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In recent years, the aging of existing reinforced concrete deck slabs of road bridges in Japan has been attributed to the deterioration of the concrete on the upper surface, and partial replacements have been carried out as a measure to extend service life. This study comparatively verifies the effectiveness of the partial cross-section replacement method, using a wheel load running test and focusing on the combination of the removal method of the existing concrete and the repair material. An appropriate method of partial replacement of existing reinforced concrete deck slabs is also proposed.

Distributed applications such as key-value stores and databases avoid frequent writes to secondary storage devices to minimize performance degradation. They provide fault tolerance by replicating variables in the memories of different nodes, and using data consistency protocols to ensure consistency across replicas. Unfortunately, the reduced data durability guarantees provided can cause data loss or slow data recovery. In this environment, non-volatile memory (NVM) offers the ability to attain both high performance and data durability in distributed applications. However, it is unclear how to tie NVM memory persistency models to the existing data consistency frameworks, and what are the durability guarantees that the combination will offer to distributed applications. In this paper, we propose the concept of Distributed Data Persistency (DDP) model, which is the binding of the memory persistency model with the data consistency model in a distributed system. We reason about the interaction between consistency and persistency by using the concepts of Visibility Point and Durability Point. We design low-latency distributed protocols for DDP models that combine five consistency models with five persistency models. For the resulting DDP models, we investigate the trade-offs between performance, durability, and intuition provided to the programmer.

Prefabricated pavement is increasingly applied worldwide due to the rapid construction on-site. This paper presents a state-of-the-art review of the precast systems and assembly connection of concrete slabs, as well as the precast pavement features. The previous research indicates that (1) Both Super-Slab and Michigan systems are recommended with the satisfied road performance close to the cast-in-place. (2) Flexible base material is suggested for the fabricated pavement for the satisfied leveling and stress distribution. (3) To prevent the voiding phenomenon of the fabricated pavement, the sand cushion course, dry mixed mortar or self-leveling mortar, and other flowable materials could be used for the secondary leveling of the base after the pavement splicing. (4) Two-direction dowel bars are recommended for slab connections of the fabricated pavement, which helps to improve the load transfer capacity of the joints and enhance the durability of the fabricated pavement structure. (5) The sealing treatment of precast slab joints needs strengthening to reduce the impact of surface runoff on the base course. (6) The further research focuses are designing with functional, composite, mechanized, intelligent, lightweight, and flexible pavement slabs. Besides, pavement mechanical properties induced by temperature overlapping traffic loads need to be revealed.

A variety of structures are constructed in Pakistan using different construction materials. Cement-lime mortar is widely used worldwide but not commonly used in Pakistan. Cement-lime mortar is a technique that doesn’t require water for its curing purposes. Structural durability, economy and energy efficiency are the basic parameters of a modern construction. In order to attain these parameters, several building construction techniques and environment friendly materials have been introduced. One such building technique to save energy, material and to resist the applied loads is ‘Chinese Bond Brick Masonry (CBBM)’. The structural properties, construction cost, energy efficiency and thermal comfort is compared by testing English and Chinese bond masonry prisms. Chinese bond walls performed excellent in saving materials, less penetration of external heat waves and resistance against compressive and lateral loadings. In this study, it has been tried to explain the importance of CBBM methodology along with construction details. It also provided some comparative calculations to highlight the requisite strength against failure of structure, durability and cost savings that can be achieved against the conventional brick masonry. Compressive strength of Chinese bond prisms did not increase over time but shear and diagonal compressive strength increased. Thus, it is found that compressive strength is related to strength of brick while shear strength, representative of masonry unit, was more related to mortar strength. It is also noted that addition of lime to mix increased the strength of mortar after 28 days and water require for curing of masonry structures can also be saved efficiently.

This paper presents a case study of the condition evaluation, structural assessment and durability analysis of the Al Maktoum bridges in the UAE to provide assurance that they will meet their 100-year service life. It is considered that this holistic analysis is the first of its kind in the UAE. The project included a detailed structural assessment utilising three-dimensional finite-element methods. The analysis indicated that the stresses in all the critical elements were well below the yield limit. The results of the structural assessment were used in combination with the durability assessment to inform the life cycle cost analysis and asset maintenance strategy. The durability analysis incorporated a probabilistic assessment method to verify the remaining service life of the structures. This method utilised a 90% confidence level using the fib Model Code for Service Life Design. The results of modelling were verified against the inspection and testing results, which included concrete strength tests, half-cell potential mapping and chloride ion sampling. Overall, this project case is the first of its kind in the UAE and provided a platform of asset management strategy implementation to establish the current condition of the structures, assess their structural integrity and verify their remaining service life.

Graphical abstract CDs are utilized as crucial structure-directing agents to elaborately design 3D cross-linked rod-like structured Bi2Se3/CDs composites. Computational simulations combined with experiments demonstrate that such robust 3D framework and the existence of interface Bi-O-C bond can simultaneously enhance the intrinsic sluggish kinetics and structural stability, endowing Bi2Se3/CDs anode with fast-charging capability and durable cycling life. Download : Download high-res image (205KB) Download : Download full-size image Advanced electrode materials for fast-charging lithium-ion batteries are of great significance to next-generation energy-storage systems. Herein, three-dimensional (3D) hierarchical rod-structured Bi2Se3/carbon dots (Bi2Se3/CDs) composite is elaborately designed for fast-kinetics lithium storage. It is proposed that CDs-induced self-assembly growth and site-selective ion-exchange transform nanosheets into cross-linked architecture. Such robust 3D framework provides efficient channels for electron/ion transport and sufficient inner space for volume variation as confirmed by theoretical prediction. Notably, the existence of interface Bi-O-C bond would effectively enhance its inherent bulk electronic conductivity and accelerate ionic transportation by narrowing the bandgap and reducing the Li+ migration energy barriers. Consequently, intrinsic sluggish kinetics and structural stability are simultaneously improved, endowing Bi2Se3/CDs composite electrode fast charging/discharging capability of 165 mAh g−1 at 20 A g−1 (corresponding to charge in ≈27 s) and excellent long-term durability with the capacity of 502 mAh g−1 over 950 cycles at 1 A g−1. Moreover, the intercalation-conversion-alloying type lithium storage mechanism of Bi2Se3/CDs is revealed by in-situ XRD. This work provides a train of thoughts for other CDs-tailored composites with tunable morphology and structure.

Solid oxide fuel cell (SOFC) is known for its higher efficiency compared to the other types of fuel cells. Even so, the application of SOFC is hindered by the operational temperature of 800 °C–1000 °C. Lowering the operational temperature below 1000 °C of SOFC becomes the major concern to allow wider applications as well as to increase the durability of the system. Improving the electrochemical performance for SOFC requires further improvement on the main components of SOFC including the air/oxygen electrode namely, the cathode. The manganite, cobaltite, ferro-cobaltite, and ferrite-based materials are known to be used as SOFC cathode, alongside new candidates such as lithiated-based material. Nonetheless, the key challenges for SOFC cathode are to find a suitable material with high electrocatalytic property at lower operational temperature of 400 °C–800 °C. This review paper provides brief information that covered as-mentioned cathode categories, taking into account the microstructural modifications performed via composite, doping, infiltration technique, and synthesis method. Finally, electrolyte-layer free fuel cell (EFFC) is introduced as a new type of SOFC that use natural resources in the fuel cells as a process to reduce its cost.

One of the most widely used Construction material is Concrete. The quality of the concrete is highly dependent on the material proportion which in turn depends on the application that it is being used for. In the conventional method, hike in the cost of the project is majorly synonymous to the use of formwork. And this gets added up with a list that includes safety issues, wastage of material, time elapse, space constrain, labour problems, etc. The aforementioned subjects can be made effective with the application of 3D Printing Techniques in Concrete Technology. This Paper targets on optimizing the mortar mix for 3D Printing Concrete with adaptable mineral and chemical admixtures. Use of accelerators reduced the final setting time to 95 min from conventional time of 310 min. Also the use of fly ash as replacement to sand enhanced the compressive strength to 30 MPa compared to conventional concrete that had 25 MPa. Other durability parameters were also improved compared to control mix.

The hydropower sector is currently experiencing several technological developments. New technologies and sustainable practices are emerging to make hydropower more flexible and eco-friendly. Novel materials have also been recently developed to increase performance, durability, and reliability; however, no systematic discussions can be found in the literature. Therefore, in this paper, novel materials for hydropower applications are presented, and their performance, advantages, and limitations are discussed. For example, composites can reduce the weight of steel equipment by 50% to 80%, polymers and superhydrophobic materials can reduce head losses by 4% to 20%, and novel bearing materials can reduce bearing wear by 6%. These improvements determine higher efficiencies, longer life span, waste reduction, and maintenance needs, although the initial cost of some materials is not yet competitive with respect to the costs of traditional materials. The novel materials are described here based on the following categories: novel materials for turbines, dams and waterways, bearings, seals, and ocean hydropower.

s Cracks are vitally detrimental to the load-bearing capacity of materials and further to the durability and service-life of various structures. Autonomous self-healing via embedded capsules or hollow fibres with healing agent has recently become more popular to repair the damage of structural materials. Figuring out the exact amount of capsules required to repair the cracks is indispensable to develop and design the capsule-based self-healing materials. In this paper, by means of surveying the irregular crack patterns appear on the surface of composite materials the approximated cracks models are induced in the self-healing materials and the probability model of capsules which are randomly dispersed intersecting with the crack networks is developed from the viewpoint of geometry probability. Further, the proposed probabilities for different crack patterns are applied to gain the theoretical solutions on the exact dosage of capsules containing healing agent that are used to obtain a specific self-healing efficiency in capsule-based self-healing materials (cementitious materials, for instance). Finally, the accuracies of these probabilities values and theoretical solutions are verified via computer simulation where the event of capsules intersection with different crack networks are reproduced.

The application of the step lap joint has been increased due to its good characteristics such as lightweight, high stiffness, and good fatigue durability. Moreover, it has a wide application in the aerospace, automotive and marine sector because of its efficient strength and less stress concentration. The present study is concentrated on the effect of the kind of joint used for lap joint like the adhesive joint, riveted joints, and bolted joints. In addition, the length of the steps has been changed to study the behavior of adhesive lap joint in detail. Also, the hybrid joint such as a bolted-adhesive and riveted-adhesive joint is examined in the current study. The variation in the number of bolts and rivets are made for detailed analysis. The main objective of this project is to analyze the step lap joint with different length, different material for adherend and adhesive and also compare it with different mechanical fasteners such as rivets and bolts considering hybridization of it with and without the adhesive, Finite Element Analysis (FEA) is carried out in ANSYS Workbench for analysis and SolidWorks software is used for 3-D modelling.

Space industry has the never-ending demands in evolution of materials and urge on enhancing mechanical, thermal and chemical properties. In regard to weight, reliability and durability the studied materials are evolving, being inspected and monitored at microstructure datum. A dominant area would be strengthening mechanism, advancements in conventional fabrication techniques in materials like Aluminium, Titanium, Nickel and Polymers. Certain properties like susceptibility to corrosion, coefficient of thermal expansion in adverse temperature conditions are key note points to be analyzed for developing a progressive and viable alternative material for various space applications. In case of Aluminum based alloys, Al-Li (Aluminum-Lithium) is anticipated to have substantial impacts when replaced from conventional Al based alloys, they have optimized thermal and thermomechanical properties. Making Carbon Fibre Reinforced Plastics more cost effective, latest developments in 3D fiber reinforcements are happening. Self-healing matrices can be the newest domain for research in said field. In case of nickel-based alloys, their unique property of stability at elevated temperatures needs to be economically addressed and improvements can be done by controlling microstructure and innovating processing technologies.

One of the major durability issues of Reinforced Concrete (RC) structures is the steel reinforcement corrosion. Its effect needs to be evaluated on the lateral load capacity of the structures for understanding their seismic performance. In the present paper, the precise FE modelling and simulation of corroded RC frames subjected to lateral loads and its validation with full scale shake table tests on corroded RC frames is demonstrated. The rebar corrosion is induced in RC frames by accelerated impressed current technique and shake table tests are performed by simulating real time earthquakes with increasing excitation till failure of the frames is achieved. The tests showed that there was higher degradation of the frequency of the corroded structure with respect to pristine structure with increase in earthquake excitation levels. Numerical simulation of the tests is carried out using 2D micro-modelling, incorporating the effect of bond strength reduction, reduction in rebar diameter and decrease in mechanical properties of corroded steel in the model. Nonlinear static pushover analysis is performed to evaluate load displacement characteristics of the corroded and uncorroded frames and the results are compared with dynamic pushover obtained from shake table tests. It was observed that compared to un-corroded frame there is 13% reduction in the failure load due to earthquake excitation for the 7.5% corroded frame and numerical results for 10% corroded frame showed 22% reduction in the lateral load carrying capacity.

Concrete, owing to its brittle nature is weak in tension and therefore, a significant amount of published research has focused on the addition of fibers to improve the flexural performance of concrete. The addition of fibers in a concrete matrix improves its overall performance in terms of strength, ductility, and durability by the mechanism of restraining crack width. Steel fibers are found to be the most efficient in improving the flexural strength of concrete. The design mix for Steel Fiber-Reinforced Concrete (SFRC) is chosen mostly based on the trial mixes. To aid the mix design of SFRC, this study attempts to provide predictive models using machine learning techniques such as non-linear regression on a database of 146 samples, collated from literature. 80% of the randomly chosen samples are used for training the model and the remaining 20% are used to test it. The Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), the statistical significance of the model coefficients, and the coefficient of determination are adopted as criteria to check the performance of the model on both the training and test data. Interaction terms such as fiber factor and number of fibers within a volume were inferred from literature to improve the efficacy of the predictive modeling. Two non-linear models for the prediction of compressive and flexural strength of hooked-end SFRC are proposed and validated. Using the proposed models, the variations in compressive and flexural strength with the key parameters were plotted and discussed. With a decrease in the water-to-binder ratio, there was a significant improvement in compressive strength from 55 MPa to 85 MPa at an aspect ratio of 60. A significant improvement of about 200% to 300% in flexural strength was noted with an increase in fiber factor from 0 to 150.

According to recent data, many bridges tend to fail due to seismic inadequacy in design. Circular piers are more effective in reducing scour depth and increasing the durability of bridges than an elliptical bridge pier. The question is “whether circular pier performs better under seismic action than elliptical pier or not”. So a comparative study was conducted to analyze the behavior of circular and elliptical piers under earthquake forces, and complete nonlinear static pushover analysis was carried out for two different bridge models separately. Pushover curve data from Indian Standard Code was used to formulate the problem and performance outcomes of the bridges were analyzed. It was found that single circular pier showed no failure and better performance in both directions of the bridge, with more displacement capacity than double elliptical piers when subjected to incremental lateral loads. The design capacity (D/C) ratio in the longitudinal direction was 1.8 times more for single circular pier bridge and in the transverse direction, the ratio was 1.4 times more for double elliptical pier bridge for the considered earthquake situation. Results also showed 47% less drift value for single circular pier bridge compared to double elliptical pier bridge.

In this review, we evaluated health care problems, which were not common before pandemic outbreak but have been common issues after its appereance and approaches to control pandemic considering its influences on people. We revised current health care developing approaches under the light of experience obtained throughout the pandemic so far. The aim is to be prepared in advance for possible upcoming pandemics. As in Covid 19 pandemics, such long lasting and widely affecting situations, durability is also very important together with flexibility and quickness. To provide durability, we need global policies taking the health to its center as well as health system policies.

The use of Ultra-High Performance Concrete (UHPC) has been growing rapidly in the past two decades because of its superior mechanical and durability properties compared to conventional concrete (CC). Flexural strength prediction models of CC components underestimate the flexural strength of non-prestressed UHPC components as they ignore the tensile strength of concrete and assume different stress–strain relationships and failure mode from those of UHPC. The objective of this paper is to evaluate the current flexural strength prediction models of non-prestressed UHPC components using test data collected from the literature and validate them using experimental data of a UHPC ribbed slab tested in flexure. Measured and predicted flexural strengths are compared at different curvatures. Evaluation results indicated that neglecting the tensile strength of UHPC significantly underestimates the flexural strength of non-prestressed UHPC components. Peak moment curvature of non-prestressed UHPC components is significantly smaller than ultimate moment curvature. In addition, the differences among idealized stress–strain relationships of UHPC in compression and tension do not have significant effect on the predicted flexural strength.

Structural concrete is a composite material commonly used for the construction of buildings and structures. Reinforced concrete members should be designed for strength, as well as durability. The long service life of the entire structure depends on the durability of concrete. The quality of construction materials, cover to the concrete, exposure conditions and quality of concrete are some of the key factors that affect the durability of concrete. Also, water penetrates easily and finds its way inside concrete through connected pores if the degree of compaction is not proper. Stagnant rainwater in the roof or a high water table may pave the way for the entry of water. The entry of water into structural concrete mainly causes corrosion, thereby reducing the strength of structural elements and initiating the spalling of concrete. A case study based on diagnosis, non-destructive testing and failure analysis of a reinforced concrete building in India is presented. The rehabilitation measures to be undertaken to maintain the service life of the building are also presented.

Preflex beam girders with remarkable advantages are widely used in bridge structures. With aging, preflex beam bridges undergo concrete cracking and degrade as the cracks propagate and deteriorate due to repeated service load application and exposure to humid and saline environment. The objective of this study was to evaluate concrete cracking, changes in prestress, and consequent changes in sectional properties as the preflex beam undergoes deterioration in its concrete casing under cyclic loading. The experimental study investigated the behavior of a preflex beam specimen under multiple cyclic loading ranges, reproducing different deterioration levels in the concrete casing of the specimen. Relating concrete deterioration to resulting changes in the girder’s structural behavior, the study outlined recommendations for monitoring approaches in actual bridges. The study concluded that with advancement in concrete deterioration, the preflex beam girder loses prestress that results in reduced strength of the girder and remarkable changes in its sectional properties. The study also concluded to minimize prestress loss and changes in sectional properties of the girder, closer spacing for shear ribs welded to the lower flange can be helpful., 論文

Concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) are attractive as beams and arches in harsh environments due to their durability and ease of erection. A successful infrastructure application is the use of multiple, buried CFFT arches in short-span bridges. To effectively analyze and design CFFT arches under complex loadings, there is a need for numerical procedures that capture the structural behavior of CFFT arches including the effects of FRP confinement on the concrete core and second-order response. Here, a computationally efficient structural finite-element analysis technique for the second-order inelastic behavior of these CFFT arches is detailed. A curved, flexibility-based, layered-frame element is employed to handle geometric and material nonlinearities. A concrete constitutive model that explicitly considers the effect of dilation of the concrete core and confinement provided by the FRP tube is implemented. A bending test was performed on a CFFT arch, and experimental data compared with model predictions. Additional comparisons are made with CFFT arch and beam bending tests available in the literature. The model is shown to accurately predict the load-carrying capacity and ductility of CFFT members, and to capture arch collapse mechanisms arising from FRP rupture and concrete crushing.

Sisal fibers are reported to have outstanding textile properties including high strength, absorbency, good dye uptake, exceptional durability and abundant availability suggesting their potential in...

Recently, flexible electronic device technology has evolved beyond curved devices with the development of flexible/stretchable devices that can be crumpled or stretched. Both elasticity and durability are essential for these devices, which should have high-conductivity for antennas and repeatability for sensors. In addition, electronic-skins, which can have a direct impact on the human-body, should be harmless to the human-body and should not be deformed by contact with sweat or organic matter. In this study, PDMS substrates were used to satisfy the above conditions. PDMS is used to fabricate human-friendly, flexible/stretchable substrates, and it has excellent repeat durability characteristics. To improve the adhesion of these PDMS films and electrodes, conductive paste was produced based on PDMS resins of the same properties. In addition, two types of Ag particles were selected as conductive fillers because the electrode characteristics of the antenna application requires excellent conductivity, and conductive paste were produced using flake Ag, which could affect conductivity, and Ag nanoparticles that affect stretchability and repeatability. The paste was applied using a high-efficiency printing technique. The printed electrodes were cured in a thermal oven. For higher conductivity, photonic-sintering was carried out during post-processing. As a result, 1.1117×106 (S/m) had excellent conductivity, performed well in repeated tensile-durability experiments of 30% to 100 times, and produced a bow-tie antenna for the above electrodes. As a result of tensing up to 35% through a Network-Analyzer, there was no performance change in the resonance-frequency or return-loss values, and excellent electrodes were developed that would achieve excellent performance even if they are applied in the sub-frequency area of 5G-antennas in the future.

Ultra-High-Performance Concrete (UHPC) has the remarkable durability and outstanding mechanical properties such as exceptionally high compressive strength and superior tensile strength. Therefore, the cross section of UHPC structure is generally optimized to make members light and thin. This paper investigated the behavior of single bolt embedded in thin HSC (high strength concrete) and UHPC members under tension loading. Fourteen tension tests were conducted to study the influences of concrete type, embedment depth and diameter of bolt on anchorage performance. The anchorage performance of these anchors embedded in UHPC were significantly improved compared with the bolts in HSC concrete, in both load capacities and displacement capacities. The superior strength and fiber bridging reduced the Angle of fracture, which is approximately 20° to 24°. As a result, the concrete breakout failure area was improved, resulting in an increase in breakout strength and displacement capacity. The test results were discussed in detail to emphasize the influence of concrete splitting on the anchorage performance of bolts embedded in UHPC members. Compared with HSC members, due to the fiber bridging, failure of UHPC members did not happen when splitting. However, the concrete splitting resulted in the decrease of breakout strength. Finally, a splitting modification factor is proposed to predict anchorage strength based on the test results obtained in this paper and others.

Reinforced concrete (RC) slabs of highway bridge decks are gradually deteriorated due to the traffic vehicle wheel-loading. Fatigue is one of a number of possible causes for the deterioration. Cantilever RC slabs of the bridge are also damaged by fatigue loading. To increase the fatigue durability of the bridge deck slab, the near-surface mounted (NSM) technique is used with carbon fiber reinforced polymer (CFRP) rods embedded in the RC slab as an effective strengthening method. This study presents the fatigue characteristics of cantilever RC slabs strengthened with CFRP rods with a high-modulus of elasticity. A cantilever RC slab specimen with embedded CFRP rods with high moduli was constructed on a moving-wheel load testing machine and tested for approximately 11 months. The slab had a minimum thickness of 160 mm (as stipulated by the Japanese design code), and the minimum number of steel reinforcements was embedded to ensure (negative) flexural failure of the RC slab where CFRP rods were not used. During the test, the CFRP strengthened slab specimen was subjected to a negative bending moment from repeated moving-wheel loads. Very limited experimental data are available for the evaluation of the structural behavior of cantilever bridge decks subjected to wheel loads. Therefore, the moving-wheel fatigue experiment of the cantilever RC slab with NSM CFRP rods would be useful information for strengthening. The moving-wheel loading test confirmed the increase in fatigue durability of the CFRP strengthened slab as the slab specimen endured approximately 3.56 million equivalent-cycles at an initial load of 60 kN, which was 32% higher than the designed service load. The experimental investigation revealed that the ultimate failure of the cantilever slab was punching shear failure attributed to the rupture of the CFRP rods.

Delivery of adeno-associated viral vectors (AAVs) to cerebrospinal fluid (CSF) has emerged as a promising approach to achieve widespread transduction of the central nervous system (CNS) and peripheral nervous system (PNS), with direct applicability to the treatment of a wide range of neurological diseases, particularly lysosomal storage diseases. Although studies in small animal models have provided proof of concept and experiments in large animals demonstrated feasibility in bigger brains, there is not much information on long-term safety or durability of the effect. Here, we report a 7-year study in healthy beagle dogs after intra-CSF delivery of a single, clinically relevant dose (2 × 1013 vg/dog) of AAV9 vectors carrying the canine sulfamidase, the enzyme deficient in mucopolysaccharidosis type IIIA. Periodic monitoring of CSF and blood, clinical and neurological evaluations, and magnetic resonance and ultrasound imaging of target organs demonstrated no toxicity related to treatment. AAV9-mediated gene transfer resulted in detection of sulfamidase activity in CSF throughout the study. Analysis at tissue level showed widespread sulfamidase expression and activity in the absence of histological findings in any region of encephalon, spinal cord, or dorsal root ganglia. Altogether, these results provide proof of durability of expression and long-term safety for intra-CSF delivery of AAV-based gene transfer vectors encoding therapeutic proteins to the CNS., Graphical abstract, Seven-year follow-up of dogs after intra-CSF administration of AAV9-sulfamidase vectors results in detection of sulfamidase activity in CSF and widespread transgene expression in CNS, PNS, and liver, in the absence of any adverse events. Proof of durability and safety of this gene therapy support its clinical translation to treat CNS diseases.

There is a global drive to promote and optimize the design of high performance buildings at low cost and minimum environmental impact. Although reinforced masonry construction is known for its better fire protection, structural durability, and construction cost reduction, its use is hindered by a lack of understanding of its resistance to earthquake loads. This research aims to quantify the effect of influential parameters on the seismic performance of Reinforced Masonry Shear Walls (RMSW) with masonry boundary elements (MBEs). A new system/configuration for RMSW with C-shaped masonry units has been proposed. A new experimental test setup was designed and built to capture the response of the lower panel of RMSW in a 12-storey building subjected to quasi-static loading protocol. Test results showed that the proposed system could provide the lateral strength and ductility required to resist earthquake events and that the average measured compressive strain was almost four times the limit specified in CSA S304-14. The results also showed that single out-of-plane support at the loading beam level was inadequate, leading to out-of-plane failure. When additional out-of-supports were provided, the failure mode changed to web crushing and buckling of vertical web reinforcement.

Textures of concrete pavements not only provide essential functions for vehicles but also affect the durability of pavements. The development of 3D printing and prefabrication technologies enables ...

Despite increasing attention on how community enterprises support community well-being and public services, we know little about how durable they are to sustain their activities. Previous research has studied individual conditions for durability, ignoring the intricate interplay between these conditions. Based on literature on community enterprises, we identified five key conditions for durability. Using semi-structured interviews with representatives of 19 community enterprises, this article aims to better understand the interplay between these five conditions affects community enterprises’ durability. A fuzzy-set Qualitative Comparative Analysis revealed ‘aligned entrepreneurial culture’ as a necessary condition and identifies two configurations of conditions sufficient for durability.

Automobiles, while making living easy and convenient, have also made human life more complex and vulnerable to toxic emissions. Transport sector is huge contributor in polluting air in the entire world in the tune of around 23%.Mass transport uses buses as the medium for generalized and convenient means for commutation from one place to other. Similar pattern is observed in India for mass transportation mainly in the cities. However, commuting through buses comes with penalty of environmental pollution. City buses are large contributor in GHG emission and can be considered as prime candidates for making any kind of changes which will help in reducing environmental pollution. Immense potential lies in existing bus designs for weight optimization which has direct impact in improving fuel economy and hence will have sustainable impact in reducing carbon emissions. This paper outlines systematic approach used for development of lightweight buses using Aluminium addressing safety, durability and necessary regulatory requirements. Effective use of aluminium in development of lightweight bus structure is demonstrated in this project. While designing lightweight structure for weight optimization due care is taken for addressing prevailing regulatory norms related to AIS:052 bus body code, AIS:153 outlining safety requirements and Urban Bus Specification issued by Ministry of Road Transport and Highways specifying strength and safety requirements of bus structure. Aluminium bus designs developed shows more than 30% weight reduction compared to steel structured buses of similar class. Fuel efficiency improvement in the tune of minimum 8% and maximum 10% are observed during field level trials.

Asphalt concrete (AC) overlays have been one of the most common treatments used by the Virginia Department of Transportation (VDOT) for maintaining/rehabilitating pavements. However, when the overlay is placed on existing composite pavements or cracked AC pavements, differential movements across any cracks or joints can result in physical tearing of the AC overlay. Thus, the long-term performance of many AC overlays will highly depend on their ability to resist cracking. The purpose of this study was to assess the viability of using high polymer-modified (HP) AC mixtures in Virginia as a crack mitigation technique or when deemed appropriate as a tool for increased resistance to rutting and cracking on higher volume facilities. Another objective was to assess the ability of various testing protocols to discern the performance of pavements through a comprehensive evaluation of three conventional polymer-modified (PMA) and five HP field-produced mixtures placed in Virginia. This included laboratory testing at multiple levels of complexity (basic, intermediate, and advanced) on collected asphalt binders, plant-produced asphalt mixtures, and field cores. The performance characteristics of PMA and HP mixes were evaluated in the laboratory in relation to durability and resistance to rutting and cracking. Based on the mixes tested, stone matrix asphalt (SMA) mixes showed better performance than dense-graded surface mixes (SM) regardless of the asphalt binder type. Moreover, HP mixes showed better performance than PMA mixes regardless of the mixture type. Overall, SMA-HP mixes showed the most promising performance among all evaluated mixes.

Background. In spinal surgery for interbody fusion, titanium implants are used predominantly, they can be integral or consist of several parts. For cancer monitoring, not only laboratory examination methods are used, but also computed tomography and magnetic resonance imaging. On computed tomography in the postoperative period using metal structures, the effect of increa­sing the radiation hardness or blurry image is determined, and on magnetic resonance imaging — an artifact of magnetic susceptibi­lity. One of the promising materials that meets the requirements of biocompatibility, strength properties and the absence of contraindications for radiation diagnosis is carbon-carbon composite. Purpose was to study in the experiment the strength characteristics of interbody cages of various designs made of carbon-carbon composite material. Materials and methods. An experimental study of the strength properties of intervertebral implants to replace removed vertebrae was carried out. All implants were made of carbon-carbon composite material. Four types of vertebral retainers of 3 specimens each were examined: a threaded connection of a screw with a cup, a pin with support on the washers, a pin with support on a cotter pin, a pin with fixation with bone cement. Results. An analysis of the obtained experimental data showed that structures with a threaded joint can withstand loads of 956.7 ± 165.0 N. The main breakdown is thread cutting and screw sagging. Samples with one expansion washer withstand the highest fracture load of 5000.0 ± 150.0 N, with 2 expansion washers, the samples were destroyed by a load of 4250.0 ± 88.9 N, with 3 washers — under a load of 3083.3 ± 160.7 N, that is, each additional expansion washer in the design statistically significantly reduces the value of the breaking load. Samples with a cotter pin withstand a destructive compressive load on average of 2833.3 ± 208.2 N, which led to the destruction of a cup with a cotter pin, which caused the pin to sag. Tests of samples without a cotter pin showed that they are able to withstand a statistically significantly greater breaking load of 5100.0 ± 100.0 N. Solid structures that do not have small structural elements — thread or cotter pin — withstand highest compressive loads. Tests of samples with cement showed that when spreading by 5 and 7 mm, there were no destructive changes at the maximum possible load of 6000 N for the experimental installation. Conclusions. Structures with a threaded connection turned out to be the weakest; constructions with a cotter pin withstood three times as much load before breaking. And although the threaded structures are considered quite durable, the features of the material (carbon) do not meet the requirements that are applied to threaded joints. Carbon materials are quite fragile, therefore, cotter pin designs also turned out to be imperfect. Designs with expansion washers proved to be quite good, but an increase in the expansion height of the implant led to a reduction in the structural strength and, as a result, to a decrease in the ability to withstand loads. The solid structures turned out to be the most durable, and the additional strength due to cement turned them into monolithic heavy-duty products.

The corrosion environment of a steel truss bridge significantly shortens its service life, particularly the chemical pollution in the air. A linear corrosion prediction model is proposed based on Miner’s linear cumulative damage concept to solve the difficulty of implementing accelerated corrosion tests. Moreover, an equivalent fatigue test is designed in combination with the corrosion prediction model. The results indicate that the bridge’s fatigue resistance can meet the design requirements when the corrosion environment is not considered. When the corrosion effects are jointly considered, the fatigue durability of the bridge is insufficient. With the increase in fatigue cycles, stiffness degradation presents a three-stage trend. The intermediate stage is a gentle development stage from the fatigue test results, accounting for approximately 80% of the total life cycles. Finally, a fatigue damage prediction model considering corrosion factors is established, and the law of fatigue damage and stiffness degradation of the structure under a corrosive environment is determined.

With increasing global research on the recycling of construction waste, the recycling of waste concrete aggregates has gradually attracted attention. Researches have shown that recycled aggregate (RA) has a certain degree of influence on the mechanical properties and durability of recycled aggregate concrete (RAC) owing to its high water absorption, high porosity, and large number of microcracks. Therefore, how to improve the mechanical properties and durability of RAC is a key issue of concern for scholars. Based on the review of related literature and comprehensive analysis, the reinforcement theories and methods such as self-reinforcement of recycled coarse aggregate (RCA), optimization of preparing technology of RAC, and external spiral constraint of RAC were systematically summarized in this paper. The results indicate that the adherent mortar of RCA can be enhanced by carbonation, and weak acid treatment can effectively remove the old adhesion of RCA, which is economical and environmentally friendly. The denseness of RAC can be improved by adding cementitious materials with volcanic ash effect, and the reduction of microcracks in mortar can be improved by adding fibers. The load-bearing capacity and mechanical properties of RAC are significantly improved by the spiral constraint of materials such as fiber reinforced polymer (FRP) and so on. The optimization of the production process not only improves the quality of RAC, but also enhances the production efficiency. The microstructure analysis of RAC was also summarized in this paper. Moreover, the results of this study can provide a technical reference for research on the mechanical strength and durability of RAC, develop the further research ideas, and promote the application of RAC. Finally, some potential opportunities and development directions have been suggested for future research on the improvement methods of RAC.

The popular use of silver nanoparticles (Ag NPs) in commercial textile products that inhibit odor- and/or infection-causing bacteria has continuously raised concerns about their washing durability. The poor durability not only deteriorates the antibacterial performance, but also results in unwanted leaching of NPs into washing solutions. In this study, we showed how the incorporation location of Ag NPs—interior vs. exterior of cotton fiber—governs their durability against consecutive simulated home launderings. The superior washing durability of interior NPs was confirmed. The Ag losses after 50 laundering cycles for interior and exterior systems were 16% and 63% in water and 24% and 78% in detergent solution, respectively. The cotton fabric containing interior NPs predominantly released ionic Ag, whereas the fabric containing exterior NPs released particulate Ag.

This paper shows how to use the spent cells from the geoning of laminates. Building stages of the molding mix in the shells are preset which is extending their period of operation and then achievement of significant economic savings.

Self-compacting concrete (SCC) is a highly stabilized flowable concrete that can be used in both dynamic and static states without segregation. Additionally, the exceptional homogeneity of the material contributes to its strength and durability. To produce sustainable SCC, it is necessary to incorporate appropriate supplementary cementitious materials (SCMs) to enhance mass construction applications. Thus, this review of SCC examines the stages of development and adoption, with a particular emphasis on the role of various calcium-rich, silica-rich, and engineered/reactive silica-rich SCMs as blends in achieving sustainable concrete. By summarising and comparing the properties of SCC in the plastic and hardened states in terms of workability, segregation, strength, and durability. According to the annotations in this review, researchers proposed that during the early stages of developing studies on SCC, the limits of constituent material proportioning be designed with the influence of ultra-fine fly ash (UFFA), an improved reactive supplementary material with a more appropriate particle size that is engineered from high silica-rich fly ash. Additionally, prior research indicates that an artificial neural network (ANN) is a more effective prediction tool for conducting and validating SCC experiments. However, no comprehensive study has been conducted on the effect of ultra-fine fly ash (UFFA) on SCC in the plastic and hardened states; additionally, the ANN can be an excellent tool for validating those properties, which is the novel scope of this review.

The feasibility of a machine-learning algorithm is discussed in terms of strain-history prediction and durability evaluation of automotive components. Additionally, an additional benefit using the machine-learning is reported; that is the acquisition of strain histories from sensors other than strain-gages. More specifically, the strain-history prediction performance was compared depending on how to prepare and learn data from each driving event, and the accuracy was analyzed with respect to the dominant direction of wheel-forces. Moreover, detailed information on the strain-history extraction was provided. Consequently, the performance of the network that learned the data generated from whole PG was better than one that learned a single driving data. For better application of machine learning to strain estimation for automotive components, timesteps of 80 were found to be the optimal parameter. And it was suggested that the data ranges for machine-learning training be larger than that in real-application to minimize discrepancies around peaks.

Particleboard composites for building application has become very attractive because of their huge benefits which includes but is not limited to low cost, lightweight, durability and environmental benign. However, the vulnerability of these composite types when exposed to fire restricts their use in areas where stringent fire safety conditions may not apply. Experimental determination at bench scale of composite particleboard fire behaviour has shown that the addition of flame retardants (FR) can delay the start and spread of fire. Bench scale data obtained in the cone calorimeter (CC) may not represent accurately a real scale fore behaviour during a fire scenario as documented by various researchers. The convolution model is a significant tool for predicting in real scale, fire behaviour of composites which depends on experimental inputs from CC data. In this paper, particleboards made from wood sawdust reinforced polyester composite were processed with FR at 0, 15 and 18% loading ratio using compression moulding technique. Test specimens cut from the FR-particleboards was exposed in horizontal orientation in the CC at 50kW/m2 to obtain experimental data and these were used as inputs to the prediction model. The predictive tool was used to predict the heat released rate and smoke production rate for the FR-particleboard. The results obtained shows that the FR-particleboard contributes very limited fire in real scale and compares well based on Euro-classification with particleboards from literature.

One solution to the high cost and scarcity of building materials is to use alternative and sustainable materials. The study presented herein developed an eco-friendly masonry grout using high volumes of palm oil clinker powder to replace cement and palm oil clinker to replace coarse aggregate. Several batches of grouts with different amounts of these materials were made to determine the technical viability of the grout. Scanning Electronic Microscope (SEM), X-Rays Diffraction (XRD), Energy Dispersive X-Ray (EDX) and Thermogravimetric Analyzer (TGA) analyses were conducted to investigate the microstructure characteristics of the grout, and water absorption, initial rate of absorption, sulphate attack and electrical resistivity tests were conducted to determine its durability. Compressive strength tests were conducted at different curing ages and the drying shrinkage of the grout was monitored for 180 days. The results indicate that the new grout is as good as a conventional grout but with added sustainable and economic benefits. The new grout can be used in masonry construction and can be used to alleviate the inadequate supply of affordable housing.

Bearing units of lifting machines, products of construction, road, aviation, space and other branches of technology are very important structural elements, since the failure of even one bearing can cause the failure of the entire product. The results of experimental verification of the theoretical model of bearing operation under combined loading conditions are presented. The behavior under load of bearing units in the most general case can be represented by a sequence of five design schemes, expressed in the form of five statically indeterminate beams. The purpose of the experiments was to test this model under real loading conditions. The experiments were based on the analysis of the geometric shape of the curved elastic line, which the shaft of the bearing assembly acquires under load. The experimental results confirmed the validity of the model and showed that the previously generally accepted model of a two-support beam is not implemented. The conclusion is confirmed that in responsible lifting machines, as well as in responsible products of construction, road, aviation, space and other branches of technology, it is impractical to calculate bearings according to the traditional method, since an erroneous value of bearing durability can be obtained, overestimated from 28.37 to 26.663.9 times.

Ultra-high performance concrete (UHPC) been an advanced concrete introduced as reactive powder concrete (RPC) over twenty years ago, is now being employed for use in the construction industry of some developed countries like China, Germany and United States of America. Its excellent properties in structural performance and durability make it the civil engineering material that will reshape the future of the construction industry in terms of structural performance; and this paper aims at helping construction experts and developing countries to understand and accept UHPC for use in everyday construction works. The paper gives an in-depth review on the classification of UHPCs based on mix proportion and mechanical properties. Firstly, the mixture design and the mechanical properties of UHPC were discussed. Then UHPC was classified into different types based on mechanical properties and the manufacturer’s modification of the ingredients used for reactive powder concrete or multi-scale cement composite production. This review shows that Funk and Dinger model (also known as Modified Andreasen and Andersen model (MAA)) is the most accepted and widely used mix design method for UHPC. It also revealed that UHPC’s compressive strength, tensile strength and flexural strength are in excess of 150, 7 and 40 MPa respectively. It further classified UHPC into BCV®, BSI®, Cemtec®, Ceracem, Ductal, DURA and UHPC with coarse aggregate; and this classification (especially UHPC with coarse aggregate) is a good sign that local materials can be incorporated into UHPC by developing countries for cost minimisation.

High-volume fly ash (HVFA) cementitious composites (paste, grout, mortar, and concrete) have been widely investigated as a class of sustainable materials due to their lower carbon footprint and often better life cycle performance than conventional Portland cement mixtures. Recent years have seen increased research in HVFA-based materials, and the potential of this type of mixtures in engineering applications has significantly improved. In this context, this work reviews the renewed knowledge of HVFA mixtures, focusing on the relevant papers published over the last decade. The effects of replacing cement with a HVFA binder on the fresh properties, mechanical properties, durability performance, and environmental impact of HVFA cementitious composites are explored. Measures that can compensate for the main drawbacks that limit the wider application of HVFA mixtures are discussed in detail. At last, we summarize the research needs and remaining challenges of HVFA cementitious composites.

The paper provides an overview of the known designs of water wells. A new design of a two-column two-filter water intake well has been also proposed, in which the filters are arranged in two tiers. This will lead to an increase in water intake capacity and will reduce the filtration rate on the approach to the filters. This, in turn, will create conditions for reducing head losses and will make it possible to reduce drawdowns in the well, ensuring a reduction in the cost of produced water. This design combines both working and reserve wells located in one borehole, which increases its reliability, durability and uninterrupted water supply to the consumer. A method for calculating the hydraulic parameters of a two-column two-filter water intake well is presented in the paper. It is based on dependencies for calculating the main geometric dimensions for a given design flow rate and hydrogeological characteristics of an aquifer, as well as formulas for determining a decrease in a well for a given period of operation when one and two pumps operate simultaneously. The basics of designing a well of the proposed design are outlined in the paper. The paper considers an example of calculation for a new well design instead of an existing typical well that has reduced its specific flow rate.

It presents various combinations of primary hardfacing technology for the renovation and improvement of the resource details of ship machinery. Currently, promising are integrated or combined methods hard facing (hybrid technology) coating in conjunction with the modification, the application of multi-layer, multi-functional coatings; development of integrated multioperational technologies. In all conditions, increasing scarcity of expensive alloying materials included in the composition of steels requiring high strength properties of the complex, are promising hybrid technology peening (restore) the surfaces of mild steel Combinations of various primary technologies of application of multipurpose coverings for restoration and increase of a resource of details of knots and units of vehicles are presented. Currently promising are combined methods of application of multifunctional coatings (integrated, hybrid technologies), methods of coating in combination with methods of modification, application of multilayer, multifunctional coatings; development of combined (integrated, hybrid) multioperational technologies. In the conditions of growing shortage of expensive alloying materials which are a part of the steels demanding a high complex of properties of durability, the combined methods of restoration of surfaces are perspective.At present, a methodology for the synthesis of combined multi-operational technologies has not been developed. An empirical-intuitive approach prevails in the combination of multifunctional coating restoration methods. The optimal choice of restoration methods and their sequence is determined by the increase of hardness, complex of mechanical properties, wear resistance, as well as the roughness of the restored surface and the accuracy of the dimensions of the restored part. In the first-best case of combined (hybrid) methods of recovery, the criterion of choice is the comparison of costs and increase the set of mechanical properties of the recoverable parts of components and units of vehicles [13-14]. Each method of recovery has its niche of optimal conditions of use, including even the technological traditions that have developed in a particular enterprise. The decisive factor in the choice of primary methods of applying multifunctional coatings in the combined restoration process is the presence of certain types of equipment at the enterprise and the ability to integrate them intoa single technological cycle. In order to restore vehicle parts with multifunctional coatings with high adhesion strength, hardness and wear resistance, we have proposed a combined (integrated) technology that includes electric arc spraying, electrospark doping and pulsed ion nitriding.

The paper comprehensively reviews durable polylactic acid (PLA)-based engineered blends and biocomposites supporting a low carbon economy. The traditional fossil fuel derived nonrenewable durable p...

Rolling bearings are widely used in the products of aviation and space technology. To ensure their long-term trouble-free operation, it is necessary to have accurate and reliable information about the forces acting on the bearings. The required values of forces and, accordingly, the required durability of bearings are usually determined on the basis of the traditional design scheme of a double-support beam (smooth beam mounted on two hinged supports). The paper presents a new interpretation of the features of the operation of bearing units on ball radial single-row bearings installed according to the cross located arrangement. It is shown that under conditions of combined loading, including radial and axial forces, the generally accepted theoretical model of a doublesupport beam is not implemented. There is no single calculation model that adequately reflects the nature of the interaction of bearing parts over the entire range of external loads. In the most general case, this model can be represented by a sequence of five statically indeterminate calculation schemes, which are modified and transformed into one another. So, with an increase in the external radial force, the cantilevered beam with additional hinge support scheme is first implemented, which, then, is transformed into the double-sided jamming scheme, and that, later, is transformed into the two double hinge supports scheme. It is also possible to implement two intermediate transition schemes. A specific example shows that in the products of aviation and space technology, determining the durability of bearings based on the traditional model is not advisable, since it can give an overestimated value with an error of 28,37 to 26663,9 times.

With the rapid development of society and industry, novel technologies and materials related to pavement engineering are constantly emerging. However, with the continuous improvement of people’s demands, pavement engineering also faces more and more enormous challenges that the pavement materials must have excellent engineering properties and environmental benefits. Meanwhile, the intelligence is the mainstream development direction of modern society, and the development trend of future transportation infrastructure. Materials Genome Initiative, a program for the development of new materials that materials design is conducted by up-front simulations and predictions, followed by key validation experiments, the rapid development of science and technology and AI toolset (big data and machine learning) provide new opportunities and strong technical supports for pavement materials development that shorten the development-application cycle of new material, reduce cost and promote the application of new carriers such as intelligent sensing components in transportation engineering, to achieve the intelligence of transportation engineering. However, traditional pavement materials possess several unavoidable shortcomings, indicating that it is exceedingly difficult for them to meet the above requirements for future pavement materials. Therefore, the development of future new pavement materials, which can be designed on-demand as well as possessing enough mechanical properties, high durability, practical functionality, and high environmental protection, is urgent. In recent years, as a “designable” polymer material with various excellent engineering performances, polyurethane (PU) has been widely applied in pavement practices by changing the chemical structures of raw materials and their mix proportions, for instance pavement repairing material, permeable pavement material, tunnel paving material and bridge deck paving materials, etc. Although PU material has been widely applied in practices, a systematically summarization is still quite necessary for further understanding the working mechanism of PU materials and optimization it’s engineering applications. To fill the gap, this article puts forward the special requirements for future transportation infrastructure materials, and introduces the basic properties and working mechanism of PU materials in order to make up for the defects of conventional road materials. Based on this, this article also summarizes the engineering performances and environmental benefits of applying PU as the binder for different road infrastructure materials in recent years. Considering the gene-editable nature of polyurethane, further research of the on-demand design principles of PU pavement materials is recommended. The establishment of raw material gene database, material terminal performance database and their structure-activity relationship are highlighted. The current research is essential to the practice guidance and further optimization of the PU materials for road infrastructures, which in line with the future Carbon neutral policy.