scholarly journals Self-Compacting Concrete Reinforced with Twisted-Bundle Macro-Synthetic Fiber

2019 ◽  
Vol 9 (12) ◽  
pp. 2543 ◽  
Author(s):  
Estela Oliari Garcez ◽  
Muhammad Ikramul Kabir ◽  
Alastair MacLeod ◽  
Mahbube Subhani ◽  
Kazem Ghabraie
Keyword(s):  
Flexural Strength ◽  
Large Scale ◽  
Precast Concrete ◽  
Crack Opening ◽  
Fiber Content ◽  
Constitutive Law ◽  
Synthetic Fiber ◽  
Self Compacting Concrete ◽  
Cracking Behavior ◽  
Twisted Bundle

The use of self-compacting concrete (SCC) reinforced with fibers has great potential in the precast concrete industry as the concrete can be delivered straight into the moulds, without any vibration or compacting effort. Similarly, it has the potential to replace traditional steel reinforcement depending on the design requirements. Novel synthetic fibers have recently become available in the market, but still, limited information is available on the performance of SCC reinforced with such fibers. This paper investigates the use of twisted-bundle macro-synthetic fiber in self-compacting concrete. Three different concrete mixtures with fiber dosage of 4, 6, and 8 kg/m3 were produced in large scale batches, and their performance was compared in terms of slump-flow, compressive strength, split tensile strength, modulus of elasticity, and flexural strength. Moreover, a comprehensive evaluation of the post-cracking residual strength is presented. It was found that the mixture with 4 kg/m3 fiber content has the most satisfactory flowability, whereas 8 kg/m3 mixture achieved the highest residual flexural strength. Based on the observed post-cracking behavior, a simplified stress-crack opening constitutive law is proposed. Since the fiber dosage affects the residual flexural strength, a factor related to fiber content is recommended while determining the ultimate residual flexural strength.

scholarly journals Influence of polypropylene fiber on early strength of self-compacting concrete

2019 ◽  
Vol 258 ◽  
pp. 01020
Author(s):  
Rahmi Karolina ◽  
Abdiansyah Putra Siregar
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Polypropylene Fiber ◽  
Fiber Content ◽  
Polypropylene Fibers ◽  
Self Compacting Concrete ◽  
Concrete Technology ◽  
Early Strength

One of the development of concrete technology in construction’s world is Self-Compacting Concrete. Self-Compacting Concrete (SCC) is an innovative concrete that able to “flow” and condensed by gravity and its own weight with little vibration or even without a vibration device at all. However, these concrete still have deficiencies like general concrete that is weak to tensile. To increase the tensile strength of the concrete is by adding fiber into the mix. One type of fiber that can be used as an additive to the mix is Polypropylene fibers. This study aims to determine the effect of adding polypropylene fibers to the mechanical properties and characteristics of SCC concrete and to know the optimal polypropylene fiber content in the manufacture of Self Compacting Concrete. Fiber addition variations are 0 kg / m3; 0.25 kg / m3; 0.5 kg / m3 and 0.75 kg / m3. The result of the research showed that the variation of 0.5 kg / m3 and 0.75 kg / m3 addition of fibers didn’t fulfill the requirements to be categorized as a SCC concrete. The results of hard concrete test showed the highest compressive strength that is on the SCC PP concrete of 22.31 MPa at the age of 1 day and 46.24 at the age of 28 days. The highest strength is on the SCC 0.25 PP concrete of 6.52 MPa at the age of 1 day and 10.07 at the age of 28 days. The highest flexural strength is on the SCC 0.25 PP concrete of 6.76 at the age of 1 day and 8.60 at the age of 28 days.

A Strain Based Criterion to Evaluate the Tensile Capacity of Transmission Pipelines Under Large Scale Cyclic Bending

2018 ◽  
Author(s):  
Y. Andrés Plata Uribe ◽  
Claudio Ruggieri
Keyword(s):  
Structural Steel ◽  
Large Scale ◽  
Axial Loading ◽  
Tensile Failure ◽  
Void Coalescence ◽  
Ductile Crack ◽  
Tubular Specimen ◽  
Pipe Surface ◽  
Cracking Behavior ◽  
Tension Tests

This study explores the capability of a computational cell methodology and a stress-modified, critical strain (SMCS) criterion for void coalescence implemented into a large scale, 3-D finite element framework to model ductile fracture behavior in tensile specimens and in damaged pipelines. In particular, the cell methodology provides a convenient approach for ductile crack extension suitable for large scale numerical analyses which includes a damage criterion and a microstructural length scale over which damage occurs. A series of tension tests conducted on notched tensile specimens with different notch radius for a carbon steel pipe provides the stress-strain response of the tested structural steel from which the cell parameters and the SMCS criterion are calibrated. To investigate ductile cracking behavior in damaged pipelines, full scale cyclic bend tests were performed on a 165 mm O.D tubular specimen with 11 mm wall thickness made of a pipeline steel with very similar mechanical characteristics to the structural steel employed in the tension tests. The tubular specimen was initially subjected to indentation by 3-point bend loading followed by a compressive axial loading to generate large localized buckling in the dented region. The axial loading was then reversed to a tension loading applied until a visible ductile crack could be observed in the pipe surface. These exploratory analyses predict the tensile failure load for the pipe specimen associated with ductile crack initiation in the highly damaged area inside the denting and buckling zone which is in good agreement with experimental measurements.

A Micromechanics Approach to Assess Ductile Crack Initiation in Damaged Pipelines

2003 ◽  
Author(s):  
Claudio Ruggieri ◽  
Fernando F. Santos ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Ductile Fracture ◽  
Large Scale ◽  
Cell Model ◽  
High Strength ◽  
Void Coalescence ◽  
Model Parameters ◽  
Ductile Crack ◽  
Cracking Behavior ◽  
Damage Criterion ◽  
Limited Applicability

This study explores the capabilities of a computational cell framework into a 3-D setting to model ductile fracture behavior in tensile specimens and damaged pipelines. The cell methodology provides a convenient approach for ductile crack extension suitable for large scale numerical analyses which includes a damage criterion and a microstructural length scale over which damage occurs. Laboratory testing of a high strength structural steel provides the experimental stress-strain data for round bar and circumferentially notched tensile specimens to calibrate the cell model parameters for the material. The present work applies the cell methodology using two damage criterion to describe ductile fracture in tensile specimens: (1) the Gurson-Tvergaard (GT) constitutive model for the softening of material and (2) the stress-modified, critical strain (SMCS) criterion for void coalescence. These damage criteria are then applied to predict ductile cracking for a pipe specimen tested under cycling bend loading. While the methodology still appears to have limited applicability to predict ductile cracking behavior in pipe specimens, the cell model predictions of the ductile response for the tensile specimens show good agreemeent with experimental measurements.

scholarly journals Kajian Karakteristik Beton Memadat Sendiri yang Menggunakan Serat Ijuk (Hal. 54-65)

2018 ◽  
Vol 4 (4) ◽  
pp. 54
Author(s):  
Iis Nurjamilah ◽  
Abinhot Sihotang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
High Strength ◽  
Self Compacting Concrete ◽  
Palm Fiber ◽  
Fiber Concrete ◽  
Dilute Mixture

ABSTRAKKajian karakteristik beton memadat sendiri yang menggunakan serat ijuk merupakan sebuah kajian yang dilakukan untuk mengetahui pengaruh penambahan serat ijuk terhadap karakteristik beton memadat sendiri (SCC). Beton memadat sendiri yang menggunakan serat ijuk (PFSCC) didesain memiliki campuran yang encer, bermutu tinggi (= 40 MPa) dan memiliki persentase kekuatan lentur yang lebih baik. PFSCC  didapatkan dari hasil pencampuran antara semen sebanyak 85%, fly ash 15%, superplastizicer 1,5%, serat ijuk 0%, 0,5%; 1%; 1,5%; 2% dan 3% dari berat binder (semen + fly ash), kadar air 190 kg/m3, agregat kasar 552,47 kg/m3 dan pasir 1.063 kg/m3. Semakin banyak persentase penambahan serat ijuk ke dalam campuran berdampak terhadap menurunnya workability beton segar. Penambahan serat ijuk yang paling baik adalah sebanyak 1%, penambahan tersebut dapat meningkatkan kekuatan tekan beton sebesar 13% dan lentur sebesar 1,8%.Kata kunci: beton memadat sendiri (SCC), beton berserat, beton memadat sendiri yang menggunakan serat ijuk (PFSCC), serat ijuk ABSTRACTThe study of characteristics self compacting concrete using palm fibers is a study conducted to determine the effect of adding palm fibers to characteristics of self compacting concrete (SCC). palm fibers self compacting concrete (PFSCC) is designed to have a dilute mixture, high strength (= 40 MPa), and have better precentage flexural strength. PFSCC was obtained from mixing of 85% cement, 15% fly ash, 1.5% superplastizicer, 0%, 0.5%, 1%, 1.5%, 2% and 3% palm fibers from the weight of binder  (cement + fly ash), water content 190 kg/m3, coarse aggregate 552.47 kg/m3 and sand 1,063 kg/m3. The more persentage palm fibers content added to the mixture makes workability of fresh concrete decreases. The best addition of palm fiber is 1%, this addition can increases the compressive strength 13% and flexural strength 1.8%.Keywords: self compacting concrete (SCC), fiber concrete, Palm fiber self compacting concrete (PFSCC), palm fiber

scholarly journals STUDI KUAT LENTUR BETON DENGAN BAHAN TAMBAH SERAT ABAKA

Teras Jurnal ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 53
Author(s):  
Yudi Pranoto ◽  
Lina Halim ◽  
Anung Sudibyo
Keyword(s):  
Flexural Strength ◽  
Bending Strength ◽  
Fiber Content ◽  
Mix Design ◽  
Fine Aggregate ◽  
Test Results ◽  
Concrete Mix Design ◽  
Banana Tree ◽  
Flexible Fiber ◽  
Test Objects

<p align="center"><strong>Abstrak</strong></p><p> </p><p class="11daftarpustaka">Serat abaka merupakan serat yang awet dan lentur yang diambil dari pohon pisang. Serat ini masih sangat jarang dimanfaatkan, sementara di Indonesia serat abaka bisa ditemukan di mana mana. Tujuan penelitian ini adalah untuk mengetahui sejauh mana pengaruh serat abaka terhadap kuat lentur beton. Penelitian ini diawali dengan studi literature, pengujian material (Agregat halus, agregat kasar, semen dan serat abaka), mix design beton, pembuatan benda uji, perawatan dan dilanjutkan dengan pengujian kuat lentur beton serta terakhir dilakukan analisis hasil pengujian. Dari hasil pengujian didapatkan kuat lentur maksmum terjadi pada kadar serat abaka sebesar 0,6% dengan kuat lentur 3,75 MPa, sedangkan kuat lentur terkecil terjadi pada kadar serat abaka 0% dengan kuat lentur 3,34 MPa.</p><p class="11daftarpustaka"> </p><p class="11daftarpustaka">Kata kunci: <em>serat abaka,</em><em> kuat lentur, mix deisgn</em><em></em></p><p align="center"><strong> </strong></p><p align="center"><strong> </strong></p><p align="center"><strong>Abstract</strong></p><p class="11daftarpustaka"> </p><p class="11daftarpustaka">Abaca fiber is a durable and flexible fiber taken from the banana tree. This fiber is still very rarely used, while in Indonesian abaca fiber can be found everywhere. The purpose of this study was to determine the extent of the influence of abaca fiber on the flexural strength of concrete. This research begins with literature studies, material testing (fine aggregate, coarse aggregate, cement, and abaca fiber), concrete mix design, manufacture of test objects, curing, and continues with concretes flexural strength testing and finally an analysis of the test results. From the test results, it founded that the maximum flexural strength occurred at the abaca fiber content of 0.6% with a bending strength of 3.75 MPa, and the smallest flexural strength occurred at 0% abaca fiber content with a flexural strength of 3.34 MPa.</p><p class="11daftarpustaka"> </p><p class="11daftarpustaka">Keywords: <em>Abaka fiber,</em><em> flexural strength, mix design</em><em></em></p>

Fully Plastic Solutions and Large Scale Yielding Estimates for Plane Stress Crack Problems

1976 ◽  
Vol 98 (4) ◽  
pp. 289-295 ◽  
Author(s):  
C. F. Shih ◽  
J. W. Hutchinson
Keyword(s):  
Plane Stress ◽  
Large Scale ◽  
Crack Opening ◽  
Opening Displacement ◽  
Stress Strain ◽  
Linear Elastic ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Crack Problems ◽  
Scale Yielding

Fully plastic plane stress solutions are given for a center-cracked strip in tension and an edge-cracked strip in pure bending. In the fully plastic formulation the material is characterized by a pure power hardening stress-strain relation which reduces at one limit to linear elasticity and at the other to rigid/perfect plasticity. Simple formulas are given for estimating the J-integral, the load-point displacement and the crack opening displacement in terms of the applied load for strain hardening materials characterized by the Ramberg-Osgood stress-strain relation in tension. The formulas make use of the linear elastic solution and the fully plastic solution to interpolate over the entire range of small and large scale yielding. The accuracy of the formulas is assessed using finite element calculations for some specific configurations.

scholarly journals A Review of Precast Concrete Beam-to-Column Connections Subjected to Severe Fire Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-23
Author(s):  
Noor Azim Mohd Radzi ◽  
Roszilah Hamid ◽  
Azrul A. Mutalib ◽  
A. B. M. Amrul Kaish
Keyword(s):  
Large Scale ◽  
Concrete Beam ◽  
Structural Integrity ◽  
Precast Concrete ◽  
Analytical Models ◽  
Fire Effect ◽  
The Moment ◽  
The Impact ◽  
Comprehensive Study ◽  
Fire Conditions

Fire exposure can have a significant impact on the structural integrity and robustness of precast concrete beam-to-column connections. Given the importance of fire safety in the design of a structure, it is critical to understand the damage that may occur in the event of a fire to be able to prevent the building from collapsing. No comprehensive study has been carried out to determine the effects of fire on semirigid and pinned concrete beam-to-column connections. Most studies focused on the impact of exposure of rigid concrete beam-to-column connections to high temperatures. This paper is a comprehensive review of the literature on the performance of precast concrete beam-to-column connections under fire conditions. The key areas in this review are the moment-rotation-temperature characteristics and fire effect on precast concrete beam-to-column connections. This paper focuses primarily on the case studies of real fires, large-scale fire tests, computer simulations and analytical models, fire resistance tests on the connection elements, and assessment and rehabilitation of fire-damaged precast concrete. The paper also discusses the current issues and possible challenges.

Assessment of Damage and Fracture Behaviours in a Cast Aluminium Alloy via In Situ Synchrotron Microtomography

2006 ◽  
Vol 519-521 ◽  
pp. 1005-1010 ◽  
Author(s):  
Shin Yamamoto ◽  
Hiroyuki Toda ◽  
L. Qian ◽  
Tomomi Ohgaki ◽  
Masakazu Kobayashi ◽  
...  
Keyword(s):  
Driving Forces ◽  
Crack Opening ◽  
Crack Tip ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Contrast Imaging ◽  
Cracking Behavior ◽  
Damage And Fracture ◽  
Void Initiation

High resolution phase contrast imaging technique has been applied to obtain clear crack images together with the detailed of microstructural features in a cast aluminum alloy. Crack opening/closure, crack extension and damage evolution in the vicinity of a crack-tip is observed three-dimensionally (3-D). 3-D image analysis is performed to evaluate void initiation and growth near the crack-tip. The information on physical displacement of each microstructural feature is provided for analyzing local crack driving forces at crack front. This technique has been identified to provide a unique possibility to quantitatively interpret the 3-D cracking behavior in bulk materials.

Sign in / Sign up

Export Citation Format

Share Document