Advances in Design, Repair and Materials of Structural Concrete

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Civil Engineering".

Deadline for manuscript submissions: closed (30 April 2021) | Viewed by 30513

Special Issue Editors


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Guest Editor
School of Architecture, Konkuk University, Seoul, Korea
Interests: earthquake engineering of building structures; reinforced concrete design; steel–concrete composite design; artificial intelligence; bond mechanism of reinforcement bars; impact loading and resistance of reinforced concrete; progressive collapse of building structures
Spatial and Environment System Engineering, Handong Global University, Pohang, Gyeongbuk, Korea
Interests: material engineering for civil and architectural structures; cement-based composites; polymer-based composites; smart materials; carbon nanomaterials; fiber-reinforced plastics; functional composites; electromagnetic wave shielding/absorbing; self-sensing and monitoring; image analysis on microstructures; piezoelectric energy harvesting
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Guest Editor
Civil Engineering and Environmental Sciences, Korea Military Academy, Nowon-gu, Seoul, Korea
Interests: reinforced concrete design; seismic design of reinforced concrete; non-structural element; blast loading and resistance of reinforced concrete; shear strength and shear-friction strength of reinforced concrete structures; artificial intelligence

Special Issue Information

Dear Colleagues,

Structural concrete is the most widely used material in the field of construction due to its advantages, such as ease of production, low cost, high durabilty, versatility in moulding, and energy efficiency.

For better use of structural concrete, various studies on advances in design, strengthening/retrofitting, and material have recently been carried out in architectural and civil engineering.

This Special Issue covers various research topics related, but not limited, to design, repair, and materials of structural concrete. The results published in this Special Issue will contribute to enhance our understanding of structual concrete, to be applied in the field of architectural and civil engineering by utilizing scientific and engineering methods, which is of interest for potential readers of Applied Sciences. The manuscripts submitted to this Special Issue will be subject to a prompt peer review process for the rapid and wide dissemination of research results, developments, and applications.

The scope of this Special Issue, “Advances in Design, Repair and Materials of Structural Concrete”, covers all the aspects of design, strengthening/retrofitting, and materials of strucural concrete, including the behavior/performance of materials, structural components, and systems.

Dr. Hyeon-Jong Hwang
Dr. Il-Woo Nam
Dr. Jang-Woon Baek
Guest Editors

Manuscript Submission Information

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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. Applied Sciences 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 2400 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

  • analysis and design models
  • composite materials
  • construction materials
  • extreme loads
  • experimental testing
  • functional composites
  • reliability
  • strengthening and retrofitting
  • structural design and safety
  • smart materials
  • structural health monitoring

Published Papers (11 papers)

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Research

11 pages, 3591 KiB  
Article
Development of Decision-Making Factors to Determine EMP Protection Level: A Case Study of a Brigade-Level EMP Protection Facility
by Kukjoo Kim and Young-Jun Park
Appl. Sci. 2021, 11(11), 5227; https://0-doi-org.brum.beds.ac.uk/10.3390/app11115227 - 04 Jun 2021
Cited by 4 | Viewed by 2956
Abstract
This study developed decision-making factors to classify electromagnetic pulse (EMP) protection levels and determine various protection measures. We proposed three EMP protection levels of 80, 60, and 40 dB by considering the characteristics of military equipment and factors that determine EMP protection level, [...] Read more.
This study developed decision-making factors to classify electromagnetic pulse (EMP) protection levels and determine various protection measures. We proposed three EMP protection levels of 80, 60, and 40 dB by considering the characteristics of military equipment and factors that determine EMP protection level, based on a Delphi study. We modeled EMP protection facilities for brigade-level troops to evaluate the derived decision-making factors and applicability of differential protection levels. The natural attenuation effect of soil was confirmed for structures installed underground. The shielding effect of wet soil was up to 30 dB. Considering the 20 dB EMP resistance of military equipment and the 30 dB of attenuation of wet soil, new materials with 30 dB of shielding efficiency could be used to meet an EMP protection level of 80 dB. Therefore, we confirmed that EMP protection measures could be established to build mobile, lightweight shelters. If lightweight shelters are constructed by applying the differential protection level scheme, they can be applied as a more effective EMP protection measure. Furthermore, differential protection measures can be adopted as a sustainable defense facility policy approach, wherein lightweight protection facilities replace conventional heavyweight facilities. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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17 pages, 6802 KiB  
Article
Development of Multi-Tee-Type Precast Concrete Slabs with Insulating Materials for Structural Safety at the Construction Stage
by Jang-Woon Baek and Su-Min Kang
Appl. Sci. 2021, 11(4), 1693; https://0-doi-org.brum.beds.ac.uk/10.3390/app11041693 - 13 Feb 2021
Viewed by 5596
Abstract
Multi-tee-type precast concrete (PC) slab systems are widely used for the construction of modular high-load long-span buildings. However, the structural safety of the dapped end is uncertain, owing to the unanchored shear reinforcement at the construction stage. This study proposes the use of [...] Read more.
Multi-tee-type precast concrete (PC) slab systems are widely used for the construction of modular high-load long-span buildings. However, the structural safety of the dapped end is uncertain, owing to the unanchored shear reinforcement at the construction stage. This study proposes the use of clip-type shear reinforcement at the dapped ends of multi-tee PC slabs to secure their structural performance at the construction stage. To investigate the performance of this approach, a monotonic loading test was performed on simply supported PC slabs, considering structural safety at the construction stage. The reinforcement details of the PC slab’s dapped end (with existing Z-type or proposed clip-type shear reinforcement) and the shear-to-span ratio (12.8 or 6.4) were considered as test parameters. The load–deflection relationship, failure mode, strength ratios to the predicted strength, and shear reinforcement strains were analyzed. The results showed that the tested flexural strength ratio of the PC slabs at the construction stage to the design flexural strength was 1.20–1.40. The enclosed shape and diagonal arrangement of the clip-type shear reinforcement enabled sufficient anchorage performance at the dapped end, indicating that clip-type shear reinforcement can be viable for use at the dapped ends of PC slabs under construction loads. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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15 pages, 7676 KiB  
Article
Simplified Plastic Hinge Model for Reinforced Concrete Beam–Column Joints with Eccentric Beams
by Hyeon-Jong Hwang and Chang-Soo Kim
Appl. Sci. 2021, 11(3), 1303; https://0-doi-org.brum.beds.ac.uk/10.3390/app11031303 - 01 Feb 2021
Cited by 2 | Viewed by 3062
Abstract
In nonlinear analysis for performance-based design of reinforced concrete moment frames, a plastic hinge spring element is predominantly used in order to simply and accurately describe the inelastic behavior of beam–column joints, including strength degradation. Although current design codes and guidelines provide various [...] Read more.
In nonlinear analysis for performance-based design of reinforced concrete moment frames, a plastic hinge spring element is predominantly used in order to simply and accurately describe the inelastic behavior of beam–column joints, including strength degradation. Although current design codes and guidelines provide various beam–column joint models, the focus is on concentric beam–column joints. Therefore, more studies are required for eccentric beam–column joints, which are also common in practice. In the present study, to consider the effect of beam eccentricity on the behavior of beam–column joints, a simplified plastic hinge model was proposed using the effective joint width of current design codes. The proposed model was compared to the cyclic loading test results of beam–column joints with/without beam eccentricity. The comparison showed that the simplified plastic hinge model with the effective joint width of NZS 3101-2006 or Eurocode 8 is considered acceptable for design purpose. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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17 pages, 4222 KiB  
Article
Influence of the Modulus of Elasticity of CFRPs on the Compressive Behavior of Confined Test Pieces and on the Flexural Behavior of Short Concrete Beams
by Daniela Brizuela Valenzuela, María de las Nieves González García and Alfonso Cobo Escamilla
Appl. Sci. 2021, 11(2), 491; https://0-doi-org.brum.beds.ac.uk/10.3390/app11020491 - 06 Jan 2021
Viewed by 1696
Abstract
In this study, we compare the behavior of confined compression-tested concrete test pieces and short concrete beams subjected to three-point flexural strength testing when they are reinforced with high-modulus, high-strength carbon fibers reinforced polymers (CFRP). The fabrics used have roughly the same mechanical [...] Read more.
In this study, we compare the behavior of confined compression-tested concrete test pieces and short concrete beams subjected to three-point flexural strength testing when they are reinforced with high-modulus, high-strength carbon fibers reinforced polymers (CFRP). The fabrics used have roughly the same mechanical capacity but very different rigidities. As such, the results make it possible to obtain the influence of the rigidity of the CFRP on the structural behavior of the elements tested. The results obtained show that the type of fabric used does not cause significant differences in the values of tension of rupture and the form of rupture of the test pieces subjected to compression and flexural strength testing, which suggests that the variable which determines the mechanical response of the elements which have been reinforced and subjected to these kinds of demands is the mechanical capacity of the reinforcement, not its rigidity. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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16 pages, 4278 KiB  
Article
A Study on Mechanical Characteristics of Cement Composites Fabricated with Nano-Silica and Carbon Nanotube
by Ali Raza, Manan Bhandari, Hyeong-Ki Kim, Hyeong-Min Son, Baofeng Huang and Il-Woo Nam
Appl. Sci. 2021, 11(1), 152; https://0-doi-org.brum.beds.ac.uk/10.3390/app11010152 - 25 Dec 2020
Cited by 7 | Viewed by 2348
Abstract
In this study, cement composites were fabricated with various contents of added nano-silica (NS) and multi-walled carbon nanotubes (MWNTs). The compressive and flexural strengths of the resultant cement composites were examined. To explore the microstructures and MWNT distribution, electrical conductivity tests, and scanning [...] Read more.
In this study, cement composites were fabricated with various contents of added nano-silica (NS) and multi-walled carbon nanotubes (MWNTs). The compressive and flexural strengths of the resultant cement composites were examined. To explore the microstructures and MWNT distribution, electrical conductivity tests, and scanning electron microscopy were conducted. In addition, the strength results were analyzed based on thermal analysis and porosity evaluations. The electrical conductivity results indicated that MWNTs were satisfactorily distributed in the cement composites. In the mechanical strength tests, the composite with a 0.6% MWNT and 5% NS content and another with a 0.3% MWNT and 5% NS content yielded enhancements in the compressive and flexural strengths of 17.2% and 52% compared with the control samples, respectively. However, composites containing relatively large amounts of both NS and MWNTs showed degradation in the mechanical strength. The enhancement or degradation of the strength was supported by porosity evaluations and thermal analysis results. In particular, the degradation of the strength due to the incorporation of large amounts of both MWNTs and NS was explained by thermogravimetric analysis, which indicated a limited generation of calcium silicate hydrate (C-S-H) hydration products. The lower generation of C-S-H was likely due to the dense microstructure of MWNT/NS-incorporated cement hindering the reactions between calcium hydroxide and the NS. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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22 pages, 6293 KiB  
Article
Experimental Study on Flexural Capacity of Corroded RC Slabs Reinforced with Basalt Fiber Textile
by Liang Fang, Yun Zhou, Duhang Yi and Weijian Yi
Appl. Sci. 2021, 11(1), 144; https://0-doi-org.brum.beds.ac.uk/10.3390/app11010144 - 25 Dec 2020
Cited by 4 | Viewed by 1655
Abstract
This experimental study investigated the flexural performance of corroded reinforced concrete (RC) slabs strengthened with basalt textile-reinforced mortar (BTRM) and basalt fiber-reinforced polymers (BFRP). Ten RC slabs were designed to achieve the expected corrosion levels (8% mass loss for moderate corrosion and 16% [...] Read more.
This experimental study investigated the flexural performance of corroded reinforced concrete (RC) slabs strengthened with basalt textile-reinforced mortar (BTRM) and basalt fiber-reinforced polymers (BFRP). Ten RC slabs were designed to achieve the expected corrosion levels (8% mass loss for moderate corrosion and 16% mass loss for severe corrosion) by accelerated corrosion methods. Two slabs served as reference specimens, and eight slabs were strengthened with BFRP or BTRM. The specimens were loaded to failure by the four-point bending method. The corrosion ratio, strengthening materials and the number of layers were tested for comparison. The failure modes, flexural capacities, load–deflection curves and deformation performances of the slabs were obtained from experiments. It was found that the use of BTRM layers was more effective in improving the flexural response than the use of the same amount of BFRP layers externally bonded with the corroded RC slabs under a state of serviceability. The results also showed that the strengthening effects of BFRP and BTRM were affected by the initial corrosion ratio and the number of textile layers. In a moderate state of corrosion, the flexural capacities and deflection capacities of RC slabs strengthened by BFRP and BTRM were increased substantially; the flexural capacities were increased by 27.81%~61.85%. In a severe corrosion state, the increase in flexural capacity of strengthened slabs is marginal but the increase in ductility indexes was 18% to 35% compared with the corresponding control slabs. By increasing the number of textile layers from three to five, the increments of the flexural capacity of strengthened slabs are almost doubled. Finally, the calculated results of the flexural capacity of the corroded RC slabs strengthened with BFRP and BTRM were found to be in good agreement with the experimental results. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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17 pages, 17850 KiB  
Article
Numerical Simulation of the Degree of Protection for K9 Artillery Position under Explosion Scenario Using METT+TC
by Kukjoo Kim and Young-Jun Park
Appl. Sci. 2020, 10(24), 8808; https://0-doi-org.brum.beds.ac.uk/10.3390/app10248808 - 09 Dec 2020
Viewed by 1805
Abstract
This study proposes a method to evaluate the protective performance of an existing K9 artillery position according to various explosion scenarios. Thus, a commercial software package AUTODYN was used to create a 3D model of the existing artillery position. Following the mission, enemy, [...] Read more.
This study proposes a method to evaluate the protective performance of an existing K9 artillery position according to various explosion scenarios. Thus, a commercial software package AUTODYN was used to create a 3D model of the existing artillery position. Following the mission, enemy, terrain and weather, troops and support available, time available, and civil consideration (METT+TC) analysis, a total of three blast loading scenarios were selected. According to the results, the wall rotation angle of a near-miss explosion was within the standard of 2°; considering contact explosions, the rotation angles were also within 2°. This confirmed that the K9 artillery position under examination for protective performance was within the elastic design range. Considering the final evaluation and combining the results, the walls and slabs of the K9 artillery position were determined to be able to withstand the corresponding blast pressures and have no issues in protective performance. Meanwhile, due to the limitations of the actual blast tests for evaluating the protective performance of civilian protective structures and those of the ROK Armed Forces, these tests were replaced with numerical analysis-based evaluations. However, due to the lack of specified procedures for numerical analysis based on finite element analysis, there were several difficulties in practice. Therefore, this study aims to provide a basic procedure for evaluating the protective performance of protective structures in the future by presenting analytical and blast loading conditions which are necessary for evaluating protective performance. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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22 pages, 4073 KiB  
Article
Assessment of Existing Bond Models for Externally Bonded SRP Composites
by Rafał Krzywoń
Appl. Sci. 2020, 10(23), 8593; https://0-doi-org.brum.beds.ac.uk/10.3390/app10238593 - 30 Nov 2020
Cited by 3 | Viewed by 1419
Abstract
This manuscript assessed the applicability of the existing ultimate bond formulas originally developed for externally bonded carbon fiber-based composites in the analysis of steel-reinforced polymers (SRPs). In the first part, the methods of predicting the bond capacity are reviewed, the differences are indicated, [...] Read more.
This manuscript assessed the applicability of the existing ultimate bond formulas originally developed for externally bonded carbon fiber-based composites in the analysis of steel-reinforced polymers (SRPs). In the first part, the methods of predicting the bond capacity are reviewed, the differences are indicated, and the factors determining the bond are discussed; then, using the bond test results of over 400 samples available in the literature, the bond prediction methods are assessed by graphical comparison. The evaluation mainly concerned concrete elements and epoxy adhesives; however, to a lesser extent, a similar analysis was performed for the masonry substrate and grout matrices. The results showed the relatively good applicability of the majority of bond prediction models for the analysis of SRP composites. In most cases, the ultimate bond force was slightly underestimated, which was beneficial in the design of this type of strengthening. Larger discrepancies concerned weaker grout matrices. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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16 pages, 7689 KiB  
Article
Experimental Investigation of the Multi-Physical Properties of an Energy Efficient Translucent Concrete Panel for a Building Envelope
by Baofeng Huang and Wensheng Lu
Appl. Sci. 2020, 10(19), 6863; https://0-doi-org.brum.beds.ac.uk/10.3390/app10196863 - 29 Sep 2020
Cited by 9 | Viewed by 3175
Abstract
The multi-physical properties of the building envelope play a major role in the energy efficiency of buildings. Translucent concrete panels (TCPs) with various volumetric ratios of optical fibers (OFs) were cast. To understand the multi-physical properties of the TCP for the building envelope, [...] Read more.
The multi-physical properties of the building envelope play a major role in the energy efficiency of buildings. Translucent concrete panels (TCPs) with various volumetric ratios of optical fibers (OFs) were cast. To understand the multi-physical properties of the TCP for the building envelope, compressive strength, thermal and light transmittance tests were carried out. The compressive strength test showed that TCP with light-weight mortar (LWM) has higher strength compared to that with normal-weight mortar (NWM), but it did not exhibit an apparent ductile behavior. The U-values of the plain panel were 4.25 and 5.45 W/(m2 K) for TCPs with the LWM and NWM, respectively. The existence of the OFs improved the thermal insulation property. The K-values of the LWM TCP were smaller than that of the common façade, which proved its excellent energy-efficient performance. The solar heat gain coefficients (G-values) of the two tested TCP types—LWM and NWM—were 0.198 and 0.242, respectively. The visible light transmission test showed that the light transmitted by the TCP was proportional to the density of the OFs in a matrix of concrete. The experimental light acceptance angle of the OF was close to the computational value (35 °C). Therefore, all the experimental results demonstrated that TCPs can improve the energy efficiency of buildings. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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17 pages, 7569 KiB  
Article
Approach for Optimisation of Tunnel Lining Design
by Marek Mohyla, Karel Vojtasik, Eva Hrubesova, Martin Stolarik, Jan Nedoma and Miroslav Pinka
Appl. Sci. 2020, 10(19), 6705; https://0-doi-org.brum.beds.ac.uk/10.3390/app10196705 - 25 Sep 2020
Cited by 3 | Viewed by 3513
Abstract
This paper presents an approach that enables the specific characteristics of a primary tunnel lining implemented using numerical modelling to be taken into account during its design. According to the fundamental principles of the New Austrian Tunnelling Method, the primary lining undergoes time-dependent [...] Read more.
This paper presents an approach that enables the specific characteristics of a primary tunnel lining implemented using numerical modelling to be taken into account during its design. According to the fundamental principles of the New Austrian Tunnelling Method, the primary lining undergoes time-dependent deformation, which is determined by its design. The main design element is shotcrete, which, shortly after its application, interacts with the surrounding rock mass and steel arch frame. The primary lining ensures the equilibrium stress–strain state of “rock mass–tunnel lining” during excavation. The structural interaction varies depending on the hardening of the shotcrete, the rheological properties of the rock mass, and other factors. The proposed approach uses the Homogenisation software application, which was developed by the Faculty of Civil Engineering at the Department of Geotechnics and Underground Engineering of the VSB—Technical University of Ostrava. This software allows the heterogeneous structure of the lining to be considered by replacing it with a homogenous structure. The parameters of the homogeneous primary lining, which take into account the steel reinforcement elements and the time-dependent property of the shotcrete, are included in numerical models. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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16 pages, 3280 KiB  
Article
Research on Strength Prediction Model of Sand-like Material Based on Nuclear Magnetic Resonance and Fractal Theory
by Hongwei Deng, Guanglin Tian, Songtao Yu, Zhen Jiang, Zhiming Zhong and Yanan Zhang
Appl. Sci. 2020, 10(18), 6601; https://0-doi-org.brum.beds.ac.uk/10.3390/app10186601 - 21 Sep 2020
Cited by 22 | Viewed by 2356
Abstract
Micro-pore structure has a decisive effect on the physical and mechanical properties of porous materials. To further improve the composition of rock-like materials, the internal relationship between microscopic characteristics (porosity, pore size distribution) and macroscopic mechanical properties of materials needs to be studied. [...] Read more.
Micro-pore structure has a decisive effect on the physical and mechanical properties of porous materials. To further improve the composition of rock-like materials, the internal relationship between microscopic characteristics (porosity, pore size distribution) and macroscopic mechanical properties of materials needs to be studied. This study selects portland cement, quartz sand, silica fume, and water-reducing agent as raw materials to simulate sandstone. Based on the Nuclear magnetic resonance (NMR) theory and fractal theory, the study explores the internal relationship between pore structure and mechanical properties of sandstone-like materials, building a compressive strength prediction model by adopting the proportion of macropores and the dimension of macropore pore size as dependent variables. Test results show that internal pores of the material are mainly macropores, and micropores account for the least. The aperture fractal dimension, the correlation coefficient of mesopores and macropores are quite different from those of micropores. Fractal characteristics of mesopores and macropores are obvious. The macropore pore volume ratio has a good linear correlation with fractal dimension and strength, and it has a higher correlation coefficient with pore volume ratio, pore fractal dimension and other variable factors. The compressive strength increases with the growth of pore size fractal dimension, but decreases with the growth of macropore pore volume ratio. The strength prediction model has a high correlation coefficient, credibility and prediction accuracy, and the predicted strength is basically close to the measured strength. Full article
(This article belongs to the Special Issue Advances in Design, Repair and Materials of Structural Concrete)
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