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Infrastructures
Volume 8
Issue 10
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Infrastructures, Volume 8, Issue 10 (October 2023) – 18 articles

Cover Story (view full-size image): This paper presents the installation and use of an innovative pavement monitoring system based on FBG optical sensors that measure the strains imposed on the pavement and the corresponding temperature. A calibration procedure was implemented with FWD tests and heavy vehicles passing over sensors to validate the system installation. The results obtained confirmed the importance of adequately choosing the distance between sensors and increasing the sensor concentration in wheel paths. Furthermore, for loads between 25 kN and 65 kN, raising the temperature by 8 °C caused an increase of about 20% in the horizontal tensile strains measured in the pavement. In summary, this innovative system can capture the effects of temperature and vehicle speed on the pavement response, which may be considered an advantage of this monitoring system. View this paper
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18 pages, 7969 KiB  
Article
Cracking Resistance of Steam-Cured Precast Concrete Using High Alite Cement with Modified Fly Ash
by Aghiad Alhafez, Shingo Miyazawa, Nobukazu Nito, Ryuichiroh Kuga and Etsuo Sakai
Infrastructures 2023, 8(10), 154; https://doi.org/10.3390/infrastructures8100154 - 23 Oct 2023
Viewed by 2007
Abstract
Cement with fly ash has rarely been used in Japan, mainly because its strength development is slower than ordinary Portland cement. In this research, the effect of the new type of fly ash (which was modified by the electrostatic belt separation method) with [...] Read more.
Cement with fly ash has rarely been used in Japan, mainly because its strength development is slower than ordinary Portland cement. In this research, the effect of the new type of fly ash (which was modified by the electrostatic belt separation method) with high alite (C3S) cement on cracking resistance of precast concrete prepared by steam curing was studied. The mechanical and shrinkage properties of the proposed fly ash concrete were compared with those of concrete made using OPC cement without fly ash. In order to study the cracking tendency of precast concrete with the proposed cement with fly ash, thermal stress analysis was conducted, taking into consideration the experimental data of concrete properties with the different concrete mix proportions. A standard precast concrete box culvert model was used in this 3D FEM analysis, and the distribution of temperature and relative humidity in the cross-section and induced restraint stress during and after steam curing were discussed. Steam-cured concrete with fly ash and high alite cement developed higher compressive strength on the first day of age than concrete with OPC. The proposed fly ash concrete developed high cracking resistance in the early days. On the other hand, the results showed that the drying shrinkage at later ages was the main cause of cracking. Full article
(This article belongs to the Section Infrastructures Materials and Constructions)
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15 pages, 4574 KiB  
Article
Multi-Parametric Delineation Approach for Homogeneous Sectioning of Asphalt Pavements
by Naga Siva Pavani Peraka, Krishna Prapoorna Biligiri and Satyanarayana N. Kalidindi
Infrastructures 2023, 8(10), 153; https://doi.org/10.3390/infrastructures8100153 - 21 Oct 2023
Viewed by 2200
Abstract
The demand for preserving existing roadway infrastructure has been increasing to regulate expensive reconstruction activities. The maintenance of homogeneous road sections is one of the approaches to economize the overall management of pavement systems. The existing homogeneous delineation methods consider one or two [...] Read more.
The demand for preserving existing roadway infrastructure has been increasing to regulate expensive reconstruction activities. The maintenance of homogeneous road sections is one of the approaches to economize the overall management of pavement systems. The existing homogeneous delineation methods consider one or two parameters for segmenting the pavements based on similar characteristics, which are found to be a repetitive process. Also, there is a need to consider multiple parameters that represent the functional, structural, and traffic characteristics in segmentation process. Therefore, the objective of this study was to develop a multi-parameter-based delineation approach (MPDA) to segment the pavements into subsections with similar features considering functional, structural, and traffic characteristics. Deflection bowl parameters, unified pavement health index (functional performance metric), surface layer modulus, and traffic reported in terms of AADT were employed for developing a multi-parametric delineation index (MPDI). A total of 1781 datapoints covering 26 road sections in the State of Andhra Pradesh, India, were used. The C-charts method-based segmentation for MPDI was applied to obtain the homogeneous sections. The devised approach was found to be efficient in segmenting the pavements as well as robust in selecting suitable maintenance strategies for each group of the homogeneous sections. Further, the segmentation processes were automated for easier implementation by the agencies. Full article
(This article belongs to the Special Issue Maintenance and Rehabilitation of Constructed Infrastructure Facilities)
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27 pages, 12415 KiB  
Article
Vision-Based Structural Monitoring: Application to a Medium-Span Post-Tensioned Concrete Bridge under Vehicular Traffic
by Fabio Micozzi, Michele Morici, Alessandro Zona and Andrea Dall’Asta
Infrastructures 2023, 8(10), 152; https://doi.org/10.3390/infrastructures8100152 - 17 Oct 2023
Cited by 2 | Viewed by 2554
Abstract
Video processing for structural monitoring has attracted much attention in recent years thanks to the possibility of measuring displacement time histories in the absence of stationary points close to the structure, using hardware that is simple to operate and with accessible costs. Experimental [...] Read more.
Video processing for structural monitoring has attracted much attention in recent years thanks to the possibility of measuring displacement time histories in the absence of stationary points close to the structure, using hardware that is simple to operate and with accessible costs. Experimental studies show a unanimous consensus on the potentialities of vision-based monitoring to provide accurate results that can be equivalent to those obtained from accelerometers and displacement transducers. However, past studies mostly involved steel bridges and footbridges while very few applications can be found for concrete bridges, characterised by a stiffer response with lower displacement magnitudes and different frequency contents of their dynamic behaviour. Accordingly, the attention of this experimental study is focused on the application of a vision-based structural monitoring system to a medium-span, post-tensioned, simply supported concrete bridge, a very common typology in many road networks. The objective is to provide evidence on the quality of the results that could be obtained using vision-based monitoring, understanding the role and influence on the accuracy of the measurements of various parameters relevant to the hardware settings and target geometry, highlighting possible difficulties, and providing practical recommendations to achieve optimal results. Full article
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14 pages, 7661 KiB  
Article
Experimental Study on the Physical and Mechanical Characteristics of Refractory Concrete Using Heat-Treated Steel Slag Coarse Aggregates
by Munaf Alkhedr, Majed Asaad, Mahmoud Ismail and George Wardeh
Infrastructures 2023, 8(10), 151; https://doi.org/10.3390/infrastructures8100151 - 17 Oct 2023
Cited by 1 | Viewed by 2060
Abstract
The aim of this study is to compare the properties of refractory concrete made with thermally treated and untreated steel slag. Five concrete compositions were prepared and investigated in the present work. The first mixture, referred to as the reference, was formulated using [...] Read more.
The aim of this study is to compare the properties of refractory concrete made with thermally treated and untreated steel slag. Five concrete compositions were prepared and investigated in the present work. The first mixture, referred to as the reference, was formulated using dolomite aggregates, whereas the second and third mixtures were developed by replacing natural coarse aggregate with 50 and 100% by weight of thermally untreated steel slag, respectively. The same replacement ratio (50% and 100%) of thermally treated steel slag was used to produce the fourth and fifth mixtures. Specimens of each specimen were placed in a furnace and heated to 400 °C and 800 °C. The mass loss for all the specimens heated to 400 °C was about 8%, while the reference suffered the maximum mass loss at 800 °C, which was 21.6%. The mixture with a 100% substitution of thermally treated steel slag produced the maximum compressive strength when compared to other mixtures at a temperature of 800 °C. The compressive strength of the M5 mixture was 18 MPa versus 10.87 MPa for the reference mixture. Additionally, optical microscope examination of specimens containing thermally treated steel slag revealed less damage than that observed in mixtures with dolomite. Full article
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18 pages, 2523 KiB  
Article
Contemplation of Improvement Efforts to Manage Combined Sewer Overflows
by Younghan Edwin Jung, M. Myung Jeong, Hwandon Jun and Trevor Smith
Infrastructures 2023, 8(10), 150; https://doi.org/10.3390/infrastructures8100150 - 13 Oct 2023
Cited by 1 | Viewed by 3708
Abstract
Combined sewer overflow (CSO) is a significant environmental concern and public health risk (e.g., water contamination, eutrophication, and beach closure). The Environmental Protection Agency (EPA) has introduced the National Pollutant Discharge Elimination System (NPDES) permitting program to regulate and address this matter. This [...] Read more.
Combined sewer overflow (CSO) is a significant environmental concern and public health risk (e.g., water contamination, eutrophication, and beach closure). The Environmental Protection Agency (EPA) has introduced the National Pollutant Discharge Elimination System (NPDES) permitting program to regulate and address this matter. This program mandates the control of CSOs for more than 700 municipalities obligated to devise Long-term Control Plans (LTCPs) to curb combined sewer overflows and reduce them to safe levels. The LTCP involves diverse strategies, including sewer separation, green infrastructure improvements, and conventional gray infrastructure upgrades. This study investigates several municipalities’ solutions for CSO problems that use conventional methods and wireless sensor technology as real-time control, mainly focusing on a comparative analysis of two cities, Richmond, Virginia, and South Bend, Indiana, such as their average rainfall, the frequency of overflows, and the capacity of treatment plants. The findings indicate that integrating sensor technology could significantly enhance modeling endeavors, bolster the capacity of existing structures, and substantially enhance preparedness for storm events. The EPA’s Storm Water Management Modeling (SWMM) software is utilized. Through an analysis of SWMM data, the study suggests the potential for leveraging wireless sensor technology to achieve more robust control over CSOs and significant cost savings as a part of LTCPs. Full article
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23 pages, 11968 KiB  
Article
Installation and Use of a Pavement Monitoring System Based on Fibre Bragg Grating Optical Sensors
by Francisco J. P. Rebelo, Joel R. M. Oliveira, Hugo M. R. D. Silva, Jorge Oliveira e Sá, Vânia Marecos and João Afonso
Infrastructures 2023, 8(10), 149; https://doi.org/10.3390/infrastructures8100149 - 13 Oct 2023
Cited by 1 | Viewed by 2146
Abstract
The evolution of technological tools, namely affordable sensors for data collection, and the growing concerns about maintaining roads in adequate conditions have promoted the development of continuous pavement monitoring systems. This paper presents the installation and use of an innovative pavement monitoring system, [...] Read more.
The evolution of technological tools, namely affordable sensors for data collection, and the growing concerns about maintaining roads in adequate conditions have promoted the development of continuous pavement monitoring systems. This paper presents the installation and use of an innovative pavement monitoring system, which was developed to measure the effects of vehicle loads and temperature on the performance of a pavement structure. The sensors used are based on fibre Bragg grating optical technology, collecting data about the strains imposed in the pavement and the temperature at which those measurements are made. The site selection for the system’s installation and the essential installation details to ensure successful data collection are addressed. A calibration procedure was implemented by performing falling weight deflectometer tests and passing preweighed heavy vehicles over the sensors. In addition to validating the system installation, the results obtained in the calibration confirmed the importance of adequately choosing the distance between sensors. Differences of 50 mm in the position of the load may cause differences of about 20% to 25% in the resulting strains. These results confirmed the importance of increasing the sensor concentration in wheel paths. Furthermore, for loads between 25 kN and 65 kN, raising the temperature by 8 °C caused an increase of about 20% in the horizontal tensile strains measured in the pavement. In summary, it was possible to conclude that this innovative system is capable of capturing the effects of temperature and vehicle speed on the response of the pavement, which may be considered an advantage of this type of monitoring system when compared to those that are only used to determine the loads applied to the pavement or to characterise the type of vehicle. Full article
(This article belongs to the Special Issue Sustainable and Digital Transformation of Road Infrastructures)
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29 pages, 5318 KiB  
Article
Delving into Earth Dam Dynamics: Exploring the Impact of Inner Impervious Core and Toe Drain Arrangement on Seepage and Factor of Safety during Rapid Drawdown Scenarios
by Yelbek Bakhitovich Utepov, Timoth Mkilima, Aliya Kairatovna Aldungarova, Zhanbolat Anuarbekovich Shakhmov, Sungat Berkinovich Akhazhanov, Nargul Amanovna Saktaganova, Uliya Baktybaevna Abdikerova and Aigul Moldashevna Budikova
Infrastructures 2023, 8(10), 148; https://doi.org/10.3390/infrastructures8100148 - 12 Oct 2023
Cited by 5 | Viewed by 2586
Abstract
The study examined the intricate relationships between embankment slope configurations, toe drain designs, and drawdown scenarios. It utilized a unique combination of numerical, physical, and mathematical models. The investigation involved 16 numerical models and 8 physical models with distinct characteristics. The research explored [...] Read more.
The study examined the intricate relationships between embankment slope configurations, toe drain designs, and drawdown scenarios. It utilized a unique combination of numerical, physical, and mathematical models. The investigation involved 16 numerical models and 8 physical models with distinct characteristics. The research explored the correlations of key parameters: matric suction, horizontal water conductivity, time, and factor of safety. The factor of safety values varied from 0.62 to 1.03 as a result of the different investigated combinations. For instance, a 1:2 embankment slope without a toe drain under instantaneous drawdown led to the factor of safety values ranging from 1.22 to 1.57. Additionally, incorporating elements like a 30 m toe drain and a 1 m per day drawdown rate influenced these values, with extremes recorded from 1.337 to 2.21, shedding light on embankment stability under diverse conditions and configurations. When subjected to a 1 m per day drawdown, water flow rates decreased significantly at the upstream face and increased downstream, accompanied by an increase in water mass flux at the upstream face and a decrease at the downstream toe, suggesting dynamic changes in water behavior in response to drawdown. Moreover, the findings unveiled significant correlations between matric suction and time (correlation coefficient of 0.950) and factor of safety and water conductivity (correlation coefficient of 0.750). Conversely, a distinct negative correlation emerged between matric suction and factor of safety (correlation coefficient of −0.864). The study’s distinctive insights contribute to our understanding of seepage behavior and dam stability across varied scenarios, offering valuable input for resilient dam construction approaches that will ensure the longevity and effectiveness of these essential structures. Full article
(This article belongs to the Special Issue Advances in Dam Engineering of the 21st Century)
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23 pages, 8210 KiB  
Article
Assessment of Soil–Structure Interaction Effects on the Beirut Port Silos Due to the 4 August 2020 Explosion: A Coupled Eulerian–Lagrangian Approach
by Ali Jahami, Jana Halawi, Yehya Temsah and Lina Jaber
Infrastructures 2023, 8(10), 147; https://doi.org/10.3390/infrastructures8100147 - 12 Oct 2023
Cited by 2 | Viewed by 2213
Abstract
Blast loadings have become the subject of research in recent decades due to the threats they pose to the surrounding medium. On 4 August 2020, a huge explosion occurred in the Port of Beirut that led to massive damages in the medium surrounding [...] Read more.
Blast loadings have become the subject of research in recent decades due to the threats they pose to the surrounding medium. On 4 August 2020, a huge explosion occurred in the Port of Beirut that led to massive damages in the medium surrounding it. Researchers have conducted studies in order to estimate the equivalent explosive mass as well as the damage extent left on structures; however, the studies considered the soil–structure interaction by simple methods. For that, this paper aims to understand the effect of explosion on the grain silo structure present at the port with an emphasis on the soil–structure interaction effects. The structure consists of a group of silos resting on a raft footing that is supported by group of driven piles. A soil–structure model analysis is performed in order to investigate the soil behavior, the damage extent in piles, and the soil–structure interaction due to the Beirut explosion using the CEL (Coupled Eulerian–Lagrangian) approach that suits events involving large deformation. The analysis is performed using the ABAQUS/Explicit FEM software (version 6.14) taking into account the properties of soil medium, the contact algorithm at the soil–structure interface, and the boundary conditions in order to better simulate the real field conditions and ensure accurate results. The work is primarily validated through site data such as the crater size and silo damage. Full article
(This article belongs to the Topic Advances on Structural Engineering, 2nd Volume)
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19 pages, 3847 KiB  
Article
Data-Driven Prediction of Cement-Stabilized Soils Tensile Properties
by Mario Castaneda-Lopez, Thomas Lenoir, Jean-Pierre Sanfratello and Luc Thorel
Infrastructures 2023, 8(10), 146; https://doi.org/10.3390/infrastructures8100146 - 12 Oct 2023
Viewed by 1826
Abstract
The indirect tensile strength of two geomaterials treated with variable cement contents, degrees of compaction and water contents were tested after several curing times. A statistical review through an analysis of variance allows for identifying the significant variables and generating prediction models. The [...] Read more.
The indirect tensile strength of two geomaterials treated with variable cement contents, degrees of compaction and water contents were tested after several curing times. A statistical review through an analysis of variance allows for identifying the significant variables and generating prediction models. The distribution of associated uncertainties was measured. Based on these probabilistic results, numerical models were constructed using Latin Hypercube Sampling as the space filling technique. Predictions from the numerical sampling were in accordance with the experimental results. The numerical results suggest that the net gain in accuracy was not affected by the soil type. In addition, it increases rapidly as a function of the sampling size. The proposed approach is broad. It can help to highlight the physical mechanisms involved in behaviors of multi-component materials. Full article
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27 pages, 18207 KiB  
Article
Modeling Visit Potential to Predict Hotspots of a Future District
by Younes Delhoum and Rachid Belaroussi
Infrastructures 2023, 8(10), 145; https://doi.org/10.3390/infrastructures8100145 - 11 Oct 2023
Viewed by 1764
Abstract
Understanding frequentation patterns allows urban planners to optimize the allocation of resources and infrastructure development. This includes determining the locations for schools, hospitals, public transportation, parks, and other amenities to efficiently meet the needs of the population. This paper proposes a study of [...] Read more.
Understanding frequentation patterns allows urban planners to optimize the allocation of resources and infrastructure development. This includes determining the locations for schools, hospitals, public transportation, parks, and other amenities to efficiently meet the needs of the population. This paper proposes a study of the Visit Potential Model, an integrated model for evaluating the characteristics of public spaces. It is used to predict the potential potential presence of people in specific locations or public places. The model combines a universal law of visit frequencies in cities with a gravity measurement of accessibility. The adapted Visit Potential Model is represented as a graph by connecting public spaces to other spaces: population objects and attractor objects. Population objects represent places where people go in and out, such as houses, offices, and schools. Attractor objects include destinations that people visit, such as leisure parks and shopping malls. Originally, this static model was defined for a single time-frame by explicitly taking into the account the time component and a dynamic model was derived. A future district under construction was used as a case study: a multimodal transportation model was built to simulate and analyze the motion of people. The reported outcomes can be analyzed to provide us first insights of the potential for visiting the district’s public spaces and define its future hotspots and places of interaction. Full article
(This article belongs to the Section Smart Infrastructures)
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13 pages, 915 KiB  
Article
Life Cycle Assessment of Environmentally Friendly Solutions for the Construction of Unpaved Rural Roads
by Mattia Di Sessa, Pier Paolo Riviera, Lucia Tsantilis, Leonardo Urbano, Orazio Baglieri and Ezio Santagata
Infrastructures 2023, 8(10), 144; https://doi.org/10.3390/infrastructures8100144 - 11 Oct 2023
Viewed by 2242
Abstract
In recent decades, the international community has recognized the detrimental impact of the construction industry on the environment. In recent years, the use of recycled aggregates has attracted increasing interest as a sustainable and cost-effective solution for the construction and maintenance of road [...] Read more.
In recent decades, the international community has recognized the detrimental impact of the construction industry on the environment. In recent years, the use of recycled aggregates has attracted increasing interest as a sustainable and cost-effective solution for the construction and maintenance of road pavements. The life cycle assessment (LCA) represents a valuable methodology for evaluating the environmental sustainability of technologies involving the use of such materials. This study deals with the LCA of alternative solutions for the construction and maintenance of unpaved rural roads. Different scenarios using recycled materials, such as reclaimed asphalt and mineral sludge, are analyzed and compared to a reference solution that employs only virgin aggregates. The environmental sustainability of the proposed alternatives is assessed by considering the global warming potential (GWP), energy requirements, and water consumption. The LCA analysis is performed using SimaPro software (version 9.1.1.7). The obtained results demonstrate that solutions involving the use of recycled materials represent a more sustainable and environmentally friendly option. In particular, a significant reduction in water depletion was found for the alternative scenarios, with savings between 56% and 99%. For GWP and energy, the total savings ranged from approximately 20% to 40%. Full article
(This article belongs to the Special Issue Maintenance and Rehabilitation of Constructed Infrastructure Facilities)
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13 pages, 435 KiB  
Article
Transportation Asset Management Decision Support Tools: Computational Complexity, Transparency, and Realism
by Babatunde Atolagbe and Sue McNeil
Infrastructures 2023, 8(10), 143; https://doi.org/10.3390/infrastructures8100143 - 11 Oct 2023
Viewed by 2016
Abstract
Asset management decision support tools determine which action (maintenance, rehabilitation, or reconstruction) is applied to each facility in a transportation network and when. Sophisticated tools recognize uncertainties and consider emerging priorities. However, these tools are often computationally complex and lack transparency, the models [...] Read more.
Asset management decision support tools determine which action (maintenance, rehabilitation, or reconstruction) is applied to each facility in a transportation network and when. Sophisticated tools recognize uncertainties and consider emerging priorities. However, these tools are often computationally complex and lack transparency, the models are difficult to evaluate, and the outputs are challenging to validate. This paper explores computational complexity, transparency, and realism in transportation asset management decision support tools to better understand how to select the right tools for a particular context. Descriptions of how state departments of transportation in the United States make use of optimization in their mandated transportation asset management plans to make decisions are used to understand the needs of states. This qualitative analysis serves as a review of the goals and practices of state agencies. An existing asset management tool is then used to demonstrate the tradeoffs involved in accurately capturing the decision-making process and complexity. The results provide examples of strategies that agencies can use when selecting decision support tools and for researchers and tool developers working toward developing the right tool for an application. Full article
(This article belongs to the Special Issue Maintenance and Rehabilitation of Constructed Infrastructure Facilities)
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16 pages, 1528 KiB  
Article
Evolution of the Road Network Topology of Central European Housing Estates
by Pál Hegyi, Attila Borsos and Csaba Koren
Infrastructures 2023, 8(10), 142; https://doi.org/10.3390/infrastructures8100142 - 5 Oct 2023
Viewed by 1780
Abstract
The analysis of road network topology has attracted the attention of researchers in the past few decades. In this study, the road topology of housing estates in a few selected Central European countries (Hungary, Austria, Czech Republic, and Slovakia) was analysed. This research [...] Read more.
The analysis of road network topology has attracted the attention of researchers in the past few decades. In this study, the road topology of housing estates in a few selected Central European countries (Hungary, Austria, Czech Republic, and Slovakia) was analysed. This research was carried out in three steps: (1) the road network topology of different decades from the 1950s to the 1980s was described, (2) the ratio of intersections and dead-ends was investigated, and (3) the connectivity indices were analysed and compared. The research was carried out using ESRI ArcGIS software. The results show that the design of road networks built in different countries is similar in the housing estates studied. When analysing the road networks over time, significant differences could be found in the case of Hungary for housing estates built after the 1960s. In general, connectivity has become more important, as it has gradually increased over time. Full article
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13 pages, 505 KiB  
Review
The Potential Role of Railway Stations and Public Transport Nodes in the Development of “15-Minute Cities”
by Michał Wolański
Infrastructures 2023, 8(10), 141; https://doi.org/10.3390/infrastructures8100141 - 5 Oct 2023
Cited by 5 | Viewed by 3205
Abstract
In 2016, Carlos Moreno proposed the concept of “15-minute cities” based on the principles of proximity, diversity, density, and ubiquity. In fact, he re-formulated (“re-invented”) some of the already existing planning principles, making them recognized and desired by non-professionals. Moreno, however, paid little [...] Read more.
In 2016, Carlos Moreno proposed the concept of “15-minute cities” based on the principles of proximity, diversity, density, and ubiquity. In fact, he re-formulated (“re-invented”) some of the already existing planning principles, making them recognized and desired by non-professionals. Moreno, however, paid little attention to the external connectivity of neighborhoods, assuming that most needs would be satisfied locally. This paper aims to discuss the concept of “15-minute cities” from the transport planning point of view and investigate how the concept can contribute to such planning. The research review conducted in this paper suggests that similar actions in the past caused a modal shift from the use of cars to public transport, rather than a radical limitation of total transport needs. To simplify, if a neighborhood is well designed, people are more likely to walk, ride a bike, and use public transport, but the majority will still commute outside of the neighborhood for work. In the metropolis of the ideal “15-minute city”, Barcelona, the majority of the inhabitants travel to work either by car or public transport, which proves that they need to move outside the neighborhood. This leads us to the conclusions that (1) “15-minute cities” should incorporate the transit-oriented development concept and include public transport nodes, such as railways or underground stations, as the central point of walkable, multifunctional neighborhoods, and (2) railway/underground station planners should pay more attention to the creation of a proper mix of services at and around the stations according to “15-minute cities” principles. In the future, there should also be more emphasis on re-allocating workplaces to neighborhoods, as well as on researching the actual impact of the (improved and current) “15-minute cities” design on transport volumes. Full article
(This article belongs to the Special Issue Railway in the City (RiC))
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16 pages, 1744 KiB  
Review
Utilizing Industrial By-Products for Sustainable Three-Dimensional-Printed Infrastructure Applications: A Comprehensive Review
by Eka Oktavia Kurniati and Hee-Jeong Kim
Infrastructures 2023, 8(10), 140; https://doi.org/10.3390/infrastructures8100140 - 4 Oct 2023
Cited by 4 | Viewed by 2705
Abstract
Industrial secondary products (e.g., fly ash, blast furnace slag, and silica fume) have found extensive application as alternative construction materials in conventional manufacturing methods to reduce carbon emissions due to cement usage and solve the waste management problem. To date, additive manufacturing or [...] Read more.
Industrial secondary products (e.g., fly ash, blast furnace slag, and silica fume) have found extensive application as alternative construction materials in conventional manufacturing methods to reduce carbon emissions due to cement usage and solve the waste management problem. To date, additive manufacturing or 3D printing has been massively developed for every material, including cement-based materials. Some possibilities have arisen to incorporate industrial wastes in cement mixtures in 3D printing applications. However, a comprehensive study about fly ash (FA), ground granulated blast-furnace slag (GGBFS), and silica fume (SF) usage in 3D-printed materials needs to be conducted. This paper shows that some aspects of 3D printing, such as printability, buildability, and rheological properties, need to be considered, and waste materials affect these fresh mixture properties. Applying waste materials as supplementary cementitious materials also gives different mechanical properties and durability performances. Furthermore, the environmental and economic benefits of 3D-printed and conventional materials are compared. The results show that 3D printing methods can enhance the environmental and economic benefits while maintaining the performance of materials created using traditional methods. Studying industrial waste application in 3D printing has become a promising way to develop sustainable materials in this digitalization era. Full article
(This article belongs to the Special Issue Selected Papers from the 5th International Conference on Transportation Infrastructures Conference)
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20 pages, 5763 KiB  
Article
Investigating the Calcination Temperature and Grinding Time of Calcined Clay on the Mechanical Properties and Durability of LC3 Concrete
by Sina Nasiri, Rahmat Madandoust and Malek Mohammad Ranjbar
Infrastructures 2023, 8(10), 139; https://doi.org/10.3390/infrastructures8100139 - 2 Oct 2023
Cited by 2 | Viewed by 3026
Abstract
The impact of the calcination temperature and grinding time on the mechanical properties and durability of limestone-calcined clay concrete (LC3) is crucial. In this research, calcined clay was produced within the temperature range of 700 °C to 900 °C, and the grinding time [...] Read more.
The impact of the calcination temperature and grinding time on the mechanical properties and durability of limestone-calcined clay concrete (LC3) is crucial. In this research, calcined clay was produced within the temperature range of 700 °C to 900 °C, and the grinding time varied from 15 to 120 min. This study examines compressive strength and chloride penetration resistance using the rapid chloride migration test on LC3 concrete over a period of 180 days. The findings reveal that clay calcined at 800 °C for 120 min exhibited the highest specific surface area compared to other calcined clays. Furthermore, the compressive strength of LC3 concrete incorporating clay calcined at 800 °C for 60 min surpassed that of other mixtures investigated. Additionally, the chloride diffusion coefficient of LC3 concrete with calcined clay prepared at 800 °C for 120 min was lower than other mixtures. Full article
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15 pages, 3147 KiB  
Article
Numerical Investigation of the Effect of Longitudinal Fiberglass Dowels on Tunnel Face Support in Layered Soils
by Morteza Esmaeili, Jafar Hosseini Manoujan, Jafar Chalabii, Farshad Astaraki and Majid Movahedi Rad
Infrastructures 2023, 8(10), 138; https://doi.org/10.3390/infrastructures8100138 - 24 Sep 2023
Cited by 1 | Viewed by 1957
Abstract
Tunnel face extrusion rigidity is an important factor for solving stress–strain problems in loose ground conditions. In previous studies, the effect of horizontal and vertical soil layering on tunnel excavation face stability in the presence of longitudinal fiberglass dowels has not been studied. [...] Read more.
Tunnel face extrusion rigidity is an important factor for solving stress–strain problems in loose ground conditions. In previous studies, the effect of horizontal and vertical soil layering on tunnel excavation face stability in the presence of longitudinal fiberglass dowels has not been studied. Therefore, in this study, the effect of fiberglass dowels on the stability of the tunnel face in layered soil has been investigated. In this matter, the best dowel arrangement for minimizing the excavation face extrusion in the case of two-layer soil (horizontal or vertical) has been focused on. For this purpose, firstly, a 3D numerical model was validated based on field data provided previously, and then a 3D numerical tunnel was developed in FLAC3D, adopting the Mohr–Coulomb failure criterion. In continuation, the effect of tunnel diameter, initial pressure ranging from 0.5 to 1.5 MPa, and different placement angles of fiberglass dowels ranging from 0 to 9 degrees, with respect to the tunnel longitudinal axes on the tunnel face extrusion, have been investigated. In the case of horizontal layering, the results showed that the maximum extrusion rate is significantly increased where the elasticity modulus of the soil is reduced. In addition, comparing the maximum extrusion in vertical and horizontal layering, it was found that its value in the horizontal mode is much higher than in the vertical. Additionally, the extrusion of the tunnel face has changed significantly due to an alteration in the initial stress. Finally, it was discovered that tunnel face extrusion is not significantly affected by altering the angle of the fiberglass dowels. Full article
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14 pages, 2498 KiB  
Article
Relationships between Mortar Spread and the Fresh Properties of SCC Containing Local Metakaolin
by Abderrazak Barkat, Said Kenai, Belkasem Menadi, El-Hadj Kadri and Jamal Khatib
Infrastructures 2023, 8(10), 137; https://doi.org/10.3390/infrastructures8100137 - 23 Sep 2023
Cited by 2 | Viewed by 1879
Abstract
Self-compacting concrete (SCC) production is a complex operation that requires finding a good combination and suitable dosages for its constituents. Several formulation methods have been developed to meet the workability requirements of SCC. Mortar spread is used to estimate SCC’s rheological properties, but [...] Read more.
Self-compacting concrete (SCC) production is a complex operation that requires finding a good combination and suitable dosages for its constituents. Several formulation methods have been developed to meet the workability requirements of SCC. Mortar spread is used to estimate SCC’s rheological properties, but the use of supplementary cementitious materials, such as metakaolin, could affect the accuracy of the estimation. In this paper, the relationships between the fresh properties of local-metakaolin (MK)-based SCC and the spreading of its mortar portion were investigated. The results showed the existence of good correlations between the spreading of mortar portion of SCC and its fresh state properties. The partial substitution of cement with MK did not affect these correlations. The mortar flow should be chosen according to the required rheological properties of the SCC. This can be achieved by using an appropriate viscosity-enhancing agent (VEA). Full article
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