly contributes to the performance enhancement of conventional concrete. In the investiga-tion, nine batches of concrete mix were prepared with different amounts of cement, fly ash (FA) and rice husk ash (RHA). This experiment investigated the consequence of substituting cement with FA at various water-to-binder (W/B) proportions. The FA content was ranged from 5% to 20% of cement by weight, and the W/B ratio was adjusted to 0.3, 0.35, 0.4, and 0.45. Further-more, for 10% cement replacement, FA and RHA combination of 10:0, 7.5:2.5, 5:5, 2.5:7.5 and 0:10 by weight were used. When FA alone was used as cement replacement, the optimal mix achieved a 28-day compressive strength of 31.33 MPa at a W/B ratio 0.40 with 10% FA. Moreover, incorpo-rating FA and RHA resulted in a cost reduction of approximately 15% per cubic meter of concrete and a decrease in CO₂ emissions by 20% compared to conventional concrete production. The findings demonstrate that FA and RHA can be effectively combined to manufacture pervious concrete that enhances performance, reduces costs, and minimizes environmental pollu-tants.… More
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  • Seismic energy dissipation capacity of confined concrete columns with infilled-AAC bricks subjected to quasi-static cyclic loading
  • Abstract Autoclaved Aerated Concrete (AAC) is still designated as a non-engineering material because it is considered not to contribute to the stiffness and strength of structural members and is considered limited to infilling material within structural building frames. This provision needs to be reviewed because based on several studies its contribution to the stiffness and strength of the building structure is quite significant. This study involved tests of confined concrete column specimens infilled with AAC. The results indicate that its capability to dissipate the earthquake energy still satisfies all three criteria of the ACI 374.1-05 provisions, such as capability to carry loads > 0.75Ph-max, relative energy dissipation ratio (β) > 0.125, and gradient hysteresis loop limited by drift ratio limit (-0.35% and +0.35) > 0.05. Apart from that, it is also able to enhance the column ductility to reach up to 9.285 (greater than 4), which is categorized as high ductility criteria in FEMA 356. All test columns in the study failed in flexural modes as designed (no shear failures occurred).… More
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  • Study on seismic performance of high-strength steel earthquake-resilient beam-column joint with double damage elements
  • Abstract The mutual constraint between bearing capacity, stiffness, and post earthquake recoverability has always been the contradiction of earthquake resilient joint. Taking into account the above three factors, this paper proposes a high-strength steel earthquake resilient beam column joint with double damage elements. Low cycle reciprocating loading tests were conducted, and a refined finite element model was established for parameter expansion analysis. The research findings show a significant time sequence in the joint double damage element, with both components dissipating over 90% of energy. In contrast, main components like beams and columns dissipate less than 10% of energy. The residual deformation of the joints is within the specified DS2 level limit in the FEAM P-58 standard, indicating excellent post-earthquake recoverable performance. The influence of the length lb of the energy dissipation section in the middle of the flange cover plate, the height hs of the stiffening rib, the length lc of the cantilever beam, and the cutting angle αa of the butterfly damper on the joint performance was studied. The results show that lb significantly affects the loading stability of the flange cover plate, thereby affecting the joint performance. It is recommended to ensure that the stability coefficient of the flange cover plate is not less than 0.967; Considering all factors, it is recommended that hs be taken as 0.2 times the width of the flange cover plate, lc be taken as 1.3 times the height of the beam, and αa taken as 50°. Finally, a calculation method for the joint trilinear skeleton curve model was proposed through theoretical derivation and data fitting. By comparing the theoretical calculation results with experimental and finite element calculation results, it was found that the curves matched well, proving the effectiveness of the proposed joint skeleton curve calculation method.… More
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  • Transforming waste into strength with recycled tire steel fibers for superior concrete performance
  • Abstract Despite extensive research on using waste tire fibers in concrete, a detailed examination of flexural toughness, impact resistance, and optimized fiber dosage for applications in high-stress industrial floors and slabs remains limited. This study uniquely focuses on maximizing these properties by varying waste tire steel fiber content to determine the ideal mix for enhanced performance in concrete, providing a sustainable alternative to conventional steel fibers. The fibers’ diameter was 0.82mm and length was equal to 50 mm with an aspect ratio of 61. A design mix with compressive strength equal to 25-30 MPa at different dosages of fibers i.e., 0.5%, 1%, and 1.5% by volume of concrete was prepared and results were compared with control concrete samples for applicability in slabs on grade and industrial floors. Workability was reduced by fiber addition, but SP was adjusted to achieve the target slump. Split tensile strength, compressive strength, and flexure strength were improved with maximum values at 1.5% fiber content. Post-peak behavior and toughness were significantly improved by adding fibers. Impact resistance results were also promising for the first crack and ultimate failure.… More
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  • Behavior of eco-friendly concrete reinforced with hybrid recycled fibers
  • Abstract Recycling waste materials is a crucial strategy to reduce landfill disposal. The emission of greenhouse gases like methane and carbon dioxide into the atmosphere by landfills is well-known to be harmful to both people and the environment. Urgent action is required to address the pressing social and environmental issue of how to dispose of used tires. This study aimed to develop an eco-friendly concrete (EFC) mix that uses recycled aluminum cans and tire wire as reinforcement. Examine how EFC's workability and mechanical qualities are impacted by recycled fibers as well. Ten concrete mixes were experimented with in this research and divided into three groups. Three mixes contain 0.5%, 1%, and 2% of the aluminum can fibers (ACF), and three mixes include 0.5%, 1%, and 2% of tire wire fibers (TWF), three mixtures incorporate 0.5%, 1%, and 2% of hybrid recycled fibers (HRF) of both ACF and TWF, in addition, control mix. The workability and mechanical tests of eco-friendly concrete were investigated. The experimental results show that the recycled fiber volume fractions (RFVFs) are inversely proportional to the concrete workability. The recycled fibers don’t reveal any significant effects on the compressive strength and the elastic modulus of concrete. All recycled fiber ratios improved the concrete behavior for tensile and flexural resistance. The development ratio of concrete mix containing 1% TWF reached 53.2% and 62.4% for tensile and flexural strengths, respectively. It can be noticed that the recycled fibers are enhancing the failure of the concrete matrix to become ductile failure rather than brittle behavior. However, the recycled fibers have arrested the development of cracks in the internal concrete structure.… More
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  • Mechanical behavior of additive manufactured wood-based composites for construction
  • Abstract Additive manufacturing of composites composed of wood residues and ecofriendly binders such as sodium silicate could reduce the carbon footprint of the construction industry. In this paper the spatially varying mechanical behavior of a single layer of a 3D-printed wood-sodium silicate composite with a 50:50 wt.% known as PrinTimber was investigated. Flexural testing revealed the outer edges of a single printed layer of composite material exhibited greater strength compared to the inner regions of the same sample. Furthermore, tensile tests demonstrated that the longitudinal modulus of elasticity of a single layer was lower than the transverse modulus of elasticity of the same layer. Optical images revealed the 3D printing process tended to arrange wood fibers in a particular manner. The unique fiber arrangement within the layer explains the observed directional dependent response of the sample.… More
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