Recently, 3D concrete printing has progressed rapidly in the construction industry. However, this technique still contains several factors that influence buildability and mechanical properties of printed concrete. Therefore, study investigated effects nozzle speed, interlayer interval time, rotations per minute (RPMs) screw device, presence lateral supports on printing. In addition, paper presents results properties, including compressive, splitting tensile, flexural tensile strengths The...

The flexural behavior of prestressed ultra high performance concrete (UHPC) beams is investigated in this study. paper proposes a method for predicting the strength UHPC...

Ultrahigh-performance concrete (UHPC) and high-strength (HSC) are currently widely used because of their distinct superior properties. Thus, a comprehensive comparison the flexural behavior UHPC HSC beams is presented in this study. Nine three were subjected to pure bending tests investigate effect various reinforcement ratios steel fiber volume contents on cracking failure patterns, load-deflection behavior, ductility, toughness these beams. The addition fibers improved energy absorption...

This paper proposes a method for predicting the flexural response of ultra-high-performance fibre-reinforced concrete (UHPFRC) beams, including an experimental test framework and associated numerical analyses. The programme includes compressive tensile tests at material level beam structural level. Detailed results behaviour UHPFRC beams are also provided. An analytical is described to predict bending, this applied interpret results. study focuses primarily on bending beams. model takes...

The experimental results of shear strength and deformation tests for 12 ultra-high-performance fibre-reinforced concrete (UHPFRC) beams without stirrups are presented in this paper. I-beam specimens with a depth 700 mm were cast using UHPFRC the compressive 160–190 MPa. parameters span to effective ratio, volume fraction steel fibres, presence or absence prestress. failure mode, indicating tensile web beam, was accompanied by fibre pull-out along major diagonal crack. test indicated that...

The flexural responses of high‐strength fiber‐reinforced concrete (HSFRC) beams and (HSC) are compared in this study. A series HSFRC HSC were tested under pure loading. effects the type concrete, compressive strength tensile rebar ratio on behavior investigated. including induced crack failure patterns, load deflection capacity, stiffness, ductility index, toughness was compared. stiffness increased with ratio. For same ratios, much greater than that beams. index decreased sharply an...

Although there is a growing trend to use higher strength for concrete and steel in reinforced structures due the lightness slenderness of these members together with simplified arrangement their reinforcement, still necessity inspect reduction ductility resulting from gain strength. Taking into account that this also concerns design torsion, study intends investigate regulations related torsional minimum reinforcement ratio view requirement focus on Eurocode 2. To goal, relation between...

This paper describes an experimental study on the mechanical properties of high‐strength fiber‐reinforced concrete (HSFRC). The parameters included content and length steel fiber as well use either a single‐type or hybrid fibers. contents were 1.0, 1.5, 2.0% based volume HSFRC, lengths 13, 16.5, 19.5 mm. In addition, fibers incorporating different used. Compression tests crack mouth opening displacement performed for each HSFRC mixture with parameters. such compressive strength, elastic...

The purpose of this paper is to examine the basic behavior ultra high strength concrete beams reinforced with steel fibers. experimental parameters included rebar ratio less than 0.02 and method placing performance concrete. did not use coarse aggregate had a volumetric 2%. test results from static loading revealed characteristics flexural fiber-reinforced Flexural cracking, failure pattern, deflection, ductility, measurements. study provide more information help establish prediction model...

This paper presents a new approach on non-destructive stress estimation that involves measuring the magnetic Barkhausen noise (MBN) prestressed strands using solenoid-type sensor. Using contact-type sensor infrastructure is difficult because are wrapped with protective materials and cannot be directly touched. To test feasibility of idea, MBN developed measures seven-wire strand. The consists magnetic-field inducing coil sensing coil, designed to generate varying field measure change in...

This study proposed a prediction formula for the torsional strength enabling to reflect tensile of ultra high performance concrete (UHPC) beams based upon thin-walled tube theory. The remarkable ductile behavior UHPC can also be attributed steel fiber reinforcement. feature must considered provide rational explanation structures. In this study, design adopts modified theory so as consider UHPC. And torsion test was conducted on box validate through comparison predicted with experimental...

This paper investigates experimentally the feasibility of estimating stress in prestressing tendons prestressed concrete bridges using magnetic field induced by an electromagnet and Villari effect which susceptibility or permeability a ferromagnetic material changes when subjected to mechanical stress. The test results show good linearity between tendon flux density within practical range tendons. In addition, appears depend on intensity distance regardless cover. Accordingly, although...

An ultrasonic array device like the A1040 MIRA is used to non-destructively visualize inside of concrete structures. A data set acquired by so unfocused that an image reconstruction algorithm required transform into understandable image. The total focusing method exploits time-of-flight pulse when While a high frequency barely affects accuracy results, low with long wavelength causes overall sagging resulting around half pulse, which results in poor quality results. In this research,...

The application of Ultra-High-Performance Concrete (UHPC) materials in rehabilitating bridges and constructing primary bridge components is increasing rapidly across the world because their superior strength durability characteristics when compared to regular concretes. However, there have been few new constructed using UHPC with formworks, ready-mix trucks, construction equipment. This paper presents a comprehensive report encompassing design, construction, performance monitoring Iowa...

이 연구에서는 강섬유로 보강된 초고성능 콘크리트(UHPC)의 정적재하 실험을 통하여 UHPC를 적용한 구조 부재의 휨거동 특성을 파악하고자 하였다. 부피비 2%의 강섬유를 혼입하여 철근비가 0.02 이하인 통해 주요 파악하였다. 연구 결과는 추후 UHPC의 처짐산정 및 휨강도 산정 모델링에 주요한 기초 실험 자료로 활용될 수 있을 것으로 사료된다. 강섬유 보강 UHPC는 균열제어에 효과적이며, 연성지수는 6.29~10.44 범위에서 산정되고 있어 우수한 연성거동 나타낸다. 또한 단부타설 방법으로 제작한 UHPC 보의 휨강도는 중앙타설방법으로 휨강도보다 크게 나타나고 있으며, 이는 타설 방법에 의한 배열 특성이 휨강도에 영향을 미치고 있음을

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