[go: up one dir, main page]
More Web Proxy on the site http://driver.im/
You seem to have javascript disabled. Please note that many of the page functionalities won't work as expected without javascript enabled.
 
 
Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (1,231)

Search Parameters:
Keywords = concrete corrosion

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
20 pages, 7871 KiB  
Article
Influence of Freeze–Thaw Cycles and Sustained Load on the Durability and Bearing Capacity of Reinforced Concrete Columns
by Chen Chen, Kai Zhang and Lin Ye
Materials 2024, 17(24), 6129; https://doi.org/10.3390/ma17246129 - 15 Dec 2024
Viewed by 426
Abstract
The deterioration of concrete structures is mainly due to the combined action of the environment and external load. In this study, 32 reinforced concrete columns were prepared to evaluate the coupling actions on the properties of reinforced concrete structures. The durability, bearing capacity, [...] Read more.
The deterioration of concrete structures is mainly due to the combined action of the environment and external load. In this study, 32 reinforced concrete columns were prepared to evaluate the coupling actions on the properties of reinforced concrete structures. The durability, bearing capacity, and failure mode of reinforced concrete columns were investigated under the combined action of freeze–thaw (F–T) cycles, sustained load, and salt corrosion (water or composite salt solution). Results show that the mass fluctuation of reinforced concrete columns under a sustained load was more obvious during F-T cycles. During the early F-T cycles, the sustained load was beneficial to the F-T resistance of the reinforced concrete columns. With the increase in F-T cycles, the damage to the columns with a sustained load gradually aggravated. In the composite salt solution, the damage to the reinforced concrete columns was postponed, and its durability showed a two-stage evolution. After 100 F-T cycles, the mass loss and relative dynamic modulus of elasticity (RDME) deterioration of the columns with a sustained load sped up significantly. The combined action of salt corrosion, load, and F-T cycles has the most significant influence on the bearing capacity, stiffness deterioration, and crack development of reinforced concrete columns. Full article
Show Figures

Figure 1

Figure 1
<p>Schematic diagram of reinforced concrete column.</p>
Full article ">Figure 2
<p>Diagram of sustained loading device.</p>
Full article ">Figure 3
<p>Schematic diagram of electromigration-accelerated ion corrosion device. (<b>a</b>) Working principle, (<b>b</b>) full view of the test, (<b>c</b>) local view of the test.</p>
Full article ">Figure 4
<p>Schematic of axial loading device.</p>
Full article ">Figure 5
<p>Damage after different F-T cycles under water medium. (<b>a</b>) H0Y0, (<b>b</b>) H1Y0.</p>
Full article ">Figure 6
<p>Damage after F-T cycles under composite salt solution. (<b>a</b>) H0Y1, (<b>b</b>) H1Y1.</p>
Full article ">Figure 7
<p>Mass loss rate after frost damage. (<b>a</b>) H0Y0 and H1Y0, (<b>b</b>) H0Y1 and H1Y1.</p>
Full article ">Figure 8
<p>RDME under F-T cycles. (<b>a</b>) H0Y0 and H1Y0, (<b>b</b>) H0Y1 and H1Y1.</p>
Full article ">Figure 9
<p>Failure characteristics of reinforced concrete columns under axial loading with different F-T cycles. (<b>a</b>) H0Y0, (<b>b</b>) H1Y0, (<b>c</b>) H0Y1, (<b>d</b>) H1Y1.</p>
Full article ">Figure 9 Cont.
<p>Failure characteristics of reinforced concrete columns under axial loading with different F-T cycles. (<b>a</b>) H0Y0, (<b>b</b>) H1Y0, (<b>c</b>) H0Y1, (<b>d</b>) H1Y1.</p>
Full article ">Figure 10
<p>Local failure characteristics of reinforced concrete columns under axial compression with different F-T cycles. (<b>a</b>) H0Y0D0, (<b>b</b>) H1Y1D125, (<b>c</b>) H0Y1D125, (<b>d</b>) H1Y0D150.</p>
Full article ">Figure 11
<p>Force–displacement curves of reinforced concrete columns under axial compression with different F-T cycles. (<b>a</b>) H0Y0, (<b>b</b>) H1Y0, (<b>c</b>) H0Y1, (<b>d</b>) H1Y1.</p>
Full article ">Figure 12
<p>Force–displacement curves of reinforced concrete columns under different conditions with the same F-T cycles. (<b>a</b>) N = 0 cycles, (<b>b</b>) N = 100 cycles, (<b>c</b>) N = 125 cycles, (<b>d</b>) N = 150 cycles.</p>
Full article ">Figure 13
<p>Stress–strain curves of reinforced concrete columns under axial compression with different F-T cycles. (<b>a</b>) H0Y0, (<b>b</b>) H1Y0, (<b>c</b>) H0Y1, (<b>d</b>) H1Y1.</p>
Full article ">Figure 14
<p>Stress–strain curves of reinforced concrete columns under axial compression with different F-T cycles. (<b>a</b>) relative peak stress, (<b>b</b>) Peak strain.</p>
Full article ">
35 pages, 12083 KiB  
Review
Flexural Behavior and Failure Modes of Pultruded GFRP Tube Concrete-Filled Composite Beams: A Review of Experimental and Numerical Studies
by Mohammed Jalal Al-Ezzi, Agusril Syamsir, A. B. M. Supian, Salmia Beddu and Rayeh Nasr Al-Dala’ien and Rayeh Nasr Al-Dala’ien
Buildings 2024, 14(12), 3966; https://doi.org/10.3390/buildings14123966 - 13 Dec 2024
Viewed by 316
Abstract
Pultruded glass fiber-reinforced polymer (GFRP) materials are increasingly recognized in civil engineering for their exceptional properties, including a high strength-to-weight ratio, corrosion resistance, and ease of fabrication, making them ideal for composite structural applications. The use of concrete infill enhances the structural integrity [...] Read more.
Pultruded glass fiber-reinforced polymer (GFRP) materials are increasingly recognized in civil engineering for their exceptional properties, including a high strength-to-weight ratio, corrosion resistance, and ease of fabrication, making them ideal for composite structural applications. The use of concrete infill enhances the structural integrity of thin-walled GFRP sections and compensates for the low elastic modulus of hollow profiles. Despite the widespread adoption of concrete-filled pultruded GFRP tubes in composite beams, critical gaps remain in understanding their flexural behavior and failure mechanisms, particularly concerning design optimization and manufacturing strategies to mitigate failure modes. This paper provides a comprehensive review of experimental and numerical studies that investigate the impact of key parameters, such as concrete infill types, reinforcement strategies, bonding levels, and GFRP tube geometries, on the flexural performance and failure behavior of concrete-filled pultruded GFRP tubular members in composite beam applications. The analysis includes full-scale GFRP beam studies, offering a thorough comparison of documented flexural responses, failure modes, and structural performance outcomes. The findings are synthesized to highlight current trends, identify research gaps, and propose strategies to advance the understanding and application of these composite systems. The paper concludes with actionable recommendations for future research, emphasizing the development of innovative material combinations, optimization of structural designs, and refinement of numerical modeling techniques. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
Show Figures

Figure 1

Figure 1
<p>Steel corrosion of reinforced concrete beam [<a href="#B8-buildings-14-03966" class="html-bibr">8</a>].</p>
Full article ">Figure 2
<p>Market share of fiber-reinforced polymer (FRP) by application.</p>
Full article ">Figure 3
<p>GFRP pultrusion process.</p>
Full article ">Figure 4
<p>Typical lay-ups of I-section [<a href="#B37-buildings-14-03966" class="html-bibr">37</a>].</p>
Full article ">Figure 5
<p>Longitudinal strain distribution of beams during the loading process [<a href="#B66-buildings-14-03966" class="html-bibr">66</a>].</p>
Full article ">Figure 6
<p>Load–displacement behavior of hollow and concrete-filled GFRP beams: H-0: hollow GFRP beam, H-10: GFRP beam filled grade 10 concrete, H-37: GFRP beam filled grad 37 concrete, and H-43: GFRP beam filled grad 43 concrete [<a href="#B7-buildings-14-03966" class="html-bibr">7</a>].</p>
Full article ">Figure 7
<p>Crack pattern at the failure of hollow and concrete-filled beams [<a href="#B7-buildings-14-03966" class="html-bibr">7</a>].</p>
Full article ">Figure 8
<p>Cross-section and dimensions of the beams (mm) [<a href="#B41-buildings-14-03966" class="html-bibr">41</a>].</p>
Full article ">Figure 9
<p>Failure behavior of GFRP concrete-filled composite beams with different hollow cores [<a href="#B41-buildings-14-03966" class="html-bibr">41</a>].</p>
Full article ">Figure 10
<p>Cross-sections of beam specimens (<b>A</b>) RC, (<b>B</b>) G0C, (<b>C</b>) G0.6A, (<b>D</b>) G1.15A, (<b>E</b>) G1.15B, and (<b>F</b>) G1.15C [<a href="#B68-buildings-14-03966" class="html-bibr">68</a>].</p>
Full article ">Figure 11
<p>Failure behavior of infill concrete [<a href="#B68-buildings-14-03966" class="html-bibr">68</a>].</p>
Full article ">Figure 12
<p>Composed beam steel angles, and penetrating long bolts to prevent concrete slip [<a href="#B40-buildings-14-03966" class="html-bibr">40</a>].</p>
Full article ">Figure 13
<p>Failure behavior of a pultruded GFRP beam (<b>a</b>) Plan view, (<b>b</b>) Transvers section, and (<b>c</b>) Longitudinal [<a href="#B69-buildings-14-03966" class="html-bibr">69</a>].</p>
Full article ">Figure 14
<p>Bending strength of single and multi-cell pultruded GFRP beams [<a href="#B43-buildings-14-03966" class="html-bibr">43</a>].</p>
Full article ">Figure 15
<p>Recommended configurations of the corner of PFRP profiles [<a href="#B72-buildings-14-03966" class="html-bibr">72</a>].</p>
Full article ">Figure 16
<p>Load–deflection curves of square and rectangular GFRP tubes [<a href="#B73-buildings-14-03966" class="html-bibr">73</a>].</p>
Full article ">Figure 17
<p>The effect of bonding on load–deflection behavior of composite beam of (A) hollow GFRP tube, (B) concrete filled GFRP tube, (C) concrete filled GFRP tube with bonded flange, and (D) concrete filled GFRP tube with bonded flange and web [<a href="#B44-buildings-14-03966" class="html-bibr">44</a>].</p>
Full article ">Figure 18
<p>Load–deflection behavior of circular GFRP concrete-filled composite beam with different configurations [<a href="#B16-buildings-14-03966" class="html-bibr">16</a>].</p>
Full article ">Figure 19
<p>(<b>a</b>) GFRP crushing at the control beam’s web-flange junction, and (<b>b</b>) failure of the central plain lightweight concrete core due to tension [<a href="#B81-buildings-14-03966" class="html-bibr">81</a>].</p>
Full article ">Figure 20
<p>Finite element models (FEMs) of midspan cross-sections with mesh for configurations C, D, and E [<a href="#B84-buildings-14-03966" class="html-bibr">84</a>].</p>
Full article ">Figure 21
<p>Typical numerical and experimental cracking patterns of infill concrete in short GFRP beam (<b>a</b>) GRRP longitudinal stress of web and bottom flange at a load of 160 kN, (<b>b</b>) GRRP in-plane shear strain of web and bottom flange at a load of 160 kN, (<b>c</b>) Infill concrete failure behavior of web-bonded beams (<b>d</b>) Infill concrete failure behavior of flange-bonded beams, (<b>e</b>) Infill concrete failure behavior of web, web-bonded beams [<a href="#B84-buildings-14-03966" class="html-bibr">84</a>].</p>
Full article ">Figure 22
<p>Solid finite element model of CFFT beam with tube cuts [<a href="#B87-buildings-14-03966" class="html-bibr">87</a>].</p>
Full article ">Figure 23
<p>(<b>A</b>) Cut length-to-radius ratio (α), and the reduction in moment capacity (ρ), (<b>B</b>) GFRP tubes without circumferential cuts under a 10 kN load, and (<b>C</b>) longitudinal stresses in GFRP tubes with 20% circumferential cuts with a 10 kN load [<a href="#B87-buildings-14-03966" class="html-bibr">87</a>].</p>
Full article ">Figure 24
<p>The failure mode of the GFRP beam with 51% fiber volume fraction, (<b>A</b>) numerical, and (<b>B</b>) experimental [<a href="#B9-buildings-14-03966" class="html-bibr">9</a>].</p>
Full article ">Figure 25
<p>Numerical and experimental results of GFRP composite beam infilled with composite fiber-reinforced polymer; (<b>a</b>) specimen 1, (<b>b</b>) specimen 2, and (<b>c</b>) specimen 3 [<a href="#B94-buildings-14-03966" class="html-bibr">94</a>].</p>
Full article ">
13 pages, 2528 KiB  
Article
Study of the Static Performance of Guyed Towers in High-Voltage Transmission Lines
by Haoyuan Chen, Yongan Wang, Hong Yin, Liwei Xia, Hengbang Wan, Musoke Paul Kalungi and Aizhu Zhu
Buildings 2024, 14(12), 3960; https://doi.org/10.3390/buildings14123960 - 13 Dec 2024
Viewed by 319
Abstract
Guyed towers in high-voltage transmission lines consist of the tower body, guy wire system, and foundation. A well-designed guy wire system with optimized tension levels is essential to maintain the stability of the tower under wind loads and other external forces. In practical [...] Read more.
Guyed towers in high-voltage transmission lines consist of the tower body, guy wire system, and foundation. A well-designed guy wire system with optimized tension levels is essential to maintain the stability of the tower under wind loads and other external forces. In practical operation, to prevent excessive corrosion of the pinned metal components at the tower base, these connections are often encased in concrete, altering the base connection conditions and affecting the structural forces on the tower. This study develops a finite element analysis model based on two guyed tower structures from a high-voltage transmission line project. By measuring the actual tensions of the guy wire and testing the basic material performance, this model considers the effects of varying base connection conditions and different guy wire tension levels. Under designed ice load and extreme wind load conditions, the analysis focuses on changes in tower body stress, tower-top displacement and inclination, and guy wire forces. The results indicate that when the tower base is uniformly pinned or fixed, the initial guy wire tension has minimal impact on maximum tower stress but significantly affects maximum tower displacement and inclination when the tower was under the ice and wind load conditions. The base connection condition has a pronounced impact on the stress states of the tower and guy wire system, especially under the designed wind loads. In particular, when the base is fixed, the maximum base stress in Tower 1 under the wind loads is 270% higher than in a pinned condition. The initial guy wire tension level significantly affects the guy wire force under the ice and wind loads; for example, when Tower 1 is subjected to approximately 85% of the design level of high wind load, some guy wires reach full relaxation prematurely, presenting localized strength failure risks at the tower foot, potentially threatening the tower safety under extreme design loads. Full article
(This article belongs to the Section Building Structures)
Show Figures

Figure 1

Figure 1
<p>On-site measurement of tension forces.</p>
Full article ">Figure 2
<p>Model diagram of the guyed tower and guy wire identification.</p>
Full article ">Figure 3
<p>Stress–strain curves of guy wires.</p>
Full article ">Figure 4
<p>Stress calculation results for guy wires G1 and G2 under different element quantity conditions.</p>
Full article ">Figure 5
<p>Typical stress and displacement contour plots. (<b>a</b>) Stress contour plot under the ice loading for Tower 1. (<b>b</b>) Stress contour plot under the high wind loading for Tower 1. (<b>c</b>) Displacement contour plot under the ice loading for Tower 1. (<b>d</b>) Displacement contour plot under the high wind loading for Tower 1.</p>
Full article ">Figure 5 Cont.
<p>Typical stress and displacement contour plots. (<b>a</b>) Stress contour plot under the ice loading for Tower 1. (<b>b</b>) Stress contour plot under the high wind loading for Tower 1. (<b>c</b>) Displacement contour plot under the ice loading for Tower 1. (<b>d</b>) Displacement contour plot under the high wind loading for Tower 1.</p>
Full article ">
17 pages, 5580 KiB  
Article
Revolutionizing Concrete Bridge Assessment: Implementing Nondestructive Scanning for Transformative Evaluation
by Wael Zatar, Felipe Mota Ruiz and Hien Nghiem
Appl. Sci. 2024, 14(24), 11590; https://doi.org/10.3390/app142411590 - 12 Dec 2024
Viewed by 345
Abstract
This study focused on analyzing the impact of ground-penetrating radar (GPR) scan spacing on accurately assessing the reinforcement of concrete bridge girders, providing practical insights. A decommissioned bridge box beam was evaluated to unveil rebars and tendons’ depth and spacing. The box beam [...] Read more.
This study focused on analyzing the impact of ground-penetrating radar (GPR) scan spacing on accurately assessing the reinforcement of concrete bridge girders, providing practical insights. A decommissioned bridge box beam was evaluated to unveil rebars and tendons’ depth and spacing. The box beam was decommissioned from the West Virginia Division of Highways inventory. An innovative algorithm was developed to fully automate the analysis of survey grid data across all sides of the beam. Implementing this algorithm into a computer code has paved the way for comprehensive automation of GPR data analyses. Comparing GPR data analyses from various profile line offsets, this study assists in producing optimal protocols for inspecting box beams. Transverse profile line offsets between 4 in. and 24 in. yielded nearly identical results, setting a new standard for precision. Utilizing more than one longitudinal profile line was highly beneficial in accurately assessing prestressed concrete box beams. This research helps redefine bridge evaluation by precisely finding rebar spacing, concrete cover, and other internal characteristics. This study’s findings offer invaluable advancements and equip state departments of transportation with the knowledge to accurately assess in-service concrete bridge box beams, empowering them to make informed decisions. Full article
Show Figures

Figure 1

Figure 1
<p>GPR system.</p>
Full article ">Figure 2
<p>Prestressed concrete box beam typical section.</p>
Full article ">Figure 3
<p>Prestressed concrete box beam plan view.</p>
Full article ">Figure 4
<p>Prestressed concrete box beam survey grid; (<b>a</b>) top face transverse (red) and longitudinal (blue) profile lines; (<b>b</b>) prestressed concrete box beam top face transverse profile lines (red).</p>
Full article ">Figure 5
<p>(<b>a</b>) EM wave travel path and (<b>b</b>) hyperbolic reflection from a rebar [<a href="#B35-applsci-14-11590" class="html-bibr">35</a>].</p>
Full article ">Figure 6
<p>Flow chart.</p>
Full article ">Figure 7
<p>Typical profile images of the prestressed concrete beam: (<b>a</b>) top face transverse profile no. 15, (<b>b</b>) top face longitudinal profile no. 2, and (<b>c</b>) bottom face transverse profile no. 20.</p>
Full article ">Figure 7 Cont.
<p>Typical profile images of the prestressed concrete beam: (<b>a</b>) top face transverse profile no. 15, (<b>b</b>) top face longitudinal profile no. 2, and (<b>c</b>) bottom face transverse profile no. 20.</p>
Full article ">Figure 8
<p>Rebar depth comparisons between manual and auto rebar picking for top rebars: (<b>a</b>) Rebar #1; (<b>b</b>) Rebar #2; (<b>c</b>) Rebar #3; and (<b>d</b>) Rebar #4.</p>
Full article ">Figure 9
<p>Rebar spacing comparisons between manual and auto rebar picking for top rebars.</p>
Full article ">Figure 10
<p>Auto rebar picking for stirrups (longitudinal profile no. 3).</p>
Full article ">Figure 11
<p>Top reinforcement row depth: (<b>a</b>) Rebar #1; (<b>b</b>) Rebar #2; (<b>c</b>) Rebar #3; and (<b>d</b>) Rebar #4.</p>
Full article ">Figure 11 Cont.
<p>Top reinforcement row depth: (<b>a</b>) Rebar #1; (<b>b</b>) Rebar #2; (<b>c</b>) Rebar #3; and (<b>d</b>) Rebar #4.</p>
Full article ">Figure 12
<p>Top reinforcement row spacing: (<b>a</b>) Space #1, (<b>b</b>) Space #2; and (<b>c</b>) Space #3.</p>
Full article ">Figure 12 Cont.
<p>Top reinforcement row spacing: (<b>a</b>) Space #1, (<b>b</b>) Space #2; and (<b>c</b>) Space #3.</p>
Full article ">
23 pages, 6774 KiB  
Article
Enhancing Strength and Corrosion Resistance of Steel-Reinforced Concrete: Performance Evaluation of ICRETE Mineral Additive in Sustainable Concrete Mixes with PFA and GGBS
by Kowshika V.R, Vijaya Bhaskaran, Ramkumar Natarajan and Iman Faridmehr
Infrastructures 2024, 9(12), 228; https://doi.org/10.3390/infrastructures9120228 - 11 Dec 2024
Viewed by 583
Abstract
This study investigates the impact of an innovative mineral additive, ICRETE, on steel-reinforced concrete’s compressive strength and corrosion resistance. Nineteen concrete mixes were designed incorporating recycled industrial by-products, including Ground Granulated Blast Furnace Slag (GGBS) and Pulverized Fuel Ash (PFA), with varying dosages [...] Read more.
This study investigates the impact of an innovative mineral additive, ICRETE, on steel-reinforced concrete’s compressive strength and corrosion resistance. Nineteen concrete mixes were designed incorporating recycled industrial by-products, including Ground Granulated Blast Furnace Slag (GGBS) and Pulverized Fuel Ash (PFA), with varying dosages of ICRETE. Compressive strength was tested using cube specimens, cured, and assessed at 3, 7, and 28 days following IS 516-2018 standards. Corrosion behavior was evaluated in accordance with ASTM G109, employing macrocell potential monitoring and electrochemical methods, including Tafel extrapolation and linear polarization resistance. The results revealed that ICRETE-enhanced mixes achieved compressive strengths of 56.93 MPa at a water–cement ratio of 0.35 and 50.61 MPa at 0.38, surpassing the control mix’s 50.9 MPa at 0.33. Microstructural analysis via X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that ICRETE improved hydration, reduced porosity, and refined the microstructure, contributing to more excellent durability. Meanwhile, results demonstrated that the ICRETE additive reduced corrosion rates, displaying lower corrosion current densities and higher polarization resistance values where the corrosion rate dropped from 0.01 mmpy in control samples to 0.0081 mmpy with ICRETE. Environmental assessments indicated that ICRETE could significantly lower CO₂ emissions, reducing up to 46.50 kg CO2 per cubic meter of concrete. These findings highlight ICRETE’s potential to enhance strength and durability, supporting its use in sustainable, eco-friendly concrete applications. Full article
Show Figures

Figure 1

Figure 1
<p>Sieve Analysis of Coarse Aggregate.</p>
Full article ">Figure 2
<p>Sieve Analysis-Crushed Stone Sand.</p>
Full article ">Figure 3
<p>Preparation, casting, and compressive strength testing of concrete specimens.</p>
Full article ">Figure 4
<p>Stages of Macrocell Corrosion Testing Setup for Concrete Specimens.</p>
Full article ">Figure 5
<p>Electrochemical Testing Setup for Corrosion Evaluation.</p>
Full article ">Figure 6
<p>28-Day Compressive Strength Results for Various Concrete Mixes Incorporating the Innovative Additive at Different Dosages.</p>
Full article ">Figure 7
<p>Relationship Between Dosage of Innovative Additive and Compressive Strength at 7-Day and 28-Day Intervals.</p>
Full article ">Figure 8
<p>Relationship Between Water–Cement (W/C) Ratio and Dosage of Innovative Additive.</p>
Full article ">Figure 9
<p>X-ray diffraction patterns of the specimen (<b>a</b>) OPC+GGBS Mix Series specimen (OPGG CON-1), (<b>b</b>) OPC+GGBS Mix Series specimen with 2% innovative additive (OPGGNA-4).</p>
Full article ">Figure 9 Cont.
<p>X-ray diffraction patterns of the specimen (<b>a</b>) OPC+GGBS Mix Series specimen (OPGG CON-1), (<b>b</b>) OPC+GGBS Mix Series specimen with 2% innovative additive (OPGGNA-4).</p>
Full article ">Figure 10
<p>SEM of the specimen (<b>a</b>) OPC+GGBS Mix Series specimen (OPGG CON-1), (<b>b</b>) OPC+GGBS Mix Series specimen with 2% innovative additive (OPGGNA-4).</p>
Full article ">Figure 11
<p>Potentiodynamic polarization curve for steel rebar embedded in concrete with and without (control) ICRETE mineral additive.</p>
Full article ">Figure 12
<p>LPR plots for steel rebar embedded in concrete with and without (control) ICRETE mineral additive.</p>
Full article ">Figure 13
<p>Bode’s plots for steel rebar embedded in concrete with and without (control) ICRETE mineral additive.</p>
Full article ">Figure 14
<p>Expansion behavior of various concrete mixes immersed in a 5% Na<sub>2</sub>SO<sub>4</sub> solution over 378 days.</p>
Full article ">Figure 15
<p>Expansion behavior of various concrete mixes exposed to seawater over 378 days.</p>
Full article ">
20 pages, 3406 KiB  
Article
Evaluation of Healing in Concretes with Chemical and Bacterial Solutions Exposed to Aggressive Chloride and Carbon Dioxide-Rich Environments
by Fernanda Pacheco, Hinoel Zamis Ehrenbring, Roberto Christ, Rodrigo Périco de Souza, Regina Celia Espinosa Modolo, Victor Hugo Valiatio, Bernardo Fonseca Tutikian and Zemei Wu
Sustainability 2024, 16(24), 10829; https://doi.org/10.3390/su162410829 - 11 Dec 2024
Viewed by 405
Abstract
This paper aimed to evaluate two self-healing mechanisms of concrete exposed to chloride ions and carbon dioxide environments using chemical and bacterial solutions, contributing to understanding the real scenarios of concrete structures application. Expanded perlite (EP) impregnated with chemical and bacterial solutions with [...] Read more.
This paper aimed to evaluate two self-healing mechanisms of concrete exposed to chloride ions and carbon dioxide environments using chemical and bacterial solutions, contributing to understanding the real scenarios of concrete structures application. Expanded perlite (EP) impregnated with chemical and bacterial solutions with the aid of either a vacuum chamber or immersion was used in partial substitution of fine natural aggregate in ratios of 10%, 20%, and 30%. Samples were characterized by a compression strength test. Healing efficiency was evaluated with high precision in stereo zoom microscopy. Further characterization of the samples was obtained from SEM/EDS, and mineral content was determined from XRD. Samples impregnated with a chemical solution formed healing products identified as C-S-H, CaCO3, and SiO2 across and overflowing the fissure. Samples impregnated with the bacterial solution presented a maximum continuous healing region of 1.67 mm and an average of 0.514 mm. A comparison of submersed and wet curing yielded an equal number of results between the techniques. Overall, the products formed were mostly calcite (CaCO3) and C-S-H, while the presence of CO2 and Cl corrosives did not affect healing, with concentrations of 5% and 3%, respectively. Full article
Show Figures

Figure 1

Figure 1
<p>Compressive strength of all samples of this study.</p>
Full article ">Figure 2
<p>HP—Sample CSI10 exposed to salt spray: (<b>a</b>) 56 days, approx. 30× mag. (<b>b</b>) 84 days, approx. 10× mag. (<b>c</b>) 84 days, approx. 20× mag. and (<b>d</b>) 84 days, approx. 20× mag. (<b>e</b>) LH at 28 days, approx. 20× mag. (<b>f</b>) CTH at 28 days, approx. 10× mag. Sample CSI10, not exposed to deteriorating agents: (<b>g</b>) surface after 84 days, CTH and IP, approx. 20× mag.; (<b>h</b>) excess runoff product over the fissure, approx. 7.5× mag.</p>
Full article ">Figure 3
<p>HP—Sample CSI20 exposed to carbonation at 56 days: (<b>a</b>) EEP and (<b>b</b>) internal zoom, approx. 30× mag. HP samples (<b>c</b>) CSV10, approx. 20× mag. and (<b>d</b>) CSV20, approx. 40× mag. HP on sample CSV20 exposed to carbonation at 84 days: (<b>e</b>) approx. 40× mag. (<b>f</b>) healing spots, approx. 50× mag. and (<b>g</b>) surface crystal, approx. 50× mag.</p>
Full article ">Figure 4
<p>HP—sample BSI10 exposed to salt spray at 56 days: (<b>a</b>) approx. 10× mag. and (<b>b</b>) approx. 30× mag. (<b>c</b>) HP—Sample BSI10 exposed to carbonation, approx. 7.5× mag, 28 days. HP—Sample BSI20 not exposed to corrosive agents 7 days, approx. 50× mag (<b>d</b>) continuous healing and (<b>e</b>) crystals on the surface. HP and surface accumulation on sample BSI30 exposed to salt spray at 7 days: (<b>f</b>) approx. 20× mag. and (<b>g</b>) approx. 50× mag. Layer formation on sample BSI30 after accelerated carbonation at 28 days: (<b>h</b>) approx. 20× mag. and (<b>i</b>) approx. 30× mag.</p>
Full article ">Figure 5
<p>Comparison of HP on sample BSV10: (<b>a</b>) at 84 days without carbonation, approx. 20× mag. and (<b>b</b>) at 56 days of carbonation, approx. 30× mag. Comparison of HP on sample BSV20 at 84 days: (<b>c</b>) exposed to salt spray, approx. 20× mag. and (<b>d</b>) no exposure, approx. 40× mag. HP products on sample CSV30 subjected to carbonation: (<b>e</b>) EEP at 28 days, approx. 20× mag. and (<b>f</b>) surface crystal accumulation at 84 days, approx. 20× mag.</p>
Full article ">Figure 6
<p>XRD of healing products formed in (<b>a</b>) CSI10 and (<b>b</b>) CSV10 samples.</p>
Full article ">Figure 7
<p>SEM images of chemical solution samples: (<b>a</b>) CSI20, approx. 1700× mag.; (<b>b</b>) CSV10, approx. 2300× mag.; and (<b>c</b>) CSV20, approx. 5000× mag.</p>
Full article ">Figure 8
<p>XRD of healing products formed in samples: (<b>a</b>) BSI30 and (<b>b</b>) BSV30.</p>
Full article ">Figure 9
<p>SEM images of bacterial solution samples: (<b>a</b>) BSI30, approx. 2000× mag.; (<b>b</b>) BSI30, approx. 5000× mag.; and (<b>c</b>) BSV30, approx. 5000× mag.</p>
Full article ">Figure 10
<p>Average and maximum healing widths of all samples of this study.</p>
Full article ">
23 pages, 46810 KiB  
Article
Investigation of Corrosion Product Distribution and Induced Cracking Patterns in Reinforced Concrete Using Accelerated Corrosion Testing
by Olfa Loukil, Lucas Adelaide, Véronique Bouteiller, Marc Quiertant, Frédéric Ragueneau and Thierry Chaussadent
Appl. Sci. 2024, 14(23), 11453; https://doi.org/10.3390/app142311453 - 9 Dec 2024
Viewed by 475
Abstract
The present study investigates the corrosion development and induced cracks in reinforced concrete specimens submitted to an accelerated corrosion test. The accelerated chloride-induced corrosion test was performed using an impressed current mode. Three current densities (50, 100 and 200 µA/cm2 of steel) [...] Read more.
The present study investigates the corrosion development and induced cracks in reinforced concrete specimens submitted to an accelerated corrosion test. The accelerated chloride-induced corrosion test was performed using an impressed current mode. Three current densities (50, 100 and 200 µA/cm2 of steel) and different exposure times were considered. The objective of the experiments is to analyse two distinct types of damage: firstly, internal damage near the steel/concrete interface, which can be observed in the distribution of corrosion products, as well as damage within the concrete cover, which manifests as cracking. Secondly, external damage, which can be observed in the form of rust spots and concrete surface cracks. The aim of this analysis is to elucidate the relationship between internal damage and external damage. The study confirmed that the corrosion products are non-uniformly distributed around and along the steel reinforcing bar. It also highlighted that the accelerated corrosion test conditions, such as current density, duration, environmental conditions and the specimen geometry, have a significant influence on the distribution of the corrosion products and their thickness around the steel reinforcement and therefore on the internal and external crack patterns. The data analysis revealed a substantial dispersion and contrast in terms of the data, which precluded the establishment of a definitive correlation between internal and external deterioration. Full article
(This article belongs to the Special Issue Advances in Reinforced Concrete Structural Health Monitoring)
Show Figures

Figure 1

Figure 1
<p>Schematic representation of RC prisms. (<b>a</b>) Side view, (<b>b</b>) cross-section view (dimensions are in mm).</p>
Full article ">Figure 2
<p>Accelerated corrosion setup: (<b>a</b>) RC prisms connected in series; (<b>b</b>) subcircuit involving a single RC prism; (<b>c</b>) cross-section view (T means top face and F means front face).</p>
Full article ">Figure 3
<p>Overview of step 1 of the methodology for physical characterizations (The orange square and blue line indicate the location of the PVC tank and the crack respectively).</p>
Full article ">Figure 4
<p>Schematic representation of a sample preparation for step 2.</p>
Full article ">Figure 5
<p>Overview of the step 2 (prism cutting) of the methodology for physical characterizations.</p>
Full article ">Figure 6
<p>Overview of step 2 (analysis of the crack patterns) of the methodology for physical characterizations (the labels used were Pn-Xd-Y-Ti, where Pn refers to the RC prism name, Xd to the time of exposure (in days), Y to the impressed current (µA/cm<sup>2</sup>) and Ti to the slice name).</p>
Full article ">Figure 7
<p>Overview of the step 3 (analysis of the steel/concrete interface) of the methodology for physical characterizations (Ti refers to the slice name, Ei to the slice name and Cj to the observed area name).</p>
Full article ">Figure 8
<p>Half-cell potential (<span class="html-italic">E<sub>corr</sub></span>) and corrosion current density (<span class="html-italic">J<sub>corr</sub></span>) of the RC prisms versus duration of the accelerated corrosion test in the first and second columns, respectively. Data obtained using different impressed current densities: (<b>a</b>) 50 µA/cm<sup>2</sup> (represented by green triangles), (<b>b</b>) 100 µA/cm<sup>2</sup> (represented by blue squares), (<b>c</b>) 200 µA/cm<sup>2</sup> (represented by red circles).</p>
Full article ">Figure 9
<p>SEM images of the steel/concrete interface showing the thickness of the corrosion products layer for a total charge equal to 168 A.h/m<sup>2</sup>. (<b>a</b>) 50 µA/cm<sup>2</sup> (P23-14d), (<b>b</b>) 100 µA/cm<sup>2</sup> (P31-7d) and (<b>c</b>) 200 µA/cm<sup>2</sup> (P14-3.5d).</p>
Full article ">Figure 10
<p>Maximum width of external cracks in RC prisms using different impressed current densities. (<b>a</b>) 50 µA/cm<sup>2</sup>, (<b>b</b>) 100 µA/cm<sup>2</sup> and (<b>c</b>) 200 µA/cm<sup>2</sup>.</p>
Full article ">Figure 11
<p>Evolution of the maximum external crack width as a function of total charge, according to the current density.</p>
Full article ">Figure 12
<p>Evolution of external crack widths from this work and from the literature [<a href="#B17-applsci-14-11453" class="html-bibr">17</a>,<a href="#B19-applsci-14-11453" class="html-bibr">19</a>,<a href="#B20-applsci-14-11453" class="html-bibr">20</a>].</p>
Full article ">Figure 13
<p>Evolution of internal cracking leading to external crack patterns 1 and 3; (<b>a</b>) current phenomenon during the corrosion process; (<b>b</b>) occurrence of the first crack H; (<b>c</b>) occurrence of the second crack V.</p>
Full article ">
23 pages, 6338 KiB  
Article
Effectiveness of UHPC Jackets in Pier Retrofitting for Lateral Load Resistance
by Zoi G. Ralli, Roberto Salazar Gonzalez and Stavroula J. Pantazopoulou
Constr. Mater. 2024, 4(4), 787-809; https://doi.org/10.3390/constrmater4040043 - 9 Dec 2024
Viewed by 668
Abstract
Ultra-high-performance concrete (UHPC) is a recently emerged material with exceptional durability and ductility. While widely used in bridge retrofitting, particularly to replace expansion joints and deck overlays, UHPC has seen limited use in jacketing piers for the improvement of lateral load resistance. It [...] Read more.
Ultra-high-performance concrete (UHPC) is a recently emerged material with exceptional durability and ductility. While widely used in bridge retrofitting, particularly to replace expansion joints and deck overlays, UHPC has seen limited use in jacketing piers for the improvement of lateral load resistance. It presents superior mechanical properties and deformation resilience, enabled by the distributed fibers and the dense microstructure, providing corrosion resistance and a maintenance-free service life. The significant tensile strength and ductility establish UHPC as an attractive resilient jacketing system for structural members. The experimental literature documents the effectiveness of this solution in enhancing the strength and ductility of the retrofitted member, whereas premature modes of failure (i.e., lap splices and shear failure in lightly reinforced piers) are moderated. A comprehensive database of tests on UHPC-jacketed piers under lateral loads was compiled for the development of practical guidelines. Various UHPC jacket configurations were evaluated, and detailed procedures were developed for their implementation in bridge pier retrofitting. These procedures include constitutive models for UHPC, confined concrete, and the strengthening of lap splices, flexure, and shear resistance. The results are supported by the database, providing a solid foundation for the broader application of UHPC in improving the lateral load resistance of bridge piers. Full article
Show Figures

Figure 1

Figure 1
<p>Tensile stress–strain response of (<b>a</b>) regular concrete, (<b>b</b>) TS-UHPC, and (<b>c</b>) TH-UHPC (modified and adopted from [<a href="#B28-constrmater-04-00043" class="html-bibr">28</a>]).</p>
Full article ">Figure 2
<p>Details of (<b>a</b>) C- and (<b>b</b>) R-specimens: test parameters and experimental configuration.</p>
Full article ">Figure 3
<p>Drift capacity and milestone points in the response curve used in the database.</p>
Full article ">Figure 4
<p>Possible arrangements of UHPC jackets and developed stresses: (<b>a</b>) gap between footing and jacket; (<b>b</b>) cold joint between footing and jacket; and (<b>c</b>) extension of jacket into the footing. (<b>d</b>) State of stress in the jacket in case of (<b>a</b>); (<b>e</b>) stresses on the jacket in the compression zone of case (<b>b</b>); (<b>e</b>,<b>f</b>) stresses in the jacket in the compression and tension zones of case (<b>c</b>).</p>
Full article ">Figure 5
<p>Definition of the confining pressured exerted by UHPC jackets, with thickness <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>t</mi> </mrow> <mrow> <mi>j</mi> </mrow> </msub> </mrow> </semantics></math>, on encased concrete: (<b>a</b>) circular encased cross-section; (<b>b</b>) rectangular encased cross section; (<b>c</b>) effectively confined region and definition of terms.</p>
Full article ">Figure 6
<p>(<b>a</b>) Flexural resistance provided by the jacket near failure (after the formation of a localized crack) affects the rate of post-peak degradation of the encased concrete’s stress–strain response; (<b>b</b>,<b>c</b>) crack patterns in experimentally tested jacketed short columns.</p>
Full article ">Figure 7
<p>Stress–strain models of TH-UHPC: (<b>a</b>) bilinear tensile behaviour; (<b>b</b>) design stress–strain model for tension; and (<b>c</b>) design model in compression (design models were adopted from [<a href="#B58-constrmater-04-00043" class="html-bibr">58</a>]).</p>
Full article ">Figure 8
<p>Analytical (<b>a</b>) moment–curvature and (<b>b</b>) lateral load–drift responses of retrofitted schemes from <a href="#constrmater-04-00043-f004" class="html-fig">Figure 4</a> for axial load ratio <span class="html-italic">ν = 0.2</span>.</p>
Full article ">Figure 9
<p>Analytical (<b>a</b>) moment–curvature and (<b>b</b>) lateral load–drift responses of retrofitted schemes from <a href="#constrmater-04-00043-f004" class="html-fig">Figure 4</a> for axial load ratio <span class="html-italic">ν = 0.2</span> (markers are explained in <a href="#sec5dot1dot4-constrmater-04-00043" class="html-sec">Section 5.1.4</a>).</p>
Full article ">Figure 10
<p>Equilibrium of rectangular cross-section slice along the longitudinal axis of the (<b>a</b>) original member and (<b>b</b>) jacketed member.</p>
Full article ">Figure 11
<p>Equilibrium of circular cross-section slice along the longitudinal axis of the (<b>a</b>) original member and (<b>b</b>) jacketed member.</p>
Full article ">Figure 12
<p>Normalized depth of compression zone against longitudinal reinforcement ratio for a scale of 1:1 and 1:4, with <math display="inline"><semantics> <mrow> <mi>ν</mi> </mrow> </semantics></math> = 0.1 and 0.2, in the original state (<span class="html-italic">NJ</span>) and after jacketing with the nuanced setups from <a href="#constrmater-04-00043-f004" class="html-fig">Figure 4</a>.</p>
Full article ">Figure 13
<p>Models for the estimation of the contribution of the UHPC jacket to (<b>a</b>) the flexural and (<b>b</b>) the shear strength for <a href="#constrmater-04-00043-f004" class="html-fig">Figure 4</a>b,c; (<b>c</b>) the kinematic relationship between the slip of tension bars and the compressive strain increment in the jacket.</p>
Full article ">Figure 14
<p>Ultimate drift ratio of (<b>a</b>) C- and (<b>b</b>) R-specimens plotted against <span class="html-italic">JI</span> and <span class="html-italic">CI</span>.</p>
Full article ">Figure 15
<p>Behavior of flexural strength as <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>p</mi> <mi>e</mi> <mi>a</mi> <mi>k</mi> </mrow> </msub> <mo>/</mo> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>f</mi> <mi>l</mi> <mi>e</mi> <mi>x</mi> </mrow> </msub> </mrow> </semantics></math> of all specimens against the confinement index <span class="html-italic">JI</span> for (<b>a</b>) C- and (<b>b</b>) R-specimens.</p>
Full article ">Figure 16
<p>Performance limit states in retrofitting systems with UHPC jackets.</p>
Full article ">
16 pages, 5877 KiB  
Article
Modification of Uniaxial Stress–Strain Model of Concrete Confined by Pitting Corroded Stirrups
by Zhiwei Miao, Yifan Liu, Kangnuo Chen and Xinping Niu
Materials 2024, 17(23), 6014; https://doi.org/10.3390/ma17236014 - 9 Dec 2024
Viewed by 419
Abstract
To investigate the impact of stirrup pitting corrosion on the stress–strain model of core concrete under compression, this study, based on existing corroded steel specimens, establishes a probabilistic model of the residual cross-sectional area distribution of steel bars to reasonably evaluate the effect [...] Read more.
To investigate the impact of stirrup pitting corrosion on the stress–strain model of core concrete under compression, this study, based on existing corroded steel specimens, establishes a probabilistic model of the residual cross-sectional area distribution of steel bars to reasonably evaluate the effect of pitting on the mechanical performance of stirrups. Considering the tension stiffening effect in reinforced concrete, a time-dependent damage model of corroded steel bars in concrete was determined, and the existing stress–strain model of concrete confined by stirrups was ultimately modified, establishing a time-dependent constitutive model that incorporates the effects of stirrup pitting corrosion. A comparison with previous experimental results indicates that the revised model presented in this paper can appropriately reflect the changes in the mechanical performance of concrete confined by corroded stirrups. The results of this study can provide theoretical support for the refined numerical analysis of reinforced concrete structures under the erosion of chloride ions. Full article
(This article belongs to the Section Construction and Building Materials)
Show Figures

Figure 1

Figure 1
<p>Flowchart of research methodology.</p>
Full article ">Figure 2
<p>Spatial distribution of remaining cross-sectional areas of 8 mm corroded rebars along the longitudinal direction [<a href="#B9-materials-17-06014" class="html-bibr">9</a>].</p>
Full article ">Figure 3
<p>Fitting analysis: (<b>a</b>) the corrosion distribution along the rebar axis and (<b>b</b>) the histogram representing the residual cross-sectional area of the steel bars along with their corresponding fitted probability density curves [<a href="#B9-materials-17-06014" class="html-bibr">9</a>].</p>
Full article ">Figure 4
<p>The regression analysis results of the dual-cluster GMM parameters [<a href="#B9-materials-17-06014" class="html-bibr">9</a>].</p>
Full article ">Figure 5
<p>The computational procedure for the micro-segment deformation accumulation method.</p>
Full article ">Figure 6
<p>Section dimensions and reinforcement retails (mm) [<a href="#B40-materials-17-06014" class="html-bibr">40</a>].</p>
Full article ">Figure 7
<p>Comparison between test results [<a href="#B40-materials-17-06014" class="html-bibr">40</a>] and calculation results for rectangular section specimens.</p>
Full article ">Figure 8
<p>Comparison between test results [<a href="#B40-materials-17-06014" class="html-bibr">40</a>] and calculation results for circular section specimens.</p>
Full article ">Figure 9
<p>Flowchart of lifetime mechanical properties for concrete confined by pitted stirrups.</p>
Full article ">Figure 10
<p>Time-variant probabilistic density curves of GMM.</p>
Full article ">Figure 11
<p>Time-variant stress–strain curves of corroded rebars.</p>
Full article ">Figure 12
<p>Time-dependent damage curves for concrete confined by pitting corroded stirrups.</p>
Full article ">
17 pages, 4309 KiB  
Article
Non-Destructive Testing of Concrete Materials from Piers: Evaluating Durability Through a Case Study
by Abraham Lopez-Miguel, Jose A. Cabello-Mendez, Alejandro Moreno-Valdes, Jose T. Perez-Quiroz and Jose M. Machorro-Lopez
NDT 2024, 2(4), 532-548; https://doi.org/10.3390/ndt2040033 - 6 Dec 2024
Viewed by 436
Abstract
Concrete is currently the most used construction material, mainly due to its mechanical strength, chemical stability, and low cost. This material is affected by wear processes caused by the environment, which lead to a reduction in the useful life of the infrastructure in [...] Read more.
Concrete is currently the most used construction material, mainly due to its mechanical strength, chemical stability, and low cost. This material is affected by wear processes caused by the environment, which lead to a reduction in the useful life of the infrastructure in the long term. These wear processes can cause cracks, corrosion of reinforcing steel, loss of load capacity, and loss of concrete section, among other problems. Considering the above, it is necessary to carry out durability studies on concrete to determine the integrity conditions in which the infrastructure is found, the reasons for its deterioration, the environmental factors that affect it, and its useful life under these conditions, and develop restoration or protection plans. Generally, the durability studies include non-destructive testing such as ultrasonic pulse velocity, electrical resistivity, porosity measurement, and capillary absorption rate. These techniques make it possible to characterize the concrete and obtain information such as the total volume of pores, susceptibility to corrosion of the reinforcing steel, decrease in mechanical resistance, cracks, presence of humidity, and aggressive ions inside the concrete. In this work, two durability studies are presented with non-destructive tests carried out on active piers that are 20 and 40 years old. These are located in coastal areas in southern Mexico on the Gulf of Mexico side, with 80% average annual relative humidity, temperatures above 33 °C on average, high concentrations of salts, load handling, vibrations, flora and fauna typical of the marine ecosystem, etc. The results obtained reveal important information about the current state of the piers and the damage caused by the environment over time. This information allowed us to make decisions on preventive actions and develop appropriate and specific restoration projects for each pier. Full article
Show Figures

Figure 1

Figure 1
<p>Schematic diagram of the methodology followed in this study.</p>
Full article ">Figure 2
<p>Representative pictures of the UPV measurement of unsaturated concrete cores.</p>
Full article ">Figure 3
<p>Electrical resistivity measurements performed on concrete cylinders: (<b>a</b>) stainless steel/copper plate, (<b>b</b>) wet sponge, and (<b>c</b>) concrete core.</p>
Full article ">Figure 4
<p>Determination of saturated and submerged weight by using a hydrostatic scale.</p>
Full article ">Figure 5
<p>Preparation of specimens for capillary absorption.</p>
Full article ">Figure 6
<p>Schematic layout showing elements, general dimensions, and sampling locations for the piers.</p>
Full article ">Figure 7
<p>Ultrasonic pulse velocity results by element type.</p>
Full article ">Figure 8
<p>Electrical resistivity results of concrete elements.</p>
Full article ">Figure 9
<p>Results of total porosity in concrete elements.</p>
Full article ">Figure 10
<p>Water capillary absorption curves obtained for M1C for the weight changes in the cores versus time.</p>
Full article ">Figure 11
<p>Water capillary absorption curves obtained for M2T for the weight changes in the cores versus time.</p>
Full article ">Figure 12
<p>Ions’ sizes, gas molecules, and the relative size of pores existing in the concrete (adapted from Mehta P. K. et al. (1986)) [<a href="#B40-ndt-02-00033" class="html-bibr">40</a>] and Neville et al. [<a href="#B15-ndt-02-00033" class="html-bibr">15</a>].</p>
Full article ">
28 pages, 10795 KiB  
Article
Advanced Structural Technologies Implementation in Designing and Constructing RC Elements with C-FRP Bars, Protected Through SHM Assessment
by Georgia M. Angeli, Maria C. Naoum, Nikos A. Papadopoulos, Parthena-Maria K. Kosmidou, George M. Sapidis, Chris G. Karayannis and Constantin E. Chalioris
Fibers 2024, 12(12), 108; https://doi.org/10.3390/fib12120108 - 5 Dec 2024
Viewed by 369
Abstract
The need to strengthen the existing reinforced concrete (RC) elements is becoming increasingly crucial for modern cities as they strive to develop resilient and sustainable structures and infrastructures. In recent years, various solutions have been proposed to limit the undesirable effects of corrosion [...] Read more.
The need to strengthen the existing reinforced concrete (RC) elements is becoming increasingly crucial for modern cities as they strive to develop resilient and sustainable structures and infrastructures. In recent years, various solutions have been proposed to limit the undesirable effects of corrosion in RC elements. While C-FRP has shown promise in corrosion-prone environments, its use in structural applications is limited by cost, bonding, and anchorage challenges with concrete. To address these, the present research investigates the structural performance of RC beams reinforced with C-FRP bars under static loading using Structural Health Monitoring (SHM) with an Electro-Mechanical Impedance (EMI) system employing Lead Zirconate Titanate (PZT) piezoelectric transducers which are applied to detect damage development and enhance the protection of RC elements and overall, RC structures. This study underscores the potential of C-FRP bars for durable tensile reinforcement in RC structures, particularly in hybrid designs that leverage steel for compression strength. The study focuses on critical factors such as stiffness, maximum load capacity, deflection at each loading stage, and the development of crack widths, all analyzed through voltage responses recorded by the PZT sensors. Particular emphasis is placed on the bond conditions and anchorage lengths of the tensile C-FRP bars, exploring how local confinement conditions along the anchorage length influence the overall behavior of the beams. Full article
Show Figures

Figure 1

Figure 1
<p>Cross-section, geometry, reinforcement details, spiral anchorage configuration, notations and positioning of PZTs for beams CFRP10-C and CFRP10-R.</p>
Full article ">Figure 2
<p>Four-point bending experimental setup, instrumentation, and SHM devices.</p>
Full article ">Figure 3
<p>Experimental behavior of specimens CFRP10-R and CFRP10-C.</p>
Full article ">Figure 4
<p>Voltage-frequency response of the PZT transducers of Beam CFRP-C; (<b>a</b>) PZT 3 and (<b>b</b>) PZT 2, (<b>c</b>) PZT C, and (<b>d</b>) PZT B.</p>
Full article ">Figure 5
<p>Voltage-frequency response of the PZT transducers of Beam CFRP-C; (<b>a</b>) PZT 1 and (<b>b</b>) PZT 4, (<b>c</b>) PZT A, and (<b>d</b>) PZT D.</p>
Full article ">Figure 5 Cont.
<p>Voltage-frequency response of the PZT transducers of Beam CFRP-C; (<b>a</b>) PZT 1 and (<b>b</b>) PZT 4, (<b>c</b>) PZT A, and (<b>d</b>) PZT D.</p>
Full article ">Figure 6
<p>Voltage-frequency response of the PZT transducers of Beam CFRP-R; (<b>a</b>) PZT 1 and (<b>b</b>) PZT 2, (<b>c</b>) PZT A, and (<b>d</b>) PZT B.</p>
Full article ">Figure 6 Cont.
<p>Voltage-frequency response of the PZT transducers of Beam CFRP-R; (<b>a</b>) PZT 1 and (<b>b</b>) PZT 2, (<b>c</b>) PZT A, and (<b>d</b>) PZT B.</p>
Full article ">Figure 7
<p>Voltage-frequency response of the PZT transducers of Beam CFRP-R; (<b>a</b>) PZT 3 and (<b>b</b>) PZT 4, (<b>c</b>) PZT C, and (<b>d</b>) PZT D.</p>
Full article ">Figure 8
<p>Cracking pattern of Beam CFRP10-C.</p>
Full article ">Figure 9
<p>RMSD index values of (<b>a</b>) PZT A, and (<b>b</b>) PZT 1 of Beam CFRP10-C.</p>
Full article ">Figure 10
<p>RMSD index values of (<b>a</b>) PZT B, and (<b>b</b>) PZT 2 of Beam CFRP10-C.</p>
Full article ">Figure 11
<p>RMSD index values of (<b>a</b>) PZT C, and (<b>b</b>) PZT 3 of Beam CFRP10-C.</p>
Full article ">Figure 12
<p>RMSD index values of (<b>a</b>) PZT D, and (<b>b</b>) PZT 4 of Beam CFRP10-C.</p>
Full article ">Figure 13
<p>Cracking pattern of Beam CFRP10-R.</p>
Full article ">Figure 14
<p>RMSD index values of (<b>a</b>) PZT A, and (<b>b</b>) PZT 1 of Beam CFRP10-R.</p>
Full article ">Figure 15
<p>RMSD index values of (<b>a</b>) PZT B, and (<b>b</b>) PZT 2 of Beam CFRP10-R.</p>
Full article ">Figure 16
<p>RMSD index values of (<b>a</b>) PZT C, and (<b>b</b>) PZT 3 of Beam CFRP10-R.</p>
Full article ">Figure 17
<p>RMSD index values of (<b>a</b>) PZT D, and (<b>b</b>) PZT 4 of Beam CFRP10-R.</p>
Full article ">
24 pages, 9067 KiB  
Article
Experimental Study on the Characteristics of Corrosion-Induced Cracks and Steel Corrosion Depth of Carbonated Recycled Aggregate Concrete Beams
by Pengfei Gao, Jian Wang, Bo Chen, Mingxin Bai and Yuanyuan Song
Buildings 2024, 14(12), 3889; https://doi.org/10.3390/buildings14123889 - 4 Dec 2024
Viewed by 431
Abstract
The durability of carbonated recycled aggregate concrete (C-RAC) beams is still unclear at present. In this paper, the characteristics of corrosion-induced cracks and the steel corrosion depth of C-RAC beams were investigated through the accelerated corrosion test. The results showed that when accelerating [...] Read more.
The durability of carbonated recycled aggregate concrete (C-RAC) beams is still unclear at present. In this paper, the characteristics of corrosion-induced cracks and the steel corrosion depth of C-RAC beams were investigated through the accelerated corrosion test. The results showed that when accelerating corrosion to the 40th day, compared to the non-carbonated recycled aggregate concrete (NC-RAC) beam, the corrosion-induced cracking area of the C-RAC beam with a 100% carbonated recycled coarse aggregate (C-RCA) replacement ratio decreased by 40.00%, while the total length of the corrosion-induced cracks (CCs) increased by 51.82%. The type of probability distribution for the width of the CCs on the tension side of the C-RAC beams was a lognormal distribution. Compared with the NC-RAC beam, the mean value of the width of the CCs of the C-RAC beam with a 100% C-RCA replacement ratio decreased by 66.67%, the crack width distribution was more concentrated, and the quartiles and median were all reduced. With an increase in the C-RCA replacement ratio, the fractal dimension and the scale coefficient of CCs on the tension side of the beams showed an approximate trend of first increasing and then decreasing. The distribution of the corrosion depth of longitudinal tensile steel bars in the C-RAC beams was a mainly normal distribution. When the C-RCA replacement ratio increased from 30% to 100%, the mean value of the corrosion depth of the longitudinal tensile steel bars decreased by 33.46%, and the trend of changes in the quartiles and medians was basically the same as the trend of changes in the mean value. The research results can provide some reference for promoting the engineering application of C-RAC beams. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
Show Figures

Figure 1

Figure 1
<p>NC-RAC and C-RAC specimens.</p>
Full article ">Figure 2
<p>Details of the beams (unit: mm).</p>
Full article ">Figure 3
<p>Steel skeletons of the beams.</p>
Full article ">Figure 4
<p>Connecting the wire and the steel bars.</p>
Full article ">Figure 5
<p>Accelerated corrosion test of the beams.</p>
Full article ">Figure 6
<p>Corrosion of steel bars.</p>
Full article ">Figure 7
<p>Distribution of the CCs on the tension side of the beams on the 8th day of accelerated corrosion (unit: mm).</p>
Full article ">Figure 8
<p>Distribution of the CCs on the tension side of the beams on the 20th day of accelerated corrosion (unit: mm).</p>
Full article ">Figure 9
<p>Distribution of the CCs on the tension side of the beams on the 30th day of accelerated corrosion (unit: mm).</p>
Full article ">Figure 10
<p>Distribution of the CCs on the tension side of the beams on the 40th day of accelerated corrosion (unit: mm).</p>
Full article ">Figure 10 Cont.
<p>Distribution of the CCs on the tension side of the beams on the 40th day of accelerated corrosion (unit: mm).</p>
Full article ">Figure 11
<p>Cracking area on the tension side of the beams.</p>
Full article ">Figure 12
<p>Total length of CCs on the tension side of the beams.</p>
Full article ">Figure 13
<p>Comparison of the microscopic morphologies between NC-RCA and C-RCA.</p>
Full article ">Figure 14
<p>Frequency distribution histograms of the width of CCs of the beams.</p>
Full article ">Figure 15
<p>Mean value of the width of CCs.</p>
Full article ">Figure 16
<p><span class="html-italic">C</span><sub>v</sub> of the width of CCs.</p>
Full article ">Figure 17
<p>Box plot of the width of CCs.</p>
Full article ">Figure 18
<p>Fractal dimension and scale coefficient of CCs on the tension side of the beams.</p>
Full article ">Figure 19
<p>Comparison of the fractal dimensions of the CCs on the tension side of the beams.</p>
Full article ">Figure 20
<p>Comparison of the scale coefficients of the CCs on the tension side of the beams.</p>
Full article ">Figure 20 Cont.
<p>Comparison of the scale coefficients of the CCs on the tension side of the beams.</p>
Full article ">Figure 21
<p>Distribution of the corrosion depth of longitudinal tensile steel bars along the length direction.</p>
Full article ">Figure 22
<p>Frequency distribution histograms of the corrosion depth of the longitudinal tensile steel bars.</p>
Full article ">Figure 23
<p>Mean value of the corrosion depth.</p>
Full article ">Figure 24
<p><span class="html-italic">C</span><sub>v</sub> of the corrosion depth.</p>
Full article ">Figure 25
<p>Box plot of the corrosion depth.</p>
Full article ">
21 pages, 4586 KiB  
Article
Axial Compressive Behavior and Calculation Model for Axial-Compressive-Load-Carrying Capacity of Locally Corroded RC Short Columns
by Xiaojuan Liu, Baorui He, Xueqiong Chen, Yang Liu and Xin Li
Buildings 2024, 14(12), 3884; https://doi.org/10.3390/buildings14123884 - 4 Dec 2024
Viewed by 396
Abstract
The individual effects of the main reinforcement corrosion and stirrup corrosion on the axial compressive behavior of reinforced concrete (RC) columns were evaluated through axial compression tests on 10 full-scale short columns. The primary experimental parameters were the corrosion location and the corrosion [...] Read more.
The individual effects of the main reinforcement corrosion and stirrup corrosion on the axial compressive behavior of reinforced concrete (RC) columns were evaluated through axial compression tests on 10 full-scale short columns. The primary experimental parameters were the corrosion location and the corrosion ratio of the steel bar. The electrochemical accelerated corrosion method was applied on nine of the columns, including three columns corroded in the main reinforcement, three columns corroded in the stirrup, and three columns corroded in both the main reinforcement and stirrup. The full-field displacement of the column and strain of concrete were evaluated using a non-contact 3D-DIC (digital image correlation) technique. The results indicated that, with the increase in the main reinforcement corrosion ratio, the width of the longitudinal corrosion crack increased. The transverse corrosion cracks appeared when the stirrup corrosion ratio is larger than 8%, and the increase in stirrup corrosion ratio increased the crack number, but had little effect on the crack width. Compared to the non-corroded RC column, the peak load of specimens with main reinforcement corrosion ratios of 8.02%, 9.01%, and 19.27% decreased by 10.53%, 13.56%, and 19.77%, respectively, and that of the specimens with stirrup corrosion ratios of 7.08%, 12.33%, and 24.36% decreased by 11.59%, 12.07%, and 17.15%, respectively. The axial-compressive-load-carrying capacity of RC columns decreased almost linearly as the corrosion ratio of the main reinforcement increases, while it exhibited an approximately bilinear degradation as the corrosion ratio of the stirrups increases. The stirrup corrosion ratio had less effect on the axial compressive loading capacity of the RC column when it was larger than 7.5%. A model for calculating the axial-compressive-load-carrying capacity of the corroded RC short columns was developed based on the impact mechanisms of the corroded main reinforcement and stirrups on the columns’ axial compressive behavior. The calculated results closely matched the test data, demonstrating that the proposed model can reliably predict the residual load-carrying capacity of corroded columns. Full article
(This article belongs to the Special Issue Seismic Analysis and Design of Building Structures)
Show Figures

Figure 1

Figure 1
<p>Dimensions and reinforcement details of specimen (unit: mm).</p>
Full article ">Figure 2
<p>Schematic diagram of accelerated corrosion apparatus.</p>
Full article ">Figure 3
<p>Test setup: (<b>a</b>) schematic; and (<b>b</b>) actual image.</p>
Full article ">Figure 4
<p>Arrangement of strain gauges: (<b>a</b>) strain gauges on concrete; and (<b>b</b>) strain gauges on steel reinforcement.</p>
Full article ">Figure 5
<p>Distribution of corrosion cracks: (<b>a</b>) RC-0-10; (<b>b</b>) RC-0-20; (<b>c</b>) RC-0-30; (<b>d</b>) RC-10-0; (<b>e</b>) RC-20-0; (<b>f</b>) RC-30-0; (<b>g</b>) RC-10-10; (<b>h</b>) RC-20-20; and (<b>i</b>) RC-30-30.</p>
Full article ">Figure 6
<p>The corrosion morphology of the steel bars in specific specimens: (<b>a</b>) RC-10-10; (<b>b</b>) RC-20-20; and (<b>c</b>) RC-30-30.</p>
Full article ">Figure 7
<p>Strain cloud diagram and failure modes of the specimen: (a) RC-0-0; (<b>b</b>) RC-0-10; (<b>c</b>) RC-0-20; (<b>d</b>) RC-0-30; (<b>e</b>) RC-10-0; (<b>f</b>) RC-20-0; (<b>g</b>) RC-30-0; (<b>h</b>) RC-10-10; (<b>i</b>) RC-20-20; and (<b>j</b>) RC-30-30.</p>
Full article ">Figure 7 Cont.
<p>Strain cloud diagram and failure modes of the specimen: (a) RC-0-0; (<b>b</b>) RC-0-10; (<b>c</b>) RC-0-20; (<b>d</b>) RC-0-30; (<b>e</b>) RC-10-0; (<b>f</b>) RC-20-0; (<b>g</b>) RC-30-0; (<b>h</b>) RC-10-10; (<b>i</b>) RC-20-20; and (<b>j</b>) RC-30-30.</p>
Full article ">Figure 7 Cont.
<p>Strain cloud diagram and failure modes of the specimen: (a) RC-0-0; (<b>b</b>) RC-0-10; (<b>c</b>) RC-0-20; (<b>d</b>) RC-0-30; (<b>e</b>) RC-10-0; (<b>f</b>) RC-20-0; (<b>g</b>) RC-30-0; (<b>h</b>) RC-10-10; (<b>i</b>) RC-20-20; and (<b>j</b>) RC-30-30.</p>
Full article ">Figure 8
<p>Comparison of vertical loads versus deformation curves by DIC and traditional measurement method: (<b>a</b>) RC-0-0; and (<b>b</b>) RC-10-10.</p>
Full article ">Figure 9
<p>Axial compressive load–displacement curves of specimens: (<b>a</b>) main reinforcement corrosion; (<b>b</b>) stirrup corrosion; and (<b>c</b>) all steel bar corrosion.</p>
Full article ">Figure 10
<p>The relationship of ultimate axial-load-carrying capacity versus steel corrosion ratio. Note: For the curve of specimens corroded in all steel reinforcements, the main reinforcement corrosion ratio is taken as the horizontal coordinate value.</p>
Full article ">Figure 11
<p>Axial compressive load-vertical strain of concrete curves: (<b>a</b>) main reinforcement corrosion; (<b>b</b>) stirrup corrosion; and (<b>c</b>) all steel bar corrosion.</p>
Full article ">Figure 12
<p>Axial compressive load-strain of main reinforcement curves: (<b>a</b>) main reinforcement corrosion; (<b>b</b>) stirrup corrosion; and (<b>c</b>) all steel bar corrosion.</p>
Full article ">Figure 13
<p>Axial compressive load–strain of stirrup curves: (<b>a</b>) main reinforcement corrosion; (<b>b</b>) stirrup corrosion; and (<b>c</b>) all steel bar corrosion.</p>
Full article ">Figure 14
<p>Schematic diagram of the buckling model of main reinforcement.</p>
Full article ">
16 pages, 2296 KiB  
Article
Hazard Study of Sludge from Mining Wastewater Treatment Systems (Tailings), Accumulation of Contaminants and Potential Utilization Proposals
by Paúl N. Malacatus, Paulina E. Manobanda and Inmaculada Romero
Sustainability 2024, 16(23), 10569; https://doi.org/10.3390/su162310569 - 2 Dec 2024
Viewed by 507
Abstract
The increase in gold mining activities has led to a substantial rise in tailings generation, which carry distinct physicochemical and microbiological properties. This study aimed to evaluate the hazardous characteristics of mining tailings using the CRETIB (corrosivity, reactivity, explosiveness, toxicity, ignitability, biological-infectious) methodology. [...] Read more.
The increase in gold mining activities has led to a substantial rise in tailings generation, which carry distinct physicochemical and microbiological properties. This study aimed to evaluate the hazardous characteristics of mining tailings using the CRETIB (corrosivity, reactivity, explosiveness, toxicity, ignitability, biological-infectious) methodology. The research analyzed concentrations of heavy metals including arsenic, cadmium, copper, chromium, lead, mercury, nickel, and zinc, alongside parameters such as pH, cyanide, hydrogen sulfide, and coliform bacteria. Tailings samples were collected from a mine in Ponce Enriquez, Ecuador, at the surface and at a depth of 2 m across three monitoring campaigns. The results indicate that the tailings do not exhibit hazardous characteristics according to CRETIB criteria. While arsenic, chromium, copper, nickel, zinc, and mercury concentrations showed significant differences between the surface and 2 m depth, accumulating at the bottom of the tailings dam by 30–72%, parameters such as pH, cyanide, and hydrogen sulfide were higher at the surface, likely due to volatilization and precipitation effects. Lead did not show significant differences, but also tended to accumulate at depth. These findings suggest that the tailings could be safely utilized in the production of construction materials such as bricks, geopolymer concrete, and fiber cement, promoting circular economy practices and sustainable development in mining. Full article
(This article belongs to the Special Issue Geological Engineering and Sustainable Environment)
Show Figures

Figure 1

Figure 1
<p>Location map of the mining processing facility.</p>
Full article ">Figure 2
<p>3D statistical analysis of physicochemical parameters for samples A and B plotted using RockWorks20 software.</p>
Full article ">Figure A1
<p>Water treatment system of the Mining Beneficiation Plant.</p>
Full article ">
16 pages, 1954 KiB  
Article
Efficient Load-Bearing Capacity Assessment of a Degraded Concrete Manhole Using Sectional Homogenization
by Tomasz Garbowski, Tomasz Grzegorz Pawlak and Anna Szymczak-Graczyk
Materials 2024, 17(23), 5883; https://doi.org/10.3390/ma17235883 - 30 Nov 2024
Viewed by 358
Abstract
This study addresses a practical and efficient approach to evaluating the load-bearing capacity of severely degraded concrete manholes. Concrete deterioration, often advanced and highly irregular, can be captured accurately through surface scanning to create a detailed model of the damaged structure and also [...] Read more.
This study addresses a practical and efficient approach to evaluating the load-bearing capacity of severely degraded concrete manholes. Concrete deterioration, often advanced and highly irregular, can be captured accurately through surface scanning to create a detailed model of the damaged structure and also to build a simplified modeling to enable rapid engineering-level assessment, filling a critical gap in infrastructure maintenance. The repair strategy involves applying an internal polyurea layer, a variable-thickness polyurethane foam layer depending on the degree of localized degradation, and an external polyurea layer to restore the original shape of the manhole. However, these repairs do not fully restore the manhole’s original load-bearing capacity. A full 3D model, encompassing millions of finite elements, would provide a detailed analysis of strength reductions but is impractical for engineering applications due to computational demands. An alternative approach utilizing sectional homogenization is proposed, where sectional properties are sequentially averaged to calculate effective parameters. This approach enables the use of only a few hundred shell elements, each representing thousands of elements from the detailed 3D model, thus providing a rapid, engineering-level assessment of load-bearing reductions in degraded manholes. The study finds that while the repair method restores up to 76% of bending stiffness in heavily corroded sections, it does not fully recover the original load-bearing capacity. Full article
Show Figures

Figure 1

Figure 1
<p>Heavily corroded manhole.</p>
Full article ">Figure 2
<p>Homogenized shell model of the repaired manhole, with homogenization applied in each visible segment.</p>
Full article ">Figure 3
<p>Representation of the 3D model and homogenized section of the corroded manhole segment. (<b>a</b>) A 3D model of the degraded concrete segment with detailed mesh capturing irregular corrosion patterns; (<b>b</b>) the repaired segment, showing the three-layer protective coating applied to the degraded area, with color-coded layers representing different materials; (<b>c</b>) a homogenized cross-section of the repaired segment, represented as shell elements for simplified simulation.</p>
Full article ">
Back to TopTop