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Strengthening, Repair, and Retrofit of Reinforced Concrete

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Construction and Building Materials".

Deadline for manuscript submissions: 20 October 2024 | Viewed by 9143

Special Issue Editors


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Guest Editor
Department of Civil Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
Interests: seismic retrofit of RC structures; fiber-reinforced polymers; fiber-reinforced concrete
Special Issues, Collections and Topics in MDPI journals

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Co-Guest Editor
Department of Civil Engineering, Feng Chia University, Taichung 40724, Taiwan
Interests: civil engineering; earthquake engineering; disaster monitoring system; mechanics of materials
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Co-Guest Editor
Department of Architecture, National Taipei University of Technology, Taipei 10608, Taiwan
Interests: building engineering; sustainable city and community; green buildings; radiative cooling materials

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Co-Guest Editor
Department of Civil Engineering, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Road, Taipei 10608, Taiwan
Interests: soil erosion; machine learning; geotechnical engineering
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Structures made of reinforced concrete (RC) are examples of human progress in the modern era, and also the most prevalent representation of modern cities. As more and more RC structures reach the end of their service lives, it is not always possible or desirable to replace them with new ones. In addition, even when structures are not nearing the end of their service life, there is often a need to reinforce them to meet new building codes or seismic performance standards. Therefore, the only viable alternative left is strengthening, repairing, or retrofitting RC structures.

Due to the critical importance of reinforcing existing RC structures, we dedicate this Special Issue to this topic and invite you to submit your most recent research and findings. Our intention for this Special Issue is to tackle three distinct but interrelated areas of research activities. These include the mechanical aspect (which includes things such as reinforcing, repairing, and retrofitting), the material aspect (which includes things such as fiber-reinforced plastic, fiber-reinforced concrete, geopolymers, and a variety of composites), and the application aspect (which includes things such as performance analysis, non-destructive testing, and case studies). We believe that an opportunity such as this will encourage a deeper level of collaboration among experts and that the issue will serve as a platform for innovative ideas and solutions to reinvigorate our aging infrastructure.

Prof. Yeou-Fong Li
Guest Editor

Prof. Dr. Bing-Jean Lee
Prof. Chih-Hong Huang
Prof. Dr. Walter Chen
Co-Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • strengthening
  • repair
  • retrofit
  • cementitious composite
  • geopolymer
  • fiber-reinforced concrete
  • fiber-reinforced mortar
  • fiber-reinforced polymer
  • material characterization
  • numerical modeling
  • strengthening material
  • structural performance
  • structural safety
  • structural analysis
  • case study
  • durability
  • concrete technology
  • special concretes
  • non-destructive testing (NDT) of concrete
  • 3D-printed building materials
  • waste and recycled materials
  • foundation repair and retrofit
  • tunnel lining repair and retrofit

Published Papers (6 papers)

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Research

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18 pages, 9961 KiB  
Article
Bond Shear Tests to Evaluate Different CFRP Shear Strengthening Strategies for I-Shaped Concrete Cross-Sections
by Muhammad Arslan Yaqub, Christoph Czaderski and Stijn Matthys
Materials 2024, 17(13), 3342; https://doi.org/10.3390/ma17133342 - 5 Jul 2024
Viewed by 331
Abstract
I-shaped concrete girders are widely used in precast bridge and roof construction, making them a common structural component in existing infrastructure. Despite well-established strengthening techniques using various innovative materials, such as externally bonded carbon fibre reinforced polymer (CFRP) reinforcement, the shear strengthening of [...] Read more.
I-shaped concrete girders are widely used in precast bridge and roof construction, making them a common structural component in existing infrastructure. Despite well-established strengthening techniques using various innovative materials, such as externally bonded carbon fibre reinforced polymer (CFRP) reinforcement, the shear strengthening of an I-shaped concrete girder is not straightforward. Several research studies have shown that externally bonded CFRP reinforcement might exhibit early debonding at the concave corners of the I-shape, resulting in a marginal increase in shear capacity. This research study aims to assess the performance of two different CFRP shear strengthening strategies for I-shaped concrete cross-sections. In the first strategy, CFRP was bonded along the I-shape of the cross-section with the provision of additional anchorage. In the second strategy, the I-shape was transformed into a rectangular shape by using in-fill blocks over which the CFRP was bonded in a U-configuration. In addition to the strengthening strategies, the investigated parameters included two different materials for the in-fill blocks (conventional and aerated concrete) and two different anchoring schemes (bolted steel plate anchor and CFRP spike anchor). To avoid testing on large-scale girders, a new test methodology has been implemented on concrete I-sections. The test results demonstrate the feasibility of comparing different shear strengthening configurations dedicated to I-sections. Among other findings, the results showed that the local transformation of the I-shape to an equivalent rectangular shape could be a viable solution, resulting in shear strength enhancement of 12% to 53% without and with the anchorages, respectively. Full article
(This article belongs to the Special Issue Strengthening, Repair, and Retrofit of Reinforced Concrete)
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16 pages, 3363 KiB  
Article
Study on the Utilization of Waste Thermoset Glass Fiber-Reinforced Polymer in Normal Strength Concrete and Controlled Low Strength Material
by Yeou-Fong Li, Yi-Wei Hsu, Jin-Yuan Syu, Bian-Yu Chen and Bo Song
Materials 2023, 16(9), 3552; https://doi.org/10.3390/ma16093552 - 5 May 2023
Cited by 6 | Viewed by 1676
Abstract
Thermoset glass fiber-reinforced polymers (GFRP) have been widely used in manufacturing and construction for nearly half a century, but the large amount of waste produced by this material is difficult to dispose of. In an effort to address this issue, this research investigates [...] Read more.
Thermoset glass fiber-reinforced polymers (GFRP) have been widely used in manufacturing and construction for nearly half a century, but the large amount of waste produced by this material is difficult to dispose of. In an effort to address this issue, this research investigates the reuse of thermoset GFRP waste in normal strength concrete (NSC) and controlled low-strength materials (CLSM). The mechanical performance and workability of the resulting concrete were also evaluated. To prepare the concrete specimens, the thermoset GFRP waste was first pulverized into granular pieces, which were then mixed with cement, fly ash, and water to form cylindrical concrete specimens. The results showed that when the proportion of thermoset GFRP waste aggregate in the concrete increased, the compressive strengths of NSC and CLSM would decrease. However, when incorporating 5% GFRP waste into CLSM, the compressive strength was 7% higher than concrete without GFRP. However, the workability of CLSM could be improved to meet engineering standards by adding an appropriate amount of superplasticizer. This finding suggests that the use of various combinations of proportions in the mixture during production could allow for the production of CLSM with different compressive strength needs. In addition, the use of recycled thermoset GFRP waste as a new aggregate replacement for traditional aggregates in CLSM was found to be a more sustainable alternative to the current CLSM combinations used in the market. Full article
(This article belongs to the Special Issue Strengthening, Repair, and Retrofit of Reinforced Concrete)
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15 pages, 11096 KiB  
Article
Mechanical Behaviors of Microwave-Assisted Pyrolysis Recycled Carbon Fiber-Reinforced Concrete with Early-Strength Cement
by Yeou-Fong Li, Jie-You Li, Jin-Yuan Syu, Tzu-Hsien Yang, Shu-Mei Chang and Ming-Yuan Shen
Materials 2023, 16(4), 1507; https://doi.org/10.3390/ma16041507 - 10 Feb 2023
Cited by 3 | Viewed by 1374
Abstract
This study aimed to investigate the mechanical performance of early-strength carbon fiber-reinforced concrete (ECFRC) by incorporating original carbon fiber (OCF), recycled carbon fiber (RCF), and sizing-removed carbon fiber (SCF). Compressive, flexural, and splitting tensile strength were tested under three fiber-to-cement weight ratios (5‰, [...] Read more.
This study aimed to investigate the mechanical performance of early-strength carbon fiber-reinforced concrete (ECFRC) by incorporating original carbon fiber (OCF), recycled carbon fiber (RCF), and sizing-removed carbon fiber (SCF). Compressive, flexural, and splitting tensile strength were tested under three fiber-to-cement weight ratios (5‰, 10‰, and 15‰). The RCF was produced from waste bicycle parts made of carbon fiber-reinforced polymer (CFRP) through microwave-assisted pyrolysis (MAP). The sizing-removed fiber was obtained through a heat-treatment method applied to the OCF. The results of scanning electron microscopy (SEM) analysis with energy dispersive X-ray spectrometry (EDS) indicated the successful removal of sizing and impurities from the surface of the RCF and SCF. The mechanical test results showed that ECFRC with a 10‰ fiber-to-cement weight ratio of carbon fiber had the greatest improvement in its mechanical strengths. Moreover, the ECFRC with 10‰ RCF exhibited higher compressive, flexural, and splitting tensile strength than that of benchmark specimen by 14.2%, 56.5%, and 22.5%, respectively. The ECFRC specimens with a 10‰ fiber-to-cement weight ratio were used to analyze their impact resistance under various impact energies in the impact test. At 50 joules of impact energy, the impact number of the ECFRC with SCF was over 23 times that of the benchmark specimen (early-strength concrete without fiber) and was also greater than that of ECFRC with OCF and RCF. Full article
(This article belongs to the Special Issue Strengthening, Repair, and Retrofit of Reinforced Concrete)
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16 pages, 6205 KiB  
Article
Seismic Behavior of Concrete Columns Retrofitted with a Brace-Type Replaceable Steel Link
by Min Sook Kim and Young Hak Lee
Materials 2023, 16(3), 1182; https://doi.org/10.3390/ma16031182 - 30 Jan 2023
Cited by 2 | Viewed by 1633
Abstract
This paper presents the results of a combined cyclic loading test on a single reinforced concrete column which was retrofitted with a newly proposed brace-type replaceable steel link. A total of four retrofitted reinforced concrete columns, with the length of the brace as [...] Read more.
This paper presents the results of a combined cyclic loading test on a single reinforced concrete column which was retrofitted with a newly proposed brace-type replaceable steel link. A total of four retrofitted reinforced concrete columns, with the length of the brace as a variable, were fabricated and tested. A companion column without retrofitting was used as the control specimen. The test results indicate that the proposed brace-type replaceable steel link can be effective in retrofitting the concrete columns, resulting in improvements in the strength, stiffness, and energy dissipation of columns. We observed that the maximum load increases by at least 87%, effective stiffness increases by 44%, and energy dissipation capacity increases by 91% when compared with non-retrofitted specimen. Full article
(This article belongs to the Special Issue Strengthening, Repair, and Retrofit of Reinforced Concrete)
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30 pages, 28920 KiB  
Article
Effect of Non-Woven Polyethylene Terephthalate (PET) Tissue on Fresh and Hardened Properties of Concrete
by Sifatullah Bahij, Safiullah Omary, Vincent Steiner, Françoise Feugeas and Mohammad Hashim Ibrahimkhil
Materials 2022, 15(24), 8766; https://doi.org/10.3390/ma15248766 - 8 Dec 2022
Cited by 5 | Viewed by 1572
Abstract
This study will investigate the effect of non-woven PET plastic tissue on the fresh, physical, mechanical, acoustic, thermal, and microstructural behaviors of concrete. Including reference specimens, non-woven fabrics were considered in two ways: (a) as a layer with four various configurations of 1-layer, [...] Read more.
This study will investigate the effect of non-woven PET plastic tissue on the fresh, physical, mechanical, acoustic, thermal, and microstructural behaviors of concrete. Including reference specimens, non-woven fabrics were considered in two ways: (a) as a layer with four various configurations of 1-layer, 2-sides, 3-sides, and full wrapping (4-sides) to strengthen specimens, and (b) as (10 × 10) mm cut pieces with three different incorporated percentages of 0.25%, 0.50%, and 0.75%. Based on the experimental results, mechanical properties (compressive, split tensile, and flexural strengths) were remarkably improved by applying non-woven sheets as a layer. For instance, the cylindrical compressive and split tensile strengths were improved by 13.40% and 15.12% for the strengthened specimens compared to the reference specimens, respectively. Moreover, control specimens were damaged to many fragments after mechanical testing, but the samples strengthened by such fabrics or containing cut pieces were maintained and not separated into many small parts. The acoustic behavior and thermal conductivity declined by 9.83% and 19.67% with the attachment of tissue on one side and 2-sides, respectively. Acoustic behaviors decreased by 10.0%, 17.60%, and 26.30% and thermal conductivity decreased by 6.60%, 12.10%, and 15.50%, with the incorporation of 0.25%, 0.50%, and 0.75% of cut pieces, respectively. Finally, it was discovered that non-woven tissue is advised to enhance particular properties of concrete. Full article
(This article belongs to the Special Issue Strengthening, Repair, and Retrofit of Reinforced Concrete)
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Review

Jump to: Research

26 pages, 2433 KiB  
Review
Autonomous Self-Healing Methods as a Potential Technique for the Improvement of Concrete’s Durability
by Anita Gojević, Ivanka Netinger Grubeša, Berislav Marković, Sandra Juradin and Anđelko Crnoja
Materials 2023, 16(23), 7391; https://doi.org/10.3390/ma16237391 - 28 Nov 2023
Viewed by 1667
Abstract
The causes of cracks in concrete are varied, and regardless of their origin, these cracks invariably have a detrimental impact on the durability of concrete structures and escalate their maintenance costs. This paper presents a comprehensive review of current knowledge regarding the methods [...] Read more.
The causes of cracks in concrete are varied, and regardless of their origin, these cracks invariably have a detrimental impact on the durability of concrete structures and escalate their maintenance costs. This paper presents a comprehensive review of current knowledge regarding the methods of self-healing in concrete, ranging from autogenic and improved autogenic self-healing to the autonomous self-healing of concrete. Particular emphasis is placed on the methods of autonomous concrete self-healing: the bacterial healing method, the crystalline hydrophilic additives healing method, and the capsule-based self-healing method. The hypothesis is that applying these self-healing methods could potentially prevent damages or cracks in concrete caused by freeze–thaw cycles, thereby extending the lifespan of concrete structures. The mechanism of action and current achievements in the field are provided for each method. Full article
(This article belongs to the Special Issue Strengthening, Repair, and Retrofit of Reinforced Concrete)
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