Repair Projects Research Articles

Enhancing mechanical properties and crack resistance of high-strength SHCC/ECC for durable transportation through ethylene-vinyl acetate polymer modification

Strain-hardening cementitious composites (SHCC) possess excellent ductility and toughness, making them suitable for reinforcement and repair projects of transit infrastructures, such as tunnel linings, bridges, and highways. Especially, polyethylene (PE) fiber is admixed to SHCC for fabricating high-strength PE-SHCC. However, the hydrophobic nature of PE fibers results in relatively weak interfacial frictional bond strength with cementitious matrix, ultimately leading to larger crack widths and wider gaps. This poses durability and safety concerns for the practical applications of PE-SHCC in transit infrastructure. In this study, ethylene-vinyl acetate (EVA) dispersible polymer is selected to address this problem. The effect of admixing EVA on mechanical and direct tensile properties of PE-SHCC is investigated. The compressive strength, first crack strength and matrix fracture toughness of PE-SHCC tended to decrease after EVA modification, however, the tensile strength and tensile strain increased significantly with doping. After that, the single fiber pullout test combined with flaw size/distribution analysis is performed to explore the improvement mechanism of PE-SHCC after EVA modification. It was found that the addition of EVA could significantly improve the interfacial transition zone (ITZ), increase the interfacial friction between PE fibers and matrix, and optimise the defect distribution within the matrix. The recommended dosage of EVA is 3–6 % comprehensive consideration of the tensile strength, strain energy, crack width, and mechanical strengths of the EVA-modified PE-SHCC. The enhancement of mechanical strengths and crack resistance in PE-SHCC contributes to the development of transit infrastructure towards greater reliability, durability, and resilience.

RePAIRing the student nurse journey: empowering interrupted students through innovative support strategies.

This article reports on a study that evaluated an innovative 6-week summer returners' programme, part of the Health Education England RePAIR project, designed to support nursing students who have interrupted their studies. Held from May to July 2022, the programme addressed diverse needs through academic guidance, mental health and resilience workshops, creative arts, professional identity development, and practical nursing skills training. The programme ran alongside support from the programme team, student engagement services, and ongoing communication via phone and email. Despite non-mandatory sessions leading to varying attendance, the combined efforts facilitated the return of 67 out of 135 interrupted students. Thematic analysis identified four key themes: anticipation and fear, making contact and reaching out, preparing for return, and psychological wellbeing. The programme's effectiveness underscores the necessity of tailored support strategies to enhance retention and wellbeing. This innovative approach highlights the importance of personalised support in aiding nursing students' return to education and addressing nursing workforce shortages.

Predictions of mechanical properties of Fiber Reinforced Concrete using ensemble learning models

Fiber Reinforced Concrete (FRC) significantly improves the tensile, crack resistance, and durability of concrete by adding fiber materials, making it highly promising for applications in structural reinforcement, repair and new construction projects. The strength of FRC is a crucial indicator of its mechanical properties. This study utilizes ensemble learning techniques to predict and analyze the compressive strength, splitting tensile strength, and flexural strength of FRC. A total of 1589 sets of compressive strength data, 1137 sets of splitting tensile strength data, and 1061 sets of flexural strength data were collected from existing literature. Four ensemble models (GBDT, Xgboost, LightGBM, RF) were used to establish prediction models and analyze influencing factors for these three FRC mechanical properties, and the results were compared with traditional models. The results show that the ensemble models can effectively solve the FRC strength prediction problems compared to traditional models. The GBDT regression model performed best in predicting compressive and flexural strength, with R2 values of 0.939 and 0.867, respectively. The Xgboost regression model performed best in predicting splitting tensile strength, with an R2 value of 0.944. Further analysis using SHAP revealed that cement and water significantly impact FRC strength. The inclusion of fibers significantly affects the splitting tensile strength and flexural strength of FRC but has a minimal impact on compressive strength. The study not only demonstrates the feasibility of using machine learning algorithms for FRC strength prediction but also provides a fast and reliable means for FRC strength prediction, offering more reliable data support for the design and application of FRC materials, aiding practical engineering applications.

Evolving nature-based solutions for Australia’s Indigenous estate in 2024 – opportunities and challenges

Globally, there is growing interest and potential for investment in Nature-based Solutions (NbS) to protect, manage or restore ecosystems through incentive schemes including Payment for Ecosystem Services (PES), Nature Repair, Carbon Markets, Common Asset Trusts. Collectively, these NbS markets establish interchangeable mechanisms to help address biodiversity and climate crises, as well as socio-economic issues concerning many Indigenous Peoples and Local Communities (IPLCs). IPLCs manage and/or own almost 32% of the world’s land area through customary and community-based tenure arrangements. Since 2000 several PES schemes have been implemented in Australia. These schemes have been overwhelmingly implemented as public-good expenditure, with governments providing ~90% of total funding. Indigenous people have either the legal right to run or veto a carbon market or nature repair project over 57% of the Australian land mass, increasing to 63% in savanna and 85% in desert regions. Here we critically assess opportunities and challenges for Australia’s Indigenous estate associated with existing and emerging NbS market approaches, especially the Commonwealth’s current Savanna Fire Management (SFM) and Human Induced Regeneration methods, evolving Integrated Farm & Land Management (IFLM) and Blue Carbon methods, and proposed Nature Repair (NR) market. To date, Indigenous NbS interests have focused especially on SFM across northern Australia, with prospective opportunities especially for IFLM and NR markets. Most available schemes focus on remediation of degraded lands and seas, ignoring cost-effective investment opportunities to maintain habitats and ecosystems in less-degraded condition. Government-supported Common Asset Trusts can provide effective models for governance of stewardship schemes relevant to on-going care for relatively intact ecosystems. In Discussion we summarise key methodological, institutional, and policy opportunities and challenges for constructive Indigenous engagement with developing NbS markets. Our purpose is to provide an Indigenous land and sea management context to inform development of rapidly evolving NbS markets in Australia.

An Expert Delphi Consensus on Risk Factors for Adverse Events After Endovascular Aortic Aneurysm Repair: Tier 1 Study From the International RIsk Stratification in EVAR (IRIS-EVAR) Working Group.

Tier 1 of the International RIsk Stratification in EndoVascular Aneurysm Repair (IRIS-EVAR) project aimed to identify important risk factors for adverse events following endovascular aneurysm repair (EVAR). Initially, the steering committee proposed a number of risk factors for adverse events following EVAR. A Delphi consensus was performed as expert panelists were presented with risk factors and provided the opportunity to propose additional risk factors during the process. Experts in EVAR completed an online survey via 3 structured rounds. The first round opened in July 2022, and the third round closed in December 2022. Panelists rated risk factors using a 4-point Likert scale. Consensus was defined as >70% of participants agreeing/strongly agreeing or disagreeing/strongly disagreeing with a statement in each round. Thirty-five panelists from 12 countries completed the 3 rounds of surveys. Of a total of 64 individual risk factors assessed by the panelists, 37 (58%) had consensus that they were important for adverse events following EVAR. Risk factors were stratified in 4 domains: 14 (38%) were related to preoperative anatomy, 3 (8%) related to the aortic device selection, 8 (22%) related to the procedure performance, and 12 (32%) related to postoperative surveillance. Factors with the highest consensus in each domain were as follows: proximal aortic neck length <15 mm (98% consensus), anatomy non-compliant with instructions for use (94% consensus), length of achieved proximal aortic neck post implantation <10 mm (98% consensus), and non-satisfactory seal at landing or overlapping zones/sac expansion/kink or stenosis (100% consensus each), respectively. Clinically important risk factors for adverse events after EVAR were identified via expert consensus. These factors will be used to develop an expert consensus-informed risk stratification and surveillance strategies. This is the first study to apply an in-depth Delphi methodology to achieve an expert consensus on risk factors for adverse events after endovascular aneurysm repair (EVAR). Important risk factors were stratified in 4 domains: preoperative anatomy (14 factors), aortic device (3 factors), EVAR procedure (8 factors), and postoperative surveillance (12 factors). This study will potentially influence future clinical practice by providing evidence informed by experts regarding predictors of adverse events following EVAR that can be taken into account during decision making and developing post-EVAR surveillance strategies. These findings will inform a risk stratification tool for everyday use by vascular surgeons.

Lived experiences of people impacted by gun violence: qualitative analysis of the prescriptions for repair project

BackgroundRestorative justice interventions can help address the harm created by gun violence, although few restorative justice programs focus solely on survivors or loved ones of victims of gun violence. Our...

An Analysis of Structural Rehabilitation and Repair Projects Involving Carbon Fiber Reinforced Concrete

Since plain concrete is brittle by nature, the flexural and split tensile strengths developed must be taken into consideration. Plain concrete is robust in solidity; nevertheless, with feeble cutting-edge tautness. Numerous fibres are commonly utilized in the construction sector to enhance concrete's flexural strength, ductile strength and durability properties. The great tensile strength of steel fiber makes it the fiber of choice for usage in the building industry. However, steel fibre has some disadvantages, including a propensity for corrosion. Carbon fibre is a promising substitute for fiber-reinforced concrete when compared to other fibers due to its corrosion resistance, low density, and superior tensile strength. According to the evaluation work conducted by numerous reviewers, carbon has only very few applications. This study gives an overview of carbon fiber, its structural uses in restoration and repair projects and the various characteristics of fiber-reinforced concrete with carbon. The strength, toughness, and flexural properties of carbon fiber as well as the feasibility research on repair and rehabilitation work using various carbon fibers have been reviewed.

Revolutionizing Project Resilience through Advanced Risk Mitigation Strategy Launched

This study examines the risks associated with project delays in the Mover Tram rail line repair project at TMII and proposes mitigation strategies using a combination of Risk Breakdown Structure (RBS), Analytical Network Process (ANP), and Bow Tie Analysis methodologies. Through expert interviews, questionnaires, and document analysis, key risks were identified and prioritized. Results indicate that construction management emerged as the dominant risk group, with specific risks including delays in critical path tasks and discrepancies between drawings and methods. Mitigation strategies were developed focusing on these dominant risks. The study underscores the importance of integrating diverse risk assessment techniques for effective project management and suggests avenues for future research to enhance risk management frameworks in construction projects. Highlights: 1. Integrated risk analysis enhances project resilience.2. Construction management pivotal for identifying and mitigating project risks.3. Future research: Explore cost-related risks for improved project outcomes. Keywords: Project delays, Risk management, Construction projects, Mitigation strategies, Analytical methodologies

Causes and treatment of bridge cracks

With the large-scale construction and operation of highway bridges in China, the maintenance and repair work of bridges has become increasingly important. The treatment of bridge cracks is a crucial aspect of maintenance and repair. Improper analysis and treatment of cracks in maintenance and repair projects can pose significant safety hazards to bridges. Therefore, it is necessary to conduct a detailed scientific analysis of the cracks in bridges and implement corresponding treatment measures. This paper summarizes common crack diseases in different bridge operation processes, analyzes their causes, and provides relevant references for later maintenance and repair, which has certain reference significance for the maintenance and repair of bridges.

Analisis Faktor Keterlambatan Pelaksanaan perbaikan Jalan rusak Lembar-Pelabuahan Gili Mas Lombok Barat

It is hoped that the repair of the damaged road at Lemi Mas Harbor, West Lombok, Gili Mas will be able to facilitate the transportation of goods and services at Gili Mas Harbor, West Lombok. This road repair work is expected to be completed according to the implementation time stated in the contract. The research location is West Lombok Regency. In this research, a survey was conducted using a questionnaire on the workforce on the project. The delay factors considered in data collection were obtained based on literature studies. Factor analysis and ranking are carried out to see the factors that have the most significant value. The results of the analysis show that the 3 factors with the highest ratings causing delays in the repair project for the damaged Lembar-Pelabuhan Gili Mas Road, West Lombok, are unfinished contract changes (Addendums); poor implementation schedule; and slow design review drawings. Keyword: Road repairs, factor analysis, delays

Predicting Traffic Flow with Neural Networks

The monitoring and analysis of traffic flow has become crucial for transportation planners to best schedule road infrastructure repair projects as well as for people to better plan and manage their daily commutes. Therefore, one of the most crucial needs of traffic management systems is the capacity to precisely predict the type of traffic stream. In this study, we will give an intelligent approach to traffic flow prediction using actual data from the Central Road Research Institute (CRRI), India for the years 2018 and 2019. The suggested method is to train a neural network model to predict traffic flow on an hourly basis in the future. The simulation's conclusions provided a reliable forecast for the traffic statistics

LOGISTICS OF MATERIAL FLOWS IN SHIP REPAIR PRODUCTION PROJECTS

A logistics system is a complexly organised, integrated economic system consisting of interconnected links in a single process of managing material and related flows. Project management in logistics systems uses the application of project management methods and models in the process of designing logistics systems and managing changes in them, as well as solving the problems of managing resource flows in logistics systems. The design, creation and management of logistics systems is accompanied by their presentation as an integral set of elements in certain relationships and connections between them. The logistics system should meet the goals of their design and management. The article outlines elements of the mechanism of logistics management of material costs of ship repair production. Efficient use of the company's resources is possible through the systematic development of a system of organisational and technical measures to reduce costs. All cost-cutting measures are closely interrelated and comprehensive, reflecting the relationship of each of them with the entirety of ship repair production elements. The paper substantiates the production features of a ship repair enterprise and analyses the factors that determine the level of costs. It identifies types of ship repair works and stages of preparation of vessels for repair, which makes it possible to plan costs for formation of the production programme. This text presents the production structure of a ship repair enterprise and discusses the peculiarities of product costing. Ship repair companies use planned, indicative, estimated (technical) and reporting costings. This makes it possible to develop a mechanism for managing the costs of ship repair projects and the production process of a ship repair company.

Improving the bonding performance of new and old cement pastes by high-temperature treatment on the surface of old cement pastes

In concrete structure repair projects, patch repair is one of the most commonly used methods. However, the bonding interface is often the weakest part of the overall repaired structure, and its performance affects the safety of the entire structure. In this study, different groups of cement specimens with similar exposed surface were prepared by splitting the cement paste samples with water–cement ratio of 0.4 and 0.2 into two halves from the middle point. The exposed/split surfaces were then activated in an oven at 600 °C, 700 °C and 800 °C (heating time 30 min and holding time 5 min) respectively, and the new cement pastes were poured on the treated surface of the old cement paste samples after the treated samples were cooled down to room temperature. The interface bonding strengths of different groups of samples were tested through a three-point bending test, and the interface microstructure and composition were analyzed through micro indentation, scanning electron microscopy, and X-ray diffraction tests. Among them, the interface bonding effect was the best with treatment temperature of 800 °C with an increase of more than 80 %. With this activation method, the old base cement can undergo rehydration reaction with the water in newly covered cement paste, thereby improving the bonding performance of the interface. However, high temperature can also cause microcracks on the surface of the old cement block, and it is necessary to control the activation temperature to achieve the required performance improvement. Combining mechanical tests, interface microstructure tests, and mechanism analysis, this study proposed and verified a method to improve the bonding interface strength between new and old cement pastes by high-temperature treatment on the surface of the old cement paste. Engineering applications were also discussed and explored.

Preparation of a bio-based PU/EP IPN concrete adhesive with optimized performance and decent adhesion

An adhesive serves as a vital tool in construction, repair, and rehabilitation projects. Typically crafted from polymer materials such as epoxies or polyurethane latex, it facilitates the creation of resilient bonds between a variety of surfaces, ranging from concrete-concrete and metal-concrete to concrete-composites. However, employing epoxy or polyurethane individually as adhesives often demonstrate insufficient performance and weak interfacial adhesion during service. In this study, an adhesive combining polyurethane and epoxy was synthesized, featuring an interpenetrating polymer network (IPN) structure. This innovative agent was created using polyols sourced from soybean oil and a commercial epoxy resin. By tuning the infusion of polyurethane content, the resultant resin exhibited favorable flowability in civil applications, simultaneously improved strength and toughness due to the IPN structure, and outstanding thermal stability. Notably, the incorporation of 20 wt% polyurethane yielded a polymer with a remarkable tensile strength of 35.9 MPa. Additionally, the bonding adhesion of the prepared resins on concrete specimens was investigated through splitting tensile test and shear strength test. The study explored the influences of polyurethane content, concrete strength, and adhesive layer thickness on interfacial bonding strength. The introduction of an IPN structure within the PU-20 agent proved advantageous for enhancing the bonding adhesion of the concrete, resulting in remarkable interfacial tensile and shear strengths of 4.56 MPa and 21.73 MPa, respectively.

Project Risk Management for the Repair and Upgrade of Nhi Thien Duong 1 Bridge, Ho Chi Minh City, Vietnam

No project is without risks, especially in the construction industry, which harbors numerous potential pitfalls. Some risks may occur with a low probability but can have a significant impact, while others may manifest repeatedly across various projects. Negative risks, when realized, result in losses that affect the project's objectives. Meanwhile, project participants aspire to capitalize on opportunities presented by positive risks. Therefore, identifying risks, elucidating risk management methods, and formulating risk response strategies for construction projects are crucial to ensure their success. Through methods such as analysis, synthesis, comparison, and reference, this article identifies risks associated with the repair and upgrade project of the Nhi Thien Duong 1 Bridge in Ho Chi Minh City. Additionally, it proposes a set of risk response solutions from the investor's perspective in terms of construction investment management.

Effect of K+ Diffusion on Hydration of Magnesium Potassium Phosphate Cement with Different Mg/P Ratios: Experiments and Molecular Dynamics Simulation Calculations.

Magnesium potassium phosphate cement (MKPC) is formed on the basis of acid-base reaction between dead burnt MgO and KH2PO4 in aqueous solution with K-struvite as the main cementitious phase. Due to the unique characteristics of these cements, they are suitable for special applications, especially the immobilization of radioactive metal cations and road repair projects at low temperature. However, there are few articles about the hydration mechanism of MKPC. In this study, the types, proportions and formation mechanism of MKPC crystalline phases under different magnesium to phosphorus (Mg/P) ratios were studied by means of AAS, ICP-OES, SEM, EDS and XRD refinement methods. Corresponding MD simulation works were used to explain the hydration mechanism. This study highlights the fact that crystalline phases distribution of MKPC could be adjusted and controlled by different Mg/P ratios for the design of the MKPC, and the key factor is the kinetic of K+.

The Arousa Island bridge. Complete refurbishment and 10 years analysis description

AbstractThe Isla de Arousa Bridge, 1980 m long, is the only road access to Isla de Arousa. Built in 1985, this single‐cell box girder divided into 40 spans runs entirely over the sea. In response to corrosion damage, the local government decided to make an intervention with an ambitious repair project in 2009. The repair, carried out with three different techniques, aims to collect data for future repairs. In this research the results of rehabilitation and comparison of the evolution of the repairs are described, together with the data on the progression of corrosion and its effect on the life cycle. At the moment, with data from 10 years of protection, both hybrid and galvanic anodes installation have shown effectiveness. Bridge Health index analysis shows that after reparation, the bridge presented a very good condition, and even after 10 years the condition is still good, except for some damaged bearings.

Perancangan Dan Implementasi Sistem Informasi Manajemen Proyek Berbasis Web Dengan Metode WATERFALL

CV Winman Konstruksi is a company that focuses on the building construction sector. The portfolio of projects that CV Winman Konstruksi has successfully undertaken covers a wide range of work, from the planning stage to the implementation of building construction and repair projects. In conducting the project management process, CV Winman Konstruksi has been using personal short messages as a means of communication between employees, but it needs to be recognized that this method may have limitations in terms of progress tracking, project documentation, and building a formal framework that can provide more systematic and structured guidance for the entire project team. The result of this research is a computerized system as a means of project management which is realized in the form of a project management information system website. In developing this system, researchers use the waterfall method which consists of the stages of needs analysis, design, design, implementation and testing. Later it is hoped that with this system, the management process at the CV Winman Konstruksi company can be monitored easily anywhere and anytime.

Evolving methodologies in the management of preserved removed parts in Japanese architectural cultural properties

AbstractIn this inquiry, the author intends to investigate the evolving methodologies in the management of preserved removed parts within the scope of Japanese architectural cultural properties, as recognized by the national government. Central to this examination is a focus on the selection criteria stipulated in the official preservation guidelines. This exploration involves a comprehensive analysis structured in three phases: firstly, scrutinizing the modifications in selection criteria as delineated in the guidelines governing repair projects; secondly, compiling and categorizing additional designated preserved removed parts recognized as cultural properties into six distinct types; and thirdly, identifying the inaugural instances of such preserved components or the initial reports pertaining to repair projects. Through this multifaceted research approach, the study endeavors to elucidate the evolving methodologies in the management of preserved removed parts in the realm of Japanese architectural cultural properties.

Navigating the Paradox of Repair: Indigenous Genocide and Public Education in Minnesota and Manitoba

This paper examines how educational institutions and individual educators in Manitoba, Canada, and Minnesota, United States (US), understand and enact reparation in their respective fields of practice. The basic principle of restorative or reparative justice is that wrongs are set right by giving back to the injured party that which restores equality, dignity, and rights. However, educational reforms reveal a structural challenge in societies reckoning with the legacies of foundational violence perpetrated against Indigenous populations. Coupling an analysis of state / provincial social studies standards with key informant interviews, we try to untangle the paradox that the public education system, including non-formal education offered in state museums or historical societies are now tasked with addressing and repairing an injustice they were- and, to a large degree, continue to be - a part of. Findings show that sometimes dissonant visions of a reparative future and conflicting attempts to seek and promote justice in public history, the curriculum, and pedagogy are negotiated in the educational arena, resulting in complementary forms of specific practices. These constitute a growing stock of knowledge and models of engagement that shed light on how institutions and individual actors navigate the project and paradox of repair.