Immersion Conditions Research Articles

Effect of biochar content and particle size on mechanical and water absorption properties of landscaping waste/polylactic acid composites

The high-value utilization of landscaping waste to produce wood-plastic composites provides a promising approach to waste management, yet remains a challenge. In this study, wood-plastic composites were prepared using landscaping waste and polylactic acid (PLA) through an extrusion-molding process, with biochar (BC) as the reinforcing material. First, the effects of biochar content (0.5 %, 1 %, 2 %, 3 %, 4 %) and particle size (100mesh, 300mesh, 800mesh, 1200 mesh) on the physico-mechanical and dynamic thermo mechanical properties of the composites were analyzed. A multivariate nonlinear model was employed to fit the flexural properties of the composites. Additionally, the water absorption properties were investigated under immersion conditions at three different temperatures (20°C, 35°C, 50°C). The results demonstrated that biochar significantly improved the interfacial compatibility between landscaping waste and PLA, enhancing the mechanical properties of this composite. When the biochar content was 1 % and particle size was 100 mesh, flexural strength reached 25.16 MPa, respectively, representing increases of 19.20 % over composites without biochar, while the change in impact strength was small. In addition, the water absorption process of composites with 1 % BC were well fitted by Fick's law. SEM morphology observation indicated that interfacial bonding was reduced after water absorption, which was consistent with the test results. Combined with Arrhenius equation and Fick's law, the water absorption model of the composites at each water immersion temperature was obtained, which can predict the water absorption behavior at 60°C.

Effects of Physical Cooling on the Temperature and Performance of Newly Laid Porous Asphalt Mixtures

Porous asphalt pavements need to be cured for 24 h~48 h before they can be opened to traffic. In an emergency, physical cooling methods, such as water sprinkling and air blowing, can be used to accelerate cooling, but the effects of the two methods on the mechanical properties and durability of porous asphalt mixtures are still unclear. In this research, firstly, the dropping and rising temperatures of the pavement surface during the water sprinkling process of newly laid porous asphalt mixtures in real projects were analyzed. The effects of the two conditions of water immersion and water sprinkling on the mechanical properties of porous asphalt mixtures were clarified, and water sprinkling technology for porous asphalt mixtures was proposed. Secondly, the effects of air blowing on the temperature reduction and strength loss of porous asphalt mixtures was analyzed, and the pavement surface temperature control standard that was suitable for air blowing was proposed. Finally, a seven-year observation was carried out on the water sprinkling cooling test section in the actual project. The research results show that water immersion or the sprinkling of water repeatedly during the curing period of porous asphalt pavements reduces the strength of the mixture. It is recommended to use a water amount of 0.3 kg/m2 once and sprinkling four times before painting road markings and two times after painting road markings; this was the best water sprinkling cooling process for porous asphalt pavements. The use of air blowing can accelerate the temperature reduction of porous asphalt mixtures, but the mechanical properties of the mixtures are attenuated after air blowing. Air blowing can be carried out when the pavement surface temperature is lower than 70 °C. Compared with the road section without water sprinkling for cooling, the use of the determined process to cool the newly laid porous asphalt mixtures by water sprinkling does not have a significant adverse effect on their durability. There is also no significant difference in the performances of the two road surfaces within a seven-year service. In an emergency, physical cooling methods, such as water sprinkling or air blowing, can be used to accelerate the temperature reduction of the newly laid porous asphalt mixtures, so as to achieve the purpose of quickly opening to traffic.

Thermal effects of immersion and ultrasonic on spray cooling in the boiling zone

This study examines the synergistic effects of ultrasound and immersion on spray cooling, highlighting cavitation and acoustic flow mechanisms. Experiments evaluated boiling zone variables. Compared heat transfer in conventional spray cooling (SC), immersion spray cooling (ISC), and immersion ultrasonic spray cooling (IUSC). The results demonstrate that both ultrasonic application and immersion conditions in boiling environments can significantly enhance heat transfer in certain cases. Spray height experiments show SC achieves its highest heat transfer efficiency at a specific spray height, while ISC and IUSC demonstrate superior performance at higher heights. Moreover, at higher spray heights IUSC increases the SC heat transfer efficiency by 17.07 %. The findings also demonstrate that spray cooling efficiency is notably influenced by the flow rate and heat flow density, exhibiting considerable improvements especially in scenarios of low flow rates and high heat flow densities. Moreover, lower water temperatures improve temperature-controlled immersion spray cooling (TCISC) and temperature-controlled immersion ultrasonic spray cooling (TCIUSC) efficiency. At higher water temperatures, TCIUSC outperforms TCISC, with an enhancement observed at up to 9.26 % at a water temperature of 20 °C. This study provides a new direction for spray cooling enhanced heat transfer.

Study on road performance of asphalt mixture based on surface modification of coal gangue

In order to solve the problem of coal gangue environmental pollution and the shortage of aggregate resources in road engineering, this paper studies the feasibility of using waste coal gangue as coarse aggregate of asphalt mixture. Through the physical and mechanical properties test, the difference between coal gangue and natural aggregate was compared and analyzed. The surface modification and strengthening treatment of coal gangue aggregate was carried out by using methyl sodium silicate solution, and the best modification scheme was determined. The influence of different content and surface modification on the road performance of coal gangue asphalt mixture was studied by laboratory test. With the help of scanning electron microscope test, the change characteristics of the microstructure of coal gangue asphalt mixture before and after surface modification were explored. The results show that although the indexes of coal gangue are inferior to those of natural aggregate, it can be used to prepare asphalt mixture within the scope of specification requirements. The modification effect of sodium methyl silicate solution with modification time of 6h is the best, which can significantly improve the water absorption, density and crushing value of coal gangue. When the content of coal gangue is controlled within 30%, the performance of asphalt mixture meets the requirements of the specification, and the amount of coal gangue in asphalt mixture can be increased after surface modification. After surface modification, the surface pores and cracks of coal gangue asphalt mixture are reduced, and the surface micro-damage under high temperature immersion and freeze-thaw cycle conditions is improved.

Thermodynamic modeling of the processes of purification of primary aluminum from vanadium impurities

This article discusses the interaction of chemical elements in the three-component Al-V-B system. Vanadium reduces electrical conductivity in primary aluminum, which requires its reduction during aluminum electrolysis to values less than 0.02%. In order to reduce the concentration of vanadium impurities, thermodynamic calculations were carried out for the reactions of separation of the metallic phase of aluminum and impurities of vanadium intermetallic compounds through the use of a boron-containing flux. The calculation of thermodynamic parameters was carried out in HSC Chemistry 9.0. for AlB2 and VB2 compounds, the chemical reaction AlB2 + V = VB2 + Al within the operating temperatures of electrolysis and casting of primary aluminum of 650–950°С and the conditions of immersion of boron-containing flux into the melt to a ladle depth of 0.5, 1.0, 1.5 and 2 m, i.e. within the pressure range of 102.39–148.99 kPa. Thermodynamic analysis showed that the Gibbs energy (ΔGT) values in the entire range of operating temperatures of the electrolysis and casting of primary aluminum for VB2 are significantly lower than AlB2, therefore, they will be formed predominantly in this temperature range. The order of stability also suggests that vanadium can be easily removed from aluminum melts by adding boron. The results obtained allow us to conclude that chemical reactions of primary aluminum purification from vanadium impurities can occur due to boron additives.

Evaluation for anti-cracking performance of polyurethane grout based on overlay test

Polyurethane grouting has garnered increasing attention in road maintenance, owing to its exceptional interfacial adhesion, mechanical robustness, and chemical resilience. In comparison to conventional SBS-modified asphalt, polyurethane grout offers superior durability and demonstrates an enhanced capacity to inhibit crack propagation within asphalt mixtures. This study investigates the anti-cracking performance of polyurethane grout in comparison to traditional SBS-modified asphalt, utilizing the Overlay Test (OT) to simulate real-world conditions of reflective cracking in asphalt pavements. Results demonstrate that polyurethane grout significantly enhances the crack resistance of asphalt mixtures, manifesting superior durability and resistance to crack propagation at a controlled temperature of 25°C, with a marked increase in the number of loading cycles relative to the control. However, the performance of polyurethane grout is notably diminished under adverse conditions of low temperatures and water immersion. The investigation employs a multi-index evaluation, with gray correlation analysis delineating the efficacy of various indices in appraising crack resistance. Recommending the use of loading cycles, allowable failure times, and cumulative fracture energy as key metrics.

Application of Resistometric Sensors for Real-Time Corrosion Monitoring of Coated Materials

Highly sensitive resistometric sensors were applied for the real-time corrosion monitoring of carbon steel protected with a polyolefin coating with and without an inhibitor under static and dynamic atmospheric and immersion conditions. The results were compared with conventional electrochemical impedance spectroscopy (EIS) data. An increase in the coating thickness from 20 µm to 50 µm and an addition of 1wt.% tannic acid significantly improved the coating corrosion stability. Based on the real-time corrosion data, the drying stage of atmospheric exposure in a chloride-rich environment was found to be the most critical. The highest corrosion rate was detected at 50% relative humidity when the electrolyte corrosiveness in coating defects reached the maximum. Resistometric sensors have the potential to become an interesting alternative for evaluating coating performance and degradation mechanisms in both laboratory and industrial applications.

The Effect of Dry Immersion on the Characteristics of Joystick Control during the Performance of a Visual-Motor Task in Men and Women

A study of the effect of Dry Immersion (DI) on the characteristics of joystick control during a visual-motor task in men and women was conducted. It is shown that in the first days of DI there is a deterioration in the performance of the visual-motor task – an increase in time indicators and a decrease in movement accuracy. By the end of DI, most of the parameters returned to the control level indicating the adaptation of the hand movement control mechanisms to immersion conditions. However, despite the similarity of the effect of DI on changes in the parameters of movement trajectories in men and women, it was shown that both in control and in DI, women performed the presented visual-motor task faster and more accurately due to a longer latency time. In the early days of DI, the characteristics of task performance in women changed less than in men, which indicated a better adaptation of women to the conditions of DI. In the process of adaptation to DI factors, men and women had different strategies for performing visual-motor tasks.

A novel energy-saving and emission-reduction strategy based on facile preparation of thermal insulation coatings doped with modified vacuum ceramic microbeads for concrete protection

The development of thermal insulation protective coatings suitable for constructions and buildings offers a multifaceted approach: it substantially reduces indoor temperatures, enhances residential comfort, decreases air conditioning energy consumption, and conserves energy. Additionally, these coatings provide robust resistance against corrosive substances, thereby significantly prolonging the service life of concrete. In this work, the modification of vacuum ceramic microbeads (VCM) through the polymerization of catechol and hexamethylene diamine to form poly(catecholamine) (PCA) was investigated by FT-IR, XRD, and TEM analysis. Increased levels of incorporation of VCM@PCA further decreased thermal conductivity and increased surface hydrophobicity, while excessive incorporation detrimentally affected the coating's mechanical properties. PDMS/VCM@PCA coating demonstrated exceptional thermal insulation performance, reducing coating temperature by 15.9 °C under simulated sunlight exposure, and in outdoor experiments, the interior temperature of the simulated house with this coating was 4.2 °C lower than the external temperature, highlighting its potential for energy conservation, emission reduction, and building temperature regulation. Additionally, PDMS/VCM@PCA coating provided excellent protection for concrete structures, significantly enhancing abrasion resistance. It also improved the interfacial adhesion between the organic layer and concrete under dry, wet, and 10% NaCl immersion conditions. The addition of VCM@PCA further enhanced resistance to chloride ion penetration, effectively reducing chloride ingress. This thermal insulation protective coating presents a novel strategy for energy conservation, emission reduction, and sustainable development in the civil construction industry.

Performance of microsphere-assisted imaging in bright-field and dark-field microscopy.

In this work, we study the imaging performance of microsphere-assisted microscopy (MAM) using microspheres with different refractive indices and immersion conditions under both bright-field illumination (BFI) and dark-field illumination (DFI). The experimental results show that the position of the photonic nanojet of the microsphere plays an important role in MAM imaging. The contrast in imaging is affected by the reflection from the microsphere, the background signal without the microsphere, and the electric field on the substrate surface. In MAM, BaTiO3 glass microspheres achieve better imaging results under BFI when immersed in a polydimethylsiloxane (PDMS) film but are challenging to image under DFI. However, SiO2 and polystyrene microspheres exhibit improved imaging performance under both BFI and DFI with PDMS-covered semi-immersion, and the imaging contrast in DFI is superior to that in BFI under the same conditions. Besides, the Talbot effect is observed by MAM under DFI when imaging 300-nm-diameter hexagonally close-packed nanoparticle arrays. This work reveals the advantage of MAM under DFI in improving the contrast.

Optimization of Desalting Conditions for the Green Seaweed Codium fragile for Use as a Functional Food with Hypnotic Effects.

Codium fragile (CF) contains various bioactive compounds, but its high salt content (39.8%) makes its use as a functional food challenging. Here, we aimed to optimize the desalination process and verify changes in functionality based on variations in salt and total phenolic contents. To optimize the CF immersion conditions for the lowest salt content and monitor the total phenolic content, a response surface methodology was used. The optimal immersion conditions were as follows: X1 (immersion temperature) = 42.8 °C; X2 (immersion time) = 1.0 h. An inverse correlation was noted between salt content and total phenolic content. Among the post-desalination processes, desalination with centrifugal dehydration (CD) significantly reduced salt content. CD ethanol extract (CD-E) induced the longest sleep duration in the pentobarbital-induced sleep test in ethanol extracts. Moreover, 1000 mg/kg CD-E had a significant effect on non-rapid eye movement sleep but did not affect delta activity. These findings highlight the potential of industrializing CF as a functional food through desalination and its promise as a natural aid for sleep promotion.

The Field Assessment of Quiescent Egg Populations of Aedes aegypti and Aedes albopictus during the Dry Season in Tapachula, Chiapas, Mexico, and Its Potential Impact on Vector Control Strategies.

Although integrated management and control programs implement intense control measures for adult, pupal, larval, and breeding sites during outbreaks, there is a lack of studies to understand the role of the vector egg stage in disease dynamics. This study aimed to assess the dry season quiescent Aedes aegypti and Aedes albopictus egg populations in houses and backyards in Tapachula, southern Mexico. Two hundred and fifty ovitraps were placed in 125 homes in the Las Americas neighborhood. A total of 7290 eggs were collected from 211 (84.4%) ovitraps. Only 5667 (77.7%) hatched under insectary water immersion and food supply conditions, with 4031 (71.1%) identified as Ae. aegypti, and 1636 (28.8%) as Ae. albopictus, respectively. The remaining 1623 (22.3%) did not hatch due to Delayed Hatching and/or quiescence tropical stage. Eighty-three larval containers were sampled with desiccated eggs during the dry season; most of them were described as trash waste because larvicides are only used for larger containers of 5-10 L. Evolutionary characteristics for the two species including partial egg hatching, ambient-regulated quiescence, the ability of the embryo to survive for a more extended period intra-seasonally, the egg sticking to inner container walls, demands urgent operational research to achieve successful egg-proof larval container methods.

Enhancing durability and oil-water separation efficiency with plasma-treated graphene oxide coated mesh

In recent years, there has been a surge in interest surrounding the fabrication and utilization of superhydrophobic and superhydrophilic surfaces, driven by their exceptional functionalities and properties. Graphene Oxide (GO) has inherent hydrophilicity and underwater superoleophobicity, which has made this material a particularly capable candidate for oil-water separation. Addressing the persistent challenge of efficient oil-water separation in industrial contexts, this study presents the fabrication of a GO-coated stainless steel mesh via a facile dip coating method augmented by an intermediate two-step O2 plasma treatment. The coated meshes were tested with various oil and water mixtures, including neutral, acidic, saline, and hot water, to find separation efficiency and recyclability. Notably, the meshes can achieve excellent separation efficiency of approximately 98.9 % and a superior flux of 11,464 L m−2 h−1 driven by gravity. This is a significant improvement over GO-coated meshes without O2 plasma treatment. Moreover, the plasma-treated meshes exhibit robust long-term durability and chemical stability, maintaining high underwater oil contact angles ≥119° even after extended immersion in diverse pH mediums and salt solutions for 150 days. This work showcases the practical viability of plasma-treated GO-coated meshes for oil-water separation applications and establishes a framework for systematically evaluating their long-term performance in harsh immersion conditions.

Metacognitive Awareness in Second Language Learning: Displaced Primary School Students’ Experiences of Learning German Upon Transition to the Target Language Environment

Drawing on international pedagogical discourse on the inclusion of ethnically diverse refugee groups in the educational systems of OECD countries as well as our previous research on the Ukrainian refugee perspectives on primary school in Switzerland, the author examines experiences of second language acquisition by displaced Ukrainian children in Swiss primary schools. The two-year research period allowed for the exploration of dynamics of German language acquisition by displaced children in conditions of full immersion in the target language environment and identification of the factors influencing their second language (German) learning and performance. The involvement of a Ukrainian researcher in the research project ensured accessibility of the target group and effective researcher-respondent communication in the course of longitudinal study carried out within the framework of a qualitative methodology with data collection through narrative inquiry and participant observations as research tools. The study identifies the effects of the two groups of factors: learner-internal (motivation, metacognitive skills, prior knowledge, and learning strategies) and learner-external ones (second language learning context, type of second language instruction available upon displacement, etc.). Metacognitive skills proved to be instrumental in second language learning in the context of the learners’ unexpected transition to a new educational setting and full immersion in the target language environment. Effects of metacognitive skills on second language learning of the studied group of displaced children vary considerably depending on the student’s age, prior knowledge and language learning experiences, and second language instruction available upon the displacement. The multidisciplinary character of the second language acquisition research undertaken by the author allows for diverse practical applications of its results in second language pedagogy, psychology of education, as well as in refugee and primary education.

Natural- and redirected walking in virtual reality: Spatial performance and user experience

AbstractImmersive virtual reality offers a range of unique possibilities. One of these is the realistic exploration of virtual worlds using natural walking. This however becomes difficult when the size of the virtual world exceeds that of the available physical space. Redirected walking in virtual reality presents a novel solution to this problem by typically making its users think to be walking in a straight line while they are in fact walking in a curve, thus allowing them to physically walk long distances in confined physical spaces. Yet, few studies have examined the effects of redirected walking on variables such as spatial memory, navigation and user experience as compared to other immersive and non-immersive locomotion methods. In a maze task we examined 1) redirected- and 2) natural walking in immersive virtual reality conditions, and 3) artificial locomotion on a non-immersive desktop monitor. Walked path lengths became shorter and distance estimates, object location memory and user experience improved using natural walking compared to a monitor condition. However, redirected walking yielded similar performance to natural walking while requiring less physical space, opening up possibilities for more pervasive use of real locomotion in virtual environments.

Attenuation Law of Performance of Concrete Anti-Corrosion Coating under Long-Term Salt Corrosion

In saline soil areas, the concrete piers of concrete bridges experience long-term corrosion, mainly caused by chloride salts due to alternating temperature changes. Waterborne concrete coatings are prone to failure in this aggressive salt environment. Implementing coating protection measures can improve the durability of concrete and enhance the service life of bridges. However, the effectiveness and longevity of coatings need further research. In this paper, three types of waterborne concrete anti-corrosion coatings were applied to analyze the macro and micro surface morphology under wet–dry cycles and long-term immersion conditions. Various indicators such as glossiness, color difference, and adhesion of the coatings were tested during different cyclic periods. The chloride ion distribution characteristics of the buried concrete coatings in saline soil, the macro morphology analysis of chloride ion distribution regions, and the micro morphology changes of the coatings under different corrosion times were also investigated. The results showed that waterborne epoxy coatings (ES), waterborne fluorocarbon coatings (FS), and waterborne acrylic coatings (AS) all gradually failed under long-term salt exposure, with increasing coating porosity, loss of internal fillers, and delamination. The chloride ion content inside the concrete decreased with increasing depth at the same corrosion time, while the chloride ion content at the same depth increased with time. The chloride ion distribution boundary in the cross-section of concrete with coating protection was not significant, while the chloride ion distribution boundary in the cross-section of untreated concrete gradually contracted towards the concrete core with increasing corrosion time. During the corrosion process in saline soil, the coatings underwent three stages: adherence of small saline soil particles, continuous increase in adhered material area, and multiple layers of uneven coverage by saline soil. The failure process of the coatings still required erosive ions to infiltrate the surface through micropores. The predicted lifespans of FS, ES, and AS coatings, obtained through weighted methods, were 2.45 years, 2.48 years, and 2.74 years, respectively, which were close to the actual lifespans observed in salt environments. The developed formulas effectively reflect the corrosion patterns of different resin-based coatings under salt exposure, providing a basis for accurately assessing the corrosion behavior and protective effectiveness of concrete under actual environmental factors.

Direct Measurement of the Diffusion Coefficient of Adhesives from Moisture Distribution in Adhesive Layers Using Near-Infrared Spectroscopy.

In this study, we used near-infrared spectroscopy to measure the moisture penetration in epoxy adhesives and investigated the difference in the diffusion coefficients between the bulk and the adhesive layer. Moisture diffusion was evaluated under 100% RH and water immersion conditions. First, the effects of the curing agents and additives on moisture diffusion in the bulk were gravimetrically evaluated using epoxy-coated quartz glass plates. Different diffusion behaviors were observed depending on the curing agent used. The presence of additives resulted in higher diffusion coefficients, whereas the overall moisture content was low. Next, the moisture distribution in the adhesive layer was visualized using a specimen sandwiched between the quartz glass plates, and the diffusion coefficient of the adhesive layer was calculated. The diffusion coefficient in the adhesive layer was larger than that in the bulk. For adhesives cured with hydrophobic diamine, the diffusion coefficient within the adhesive layer increased by approximately 1.5 times compared with that in the bulk, regardless of the exposure environment. The adhesive, composed of a resin, Dicyandiamide, and additives, showed a 2-fold increase in the diffusion coefficient under high-humidity exposure conditions but no significant change under the water immersion condition. Therefore, these results suggest that, for an accurate analysis of moisture distribution, it is important to measure the diffusion coefficient of the adhesive layer directly rather than using the diffusion coefficient of the material itself.

In Situ Fabrication of Highly Efficient and Stable Cs2NaInCl6: Sb3+@PVDF Composite Films for Optoelectronic Devices.

Lead-free double perovskites (DPs) have superior phase stability and optical properties, which make them competitive for future applications in illumination and displays. However, the preparation of DPs was mainly based on high-temperature heating and hydrochloric acid as a solvent to form powders, which increased the risk and cost of the preparation process and limited its further application. In this study, the growth of Cs2NaInCl6: Sb3+ DPs in polyvinylidene difluoride (PVDF) films was achieved using an in situ fabrication strategy with DMSO as the solvent. The prepared Cs2NaInCl6: Sb3+@PVDF composite films (CFs) can achieve a bright blue emission under 302 nm irradiation. To achieve the optimal luminescent performance of CFs, the photoluminescence (PL) intensity of Cs2NaInCl6: Sb3+@PVDF CFs under various in situ preparation conditions was compared. In addition, the photoluminescence quantum yield (PLQY) of CFs was increased from 0.72% to 83.77% by adjusting the doping amount of Sb3+, and the fluorescence lifetimes t1 and t2 were 131.08 and 1048.52 ns, respectively. Temperature-dependent PL spectroscopy and density functional theory (DFT) calculations indicate that these excellent optical properties are derived from the self-trapped excitons (STEs) at the [SbCl6]3- octahedron and [InCl6]3- octahedron connected via Cl-Na-Cl. The CFs also demonstrated excellent environmental stability, maintaining a relatively stable PL intensity even under conditions of water immersion, high temperatures, and ultraviolet (UV) radiation. Finally, we used the CFs to assemble a blue light-emitting device (LED), which showed good and stable blue emission performance at different currents. This work can provide a new idea for preparing DPs, which is conducive to promoting their commercial application in high-performance optoelectronic devices.

Augmenting home entertainment with digitally delivered touch.

In this narrative review, we take a critical look at the various attempts that have been made to augment home (or personal) entertainment experiences via the addition of some form of digitally controlled tactile stimulation. There has been an explosive growth in the market for home entertainment in recent years, and a majority of smartphones and other wearable electronic devices are now touch-enabled. As such, it is important to consider the challenges and potential opportunities for enhanced multisensory entertainment that may result from the introduction of tactile/haptic stimulation in the context of audiovisual digital storytelling and/or gaming. The key technological, financial (and legal), cognitive, and creative/artistic, challenges associated with the tactile augmentation of home entertainment experiences are outlined. Tactile augmentation, in the sphere of both public and personal entertainment, is more likely to succeed when it goes beyond the merely pleonastic vibrotactile reproduction of those interactions/events than can already be seen and/or heard on screen. At the same time, however, it remains uncertain under what conditions immersion in an entertainment experience will be enhanced by the addition of some form of primitive digital tactile stimulation. Ultimately, until a clear usage case can be made for the benefits of introducing a tactile element to home entertainment, it is unlikely to gain traction and switch from being merely a gimmick to more of a valuable element of multisensory storytelling.

Flexural behavior of coral aggregate concrete beams reinforced with BFRP bars under seawater corrosion environments

The combined utilization of fiber-reinforced polymer (FRP) composites with coral aggregate concrete (CAC) in remote island areas contributes to the reduced construction cost and construction period, offering a promising application. However, the evolution pattern and deterioration mechanism of flexural behavior for FRP bars reinforced CAC beams in marine service environments remains unclear. Thus, this paper investigates the flexural behavior of basalt-FRP (BFRP) bars reinforced CAC beams under seawater immersion and dry-wet cycle conditions using laboratory-accelerated aging methods. The research considers the effects of exposure temperature and corrosion age on their failure modes, flexural stiffness, ultimate loading capacity, and deformation deflection. The experimental results revealed that with the increase in corrosion age and exposure temperature, the amount of vertical cracks of CAC beams decreased and their crack depth also exhibited a slight reduction, but their crack width and spacing at failure significantly increased. After being attacked by seawater environments, the load-deflection curves of CAC beams experienced an enhanced slope of the ascending section (i.e., flexural stiffness), but this strengthened flexural stiffness did not result in an enhancement in the ultimate load capacity. Instead, with prolonged corrosion and higher temperatures, the ultimate load of CAC beams displayed significant degradation, accompanied by reduced mid-span deflection. After 12 months of seawater exposure to wet-dry cycle conditions at 60 °C, the ultimate load and mid-span deflection of CAC beams degraded by approximately 25.0 % and 56.6 %, respectively. The study also predicted the flexural bearing capacity of CAC beams utilizing existing specifications for FRP-reinforced normal aggregate concrete (NAC). It was concluded that the formulae for flexural loading capacity for FRP-reinforced NAC beams were still suitable for CAC beams.