Article
Nanoscience & Nanotechnology
V. V. Shastry, Gaurav Singh, U. Ramamurty
Summary: The study demonstrates that periodic "healing" treatment during fatigue testing of shape memory alloys can effectively extend the fatigue life of the alloy, with 20% of the life elapsed being the optimal treatment time point. Different timing of healing treatment affects the effectiveness of improving fatigue life, indicating irreversible damage has already occurred.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
Aleksandra Debska, Piotr Gwozdziewicz, Andrzej Seruga, Xavier Balandraud, Jean-Francois Destrebecq
Summary: This paper introduces a method of prestressing concrete hollow cylinders using shape memory alloys (SMAs). By activating the memory effect through temperature variations, high stresses are generated to achieve prestressing. The authors conducted a series of experiments, observed the prestressing effects on cylinders of different diameters, and proposed conditions for effective prestressing.
Article
Materials Science, Multidisciplinary
M. Liu, P. Diercks, A. Manzoni, J. Cizek, U. Ramamurty, J. Banhart
Summary: The study found that thermal cycling of a Ni-excess NiTi alloy led to a continuous build-up of defect structure until saturation, resulting in the formation of two types of defects, pure dislocations and vacancies attached to dislocations.
Article
Chemistry, Physical
Aleksandra Debska, Piotr Gwozdziewicz, Andrzej Seruga, Xavier Balandraud, Jean-Francois Destrebecq
Summary: This paper explores the mechanical behavior of hollow concrete cylinders prestressed with nickel-titanium shape memory alloy (SMA) wires. The stress level in the concrete is evaluated by analyzing the thermal stresses and circular concentric loading resulting from a temperature gradient and impairment of memory effect. Longitudinal compression tests confirm the long-term effectiveness of prestressing with Ni-Ti SMA material in concrete elements.
Article
Materials Science, Multidisciplinary
Swadhin Kumar Patel, Ajit Behera
Summary: NITINOL is a popular and cost-effective shape memory alloy used in various industries. Utilizing powder technology route for manufacturing these SMAs can reduce post-processing, and the uniaxial press and sinter process can yield better density.
METALS AND MATERIALS INTERNATIONAL
(2022)
Article
Nanoscience & Nanotechnology
Mingzhu Dang, Honghao Xiang, Jikang Li, Chao Cai, Qingsong Wei
Summary: A copper-based shape memory alloy Cu-11.85Al-3.2Mn-0.1Ti with desirable superelasticity and shape memory effect was successfully printed by laser powder bed fusion (LPBF) technique. The printed alloy exhibited a microstructure composed of full beta(1)' martensite with a high density of stacking faults and twin crystals. Under temperature stimulation, the printed samples showed remarkable superelasticity and shape memory effect, demonstrating reliable shape recovery ability.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Construction & Building Technology
Saim Raza, Behrouz Shafei, M. Saiid Saiidi, Masoud Motavalli, Moslem Shahverdi
Summary: The degradation of reinforced concrete structures due to aging and extreme loading can cause performance and safety concerns. Shape memory alloys (SMAs) with superelasticity and shape memory effect offer unique properties for restoring and designing RC structures. They can reduce permanent deformations, enhance strength and stiffness, and enable self-centering behavior. However, there is a lack of comprehensive review and guidance on the applications of SMAs in RC structures.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
H. Mei, J. C. Liu, F. Chen, Y. X. Tong, M. Zarinejad
Summary: NiTiTa shape memory alloys (SMAs) have higher corrosion resistance and better X-ray visibility compared to NiTi SMAs. This study investigates the martensitic transformation, microstructure, and shape memory effect (SME) of Ni49.6Ti45.4Ta5 SMA. After optimal thermomechanical treatment, the maximum recovery strain reaches up to 5.32% under a pre-strain of 7%.
Article
Materials Science, Multidisciplinary
N. Resnina, A. Sibirev, S. Belyaev, E. Ubyivovk
Summary: The aim of this study was to observe the movement of martensite interfaces in pre-deformed NiTi shape memory alloy during temperature variation using transmission electron microscopy (TEM). The Ni50Ti50 alloy was pre-deformed by 10% tension in the martensite state and then unloaded. Thin foils were prepared for in-situ TEM analysis of the movement of martensite interfaces during heating-cooling-heating cycles. The results showed that the martensite interfaces started moving at high temperatures during the first heating, lost their mobility during pre-deformation, and regained their mobility after the first heating.
Article
Thermodynamics
F. Dagdelen, C. Ozay, E. Ercan, G. Emir, I. N. Qader
Summary: The study investigated the electrical characteristics of NiMnSn shape memory alloys during phase transformation, revealing that the addition of Ta significantly decreased the phase transformation temperature and the alloys exhibited higher resistivity in the martensite phase. XRD and SEM-EDX analysis showed orthorhombic martensite phase picks and microstructures including grain boundaries and pores in the samples.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Engineering, Civil
Saebyeok Jeong, Kun-Ho E. Kim, Youngchan Lee, Dahye Yoo, Kinam Hong, Donghyuk Jung
Summary: This study investigates the compressive behavior of concrete confined with a cost-effective iron-based shape memory alloy (Fe-SMA) and finds that it provides effective reinforcement for concrete structures and comparable performance to conventional carbon fiber-reinforced composites.
EARTHQUAKES AND STRUCTURES
(2022)
Article
Nanoscience & Nanotechnology
Yu-Nien Shen, Yen-Ting Chang, Chih-Hsuan Chen
Summary: The precipitation strengthening effect of Ti50Ni15Pd25Cu10 shape memory alloy is effectively promoted by adding a small amount of vanadium. The formation of Cu-rich TiPdCu precipitates at 573 K for 1 h aging leads to improved shape memory effect, pseudoelasticity, and elastocaloric effect.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
Maximilian Schleiting, Alexander Wetzel, Andre Bauer, Johanna-Maria Frenck, Thomas Niendorf, Bernhard Middendorf
Summary: A prestressing method using Fe-Mn-Al-Ni shape memory alloy rebars is investigated in this work. The stress of about 130 MPa is achieved for the novel rebars, and an improvement in maximum flexural strength and rigidity is observed compared to non-activated rebars. Future research should focus on the design and construction applications of the shape memory alloy rebars, as well as the long-term performance of the prestressing system.
Article
Nanoscience & Nanotechnology
Jiaqi Dong, Tejas Umale, Benjamin Young, Ibrahim Karaman, Kelvin Y. Xie
Summary: We investigated the structure and substructure of a solution-treated high temperature shape memory alloy using transmission electron microscopy and precession electron diffraction. It was found that the martensite plates contained high-density internal compound twins. Four martensite variants were observed, and the orientation relationships were determined. Additionally, several low-angle grain boundaries were observed near the variant interfaces.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Physical
Niraj Nayan, Gaurav Singh, S. V. S. Narayana Murty, P. Ramesh Narayan, M. Mohan, P. V. Venkitakrishnan, Upadrasta Ramamurty
Summary: The study found that the addition of Cu to NiTi shape memory alloy can improve its hot workability, while the addition of Fe can decrease its performance. By constructing power dissipation, instability and strain rate sensitivity maps at different temperatures and strain rates, stable domains for processing and optimal processing parameters were identified.
Article
Engineering, Civil
Antoni Cladera, Luis Montoya-Coronado, Joaquin Ruiz-Pinilla, Carlos Ribas
Summary: This paper presents the technology for external shear strengthening using Fe-SMA strips, and verifies its feasibility and effectiveness through two experimental campaigns.
Article
Materials Science, Multidisciplinary
Christoph Kenel, Anthony De Luca, Christian Leinenbach, David C. Dunand
Summary: The effects of modifying a high-gamma' Ni-8.5Cr-5.5Al-1Ti model superalloy with 0.5 wt% Y2O3 through laser powder bed fusion are studied. The resulting oxide dispersion-strengthened (ODS) alloy exhibits significantly slower creep rates and better creep resistance compared to the base alloy. Two creep mechanisms, diffusional creep and dislocation creep, are observed. The ODS alloy shows potential for strengthening additively manufactured nickel-based superalloys.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Chemistry, Physical
Marvin Schuster, Anthony De Luca, Remo Widmer, Xavier Maeder, Christian Leinenbach
Summary: Additive manufacturing provides an opportunity to produce complex geometries with improved properties using novel alloys. This study investigates the precipitation formation and optimal process parameters of zirconium-modified 2618 alloy in laser powder bed fusion. The addition of zirconium results in crack-free, high-density material with a trimodal grain size distribution. The findings contribute to a better understanding of precipitate formation in Zr-modified 2xxx alloys and pave the way for the commercialization of further 2xxx alloys tailored to additive manufacturing.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Construction & Building Technology
Alejandro Frontera, Antoni Cladera
Summary: Corrosion of stirrups significantly affects the shear strength of reinforced concrete elements, and it is important to accurately predict the long-term shear strength degradation to prevent shear failures. This paper combines the Compression Chord Capacity Model (CCCM) with material deterioration models included in the new Spanish Structural Code, taking into account factors such as carbonation of concrete or chloride ions, to predict the shear strength evolution. A parametric analysis is also carried out to explore the influence of key parameters on shear strength degradation according to the used models and exposure classes.
STRUCTURAL CONCRETE
(2023)
Article
Engineering, Civil
Niloufar Moshiri, Enzo Martinelli, Christoph Czaderski, Davood Mostofinejad, Ardalan Hosseini, Masoud Motavalli
Summary: Fiber-reinforced polymer (FRP) composites are commonly used as externally bonded reinforcement (EBR) systems for strengthening reinforced concrete members. A new technique, externally bonded reinforcement on grooves (EBROG), has been proposed to enhance the bond strength between the FRP composite and concrete by using grooves in the concrete substrate. This study investigates the influence of groove depth on the debonding process of prestressed carbon FRP strips.
JOURNAL OF COMPOSITES FOR CONSTRUCTION
(2023)
Article
Engineering, Manufacturing
Viktor Lindstrom, Giandomenico Lupo, Jian Yang, Vladyslav Turlo, Christian Leinenbach
Summary: This study proposes a simple thermal scaling model for predicting the transition from balling mode to conduction mode in laser powder bed fusion. The model's accuracy and reliability are verified through experiments and simulations, and it suggests viable strategies for adjusting the operating parameters to achieve defect-free 3D printed parts.
ADDITIVE MANUFACTURING
(2023)
Article
Engineering, Civil
Luis A. Montoya-Coronado, Carlos Ribas, Joaquin G. Ruiz-Pinilla, Antoni Cladera
Summary: This research investigates the shear-transfer actions of simple supported RC beams without stirrups through crack kinematics tracking using photogrammetry techniques. The study reveals a significant redistribution of shear-transfer actions near failure, with the aggregate interlock contribution changing from irrelevant to primary. The aim of the research is to bridge the gap between shear strength design models and contradictory initial hypotheses through a better understanding of critical shear crack behavior.
ENGINEERING STRUCTURES
(2023)
Article
Chemistry, Physical
Yajiao Yang, Christian Leinenbach, Moslem Shahverdi
Summary: In this study, TC-PRISMA was used to simulate the precipitation characteristics of an FeMnSi-based shape memory alloy during one-step and two-step aging processes. The results were validated using transmission electron microscopy (TEM) to examine the microstructures, particularly the VC precipitates. Thermomechanical characterization was conducted to investigate the recovery stress of the FeMnSi-SMA under the different aging conditions. The simulation results showed that two-step aging achieved a similar precipitation state in a significantly shorter time compared to one-step aging, and the recovery stress and fracture strain differed between the two conditions.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
I. Ferretto, D. Kim, W. J. Lee, E. Hosseini, N. M. della Ventura, A. Sharma, C. Sofras, J. Capek, E. Polatidis, C. Leinenbach
Summary: The fcc-c-, hcp-e-, and bcc-a' martensitic transformation of a Fe-Mn-Si-based shape memory alloy fabricated by laser powder bed fusion (LPBF) is studied for the first time. Comparison between horizontal and vertical specimens shows that sample orientation considerably influences the alloy's shape memory and mechanical properties. The reason for this variation is found in the distinct crystallographic texture generated during the LPBF process.
MATERIALS & DESIGN
(2023)
Article
Construction & Building Technology
Muhammad Arslan Yaqub, Christoph Czaderski, Stijn Matthys
Summary: Due to increased traffic volumes, existing infrastructure needs assessment and rehabilitation. This study focuses on reinforcing prestressed concrete I-shaped girders with carbon fiber reinforced polymer (CFRP) strips and epoxy bonded concrete in-fill blocks. The use of in-fill blocks showed a significant increase in shear capacity compared to configurations without in-fill blocks or with CFRP spike anchors. However, existing formulations lack the ability to predict the shear capacity of strengthened I-girders, indicating the need for further research.
STRUCTURAL CONCRETE
(2023)
Article
Engineering, Manufacturing
R. Wrobel, P. Gh Ghanbari, X. Maeder, E. Hosseini, C. Leinenbach
Summary: Laser powder bed fusion technology has the potential to fabricate complex geometries with improved functionality, especially when combined with nickel alloys like Hastelloy X for high-temperature applications. However, little is known about the LPBF fabrication of fine structures with thin walls, and this study shows that wall thickness plays an important role in microstructure formation.
PROGRESS IN ADDITIVE MANUFACTURING
(2023)
Article
Construction & Building Technology
Celia Traver, Joaquin G. Ruiz-Pinilla, Andrea Monserrrat, Luis A. Montoya-Coronado, Pedro F. Miguel, Carlos Ribas, Antoni Cladera, Jose L. Bonet
Summary: This research focuses on the feasibility of iron-based shape memory alloy (Fe-SMA) strips to strengthen damaged structures by promoting the yielding of longitudinal reinforcement. Real-scale reinforced concrete beams previously damaged on shear were tested after being strengthened with external Fe-SMA strips. The results show a significant increase in both shear strength and ductility, highlighting the potential of Fe-SMA as a strengthening technique for damaged beams on shear.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Engineering, Manufacturing
Anthony De Luca, Christoph Kenel, David C. Dunand, Christian Leinenbach
Summary: The effects of adding 1 wt% HfO2 nano-dispersoids on the microstructure of a high-y' Ni-8.5Cr-5.5Al-1Ti model superalloy manufactured via laser-based powder-bed fusion are investigated. HfO2 dispersoids, despite their high melting point, are not fully stable in the melt pool. At the nanoscale, the superalloy grains contain various Hf-Al-O, Hf-O, and Hf-S-rich nano-dispersoids, as well as y' L12-Ni3Hf nano-precipitates, indicating reaction of HfO2 dispersoids during melting. Also, Hf-Al-O-rich slag inclusions with a two-phase HfO2-Al2O3 eutectic structure are observed at the meso-scale. Macroscopic cracks form at the boundaries of the highly textured grains, suggesting solidification cracking.
ADDITIVE MANUFACTURING LETTERS
(2023)
Article
Construction & Building Technology
Alejandro Frontera, Antoni Cladera
Summary: Corrosion of stirrups significantly affects the shear strength of reinforced concrete elements. This paper combines the Compression Chord Capacity Model with material deterioration models to predict long-term shear strength evolution, considering carbonation of concrete or chloride ions.
STRUCTURAL CONCRETE
(2023)
Article
Materials Science, Composites
Matteo Breveglieri, Christoph Czaderski
Summary: This study investigates the long-term performance of RC slabs strengthened with CFRP strips and finds that while non-prestressed strips exhibit satisfactory behavior, strain increases over time. Slabs strengthened with prestressed CFRP strips experience premature failure due to elevated temperatures and sustained loads.
COMPOSITES PART C: OPEN ACCESS
(2022)
Article
Construction & Building Technology
Qi Jiang, Wei Liu, Shaopeng Wu, Xuanwen Gou
Summary: This study analyzes the erosion mechanisms of NaCl solution on asphalt concrete and finds that NaCl solution softens asphalt and promotes the intrusion of crystalline salt into it. Salt crystallization alters the surface roughness of aggregates, resulting in a decrease in skid resistance but an improvement in compressive strength. Additionally, the concentration of NaCl solution initially has no significant impact on the mechanical performance of asphalt concrete, but its domination gradually increases with the intensification of cyclic effects.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Lili Kan, Lan-qing Dai, Ning Kong, Bin Peng, Fei Wang
Summary: This paper investigates the effect of freezing and thawing cycles on the tensile behavior of cracked ultra-high performance concrete (UHPC). The results show that long-term freezing and thawing action deteriorates the cracking strength, tensile strength, tensile strain, and strain energy of cracked UHPC. On the other hand, the action of water generally favors the development of tensile properties of UHPC. The crack distribution tends to be unsaturated under freezing and thawing environment, and the re-hydration reaction is hindered. The pore structure near the crack varies under different environments.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Xin Xiao, Jingwei Li, Qingke Meng, Xiangshan Hou, Yanhui Liu, Xujiang Wang, Wenlong Wang, Shengtao Lu, Yuzhong Li, Yanpeng Mao, Tong Li
Summary: Preparing gypsum-based self-leveling mortar (GSLM) using beta-hemihydrate gypsum and solid wastes-derived sulfoaluminate cement (WSAC) can improve the mechanical performance of the mortar, but phosphorus impurities can weaken the hydration speed and degree.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Sihang Bao, Junzhen Di, Yanrong Dong, Ziqing Gao, Qing Gu, Yuanfang Zhao, Hongyu Zhai
Summary: Tailings dam break and leakage accidents pose a threat to the safety of people in mining areas and cause severe environmental pollution. This study focuses on solidifying tailing sand using microbial induced calcite precipitation (MICP) to improve strength and fix heavy metals. The curing time of MICP bio-cemented tailings is found to significantly impact the strength of tailings, while its effect on heavy metal fixation is minimal. The optimized MICP curing time is 10 days, resulting in improved strength and cementation of tailings particles.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Ferhat Benmahiddine, Fares Bennai, Achraf Charaka, Ameur El Amine Hamami, Abdelkader Tahakourt, Rafik Belarbi
Summary: This paper studied the effects of hysteresis on the hygrothermal behavior at the building scale. Through laboratory validation and numerical simulations, it was found that hysteresis has a significant impact on the relative humidity and total heat fluxes in buildings, while it does not have a noticeable effect on temperature variations.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
You Gao, Wei He, Xiayang Zhang, De'an Sun, Pei Li
Summary: This study determined the boundary line between the swelling and compression deformation zone in lateritic clay through wetting tests, and proposed a simple bimodal SWRC model. It also found that the existing strength model underestimated the tested values in the medium to high suction range, therefore a segmented strength equation was introduced for enhanced predictions of the strength properties of lateritic clay.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Prabhath Ranjan Kumar Soda, Asheer Mogal, Kalyan Chakravarthy, Nikhil Thota, Nimish Bandaru, Sanjay Kumar Shukla, K. M. Mini
Summary: This study investigates the use of encapsulated bacteria to improve the self-healing ability of concrete. Through various tests, it is found that using 20% cement-coated alginate beads (CCAB) and 5% nanosilica (NS) can achieve optimal strength and healing. This research is significant for enhancing the durability of concrete.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Shizhe Wang, Haiping Wu, Wen Yang, Wei Wang, Zhibo Zhu, Kun Nie, Luoxin Wang, Hua Wang, Jing Wu
Summary: In this study, photothermal-heat storage concrete (PHSC) was developed with excellent photothermal conversion performance and heat storage capacity. By absorbing and storing solar energy during the day and releasing it at night, PHSC can effectively reduce energy consumption in buildings.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Robin Deb, Jialuo He, Geetika Mishra, Yaghoob (Amir) Farnam
Summary: Incorporation techniques of phase change materials in cementitious composites have a significant influence on thermal properties. This study investigated the thermal behavior of low-temperature PCM when subjected to varying temperature change rates and pore confinement inside the porous network of lightweight aggregates. The results showed that ramp rates affect the nucleation and crystallization growth process during the phase transition, and the pore structure of the aggregates affects the supercooling phenomenon and confinement pressure of the PCM.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Eduardo Ferreira, Payam Sotoudeh, Dagmar Svecova
Summary: This study investigates the fatigue behavior of concrete under different stress reversal conditions. The results indicate that stress reversal generally causes more severe damage and reduces the cycles to failure compared to tensile fatigue. Additionally, adding some level of compression contributes to the energy required for failure under stress reversal fatigue. Specimens with higher concentration of fractured aggregates achieve longer fatigue lives.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Mag Raj Gehlot, Sandeep Shrivastava
Summary: This study evaluates the compatibility relationship between plaster bonds and the substrate under an accelerated aging environment, and finds that incorporating an appropriate amount of granite cutting waste can improve the strength parameters and adhesion of the cement mortar.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Min Zhang, Qirui Luo, Mingke Deng, Shixing Zhao
Summary: This study investigated the bond behavior between carbon FRCM composites with added short fibers and concrete substrates. The effects of different factors were considered and 36 specimens were tested and discussed. The experimental results were analyzed in terms of failure mode, load-slip curve, and characteristic parameters, and the contribution of weft yarns was taken into account in the developed bondslip model.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Dengkai Liu, Hongniao Chen, Ray Kai Leung Su
Summary: The susceptibility of building stones to fire and high temperature was investigated in this study by examining their physical and mechanical properties. The results show that both compressive and tensile properties of stones are affected by temperature changes. The tensile strength is particularly sensitive to temperature changes, requiring special attention to the components subjected to tensile stress in stone buildings. Principal component analysis was used to predict the mechanical properties of stones, providing a new method for calculating the residual mechanical properties after high temperature or fire.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Joso Maria Raposo, Eduardo Cavaco, Luis Costa Neves, Eduardo Julio
Summary: This paper investigates the correlation between the friction coefficient and the surface roughness of concrete-to-concrete interfaces. Experimental tests were performed on specimens with different surface treatments, and the surface roughness parameters were analyzed and correlated with the shear strength and friction coefficient. The results showed that certain roughness parameters had a strong positive correlation with the friction coefficient, while others had little or no correlation. A novel combined roughness parameter with optimized correlation was proposed.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Chiara Riccardi, Massimo Losa
Summary: The interest in using bio materials in asphalt pavements is growing due to economic reasons and environmental benefits. This study aimed to review the use of bio extenders as additives in binders, with a focus on replacements greater than 20% of fossil binder. The properties of bio-extended binders were found to vary substantially depending on the biomass source and production process.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
