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Research on Mechanical Properties of Construction Materials

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

Deadline for manuscript submissions: closed (20 February 2022) | Viewed by 41606

Special Issue Editors


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Guest Editor
Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland
Interests: buckling; post-buckling; failure; laminates; finite element method; numerical simulations; computational mechanics; thin-walled structures
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Guest Editor
Lublin University of Technology, Department of Machine Design and Mechatronics, 36 Nadbystrzycka St., 20-618 Lublin, Poland
Interests: mechanics of materials; damage initiation and evolution; failure analysis; numerical simulations; buckling and post-buckling study; finite element method; composite materials

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Guest Editor
Department of Machine Design and Mechatronics, Faculty of Mechanical Engineering, Lublin University of Technology, 36 Nadbystrzycka St., 20-618 Lublin, Poland
Interests: computational mechanics; stability; plate elements; composites; matrix couplings; FEM; thin-walled structures; linear and nonlinear analysis
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

I am honored to announce a Special Issue of the Materials journal (IF 3.057) on “Research on Mechanical Properties of Construction Materials”. The Special Issue will cover all of the newest outcomes and trends in the research, modeling and testing of contemporary construction materials. The invitation to publish valuable papers is addressed to a wide group of scientists and practitioners, working in the field of isotropic materials, composites and other commonly used materials. Below, you will find a short summary of the scope of the abovementioned Special Issue.

Construction materials represent a wide range of engineering materials used in the construction of various types of structures. The group of these materials consists mainly of metals and their alloys, ceramics, polymers and composites. Research on the determination of mechanical and strength properties, in the case of construction materials such as isotropic or composite materials, is a current area of interest for scientists. Conducting experimental scientific research, which allows us to determine material properties, enables further implementation of the determined parameters in numerical calculations using the finite element method. This approach provides a further opportunity to carry out experimental and numerical analyses, based on predefined material parameters. With the above in mind, the ability to conduct research on material properties determines the further correctness of performing experimental tests on actual structures, subjected to different, usually complex states of external loads. Usually, studies on construction materials involve an analysis of the work and behavior of the structure, under specific operating conditions. The operational requirements primarily determine the adaptation of the structure to the failure-free performance of established tasks, mechanical strength, resistance to wear or environmental conditions, as well as protection against overload. Commonly used and maintained isotropic or composite construction materials (e.g., in the shape of thin-walled structures) are widely used in aviation, construction and the automotive industry.

In light of the above, any progress in the research on mechanical properties, design, manufacturing and testing methods is of great importance for the further expansion of the field of application of construction materials. I would like to encourage any researchers working in this field to submit their valuable papers to this Special Issue.

Dr. Patryk Rozylo
Prof. Hubert Debski
Dr. Katarzyna Falkowicz
Guest Editors

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Keywords

  • mechanical properties
  • strength properties
  • elastic and plastic properties
  • construction materials
  • isotropic materials
  • fiber-reinforced composite
  • solid structures
  • thin-walled structures
  • failure analysis
  • buckling and postbuckling
  • nondestructive testing
  • finite element modeling
  • experimental testing

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Published Papers (16 papers)

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Research

17 pages, 1787 KiB  
Article
Long-Term Behavior of PBO FRCM and Comparison with Other Inorganic-Matrix Composites
by Angelo Savio Calabrese, Tommaso D’Antino, Pierluigi Colombi and Carlo Poggi
Materials 2022, 15(9), 3281; https://doi.org/10.3390/ma15093281 - 3 May 2022
Cited by 6 | Viewed by 1743
Abstract
Fabric-reinforced cementitious matrix (FRCM) composites, comprising high-strength fiber textiles embedded within inorganic matrices, represent an effective, cost-efficient, and low-invasive solution for strengthening and retrofitting existing masonry and reinforced concrete structures. Among different textiles employed in FRCM composites, polyparaphenylene benzo-bisoxazole (PBO) textiles are adopted [...] Read more.
Fabric-reinforced cementitious matrix (FRCM) composites, comprising high-strength fiber textiles embedded within inorganic matrices, represent an effective, cost-efficient, and low-invasive solution for strengthening and retrofitting existing masonry and reinforced concrete structures. Among different textiles employed in FRCM composites, polyparaphenylene benzo-bisoxazole (PBO) textiles are adopted due to their high tensile strength and good adhesion with the matrix. Although several experimental, numerical, and analytical works were performed to investigate the mechanical properties of PBO FRCM composites, limited information is available on their long-term behavior, as well as in the case of exposure to aggressive environments. This paper presents and discusses the results of a wide experimental campaign aimed at investigating the effect of different environmental conditions on the long-term tensile behavior of a PBO FRCM composite. Tests are performed using a clamping-grip tensile test set-up. The effect of various aggressive environments on the composite matrix cracking stress, composite tensile strength, ultimate strain, and fully cracked stage slope is investigated by comparing the results of nominally equal conditioned and unconditioned (control) specimens. These results are also compared with those of other FRCM composites comprising glass and carbon textiles subjected to the same conditionings, collected from the literature. The results show only limited reductions in the tensile properties, even after long exposure to aggressive environments. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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20 pages, 6911 KiB  
Article
Development and Experimental Assessment of Friction-Type Shear Connectors for FRP Bridge Girders with Composite Concrete Decks
by William G. Davids, Dante Guzzi and Andrew P. Schanck
Materials 2022, 15(9), 3014; https://doi.org/10.3390/ma15093014 - 21 Apr 2022
Cited by 8 | Viewed by 2030
Abstract
This paper details the development and experimental assessment of a friction-type connector, designed to transfer shear flow between the top flange of a fiber-reinforced polymer (FRP) tub girder and a composite concrete deck for bridge applications. In contrast with previously used bearing-type connectors, [...] Read more.
This paper details the development and experimental assessment of a friction-type connector, designed to transfer shear flow between the top flange of a fiber-reinforced polymer (FRP) tub girder and a composite concrete deck for bridge applications. In contrast with previously used bearing-type connectors, this system relies on a deformed FRP surface to transfer shear via direct interlock with the concrete deck. The connector is materially efficient, simple to fabricate, can be used with lower-grade structural or stainless-steel fasteners, and provides a high degree of interface stiffness. Six compression-shear specimens were tested to assess the connector fatigue resistance and ultimate connection strength. Additionally, two short beam specimens were tested in three-point bending, one of which was subjected to fatigue loading. Based on the compression-shear tests and short beam tests, the connection exhibited strength exceeding that predicted by AASHTO for frictional concrete-concrete connections. The connection strengths were significantly greater than the factored demand required by AASHTO for a typical model FRP bridge girder. The cyclic loading of the connection in both compression-shear and beam bending showed that connection stiffness and strength do not significantly degrade, due to the application of 1 × 106 to 6 × 106 cycles of traffic-induced factored fatigue load. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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23 pages, 6057 KiB  
Article
Statistical Methods for Modeling the Compressive Strength of Geopolymer Mortar
by Hemn Unis Ahmed, Aso A. Abdalla, Ahmed S. Mohammed, Azad A. Mohammed and Amir Mosavi
Materials 2022, 15(5), 1868; https://doi.org/10.3390/ma15051868 - 2 Mar 2022
Cited by 43 | Viewed by 3821
Abstract
In recent years, geopolymer has been developed as an alternative to Portland cement (PC) because of the significant carbon dioxide emissions produced by the cement manufacturing industry. A wide range of source binder materials has been used to prepare geopolymers; however, fly ash [...] Read more.
In recent years, geopolymer has been developed as an alternative to Portland cement (PC) because of the significant carbon dioxide emissions produced by the cement manufacturing industry. A wide range of source binder materials has been used to prepare geopolymers; however, fly ash (FA) is the most used binder material for creating geopolymer concrete due to its low cost, wide availability, and increased potential for geopolymer preparation. In this paper, 247 experimental datasets were obtained from the literature to develop multiscale models to predict fly-ash-based geopolymer mortar compressive strength (CS). In the modeling process, thirteen different input model parameters were considered to estimate the CS of fly-ash-based geopolymer mortar. The collected data contained various mix proportions and different curing ages (1 to 28 days), as well as different curing temperatures. The CS of all types of cementitious composites, including geopolymer mortars, is one of the most important properties; thus, developing a credible model for forecasting CS has become a priority. Therefore, in this study, three different models, namely, linear regression (LR), multinominal logistic regression (MLR), and nonlinear regression (NLR) were developed to predict the CS of geopolymer mortar. The proposed models were then evaluated using different statistical assessments, including the coefficient of determination (R2), root mean squared error (RMSE), scatter index (SI), objective function value (OBJ), and mean absolute error (MAE). It was found that the NLR model performed better than the LR and MLR models. For the NLR model, R2, RMSE, SI, and OBJ were 0.933, 4.294 MPa, 0.138, 4.209, respectively. The SI value of NLR was 44 and 41% lower than the LR and MLR models’ SI values, respectively. From the sensitivity analysis result, the most effective parameters for predicting CS of geopolymer mortar were the SiO2 percentage of the FA and the alkaline liquid-to-binder ratio of the mixture. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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18 pages, 35512 KiB  
Article
Residual Fire Resistance Testing of Basalt- and Hybrid-FRP Reinforced Concrete Beams
by Kostiantyn Protchenko
Materials 2022, 15(4), 1509; https://doi.org/10.3390/ma15041509 - 17 Feb 2022
Cited by 6 | Viewed by 2523
Abstract
The fire resistance of fiber-reinforced polymer reinforced concrete (FRP-RC) elements depends on the temperature performance of the original concrete member, the fire scenario, and FRP reinforcement behavior. In this study, fire resistance tests are described, along with the characteristics obtained during and after [...] Read more.
The fire resistance of fiber-reinforced polymer reinforced concrete (FRP-RC) elements depends on the temperature performance of the original concrete member, the fire scenario, and FRP reinforcement behavior. In this study, fire resistance tests are described, along with the characteristics obtained during and after applying elevated temperatures, simulating the effects of fire. The tested beams were reinforced with basalt (BFRP) bars and with a hybrid composite of carbon fibers and basalt fibers (HFRP) bars. Fire tests were performed on full-scale beams, in which the midsections of the beams were heated from below (tension zone) and from the sides for two hours, after which the beams were cooled and subjected to flexural testing. BFRP-RC beams failed before the heating time was completed; the best failure was associated with a BFRP reinforced beam that failed approximately 108 min after heating. Contrary to the BFRP-RC samples, HFRP-RC beams were capable of resisting exposure to elevated temperatures for two hours, but showed a 70% reduction in strength capacity when compared to non-heated reference beams. According to the author, the higher resistance of HFRP-RC beams was the result of the thermal expansion coefficient of carbon fibers employed in HFRP, which “prestresses” the beams and enables smaller deflections. The preliminary findings of this study can increase the feasibility of using FRP materials for engineering purposes. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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12 pages, 2916 KiB  
Article
Impact of Adhesive Layer Thickness on the Behavior of Reinforcing Thin-Walled Sigma-Type Steel Beams with CFRP Tapes
by Ilona Szewczak, Patryk Rozylo, Malgorzata Snela and Katarzyna Rzeszut
Materials 2022, 15(3), 1250; https://doi.org/10.3390/ma15031250 - 8 Feb 2022
Cited by 10 | Viewed by 1954
Abstract
This paper presents selected issues related to the reinforcement of steel element cold-formed with CFRP tapes. The first section of the paper is a review of source literature and a presentation of the basic information on cold-formed thin-walled steel elements and CFRP composite [...] Read more.
This paper presents selected issues related to the reinforcement of steel element cold-formed with CFRP tapes. The first section of the paper is a review of source literature and a presentation of the basic information on cold-formed thin-walled steel elements and CFRP composite materials, stressing the advantages and disadvantages of using them to reinforce steel structures. Next, the authors present original research on reinforcing bent thin-walled sigma-type steel beams using adhesive CFRP tapes. Reference beams with a cross-section of Σ200 × 70 × 2 and a length of 3 m, reinforced with CFRP tape, were tested in the four-point bending scheme. Then, the paper discusses a developed numerical model that is consistent with the subject matter of the laboratory tests. The developed numerical model was prepared to represent the failure of the connection between the beam and the composite tape. This was followed by a number of numerical analyses in order to determine the optimum adhesive layer that would allow us to achieve the maximum reduction of the displacements and strains in bent thin-walled sigma-type beams. Three thicknesses of the SikaDur adhesive layer were analyzed in the study. Based on the analyzes, it was found that the increase in the thickness of the adhesive layer slightly reduced the strain and displacement in the beams, but caused a significant decrease in the load value, at which damage appeared in the glued joint. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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15 pages, 4939 KiB  
Article
Comparison of Failure for Thin-Walled Composite Columns
by Patryk Rozylo
Materials 2022, 15(1), 167; https://doi.org/10.3390/ma15010167 - 27 Dec 2021
Cited by 32 | Viewed by 2764
Abstract
The novelty of this paper, in relation to other thematically similar research papers, is the comparison of the failure phenomenon on two composite profiles with different cross-sections, using known experimental techniques and advanced numerical models of composite material failure. This paper presents an [...] Read more.
The novelty of this paper, in relation to other thematically similar research papers, is the comparison of the failure phenomenon on two composite profiles with different cross-sections, using known experimental techniques and advanced numerical models of composite material failure. This paper presents an analysis of the failure of thin-walled structures made of composite materials with top-hat and channel cross-sections. Both experimental investigations and numerical simulations using the finite element method (FEM) are applied in this paper. Tests were conducted on thin-walled short columns manufactured of carbon fiber reinforced polymer (CFRP) material. The experimental specimens were made using the autoclave technique and thus showed very good strength properties, low porosity and high surface smoothness. Tests were carried out in axial compression of composite profiles over the full range of loading—up to total failure. During the experimental study, the post-buckling equilibrium paths were registered, with the simultaneous use of a Zwick Z100 universal testing machine (UTM) and equipment for measuring acoustic emission signals. Numerical simulations used composite material damage models such as progressive failure analysis (PFA) and cohesive zone model (CZM). The analysis of the behavior of thin-walled structures subjected to axial compression allowed the evaluation of stability with an in-depth assessment of the failure of the composite material. A significant effect of the research was, among others, determination of the phenomenon of damage initiation, delamination and loss of load-carrying capacity. The obtained results show the high qualitative and quantitative agreement of the failure phenomenon. The dominant form of failure occurred at the end sections of the composite columns. The delamination phenomenon was observed mainly on the outer flanges of the structure. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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13 pages, 2962 KiB  
Article
Buckling Analysis of a Large Shelter with Composites
by Sheldon Wang and Jianyao Mou
Materials 2021, 14(23), 7196; https://doi.org/10.3390/ma14237196 - 25 Nov 2021
Cited by 1 | Viewed by 1688
Abstract
We present here linear and nonlinear finite element analyses of a newly designed deployable rapid assembly shelter (DRASH J) manufactured by DHS Systems. The structural analysis is carried out in three stages. Firstly, single composite tubes (struts) under three-point bending are modeled with [...] Read more.
We present here linear and nonlinear finite element analyses of a newly designed deployable rapid assembly shelter (DRASH J) manufactured by DHS Systems. The structural analysis is carried out in three stages. Firstly, single composite tubes (struts) under three-point bending are modeled with five layers of orthotropic materials in three different orientations and the simulation results are compared with the actual test data for validation. Secondly, a comprehensive structural model for the entire shelter is constructed with the consideration of two types of strut scissor points, namely natural and forced scissor (crossing) points, as well as partial-fixed hub joints, which allow rotations along individual hub slots (grooves). Finally, a simplified structural model is created by introducing fixed joints for the scissor points as well as rigid links for the hubs. With sufficient verifications with experiments and different modeling methods, linear and nonlinear finite element analyses are then carried out for both the comprehensive and simplified shelter models. Based on the simulation results, we are able to identify a few critical issues pertaining to proper design and modifications of such shelter systems, such as various end wall supports pertaining to the overall structural stability. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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17 pages, 6416 KiB  
Article
Experimental Study on the Compaction Characteristics and Evaluation Method of Coarse-Grained Materials for Subgrade
by Shanzhen Li, Yangsheng Ye, Liang Tang, Degou Cai, Shuang Tian and Xianzhang Ling
Materials 2021, 14(22), 6972; https://doi.org/10.3390/ma14226972 - 18 Nov 2021
Cited by 8 | Viewed by 2522
Abstract
Coarse-grained materials are widely used in high-speed railway construction, and it is of great significance to research its compaction characteristics due to the high quality control requirements. In this regard, a field compaction experiment was conducted at a subgrade near Bazhou Station of [...] Read more.
Coarse-grained materials are widely used in high-speed railway construction, and it is of great significance to research its compaction characteristics due to the high quality control requirements. In this regard, a field compaction experiment was conducted at a subgrade near Bazhou Station of Beijing-Xiong’an Intercity Railway. The test results of the compaction effect were presented in this study at first. The roller-integrated compaction measurements (i.e., compaction meter value, CMV) were compared with several traditional in-situ tests (i.e., plate load test, light falling weight deflectometer test, and shear wave velocity test). Then the stability of CMV was evaluated by the proposed δ criterion. The spatial uniformity of compaction was further investigated. Based on the analysis, the target value of CMV was preliminarily determined. It showed that Evd was more variable than CMV. The results convincingly indicated that the compaction parameters increased with the increasing number of roller passes at first. A further increase in compaction effort could result in the decompaction of material when the compaction number up to a certain value. The stability analysis method proposed in this study showed its potency of quantifying the percentage of areas with acceptable compaction. The geostatistical analysis could reflect the spatial uniformity of compaction. Overall, the conducted study could provide a useful reference for geo-material compaction control in the transportation engineering. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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23 pages, 4987 KiB  
Article
Experimental and Numerical Investigation into Failure Modes of Tension Angle Members Connected by One Leg
by Edyta Bernatowska and Lucjan Ślęczka
Materials 2021, 14(18), 5141; https://doi.org/10.3390/ma14185141 - 7 Sep 2021
Cited by 3 | Viewed by 2074
Abstract
This paper presents the results of experimental and numerical tests on angle members connected by one leg with a single row of bolts. This study was designed to determine which failure mode governs the resistance of such joints: net section rupture or block [...] Read more.
This paper presents the results of experimental and numerical tests on angle members connected by one leg with a single row of bolts. This study was designed to determine which failure mode governs the resistance of such joints: net section rupture or block tearing rupture. Experimental tests were insufficient to completely identify the failure modes, and it was necessary to conduct numerical simulations. Finite element analysis of steel element resistance based on rupture required advanced material modelling, taking into account ductile initiation and propagation of fractures. This was realised using the Gurson–Tvergaard–Needleman porous material model, which allows for analysis of the joint across the full scope of its behaviour, from unloaded state to failure. Through experimental testing and numerical simulations, both failure mechanisms (net section and block tearing) were examined, and an approach to identify the failure mode was proposed. The obtained results provided experimental and numerical evidence to validate the strength function used in design standards. Finally, the obtained results of the load capacity were compared with the design procedures given in the Eurocode 3′s current and 2021 proposed editions. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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19 pages, 7602 KiB  
Article
The Influence of Different Length Aluminum Foam Filling on Mechanical Behavior of a Square Thin-Walled Column
by Michał Rogala, Mirosław Ferdynus, Katarzyna Gawdzińska and Paweł Kochmański
Materials 2021, 14(13), 3630; https://doi.org/10.3390/ma14133630 - 29 Jun 2021
Cited by 21 | Viewed by 2267
Abstract
The demand for lightweight, strong structural profiles is currently high in the transport industry, mechanical engineering, and construction. Therefore, it is important to evaluate their properties, especially mechanical properties. The main objective of this paper is to determine energy absorption coefficients and evaluate [...] Read more.
The demand for lightweight, strong structural profiles is currently high in the transport industry, mechanical engineering, and construction. Therefore, it is important to evaluate their properties, especially mechanical properties. The main objective of this paper is to determine energy absorption coefficients and evaluate the crush resistance of thin-walled aluminum profiles using numerical simulation and empirical verification. This paper presents the compression results of testing of thin-walled aluminum profiles filled with a porous material (cast aluminum foam). The numerical analysis was conducted using the software Abaqus/CAE. Aluminum material data were obtained from a static tensile test performed on a Shimadzu machine. The experiment was performed on an Instron CEAST 9450HES dynamic hammer. Profiles with three shapes of crush initiators filled with aluminum foam measuring 40 mm–200 mm in 20 mm increments were numerically tested. A sample with a concave initiator filled with foams of 40 mm, 60 mm, 80 mm, and 120 mm in length was used to verify the numerical analyses. Energy absorption coefficients were determined from the analyses. The results of both analyses were tabulated to show the percentage differences. The study showed an increase in the Crush Load Efficiency (CLE) index by up to 33% for samples with the same crush initiator. In addition, it was noted that the use of porous fill does not increase the value of initiating Peak Crushing Force (PCF), which indicates the generation of much smaller overloads dangerous for vehicle passengers. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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12 pages, 2921 KiB  
Article
Investigation of the Behavior and Mechanism of Action of Ether-Based Polycarboxylate Superplasticizers Adsorption on Large Bibulous Stone Powder
by Zuiliang Deng, Guimin Lu, Lefeng Fu, Weishan Wang and Baicun Zheng
Materials 2021, 14(11), 2736; https://doi.org/10.3390/ma14112736 - 22 May 2021
Cited by 5 | Viewed by 2207
Abstract
The aim of this paper is to study the adsorption behavior of polycarboxylate superplasticizers (PCE) on coarse aggregates with a property of high water consumption (above 2%). The coarse aggregates were ground into a powder to create large bibulous stone powder, and it [...] Read more.
The aim of this paper is to study the adsorption behavior of polycarboxylate superplasticizers (PCE) on coarse aggregates with a property of high water consumption (above 2%). The coarse aggregates were ground into a powder to create large bibulous stone powder, and it was observed that significant amounts of the ether-based PCE were absorbed onto large bibulous stone powder. The adsorption rate immediately reached a maximum after 5 min and then gradually decreased until an equilibrium absorption was established after 30 min. Zeta potential, infrared spectroscopy, and thermogravimetric analysis (TGA) measurements confirmed that the polycarboxylate superplasticizer adsorbed on the surface of the stone powder. Hydrodynamic diameter measurements showed that the polycarboxylate superplasticizer molecules were smaller than pore size, and the surface area and pore volume were reduced by the polymer incorporation in the pores. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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14 pages, 3722 KiB  
Article
Influence of Mechanical Properties of Steel and CFRP Tapes on the Effectiveness of Strengthening Thin-Walled Beams
by Ilona Szewczak, Patryk Rozylo and Katarzyna Rzeszut
Materials 2021, 14(9), 2388; https://doi.org/10.3390/ma14092388 - 4 May 2021
Cited by 13 | Viewed by 2034
Abstract
The paper presents a comparison of the effectiveness of strengthening steel thin-walled, cold-formed sigma beams with CFRP tapes and steel tapes. For this purpose, three beams without reinforcement (reference beams) of the “Blachy Pruszyński” type, with a cross-section of ∑200 × 70 × [...] Read more.
The paper presents a comparison of the effectiveness of strengthening steel thin-walled, cold-formed sigma beams with CFRP tapes and steel tapes. For this purpose, three beams without reinforcement (reference beams) of the “Blachy Pruszyński” type, with a cross-section of ∑200 × 70 × 2 and a span of 280 cm, made of S350GD steel grade, were subjected to laboratory tests in the four-point bending scheme. In the next stage the tests included nine ∑200 × 70 × 2 beams reinforced with Sika CarboDur S512 CFRP tape and six ∑200 × 70 × 2 beams reinforced with steel tape made of S235 steel grade. The length of the reinforcement tapes as well made of steel as well of CFRP was of 175 cm. The location of the tapes within the height of the beams’ cross-section was assumed in three variants, namely placing the tape on the upper or bottom flange and on the web. In the case of beams reinforced with CFRP, three beams were tested for each reinforcement location, and in the case of beams reinforced with steel tapes, two beams were tested for each reinforcement location. SikaDur®-30 glue with a thickness of 1.3 mm was used in order to connect steel or CFRP tapes to the beams. The dimensions of the tapes cross-sections in both cases were similar (CFRP tapes: 50 × 1.2 mm, steel tapes: 50 × 1.3 mm). For all types of beams, numerical models were also developed in the Abaqus software. The main aim of this paper was investigation of the influence of mechanical properties of steel or CFRP tapes on the effectiveness of strengthening ∑ beams. For this purpose a comparison of these two solutions with respect to the limitation of displacements and deformations of the beam was performed. The obtained results were considered in the context of the mechanical properties of the materials composing the reinforcement tapes. The tests showed slight differences in the results of strain and displacements obtained for reinforcement made of two different materials. It was also noted that the decisive element was the failure of the joint at the steel-glue interface. Therefore, future studies will pay particular attention to the adhesive layer. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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25 pages, 7720 KiB  
Article
Theoretical Local Buckling Behavior of Thin-Walled UHPC Flanges Subjected to Pure Compressions
by Jeonghwa Lee, Seungjun Kim, Keesei Lee and Young Jong Kang
Materials 2021, 14(9), 2130; https://doi.org/10.3390/ma14092130 - 22 Apr 2021
Cited by 3 | Viewed by 2668
Abstract
To enhance structural performance of concrete and reduce its self-weight, ultra-high-performance concrete (UHPC) with superior structural performance has been developed. As UHPC members with 180 MPa or above of the compressive strength can be designed, a rational assessment of thin-walled UHPC structural member [...] Read more.
To enhance structural performance of concrete and reduce its self-weight, ultra-high-performance concrete (UHPC) with superior structural performance has been developed. As UHPC members with 180 MPa or above of the compressive strength can be designed, a rational assessment of thin-walled UHPC structural member may be required to prevent unexpected buckling failure that has not been considered while designing conventional concrete members. In this study, theoretical local buckling behavior of the thin-walled UHPC flanges was investigated using geometrical and material nonlinear analysis with imperfections (GMNIA). For the failure criteria of UHPC, a concrete damaged plasticity (CDP) model was applied to the analysis. Additionally, an elastic-perfectly plastic material model for steel materials was considered as a reference to establish differences in local buckling behavior between the UHPC and steel flanges. Finite element approaches were compared and verified based on test data in the literature. Finally, this study offers several important findings on theoretical local buckling and local bending behavior of UHPC flanges. The inelastic local buckling behavior of UHPC flanges was mainly affected by crack propagation due to its low tensile strength. Based on this study, possibility of the local buckling of UHPC flanges was discussed. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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17 pages, 35402 KiB  
Article
Experimental-Numerical Failure Analysis of Thin-Walled Composite Columns Using Advanced Damage Models
by Patryk Rozylo, Katarzyna Falkowicz, Pawel Wysmulski, Hubert Debski, Jakub Pasnik and Jan Kral
Materials 2021, 14(6), 1506; https://doi.org/10.3390/ma14061506 - 19 Mar 2021
Cited by 36 | Viewed by 2673
Abstract
The paper analyzes the stability and failure phenomenon of compressed thin-walled composite columns. Thin-walled columns (top-hat and channel section columns) were made of carbon fiber reinforced polymer (CFRP) composite material (using the autoclave technique). An experimental study on actual structures and numerical calculations [...] Read more.
The paper analyzes the stability and failure phenomenon of compressed thin-walled composite columns. Thin-walled columns (top-hat and channel section columns) were made of carbon fiber reinforced polymer (CFRP) composite material (using the autoclave technique). An experimental study on actual structures and numerical calculations on computational models using the finite element method was performed. During the experimental study, post-critical equilibrium paths were registered with acoustic emission signals, in order to register the damage phenomenon. Simultaneously to the experimental tests, numerical simulations were performed using progressive failure analysis (PFA) and cohesive zone model (CZM). A measurable effect of the conducted experimental-numerical research was the analysis of the failure phenomenon, both for the top-hat and channel section columns (including delamination phenomenon). The main objective of this study was to be able to evaluate the delamination phenomenon, with further analysis of this phenomenon. The results of the numerical tests showed a compatibility with experimental tests. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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21 pages, 10002 KiB  
Article
The Influence of Mixing Methods of Epoxy Composition Ingredients on Selected Mechanical Properties of Modified Epoxy Construction Materials
by Izabela Miturska, Anna Rudawska, Miroslav Müller and Monika Hromasová
Materials 2021, 14(2), 411; https://doi.org/10.3390/ma14020411 - 15 Jan 2021
Cited by 14 | Viewed by 3099
Abstract
The proper process of preparing an adhesive composition has a significant impact on the degree of dispersion of the composition ingredients in the matrix, as well as on the degree of aeration of the resulting composition, which in turn directly affects the strength [...] Read more.
The proper process of preparing an adhesive composition has a significant impact on the degree of dispersion of the composition ingredients in the matrix, as well as on the degree of aeration of the resulting composition, which in turn directly affects the strength and functional properties of the obtained adhesive compositions. The paper presents the results of tensile strength tests and SEM microphotographs of the adhesive composition of Epidian 57 epoxy resin with Z-1 curing agent, which was modified using three fillers NanoBent ZR2 montmorillonite, CaCO3 calcium carbonate and CWZ-22 active carbon. For comparison purposes, samples made of unmodified composition were also tested. The compositions were prepared with the use of six mixing methods, with variable parameters such as type of mixer arm, deaeration and epoxy resin temperature. Then, three mixing speeds were applied: 460, 1170 and 2500 rpm. The analyses of the obtained results showed that the most effective tensile results were obtained in the case of mixing with the use of a dispersing disc mixer with preliminary heating of the epoxy resin to 50 °C and deaeration of the composition during mixing. The highest tensile strength of adhesive compositions was obtained at the highest mixing speed; however, the best repeatability of the results was observed at 1170 rpm mixing speed. Based on a comparison test of average values, it was observed that, in case of modified compositions, the values of average tensile strength obtained at mixing speeds at 1170 and 2500 rpm do not differ significantly with the assumed level of significance α = 0.05. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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22 pages, 9125 KiB  
Article
Effect of Internal Support on the Tensile Properties and Fracture Mode of 304 Stainless Steel Thin-Walled Tubes
by Yue Gao, Fei Shao, Pengxian Fan, Qian Xu and Xingkun Xie
Materials 2021, 14(1), 172; https://doi.org/10.3390/ma14010172 - 31 Dec 2020
Cited by 8 | Viewed by 2546
Abstract
Steel–tube composite structures contain multiple tubular components under tension. The enhancement of the mechanical properties of tubes under ultimate operating conditions is crucial for improving structural safety. In this study, 110 pieces of 304 stainless steel thin-walled tubes (SSTWTs) under five internal support [...] Read more.
Steel–tube composite structures contain multiple tubular components under tension. The enhancement of the mechanical properties of tubes under ultimate operating conditions is crucial for improving structural safety. In this study, 110 pieces of 304 stainless steel thin-walled tubes (SSTWTs) under five internal support conditions are investigated. The ultimate tensile strength, ultimate extension, and fracture energy of different groups of specimens are measured to understand the variation mechanism of fracture modes. The elastic modulus of tube filler is treated as a variable to establish a uniaxial tensile fracture matrix of 304 SSTWTs with different tube fillers and loading rates. The results demonstrate that flexible tube fillers can effectively limit the lateral necking of 304 SSTWTs. Under the middle fracture mode, the maximum increments in the ultimate strength, extension, and fracture energy of tubes are 10.81%, 24.56%, and 35.94%, respectively. Furthermore, as the support rigidity increases, the ultimate strength exhibits an overall increasing trend, while the extension and fracture energy initially increase and then decrease. Overall, this study provides a novel route for enhancing the performance of steel–tube composite structures under ultimate loading conditions, which is of great significance for improving the safety of the structural design and reducing the engineering construction cost. Full article
(This article belongs to the Special Issue Research on Mechanical Properties of Construction Materials)
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