scholarly journals Effect of Fibers on Durability of Concrete: A Practical Review

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4562
Author(s):  
Suvash Paul ◽  
Gideon van Zijl ◽  
Branko Šavija
Keyword(s):  
Structural Integrity ◽  
Real Life ◽  
Fiber Reinforced Concrete ◽  
Protective Film ◽  
Conventional Concrete ◽  
Design Engineers ◽  
Design Service Life ◽  
Metallic Fibers ◽  
And Control ◽  
Durability Of Concrete

This article reviews the literature related to the performance of fiber reinforced concrete (FRC) in the context of the durability of concrete infrastructures. The durability of a concrete infrastructure is defined by its ability to sustain reliable levels of serviceability and structural integrity in environmental exposure which may be harsh without any major need for repair intervention throughout the design service life. Conventional concrete has relatively low tensile capacity and ductility, and thus is susceptible to cracking. Cracks are considered to be pathways for gases, liquids, and deleterious solutes entering the concrete, which lead to the early onset of deterioration processes in the concrete or reinforcing steel. Chloride aqueous solution may reach the embedded steel quickly after cracked regions are exposed to de-icing salt or spray in coastal regions, which de-passivates the protective film, whereby corrosion initiation occurs decades earlier than when chlorides would have to gradually ingress uncracked concrete covering the steel in the absence of cracks. Appropriate inclusion of steel or non-metallic fibers has been proven to increase both the tensile capacity and ductility of FRC. Many researchers have investigated durability enhancement by use of FRC. This paper reviews substantial evidence that the improved tensile characteristics of FRC used to construct infrastructure, improve its durability through mainly the fiber bridging and control of cracks. The evidence is based on both reported laboratory investigations under controlled conditions and the monitored performance of actual infrastructure constructed of FRC. The paper aims to help design engineers towards considering the use of FRC in real-life concrete infrastructures appropriately and more confidently.

Investigation of some engineering properties of waste polytetrafluoroethylene (PTFE) fiber reinforced concrete

2019 ◽  
Vol 10 (3) ◽  
pp. 56
Author(s):  
Abdulkadir Kan
Keyword(s):  
Fine Sand ◽  
Waste Material ◽  
Fiber Reinforced Concrete ◽  
Engineering Properties ◽  
Filler Material ◽  
Unit Weight ◽  
Conventional Concrete ◽  
Fiber Concrete ◽  
Mechanical Behaviours ◽  
And Control

In this study, a comparison was made between concrete with waste PTFE fiber and standard concrete. Both elastomeric and thermoplastic fluoropolymer find a wide use especially in automotive applications such as seals, pulley etc. A large amount of PTFE occurs during this applications production. PTFE fiber is not a conventional concrete additive. It is a waste material and it can be used as a concrete filler material. In order to investigate the behaviour of this waste material in the concrete, mixtures containing waste PTFE fiber in amounts of 25%, 50%, 75%, and 100%  (by weight) in order to replace to the same amount of fine sand (0-1 mm) were prepared. The compressive strength, tensile strength, workability and unit weight of the waste PTFE fiber concrete investigated. It was observed that waste PTFE fiber concretes have sufficient strength to be used as semi structural concrete. The mechanical behaviours of waste PTFE fiber concrete and control concrete were very similar. Moreover, it was observed that the unit weight and workability of the waste PTFE fiber concretes were decreased. This study provides that reusing waste PTFE fiber as an artificial filler material in concrete gives a new approach to solve some of the solid waste problems by plastics.

scholarly journals Performance evaluation of high performance concrete beams under cyclic loading

2017 ◽  
Vol 7 (1.1) ◽  
pp. 71
Author(s):  
S. Sharmila ◽  
P. Chandrasekaran
Keyword(s):  
High Performance ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Structural Parameters ◽  
Absorption Capacity ◽  
Fiber Reinforced Concrete ◽  
Aramid Fibre ◽  
Conventional Concrete

High performance concrete essentially consists of the same ingredients as in conventional concrete but the proportions are designed to provide the strength and durability which are needed for the structural and environmental requirements of the structure. Fiber-reinforced concrete is a concrete containing ingredients of conventional concrete and fibres which increases its structural integrity. Fibers act as crack arrester which are primarily due to plastic shrinkage and drying shrinkage. They also reduce the permeability of concrete. The main aim of the present experimental investigation is to combine different fibres namely crimped stainless steel fibre and Aramid fibre to produce HFRC and thus to evaluate its mechanical performance. In Addition Micro silica and Quartz powder is added to obtain high performance. Based on I.S. Code method of mix design, proportion of different ingredients was obtained to get M60 grade concrete. Samples were prepared by varying the volume fraction of Steelfibre and aramid fibre from 0 to 1.5%. Three specimens of Cubes, Cylinders, and Prisms for each volume fraction of fibers are casted. Mechanical properties of each concrete composite were studied. The structural parameters such as load carrying capacity, ductility characteristics and energy absorption capacity of HPHFRC beams were assessed.

scholarly journals Drone Deep Reinforcement Learning: A Review

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 999
Author(s):  
Ahmad Taher Azar ◽  
Anis Koubaa ◽  
Nada Ali Mohamed ◽  
Habiba A. Ibrahim ◽  
Zahra Fathy Ibrahim ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
State Of The Art ◽  
Real Life ◽  
Environment Monitoring ◽  
Simulated Environments ◽  
Infrastructure Inspection ◽  
Remote Sensing Mapping ◽  
And Control ◽  
The Military ◽  
Uav Navigation

Unmanned Aerial Vehicles (UAVs) are increasingly being used in many challenging and diversified applications. These applications belong to the civilian and the military fields. To name a few; infrastructure inspection, traffic patrolling, remote sensing, mapping, surveillance, rescuing humans and animals, environment monitoring, and Intelligence, Surveillance, Target Acquisition, and Reconnaissance (ISTAR) operations. However, the use of UAVs in these applications needs a substantial level of autonomy. In other words, UAVs should have the ability to accomplish planned missions in unexpected situations without requiring human intervention. To ensure this level of autonomy, many artificial intelligence algorithms were designed. These algorithms targeted the guidance, navigation, and control (GNC) of UAVs. In this paper, we described the state of the art of one subset of these algorithms: the deep reinforcement learning (DRL) techniques. We made a detailed description of them, and we deduced the current limitations in this area. We noted that most of these DRL methods were designed to ensure stable and smooth UAV navigation by training computer-simulated environments. We realized that further research efforts are needed to address the challenges that restrain their deployment in real-life scenarios.

scholarly journals Integrity Management of Marine Structures; With Emphasis on Design for Structural Robustness

2018 ◽  
Author(s):  
Torgeir Moan
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Design Standards ◽  
Limit States ◽  
Fabrication Errors ◽  
Integrity Management ◽  
Operational Errors ◽  
And Control

Based on relevant accident experiences with oil and gas platforms, a brief overview of structural integrity management of offshore structures is given; including an account of adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of the engineering processes. The focus is on developing research based design standards for Accidental Collapse Limit States to ensure robustness or damage tolerance in view damage caused by accidental loads due to operational errors and to some extent abnormal structural damage due to fabrication errors. Moreover, it is suggested to provide robustness in cases where the structural performance is sensitive to uncertain parameters. The use of risk assessment to aid decisions in lieu of uncertainties affecting the performance of novel and existing offshore structures, is briefly addressed.

scholarly journals APPLICATION OF COCONUT FIBER AND POLYVINYL-ALCOHOL BLENDS TO IMPROVE THE DURABILITY OF CONCRETE STRUCTURES IN VIETNAM

InterConf ◽  
2021 ◽  
pp. 418-426
Author(s):  
Thi Ngoc Quyen Nguyen
Keyword(s):  
Polyvinyl Alcohol ◽  
Calcium Hydroxide ◽  
Silica Fume ◽  
Rice Husk ◽  
Coarse Aggregate ◽  
Rice Husk Ash ◽  
Coconut Fiber ◽  
Conventional Concrete ◽  
Cement Powder ◽  
Durability Of Concrete

The biggest disadvantage of conventional concrete is brittle and hard, in addition, its durability is not high. The low durability of concrete is due to the presence of calcium hydroxide at the intersection of coarse aggregate particles and hard cement powder. The introduction of coconut fiber and polyvinyl alcohol (PVA) fibers into the concrete to improve the durability and flexibility of the concrete. In addition, the article also considers the effects of other additives such as rice husk ash, silica fume to study the performance of the structure as well as its durability when joining concrete mixes to create flexible concrete movable and more flexible than conventional concrete.

scholarly journals IoT-based Running Time Monitoring System for Machine Preventive Maintenance Scheduling

ELKHA ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 33
Author(s):  
Erwin Sitompul ◽  
Agus Rohmat
Keyword(s):  
Monitoring System ◽  
Preventive Maintenance ◽  
Real Life ◽  
Remote Access ◽  
Time Interval ◽  
Monitoring And Control ◽  
Running Time ◽  
Damage And Failure ◽  
Simulation Purpose ◽  
And Control

Machines are valuable assets that need to be protected from damage and failure through proper maintenance measures. This paper proposes a system that automatically monitors the running time of machines and sends notifications regarding their preventive maintenance (PM) schedules. The system core consists of a programmable logic controller (PLC) and a human machine interface (HMI). The HMI is connected to an online platform via internet connection provided by a router, so that the monitoring result can be accessed via Android smartphone or laptop/PC. This IoT-based running time monitoring system (IRTMS) will be particularly helpful in implementation at an production site that consists of multiple various machines. The PM items of a machine may vary from cleaning, changing single component, to an overhaul, each with different time interval. By using the IRTMS, the user will have an overview of the PM schedules anytime and anywhere. The preparation of material, components, or tools can be known ahead of time. For simulation purpose, a prototype is constructed by using components as used in industrial real-life condition. Four output connections are provided to simulate the simultaneous monitoring of four machines. The IRTMS prototype is tested and completely successful on doing the running time monitoring, the running time reset, the PM notifications, and the remote access for monitoring and control.

A Biologically Inspired Autonomous Robot Control Based on Behavioural Coordination in Evolutionary Robotics

2011 ◽  
pp. 107-129 ◽  
Author(s):  
José A. Fernández-León ◽  
Gerardo G. Acosta ◽  
Miguel A. Mayosky ◽  
Oscar C. Ibáñez
Keyword(s):  
Mobile Robots ◽  
Autonomous Vehicle ◽  
Trajectory Generation ◽  
Real Life ◽  
Evolutionary Robotics ◽  
Knowledge Based ◽  
Planning And Control ◽  
Life Problems ◽  
Path Planner ◽  
And Control

This work is intended to give an overview of technologies, developed from an artificial intelligence standpoint, devised to face the different planning and control problems involved in trajectory generation for mobile robots. The purpose of this analysis is to give a current context to present the Evolutionary Robotics approach to the problem, which is now being considered as a feasible methodology to develop mobile robots for solving real life problems. This chapter also show the authors’ experiences on related case studies, which are briefly described (a fuzzy logic based path planner for a terrestrial mobile robot, and a knowledge-based system for desired trajectory generation in the Geosub underwater autonomous vehicle). The development of different behaviours within a path generator, built with Evolutionary Robotics concepts, is tested in a Khepera© robot and analyzed in detail. Finally, behaviour coordination based on the artificial immune system metaphor is evaluated for the same application.

Abstract and Concrete Data Type Optimizations at the UML and C/C++ Level for Dynamic Embedded Software

2010 ◽  
pp. 55-83
Author(s):  
Christos Baloukas ◽  
Marijn Temmerman ◽  
Anne Keller ◽  
Stylianos Mamagkakis ◽  
Francky Catthoor ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Embedded System ◽  
High Performance ◽  
Real Life ◽  
Holistic Approach ◽  
Embedded Software ◽  
Data Types ◽  
Design Engineers ◽  
Implementation Level ◽  
Abstraction Levels

An embedded system is a special-purpose system that performs predefined tasks, usually with very specific requirements. Since the system is dedicated to a specific task, design engineers can optimize it by exploiting very specialized knowledge, deriving an optimally customized system. Low energy consumption and high performance are both valid optimization targets to increase the value and mobility of the final system. Traditionally, conceptual embedded software models are built irrespectively of the underlying hardware platform, whereas embedded-system specialists typically start their optimization crusade from the executable code. This practice results in suboptimal implementations on the embedded platform because at the source-code level not all the inefficiencies introduced at the modelling level can be removed. In this book chapter, we describe both novel UML transformations at the modelling level and C/C++ transformations at the software implementation level. The transformations at both design abstraction levels target the data types of dynamic embedded software applications and provide optimizations guided by the relevant cost factors. Using a real life case study, we show how our transformations result in significant improvement in memory footprint, performance and energy consumption with respect to the initial implementation. Moreover, thanks to our holistic approach, we are able to identify new and non-trivial solutions that could hardly be found with the traditional design methods.

scholarly journals Vision and Deep Learning-Based Algorithms to Detect and Quantify Cracks on Concrete Surfaces from UAV Videos

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6299 ◽  
Author(s):  
Sutanu Bhowmick ◽  
Satish Nagarajaiah ◽  
Ashok Veeraraghavan
Keyword(s):  
Image Segmentation ◽  
Deep Learning ◽  
Network Architecture ◽  
Structural Integrity ◽  
Real Life ◽  
Concrete Surface ◽  
Video Camera ◽  
Bending Test ◽  
Morphological Operations ◽  
Civil Infrastructures

Immediate assessment of structural integrity of important civil infrastructures, like bridges, hospitals, or dams, is of utmost importance after natural disasters. Currently, inspection is performed manually by engineers who look for local damages and their extent on significant locations of the structure to understand its implication on its global stability. However, the whole process is time-consuming and prone to human errors. Due to their size and extent, some regions of civil structures are hard to gain access for manual inspection. In such situations, a vision-based system of Unmanned Aerial Vehicles (UAVs) programmed with Artificial Intelligence algorithms may be an effective alternative to carry out a health assessment of civil infrastructures in a timely manner. This paper proposes a framework of achieving the above-mentioned goal using computer vision and deep learning algorithms for detection of cracks on the concrete surface from its image by carrying out image segmentation of pixels, i.e., classification of pixels in an image of the concrete surface and whether it belongs to cracks or not. The image segmentation or dense pixel level classification is carried out using a deep neural network architecture named U-Net. Further, morphological operations on the segmented images result in dense measurements of crack geometry, like length, width, area, and crack orientation for individual cracks present in the image. The efficacy and robustness of the proposed method as a viable real-life application was validated by carrying out a laboratory experiment of a four-point bending test on an 8-foot-long concrete beam of which the video is recorded using a camera mounted on a UAV-based, as well as a still ground-based, video camera. Detection, quantification, and localization of damage on a civil infrastructure using the proposed framework can directly be used in the prognosis of the structure’s ability to withstand service loads.

scholarly journals Use of a Novel Resistive Strain Sensor Approach in an Experimental and Theoretical Study Concerning Large Spherical Storage Tank Structure Behavior During Its Operational Life and Pressure Tests

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 525
Author(s):  
Virgil Florescu ◽  
Stefan Mocanu ◽  
Laurentiu Rece ◽  
Robert Ursache ◽  
Nicolae Goga ◽  
...  
Keyword(s):  
Storage Tank ◽  
Structural Integrity ◽  
Real Life ◽  
Fem Simulation ◽  
Strain Sensor ◽  
Sensor Data ◽  
New Approach ◽  
Integrity Assessment ◽  
Operational Life ◽  
Large Spherical

This paper introduces a new method for the use of tensor-resistive sensors in large spherical storage tank equipment (over 12,000-mm diameters). We did an experiment with 19 petroleum or ammonia product sphere-shaped storage tanks with volumes of 1000 and 1800 cubic meters, respectively. The existing literature only contains experiments based on sensors for tanks with diameters no larger than 600 mm. Based on a number of resistive strain sensor measurements on large spherical pressurized vessels regarding structural integrity assessment, the present paper is focused on the comparison between "real-life" obtained sensor data versus finite element method (FEM) simulation results. The present paper is structured in three parts and examines innovative directions: the use of the classic tensor-resistive sensors in a new approach concerning large structural equipment; an original 3D modeling method with the help of the FEM; and conclusions with possible implications on the regulations, design, or maintenance as a result of the attempt of mutual validation of the new methods previously mentioned.

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