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13 pages, 16512 KiB

Open AccessFeature PaperArticle

The Effect of Stress Level on the Resilient Modulus of Non-Engineered Mudrock Backfill Materials

by Shaymaa Kennedy, Sam Clarke and Paul Shepley

CivilEng 2022, 3(3), 630-642; https://doi.org/10.3390/civileng3030037 - 20 Jul 2022

Cited by 2 | Viewed by 2011

Abstract

In the UK, High Speed Rail 2, (London to the ‘North’) is surrounded by a number of questions regarding construction technologies which can minimise the impact of the route. The rail industry in the UK has vast experience based with ballasted track, but [...] Read more.

In the UK, High Speed Rail 2, (London to the ‘North’) is surrounded by a number of questions regarding construction technologies which can minimise the impact of the route. The rail industry in the UK has vast experience based with ballasted track, but this is not necessarily the most appropriate choice for new high speed rail construction when crossing problematic soils. This paper aims to investigate the use of different track types (ballasted and ballastless) and the influence they will have on the underlying soil in areas predominated by non-engineered mudrock backfills, relics of the UK’s mining heritage. Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. Structural performance of the railway track strongly depends on the level of stress that is transmitted to the ground and this must be reduced to an acceptable level to minimise deterioration in the mudrock if they are to be utilised effectively. The main objective for this paper is to investigate the impact of the initial stress conditions and dynamic stress on the permanent deformation of mudrock under different physical conditions. Triaxial testing is used to estimate the stiffness characteristics of the mudrock. The results show that the resilient modulus increases with a decrease in the stress amplitude. In addition, ballasted track shows a higher suitability for use in design in terms of the stiffness generated within the mudrock. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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20 pages, 10287 KiB

Open AccessArticle

Cross-Laminated Timber: A Survey on Design Methods and Concepts in Practice

by Martin Schenk, Clara Hübner and José Manuel Cabrero

CivilEng 2022, 3(3), 610-629; https://doi.org/10.3390/civileng3030036 - 6 Jul 2022

Cited by 9 | Viewed by 4491

Abstract

Cross laminated timber (CLT) is becoming increasingly popular in timber construction due to its versatility. However, its structural anistropy requires the application of particular concepts and design methods. The article on hand presents the results of a worldwide survey conducted among engineers working [...] Read more.

Cross laminated timber (CLT) is becoming increasingly popular in timber construction due to its versatility. However, its structural anistropy requires the application of particular concepts and design methods. The article on hand presents the results of a worldwide survey conducted among engineers working with this product. Thus, it presents the current state of knowledge and practice on CLT construction: an overview of the experience of engineers working with CLT design, the commonly used verification methods, and the implementation of the material properties and different required assumptions in the software. An outlook to design problems in complex design situations relevant for multi-storey buildings and potential research fields is indicated additionally. The general picture is quite heterogeneous, with little consensus on the assumptions, design methods or applied tools. A wide repertoire of different approaches based on a large range of literature is found in practice. This is in part the result of the current lack of standardisation and currently incomplete regulations. Future efforts should focus on these two aspects to increase the applicability of CLT globally and strengthen its competitiveness. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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16 pages, 6685 KiB

Open AccessArticle

WMA Overlay Optimization Based on the LTPP Database: Using the RSM Method

by Morteza Rezaeizadeh Herozi, Ali Rigabadi, Alireza Rezagholilou and Amin Chegenizadeh

CivilEng 2022, 3(3), 594-609; https://doi.org/10.3390/civileng3030035 - 1 Jul 2022

Viewed by 2021

Abstract

This study investigates the field performance of Warm Mix Asphalt (WMA) road overlays containing various amounts of RAP and binder. Rutting, the International Roughness Index (IRI), and transverse, longitudinal and alligator cracking are the key parameters considered here. Our research is based on [...] Read more.

This study investigates the field performance of Warm Mix Asphalt (WMA) road overlays containing various amounts of RAP and binder. Rutting, the International Roughness Index (IRI), and transverse, longitudinal and alligator cracking are the key parameters considered here. Our research is based on a Specific Pavement Study-10 experiment (SPS-10) conducted in nine states of North America (eight in the USA and one in Canada) that included 31 road sections in dry and wet regions. Road overlays were evaluated 1 and 4 years after their placement in terms of anti-cracking behavior and were compared with the pre-treatment status of the road. The best rutting resistance occurred at 15% and 12% RAP in dry and wet regions, respectively. For IRI, 30% and 0.0% RAP were the best for dry and wet regions as well. The maximum longitudinal crack recovery rates were found at site 3 (BA01, Arizona; dry region) and site 26 (AA65, Missouri; wet region), with RAP contents of 20% and 36%, respectively. In addition, alligator cracking did not occur post-overlay, so optimal RAP and binder contents cannot be suggested. The greatest improvements were found at site 15 (AA01, Washington state; dry) and site 30 (AA63, Oklahoma; wet). The response surface method (RSM) was also developed to explore the optimal models for RAP and selection of binder contents to minimize the rutting, IRI, and transverse and longitudinal crack lengths. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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15 pages, 2971 KiB

Open AccessArticle

Keeping Our Heads above Water: An Exploratory Study on the Equity Opportunities of Coastal Virginia Wireless Emergency Alerts

by Wendell Grinton and Frederick Paige

CivilEng 2022, 3(2), 385-399; https://doi.org/10.3390/civileng3020023 - 8 May 2022

Cited by 1 | Viewed by 3041

Abstract

Economically disadvantaged coastal communities face severe damage and casualties, which can be attributed to storm surges. Excessive amounts of inundation should be considered to a similar level to wind speeds and heavy rains that communities commonly prepare for amidst a hurricane event. Marginalized [...] Read more.

Economically disadvantaged coastal communities face severe damage and casualties, which can be attributed to storm surges. Excessive amounts of inundation should be considered to a similar level to wind speeds and heavy rains that communities commonly prepare for amidst a hurricane event. Marginalized residents, such as residents of color, disabled residents, elderly residents, and residents occupying low-income housing, suffer from storm surge events. Coastal resiliency plans are bottlenecked by factors, such as residential stability, ability to relocate, and insurance coverage, all of which are inequitably constrained for marginalized communities. This exploratory study reviews the previous literature on wireless emergency alert (WEA) equity critiques and spatial analysis of the WEAs sent to coastal Virginia communities. Two research questions are explored in this paper: (1) How does the previous literature critique equity in wireless emergency alerts? (2) How many households are below the poverty line in areas where storm surge warnings have been sent? To improve the utilization of WEAs for the protection of low-income community members, there is evidence to support the increase in the frequency of message delivery and improving the call-to-action text. This paper sets the stage for future policy analyses and message design experimentation on emergency communication in coastal regions. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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20 pages, 5273 KiB

Open AccessArticle

Modeling of Progressive Scouring of a Pier-on-Bank

by Vidya Subhash Chavan, Shen-En Chen, Navanit Sri Shanmugam, Wenwu Tang, John Diemer, Craig Allan, Nicole Braxtan, Tarini Shukla, Tianyang Chen and Zachery Slocum

CivilEng 2022, 3(2), 365-384; https://doi.org/10.3390/civileng3020022 - 22 Apr 2022

Viewed by 2977

Abstract

Scour, caused by swiftly moving water, can remove alluvial sediment and soil, creating holes surrounding a bridge component and compromising the integrity of the bridge structure. Such problems can be equally critical for bridges with piers-on-bank bridges subjected to severe storm and flooding [...] Read more.

Scour, caused by swiftly moving water, can remove alluvial sediment and soil, creating holes surrounding a bridge component and compromising the integrity of the bridge structure. Such problems can be equally critical for bridges with piers-on-bank bridges subjected to severe storm and flooding issues. In this paper, the Phillips Road Bridge over Toby Creek (35°18′28.2″ N 80°44′16.6″ W, Charlotte, NC, USA), a pier-on-bank bridge with critical/significant local scour holes and deep riverbank erosion cuts was selected as case study bridge. To investigate the scour effect on the bridge with pier-on-bank performance, the scoured area around a single pier is first quantified using a terrestrial laser and then modeled using nonlinear finite element (FE) analysis, where the local scour is modeled as progressive mass losses using the Element Removal (ER) technique. The FE results are compared to the design loading scenario and the results substantiated that the local scouring could cause large deflection and increased bending moment on the bridge pier. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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18 pages, 8125 KiB

Open AccessArticle

New Models for the Properties of Warm Mix Asphalt with Sasobit

by Morteza Rezaeizadeh Herozi, Wilfredo Valenzuela, Alireza Rezagholilou, Ali Rigabadi and Hamid Nikraz

CivilEng 2022, 3(2), 347-364; https://doi.org/10.3390/civileng3020021 - 12 Apr 2022

Cited by 8 | Viewed by 2860

Abstract

Warm Mix Asphalt (WMA) is a set of technologies that uses additives to reduce binder viscosity and increase mixture workability, which provides a complete coating of aggregates at lower temperatures around 100 °C to 130 °C. Organic wax or Sasobit is one of [...] Read more.

Warm Mix Asphalt (WMA) is a set of technologies that uses additives to reduce binder viscosity and increase mixture workability, which provides a complete coating of aggregates at lower temperatures around 100 °C to 130 °C. Organic wax or Sasobit is one of the additives that can be used for this purpose. It reduces the viscosity at the melting point of the wax, which allows the production of asphalt mixes at lower temperatures. This attempt proposes new relationships for elastic modulus, indirect tensile strength (in dry and wet conditions), dynamic modulus, fatigue, and rutting resistance of WMA asphalt samples with various Sasobit percentages. Findings show that Sasobit improves modulus of elasticity, dynamic modulus, and rutting resistance. However, it lessens the tensile strength slightly. Although Sasobit enhances the flexural stiffness, it drops the number of loading cycles, which means lower fatigue resistance. Results also showed that at 20 °C and 10 Hz frequency, the resilient modulus, dynamic modulus, and flexural stiffness of WMA improved 53%, 27%, and 39%, respectively, compared with HMA. Rutting resistance at 60 °C improves 226% in WMA with 6% Sasobit compared to the HMA mix. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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14 pages, 4927 KiB

Open AccessArticle

Eggshell and Walnut Shell in Unburnt Clay Blocks

by Nusrat Jannat, Rafal Latif Al-Mufti and Aseel Hussien

CivilEng 2022, 3(2), 263-276; https://doi.org/10.3390/civileng3020016 - 1 Apr 2022

Cited by 7 | Viewed by 3923

Abstract

Agricultural residues/by-products have become a popular choice for the manufacturing of building materials due to their cost-effectiveness and environmental friendliness, making them a viable option for achieving sustainability in the construction sector. This study addresses the utilisation of two agro-wastes, i.e., eggshell and [...] Read more.

Agricultural residues/by-products have become a popular choice for the manufacturing of building materials due to their cost-effectiveness and environmental friendliness, making them a viable option for achieving sustainability in the construction sector. This study addresses the utilisation of two agro-wastes, i.e., eggshell and walnut shell, in the manufacture of unburnt clay blocks. The experiments were carried out on three series of samples in which first eggshell (10–50%) and walnut shell (5–20%) were incorporated individually and then combined (5% walnut, 10–30% eggshell) in the mixture to assess their influences on the physical and mechanical properties of the unburnt clay blocks. This study performed the following tests: Density, capillary water absorption, linear shrinkage, flexural and compressive strength. The results indicated that eggshell enhanced the strength relative to the control sample when the materials were employed individually, but walnut shell lowered it. Moreover, combining the two materials in the mixer reduced the strength of the samples even further. Nevertheless, the inclusion of the waste materials decreased the density, capillary water absorption coefficient and linear shrinkage of the samples. The findings indicate that eggshell has great potential for unburnt clay block manufacture. However, walnut shell integration needs further research. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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18 pages, 14761 KiB

Open AccessArticle

Recycling of Excavated Soils from Mini-Trenches Made on Road or Sidewalks to Install Public Utilities

by Ali Hussan, Daniel Levacher, Salim Mezazigh, Ilona Nzabika and Philippe Dhervilly

CivilEng 2022, 3(2), 224-241; https://doi.org/10.3390/civileng3020014 - 25 Mar 2022

Viewed by 3079

Abstract

Digging trenches on roads, sidewalks, or banks to accommodate public demands is required for the installation of water pipelines, natural gas lines, electric cables, and optical fibers. The soils extracted from these trenches always have substantial environmental and economic consequences, as these soils [...] Read more.

Digging trenches on roads, sidewalks, or banks to accommodate public demands is required for the installation of water pipelines, natural gas lines, electric cables, and optical fibers. The soils extracted from these trenches always have substantial environmental and economic consequences, as these soils are frequently regarded as waste due to their poor engineering properties. As a result, a suitable location and method for disposing these excavated soils must be found, and this procedure is exceedingly costly, time consuming, and environmentally unfriendly. It is far more efficient to reuse these excavated soils for refilling the same trenches. This study is a part of a French national project. The national project aims to dig 5 to 25 cm wide trenches to install public utilities and to refill them using the same excavated material in the form of self-compacting mortar. The goal of this research is to determine the best ecofriendly binder for the soil excavated from various sites by conducting laboratory-scale physio-chemical and mechanical testing. This study examined the unconfined compressive strength (UCS) assessed by both destructive and non-destructive (ultrasonic) testing methods. By utilizing low CO₂-emitting ecofriendly binders incorporating industrial byproducts (fly ash and GGBS), this work has broadened the possibility of reusing trench cuttings to refill the same trenches. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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27 pages, 4044 KiB

Open AccessArticle

Degradation of Cycle Paths—A Survey in Swedish Municipalities

by Martin Larsson, Anna Niska and Sigurdur Erlingsson

CivilEng 2022, 3(2), 184-210; https://doi.org/10.3390/civileng3020012 - 23 Mar 2022

Cited by 2 | Viewed by 3064

Abstract

There is a need to move society in a sustainable direction. One way to contribute to this move is to change to more sustainable transport modes, such as cycling. To increase cycling, the infrastructure is important, and good quality cycle paths are needed. [...] Read more.

There is a need to move society in a sustainable direction. One way to contribute to this move is to change to more sustainable transport modes, such as cycling. To increase cycling, the infrastructure is important, and good quality cycle paths are needed. However, little is known about the degradation of cycle paths. This paper aims to investigate what modes of pavement distress are found on municipal cycle paths in Sweden, and what probable mechanisms lie behind such distress; these are determined based on questions from a state-of-practice survey, interviews, and a literature review. The main findings are that the most commonly stated distress modes are surface unevenness followed by longitudinal cracks, and the most commonly stated causes of distress are ageing, followed by structural interventions, and roots and vegetation. The results also show that for several distress modes, there are probable connections with climatic factors such as temperature and moisture, as well as with the population size of the urban areas. Objective data are needed regarding traffic load and the climatic factors that affect cycle paths, along with information on their structural design, to better understand their degradation. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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19 pages, 3499 KiB

Open AccessArticle

Experimental Study on the Minimum Required Specimen Width to Maximum Particle Size Ratio in Direct Shear Tests

by Akram Deiminiat, Li Li and Feitao Zeng

CivilEng 2022, 3(1), 66-84; https://doi.org/10.3390/civileng3010005 - 21 Jan 2022

Cited by 7 | Viewed by 5119

Abstract

Conducting laboratory direct shear tests on granular materials is a common practice in geotechnical engineering. This is usually done by following the ASTM D3080/D3080M-11 (hereafter named ASTM), which stipulates a minimum required value of 10 for specimen width (W) to the [...] Read more.

Conducting laboratory direct shear tests on granular materials is a common practice in geotechnical engineering. This is usually done by following the ASTM D3080/D3080M-11 (hereafter named ASTM), which stipulates a minimum required value of 10 for specimen width (W) to the maximum particle size (d_max) ratio. Recently, a literature review performed by the authors showed that the minimum required W/d_max ratio given in the ASTM is not large enough to eliminate the specimen size effect (SSE). The minimum required W/d_max ratio of ASTM needs to be revised. In this study, a critical analysis is first made on existing data in order to identify the minimum required W/d_max ratio. The analysis shows that more experimental data obtained on specimens having W/d_max ratios between 10 and 50 are particularly necessary. To complete this need, a series of direct shear tests were performed on specimens having different d_max by using three shear boxes of different dimensions. The results show once again that the minimum required W/d_max ratio of 10, defined in the ASTM, is not large enough to eliminate the SSE. Further analysis on these and existing experimental results indicates that the minimum required W/d_max ratio to remove the SSE of friction angles is about 60. These results along with the limitations of this study are discussed. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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16 pages, 1889 KiB

Open AccessArticle

Experimental Study on the Reliability of Scaling Down Techniques Used in Direct Shear Tests to Determine the Shear Strength of Rockfill and Waste Rocks

by Akram Deiminiat and Li Li

CivilEng 2022, 3(1), 35-50; https://doi.org/10.3390/civileng3010003 - 8 Jan 2022

Cited by 7 | Viewed by 3370

Abstract

The determination of shear strength parameters for coarse granular materials such as rockfill and waste rocks is challenging due to their oversized particles and the minimum required ratio of 10 between the specimen width (W) and the maximum particle size ( [...] Read more.

The determination of shear strength parameters for coarse granular materials such as rockfill and waste rocks is challenging due to their oversized particles and the minimum required ratio of 10 between the specimen width (W) and the maximum particle size (d_max) of tested samples for direct shear tests. To overcome this problem, a common practice is to prepare test samples by excluding the oversized particles. This method is called the scalping scaling down technique. Making further modifications on scalped samples to achieve a specific particle size distribution curve (PSDC) leads to other scaling down techniques. Until now, the parallel scaling down technique has been the most popular and most commonly applied, generally because it produces a PSDC parallel and similar to that of field material. Recently, a critical literature review performed by the authors revealed that the methodology used by previous researchers to validate or invalidate the scaling down techniques in estimating the shear strength of field materials is inappropriate. The validity of scaling down techniques remains unknown. In addition, the minimum required W/d_max ratio of 10, stipulated in ASTM D3080/D3080M-11 for direct shear tests, is not large enough to eliminate the specimen size effect (SSE). The authors’ recent experimental study showed that a minimum W/d_max ratio of 60 is necessary to avoid any SSE in direct shear tests. In this study, a series of direct shear tests were performed on samples with different d_max values, prepared by applying scalping and parallel scaling down techniques. All tested specimens had a W/d_max ratio equal to or larger than 60. The test results of the scaled down samples with d_max values smaller than those of field samples were used to establish a predictive equation between the effective internal friction angle (hereafter named “friction angle”) and d_max, which was then used to predict the friction angles of the field samples. Comparisons between the measured and predicted friction angles of field samples demonstrated that the equations based on scalping scaling down technique correctly predicted the friction angles of field samples, whereas the equations based on parallel scaling down technique failed to correctly predict the friction angles of field samples. The scalping down technique has been validated, whereas the parallel scaling down technique has been invalidated by the experimental results presented in this study. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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20 pages, 5361 KiB

Open AccessArticle

An Analysis of Local and Combined (Global) Scours on Piers-on-Bank Bridges

by Vidya Subhash Chavan, Shen-En Chen, Navanit Sri Shanmugam, Wenwu Tang, John Diemer, Craig Allan, Nicole Braxtan, Tarini Shukla, Tianyang Chen and Zachery Slocum

CivilEng 2022, 3(1), 1-20; https://doi.org/10.3390/civileng3010001 - 21 Dec 2021

Cited by 4 | Viewed by 3814

Abstract

This paper examines the scour problems related to piers-on-bank bridges resulting from frequently flooded and/or constricted waterways. While local scour problems for bridge piers in riverine channels have been addressed extensively in the literature, there have been few studies addressing piers-on-bank scour scenarios. [...] Read more.

This paper examines the scour problems related to piers-on-bank bridges resulting from frequently flooded and/or constricted waterways. While local scour problems for bridge piers in riverine channels have been addressed extensively in the literature, there have been few studies addressing piers-on-bank scour scenarios. A comprehensive three-dimensional finite element analysis using the element removal (ER) technique has been performed on a recently constructed bridge with an observable scour problem on multiple piers. The analysis is further extended to study the effect of “combined scour” or extensive erosion of soil between adjacent piles. Three different loading cases were considered in the study, and the results demonstrated that the effects of local and combined scours on bridge drilled shaft foundations can be significant under the combined actions of axial, lateral loads and bending moments. Specifically, the most critical case of combined scour is when maximum moment effect is applied to the piers. The results of this study show that the interaction of soil displacement fields between adjacent piles should be investigated for bridge crossings with piers-on-bank, with a high risk of flooding during the moderate-to-low probability of the occurrence of precipitation events, as they can increase the pile head displacements and the bending moments in the soil and result in the early failure of bridges. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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26 pages, 14794 KiB

Open AccessArticle

Assessing the Capability of Computational Fluid Dynamics Models in Replicating Wind Tunnel Test Results for the Rose Fitzgerald Kennedy Bridge

by Yuxiang Zhang, Philip Cardiff, Fergal Cahill and Jennifer Keenahan

CivilEng 2021, 2(4), 1065-1090; https://doi.org/10.3390/civileng2040057 - 19 Dec 2021

Cited by 6 | Viewed by 3669

Abstract

Despite its wide acceptance in various industries, CFD is considered a secondary option to wind tunnel tests in bridge engineering due to a lack of confidence. To increase confidence and to advance the quality of simulations in bridge aerodynamic studies, this study performed [...] Read more.

Despite its wide acceptance in various industries, CFD is considered a secondary option to wind tunnel tests in bridge engineering due to a lack of confidence. To increase confidence and to advance the quality of simulations in bridge aerodynamic studies, this study performed three-dimensional RANS simulations and DESs to assess the bridge deck aerodynamics of the Rose Fitzgerald Kennedy Bridge and demonstrated detailed procedures of the verification and validation of the applied CFD model. The CFD simulations were developed in OpenFOAM, the results of which are compared to prior wind tunnel test results, where general agreements were achieved though differences were also found and analyzed. The CFD model was also applied to study the effect of fascia beams and handrails on the bridge deck aerodynamics, which were neglected in most research to-date. These secondary structures were found to increase drag coefficients and reduce lift and moment coefficients by up to 32%, 94.3%, and 52.2%, respectively, which emphasized the necessity of including these structures in evaluations of the aerodynamic performance of bridges in service. Details of the verification and validation in this study illustrate that CFD simulations can determine close results compared to wind tunnel tests. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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13 pages, 4213 KiB

Open AccessArticle

Automatic Assessment of Buildings Location Fitness for Solar Panels Installation Using Drones and Neural Network

by Ammar Alzarrad, Chance Emanuels, Mohammad Imtiaz and Haseeb Akbar

CivilEng 2021, 2(4), 1052-1064; https://doi.org/10.3390/civileng2040056 - 18 Dec 2021

Cited by 1 | Viewed by 2599

Abstract

Solar panel location assessment is usually a time-consuming manual process, and many criteria should be taken into consideration before deciding. One of the most significant criteria is the building location and surrounding environment. This research project aims to propose a model to automatically [...] Read more.

Solar panel location assessment is usually a time-consuming manual process, and many criteria should be taken into consideration before deciding. One of the most significant criteria is the building location and surrounding environment. This research project aims to propose a model to automatically identify potential roof spaces for solar panels using drones and convolutional neural networks (CNN). Convolutional neural networks (CNNs) are used to identify buildings’ roofs from drone imagery. Transfer learning on the CNN is used to classify roofs of buildings into two categories of shaded and unshaded. The CNN is trained and tested on separate imagery databases to improve classification accuracy. Results of the current project demonstrate successful segmentation of buildings and identification of shaded roofs. The model presented in this paper can be used to prioritize the buildings based on the likelihood of getting benefits from switching to solar energy. To illustrate an implementation of the presented model, it has been applied to a selected neighborhood in the city of Hurricane in West Virginia. The research results show that the proposed model can assist investors in the energy and building sectors to make better and more informed decisions. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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33 pages, 5782 KiB

Open AccessArticle

Controlling Switchable Electrochromic Glazing for Energy Savings, Visual Comfort and Thermal Comfort: A Model Predictive Control

by Abolfazl Ganji Kheybari, Tim Steiner, Steven Liu and Sabine Hoffmann

CivilEng 2021, 2(4), 1019-1051; https://doi.org/10.3390/civileng2040055 - 7 Dec 2021

Cited by 15 | Viewed by 3670

Abstract

Dynamic façades play an important role in enhancing the overall performance of buildings: they respond to the environmental conditions and adjust the amount of transmitted solar radiation. This paper proposes a simulation-based framework to evaluate the energy and comfort performance of different control [...] Read more.

Dynamic façades play an important role in enhancing the overall performance of buildings: they respond to the environmental conditions and adjust the amount of transmitted solar radiation. This paper proposes a simulation-based framework to evaluate the energy and comfort performance of different control strategies for switchable electrochromic glazing (EC). The presented method shows the impact of a model predictive control (MPC) on energy savings and on visual and thermal comfort for different orientations compared to other strategies. Besides manual operation and conventional rule-based controls, the benchmark in this study was a simulation-based control (multi-objective penalty-based control) with optimal performance. The hourly results of various control cases were analyzed based on the established performance indicators and criteria. The cumulative annual results show the capabilities and limitations of each control strategy for an EC glazing. For a temperate climate (Mannheim, Germany), results showed that an MPC for EC glazing provides visual and thermal comfort while saving energy of up to 14%, 37%, 37%, and 34% respectively for facing north, east, south, and west relative to the base-case. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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10 pages, 2404 KiB

Open AccessArticle

A Comparative Study on the Effect of Class C and Class F Fly Ashes on Geotechnical Properties of High-Plasticity Clay

by Salar Shirkhanloo, Mohammad Najafi, Vinayak Kaushal and Mehrdad Rajabi

CivilEng 2021, 2(4), 1009-1018; https://doi.org/10.3390/civileng2040054 - 3 Dec 2021

Cited by 18 | Viewed by 5929

Abstract

Clays generally have a low strength and capacity, and additives are usually used to stabilize them. In recent years, using fly ash to stabilize soil has decreased environmental pollution while also having an economic benefit. The objective of this study is to perform [...] Read more.

Clays generally have a low strength and capacity, and additives are usually used to stabilize them. In recent years, using fly ash to stabilize soil has decreased environmental pollution while also having an economic benefit. The objective of this study is to perform a comparative investigation on the effect of class C and class F fly ashes on geotechnical properties of high-plasticity clay using the Atterberg’s limit, compaction, California Bearing Ratio (CBR), and unconfined compressive strength tests. The results showed that with an increase in the amount of fly ash, there was a decrease in the maximum dry density and an increase in the optimum moisture content. Moreover, an addition of fly ashes of up to 25% caused a reduction of the liquid limit and plasticity index, and an increase in the maximum unconfined compressive strength and CBR. Lengthening the curing time had a positive impact on the unconfined compressive strength of the soil. The soil samples with class C fly ash were seen to possess more efficient geotechnical properties as compared to class F fly ash. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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23 pages, 3231 KiB

Open AccessArticle

Knowledge Discovery by Analyzing the State of the Art of Data-Driven Fault Detection and Diagnostics of Building HVAC

by Arash Hosseini Gourabpasi and Mazdak Nik-Bakht

CivilEng 2021, 2(4), 986-1008; https://doi.org/10.3390/civileng2040053 - 10 Nov 2021

Cited by 16 | Viewed by 4271

Abstract

The automated fault detection and diagnostics (AFDD) of heating, ventilation, and air conditioning (HVAC) using data mining and machine learning models have recently received substantial attention from researchers and practitioners. Various models have been developed over the years for AFDD of complete HVAC [...] Read more.

The automated fault detection and diagnostics (AFDD) of heating, ventilation, and air conditioning (HVAC) using data mining and machine learning models have recently received substantial attention from researchers and practitioners. Various models have been developed over the years for AFDD of complete HVAC or its sub-systems. However, HVAC complexities, which partly have roots in its close coupling nature and interrelated dependencies, mean that understanding the relationship between faults and the suitability of the techniques remains an unanswered question. The literature analysis and interactive visualization of the data collected from the past implementation of AFDD models can provide useful insight to further explore this question by applying artificial intelligence (AI). Association rule mining (ARM) is deployed by this paper, using the frequent pattern (FP) growth algorithm to generate frequent fault sets for most common HVAC faults from the body of AFDD models developed in the literature to represent the status quo. A new model is developed for common HVAC faults and the techniques most frequently used to detect and diagnose them. A recommender system is developed using the ARM model to extract knowledge from the body of knowledge of HVAC data-driven AFDD in the form of rule-sets that reflect the associations. Findings of this review paper can significantly help civil and building engineers, as well as facility managers, in better management of building HVAC systems. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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26 pages, 4246 KiB

Open AccessArticle

A Neural Network Inverse Optimization Procedure for Constitutive Parameter Identification and Failure Mode Estimation of Laterally Loaded Unreinforced Masonry Walls

by Qudama Albu-Jasim and George Papazafeiropoulos

CivilEng 2021, 2(4), 943-968; https://doi.org/10.3390/civileng2040051 - 3 Nov 2021

Cited by 3 | Viewed by 3529

Abstract

A new Neural Network Optimization (NNO) algorithm for constitutive material parameter identification based on inverse analysis of experimental tests of small-scale masonry prisms under compressive loads is presented. The Concrete Damaged Plasticity (CDP) constitutive model is used for the brick and mortar of [...] Read more.

A new Neural Network Optimization (NNO) algorithm for constitutive material parameter identification based on inverse analysis of experimental tests of small-scale masonry prisms under compressive loads is presented. The Concrete Damaged Plasticity (CDP) constitutive model is used for the brick and mortar of the Unreinforced Masonry (URM) walls. By comparisons with experimental data taken from laboratory tests, it is demonstrated that the constitutive parameters calibrated by application of the proposed inverse optimization procedure on the small-scale (prism) experimental results are sufficiently accurate to allow for the prediction of the mechanical response of large-scale URM walls subject to compressive and lateral loads. This eliminates the need for large-scale URM wall experimental tests for the identification of their material properties, making the calibration process more economic. After verifying the accuracy of the calibrated constitutive parameters based on the above comparisons, a numerical parametric study is performed for the investigation of the effect of material behavior and geometrical aspect ratios on the failure mechanisms of large-scale URM walls. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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29 pages, 9688 KiB

Open AccessArticle

Laboratory Study on Non-Destructive Evaluation of Polyethylene Liquid Storage Tanks by Thermographic and Ultrasonic Methods

by Amir Behravan, Matthew M. deJong and Alexander S. Brand

CivilEng 2021, 2(4), 823-851; https://doi.org/10.3390/civileng2040045 - 28 Sep 2021

Cited by 4 | Viewed by 2920

Abstract

High-density polyethylene (HDPE) above-ground storage tanks (AST) are used by highway agencies to store liquid deicing chemicals for the purpose of road maintenance in the winter. A sudden AST failure can cause significant economic and environmental impacts. While ASTs are routinely inspected to [...] Read more.

High-density polyethylene (HDPE) above-ground storage tanks (AST) are used by highway agencies to store liquid deicing chemicals for the purpose of road maintenance in the winter. A sudden AST failure can cause significant economic and environmental impacts. While ASTs are routinely inspected to identify signs of aging and damage, current methods may not adequately capture all defects, particularly if they are subsurface or too small to be seen during visual inspection. Therefore, to improve the ability to identify potential durability issues with HDPE ASTs, additional non-destructive evaluation (NDE) techniques need to be considered and assessed for applicability. Specifically, this study investigates the efficiency of using infrared thermography (IRT) as a rapid method to simultaneously examine large areas of the tank exterior, which will be followed by closer inspections with conventional and phased array ultrasonic testing (UT) methods. Results show that IRT can help to detect defects that are shallow, specifically located within half of the tank’s wall thickness from the surface. UT has the ability to detect all defects at any depth. Moreover, phased array UT helps to identify stacked defects and characterize each defect more precisely than IRT. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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17 pages, 11444 KiB

Open AccessArticle

The Effect of Reclaimed Asphalt Pavement (RAP) Aggregates on the Reaction, Mechanical Properties and Microstructure of Alkali-Activated Slag

by Juliana O. Costa, Paulo H. R. Borges, Flávio A. dos Santos, Augusto Cesar S. Bezerra, Johan Blom and Wim Van den bergh

CivilEng 2021, 2(3), 794-810; https://doi.org/10.3390/civileng2030043 - 4 Sep 2021

Cited by 8 | Viewed by 3882

Abstract

Reclaimed asphalt pavement (RAP) is a recyclable aggregate produced during the demolition of old flexible pavements and consists of natural aggregates (NA) coated with aged bitumen. The detrimental effect caused by the bitumen coating on strength and porosity has limited the use of [...] Read more.

Reclaimed asphalt pavement (RAP) is a recyclable aggregate produced during the demolition of old flexible pavements and consists of natural aggregates (NA) coated with aged bitumen. The detrimental effect caused by the bitumen coating on strength and porosity has limited the use of RAP on traditional cementitious systems. This study investigates the potential use of fine RAP to substitute NA in the production of alkali-activated slag mortars (AAM). The effect of different activator dosages was assessed, i.e., either 4% or 6% Na₂O (wt. slag) combined with a modulus of silica equal to 0, 0.5 and 1.0. The characterisation of 100% RAP-AAM consisted of hydration kinetics (Isothermal Calorimetry), pore size distribution (Mercury Intrusion Porosimetry), mechanical performance (Compressive and Flexural strength), and microstructure analysis (Scanning Electron Microscopy and Confocal Laser Scanning Microscopy). The results show that RAP aggregates do not compromise the reaction of the matrices; however, it causes a significant strength loss (compressive strength of RAP-mortars 54% lower than reference NA-mortar at 28 days). The higher porosity at the interface transition zone of RAP-AAM is the main responsible for the lower strength performance. Increasing silicate dosages improves alkaline activation, but it has little impact on the adhesion between aggregate and bitumen. Despite the poorer mechanical performance, 100% RAP-AAM still yields enough strength to promote this recycled material in engineering applications. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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18 pages, 984 KiB

Open AccessArticle

An Adaptive Hybrid Model for Determining Subjective Causal Relationships in Fuzzy System Dynamics Models for Analyzing Construction Risks

by Seyed Hamed Fateminia, Phuong Hoang Dat Nguyen and Aminah Robinson Fayek

CivilEng 2021, 2(3), 747-764; https://doi.org/10.3390/civileng2030041 - 3 Sep 2021

Cited by 9 | Viewed by 2974

Abstract

Modeling risk management systems in construction projects is a complex process because of various internal and external factors and their interrelationships. Fuzzy system dynamics (FSD) have been commonly employed to model and analyze construction risk management systems. To run FSD simulation models, all [...] Read more.

Modeling risk management systems in construction projects is a complex process because of various internal and external factors and their interrelationships. Fuzzy system dynamics (FSD) have been commonly employed to model and analyze construction risk management systems. To run FSD simulation models, all hard (objective) and soft (subjective) causal relationships between variables must be quantified. However, a research gap exists regarding structured methods for constructing soft causal relationships in FSD models. This paper proposes an adaptive hybrid model consisting of fuzzy analytical hierarchy process, weighted principle of justifiable granularity, and fuzzy aggregation operators to determine crisp values of causality degree for soft (subjective) causal relationships in FSD modeling of construction risk analysis. The proposed model is implemented in analyzing construction risks of a windfarm project to illustrate its applicability. The proposed model generates two results: (1) optimized membership functions for linguistic terms representing the causality degree of soft relationships and (2) the crisp value for the causality degree of soft relationships. The contribution of study is to propose a structured model to improve efficiency and effectiveness of developing FSD quantitative modeling by addressing soft causal relationships between different variables in FSD models and considering multiple risk expertise of heterogeneous experts in construction risk assessment. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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18 pages, 7412 KiB

Open AccessArticle

Fiber Reinforced Polymer as Wood Roof-to-Wall Connections to Withstand Hurricane Wind Loads

by Aman Dhakal and Azadeh Parvin

CivilEng 2021, 2(3), 652-669; https://doi.org/10.3390/civileng2030036 - 8 Aug 2021

Cited by 1 | Viewed by 3477

Abstract

Light wood roof-to-wall connections are vulnerable when subjected to high-speed winds. In lieu of traditional metal connections, the present finite element analysis (FEA) study focuses on the use of epoxy and easy-to-apply, noncorrosive FRP ties to connect the roof and the walls in [...] Read more.

Light wood roof-to-wall connections are vulnerable when subjected to high-speed winds. In lieu of traditional metal connections, the present finite element analysis (FEA) study focuses on the use of epoxy and easy-to-apply, noncorrosive FRP ties to connect the roof and the walls in wood frames. The FEA models of the wood roof-to-wall GFRP connection were validated with an experimental study in the literature. Subsequently parametric study was performed on the validated FEA models. Parameters considered were the addition of anchorages to secure the GFRP ties for FEA models of shear and uplift tests, and various FRP types. Wood roof-to-wall connection uplift model was subjected to monotonic cyclic loading to simulate the effect of wind load. In addition, carbon and basalt FRP ties were also examined under monotonic cyclic loading. To evaluate the efficiency of GFRP ties with and without anchorages, the shear and uplift design loads specified in ASCE 7-16 were calculated. Finally, a formula was proposed to approximate the shear strength of GFRP connection in comparison with double shear bolted metal plate connections. The FEA models and experimental results were in good agreement. The finite element results revealed that anchorage increased the uplift load capacity by 15% but the increase in shear capacity was insignificant. Comparing glass, carbon, and basalt FRP ties, BFRP was superior in deformation capacity and CFRP provided more stiffness on uplift test simulation. GFRP ties were found to be approximately nine times stronger in shear and two times stronger in uplift resistance than hurricane clips. Finally, the proposed formula could predict the shear strength of GFRP tie connection which in turns contributes to the design and future research. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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20 pages, 3145 KiB

Open AccessArticle

Numerical Modelling and Design of Aluminium Alloy Angles under Uniform Compression

by Evangelia Georgantzia, Michaela Gkantou and George S. Kamaris

CivilEng 2021, 2(3), 632-651; https://doi.org/10.3390/civileng2030035 - 6 Aug 2021

Cited by 10 | Viewed by 3287

Abstract

Research studies have been reported on aluminium alloy tubular and doubly symmetric open cross-sections, whilst studies on angle cross-sections remain limited. This paper presents a comprehensive numerical study on the response of aluminium alloy angle stub columns. Finite element models are developed following [...] Read more.

Research studies have been reported on aluminium alloy tubular and doubly symmetric open cross-sections, whilst studies on angle cross-sections remain limited. This paper presents a comprehensive numerical study on the response of aluminium alloy angle stub columns. Finite element models are developed following a series of modelling assumptions. Geometrically and materially nonlinear analyses with imperfections included are executed, and the obtained results are validated against experimental data available in the literature. Subsequently, a parametric study is carried out to investigate the local buckling behaviour of aluminium alloy angles. For this purpose, a broad range of cross-sectional aspect ratios, slenderness and two types of structural aluminium alloys are considered. Their effect on the cross-sectional behaviour and strength is discussed. Moreover, the numerically obtained ultimate strengths together with literature test data are utilised to assess the applicability of the European design standards, the American Aluminium Design Manual and the Continuous Strength Method to aluminium alloy angles. The suitability of the Direct Strength Method is also evaluated and a modified method is proposed to improve the accuracy of the strength predictions. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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18 pages, 3746 KiB

Open AccessArticle

Enhancing Density-Based Mining Waste Alkali-Activated Foamed Materials Incorporating Expanded Cork

by Imed Beghoura and Joao Castro-Gomes

CivilEng 2021, 2(2), 523-540; https://doi.org/10.3390/civileng2020029 - 21 Jun 2021

Cited by 1 | Viewed by 2535

Abstract

This study focuses on the development of an alkali-activated lightweight foamed material (AA-LFM) with enhanced density. Several mixes of tungsten waste mud (TWM), grounded waste glass (WG), and metakaolin (MK) were produced. Al powder as a foaming agent was added, varying from 0.009 [...] Read more.

This study focuses on the development of an alkali-activated lightweight foamed material (AA-LFM) with enhanced density. Several mixes of tungsten waste mud (TWM), grounded waste glass (WG), and metakaolin (MK) were produced. Al powder as a foaming agent was added, varying from 0.009 w.% to 0.05 w.% of precursor weight. Expanded granulated cork (EGC) particles were incorporated (10% to 40% of the total volume of precursors). The physical and mechanical properties of the foamed materials obtained, the effects of the amount of the foaming agent and the percentage of cork particles added varying from 10 vol.% to 40% are presented and discussed. Highly porous structures were obtained, Pore size and cork particles distribution are critical parameters in determining the density and strength of the foams. The compressive strength results with different densities of AA-LFM obtained by modifying the foaming agent and cork particles are also presented and discussed. Mechanical properties of the cured structure are adequate for lightweight prefabricated building elements and components. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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19 pages, 2426 KiB

Open AccessArticle

Precast Concrete Building Construction and Envelope Thermal Behavior: A Case Study on Portuguese Public Social Housing

by Pedro I. Brandão and João C. G. Lanzinha

CivilEng 2021, 2(2), 271-289; https://doi.org/10.3390/civileng2020015 - 9 Apr 2021

Cited by 2 | Viewed by 3669

Abstract

A considerable part of Southern European countries building stock was constructed before the implementation of national thermal regulations, and as such, it is currently exposed to challenges such as energy poverty and climate change. Portuguese public social housing presents a significant variety of [...] Read more.

A considerable part of Southern European countries building stock was constructed before the implementation of national thermal regulations, and as such, it is currently exposed to challenges such as energy poverty and climate change. Portuguese public social housing presents a significant variety of construction systems and applied typologies. Among them, the “Novobra NK1”, a precast concrete construction system that exploits some innovative features in envelope components, has been used in several projects. Considering the importance of retrofitting to improve and adapt the thermal behaviors of buildings to face the aforementioned challenges, this article aims to provide an understanding of the behavior of a NK1 thermal envelope of a dwelling located in Covilhã, Portugal, and the impact of some constructive envelope retrofit measures applied. Results show that existing opaque envelope elements and glazed areas present characteristics that are no longer able to provide proper responses to contemporary building constructive requirements. External insulation was identified as a key retrofit measure, window replacement also being an advised solution for rigorous heating seasons. Improvements from the internal side of windows, such as roller shades, may provide few benefits during cooling seasons, and applying solar films is not advised without a proper thermal repercussion analysis. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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18 pages, 3886 KiB

Open AccessArticle

Rheology, Mechanical Properties and Porosity of Ternary Alkali-Activated Binders Based on Mining Mud Waste with Waste Glass and Metakaolin

by Abdelhakim Benhamouda, João Castro-Gomes and Luiz Pereira-de-Oliveira

CivilEng 2021, 2(1), 236-253; https://doi.org/10.3390/civileng2010013 - 8 Mar 2021

Cited by 2 | Viewed by 2515

Abstract

Alkali-activated materials have the potential to replace Portland cement in certain applications. To better understand these binders’ properties, it is relevant to study their rheological behaviour at early ages, like in the case of Portland cement paste. There are already many studies on [...] Read more.

Alkali-activated materials have the potential to replace Portland cement in certain applications. To better understand these binders’ properties, it is relevant to study their rheological behaviour at early ages, like in the case of Portland cement paste. There are already many studies on the rheological behaviour of these materials in the available literature, using fly ash, metakaolin, and ground granulated blast furnace slag as precursors. However, this study discusses the rheological behaviour, mechanical properties, and porosity of ternary alkali-activated binders based on mining mud waste, waste glass, and metakaolin. The precursor consisted of a volume mix of 70% of tungsten mining waste mud, 15% glass waste, and 15% of metakaolin. The activator was a combination of sodium hydroxide and sodium silicate solution. Five activator/precursor (A/P) ratios (0.37, 0.38, 0.39, 0.40, and 0.4) were studied. The result showed that the activator/precursor ratio affects the rheology of paste and their rheological behaviour fit the Bingham model. The relative yield stress (g) and plastic viscosity (h) increased inversely with the A/P ratio, while the workability increased proportionally. Furthermore, some empirical models are proposed to describe the characteristic of yield stress: plastic viscosity and spread diameter versus the A/P ratio and time with a correlation between the rheological parameters and the spread diameter. The increase in A/P ratio has also followed a decrease in compressive strength in all tested samples for all the ages. As expected, an increase of the porosity accompanied the increase of the A/P ratio. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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13 pages, 3913 KiB

Open AccessArticle

Proposal of Methodology for Evaluation of a Vertical Shanty Building in Beira, Mozambique

by Michael M. Santos, João C. G. Lanzinha and Ana Vaz Ferreira

CivilEng 2021, 2(1), 35-47; https://doi.org/10.3390/civileng2010003 - 5 Jan 2021

Cited by 2 | Viewed by 3630

Abstract

Emerging economies are in an almost winless situation: they would benefit from improving the extremely poor economic situation, making them self-reliant and economically productive. However, the poor fight for daily survival and, therefore, cannot afford to improve themselves. This article describes the state [...] Read more.

Emerging economies are in an almost winless situation: they would benefit from improving the extremely poor economic situation, making them self-reliant and economically productive. However, the poor fight for daily survival and, therefore, cannot afford to improve themselves. This article describes the state of the “Grande Hotel” in the city of Beira, Mozambique, built-in Portuguese colonial times, a real vertical shanty building that is occupied by approximately 1000 inhabitants trapped in poverty. To carry out any constructive intervention in a building or an urban complex, it is necessary to carry out a rehabilitation project that is developed based on a diagnosis of the building understudy, its main deteriorations, the causes, mechanisms of action, evolution, and possible treatments to be used for its repair. Analysis methods are necessary for the conservation of buildings since trying to stop, or correct buildings’ deterioration without a diagnosis of their problems or a prognosis on their evolution is a risky procedure with a high percentage of failure chances. The use of an appropriate methodology for diagnosing the damage present in the “Grande Hotel” and its prediction of evolution and development should directly impact a better quality of rehabilitation projects in the neighborhood where the building is located. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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27 pages, 5475 KiB

Open AccessArticle

Alkali-Activated Binders Based on Tungsten Mining Waste and Electric-Arc-Furnace Slag: Compressive Strength and Microstructure Properties

by Naim Sedira and João Castro-Gomes

CivilEng 2020, 1(2), 154-180; https://doi.org/10.3390/civileng1020010 - 4 Sep 2020

Cited by 7 | Viewed by 3383

Abstract

The valorization and reusing of mining waste has been widely studied in recent years. Research has demonstrated that there is great potential for reusing mining waste for construction applications. This work experimentally investigated the strength development, pore structure, and microstructure of a binary [...] Read more.

The valorization and reusing of mining waste has been widely studied in recent years. Research has demonstrated that there is great potential for reusing mining waste for construction applications. This work experimentally investigated the strength development, pore structure, and microstructure of a binary alkali-activated binder. This is based on tungsten mining waste mud (TMWM) and electric-arc-furnace slag (EAF-Slag) using different proportions of TMWM (10, 20, 30, 40, and 50 vt.%). The precursors were activated using sodium silicate (Na₂SiO₃) and potassium hydroxide (KOH 8M) as alkaline activator solution with solid:liquid weight ratio = 3. Pastes were used to assess the compressive strength of the blended binder and their microstructure. The reaction products were characterized by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), and Fourier transform infra-red (FT-IR) spectroscopy, while the porosity and the pores size properties were examined by mercury intrusion porosimetry (MIP). The results show that the partial replacement of TMWM with EAF-Slag exhibited better mechanical properties than the 100TM-AAB. A maximum strength value of 20.1 MPa was obtained in the binary-AAB sample prepared with 50 vt.% TMWM and EAF-Slag. The pastes that contained a higher dosage of EAF-Slag became more compact with lower porosity and finer pore-size distribution. In addition, the results obtained by SEM-EDS confirmed the formation of different types of reaction products in the 100TM-AAB, 100FS-AAB, and the binary-AABs mixtures such as N-A-S-H, C-A-S-H and (N, C)-A-S-H gels frameworks in the system as the major elements detected are Si, Al, Ca, and Na. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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Review

Jump to: Research

12 pages, 3071 KiB

Open AccessReview

Research and Measuring Technology Needs to Better Model and Measure Fatigue Crack Development of Thinly Surfaced Asphalt Road Pavements

by Emile Horak, Morris De Beer, Gerrie van Zyl, James Maina and Damien Ali Hamada Fakra

CivilEng 2022, 3(2), 456-467; https://doi.org/10.3390/civileng3020027 - 27 May 2022

Cited by 1 | Viewed by 2506

Abstract

The root cause of premature failures in relatively thin (<50 mm) asphalt surfaced roads is often a challenge to solve during forensic investigations in South Africa (SA). This description is based on peer review type discussions with forensic investigations experts as well as [...] Read more.

The root cause of premature failures in relatively thin (<50 mm) asphalt surfaced roads is often a challenge to solve during forensic investigations in South Africa (SA). This description is based on peer review type discussions with forensic investigations experts as well as published research papers. The areas of ignorance or areas where research effort is needed are identified. These observations serve to identify areas of new knowledge needed in terms of actual verification with measurements, measurement technology, and modeling of the observed phenomena. The main objectives of this discussion paper are to highlight the evolution of distress development in asphalt layers starting from the identification and description of the kind of microcracks, effects of microcracks in the debonding of the asphalt layer from lower layer, and vehicle–pavement interactions (VPI) of moving truck wheels focusing on the thin asphalt layer. Specific reference is made to the need to measure and model the effects of bow waves in front of and next to the loaded rolling wheel. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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14 pages, 1618 KiB

Open AccessReview

Managing Sustainability and Resilience of the Built Environment in Developing Communities

by Mariham Iskandar, Denise Nelson and Fariborz M. Tehrani

CivilEng 2022, 3(2), 427-440; https://doi.org/10.3390/civileng3020025 - 14 May 2022

Cited by 7 | Viewed by 3339

Abstract

Sustainable built environment has been the primary focus in academic and industrial fields in recent years. The major forces behind sustainable engineering are the rise in climate-related disasters, constant challenges in the energy sector, and a substantial shift in consumers’ consciousness toward conserving [...] Read more.

Sustainable built environment has been the primary focus in academic and industrial fields in recent years. The major forces behind sustainable engineering are the rise in climate-related disasters, constant challenges in the energy sector, and a substantial shift in consumers’ consciousness toward conserving natural resources. Further, many professional bodies have developed guidelines and specifications to implement sustainable practices and rate their impacts. Regardless, promoting analytical procedures for creating a context-sensitive design requires professionals to become familiar with standard sustainable practices and feel comfortable implementing more innovative materials and techniques in civil engineering design. In addition, the socio-political environment and macro-economic culture interact with engineering decisions. Hence, these considerations are necessary to deploy these elements in developing communities through best management practices during the lifecycle of sustainable and resilient projects. This paper endeavors to review these practices using lessons learned from applied examples and existing literature. Discussions cover various aspects of project development, from planning to demolition. Recommendations address challenges and opportunities in the sustainable development of resilient built infrastructure in developing regions. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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19 pages, 2644 KiB

Open AccessReview

A Review of Seven Tunnel Face Stability Models

by Mahmoud Qarmout, Diethard König and Torsten Wichtmann

CivilEng 2022, 3(1), 116-134; https://doi.org/10.3390/civileng3010008 - 10 Feb 2022

Cited by 5 | Viewed by 4628

Abstract

This paper presents a review of selected tunnel stability models that have been developed and used in calculating the minimum tunnel face pressure as described by original authors. Furthermore, this paper provides a comparison of required tunnel face pressure obtained from analytical models, [...] Read more.

This paper presents a review of selected tunnel stability models that have been developed and used in calculating the minimum tunnel face pressure as described by original authors. Furthermore, this paper provides a comparison of required tunnel face pressure obtained from analytical models, based either on limit equilibrium method or the limit analysis method (upper bound theorem) and numerical models using the finite element method. The numerical results are presented in charts for the comparative study to discuss the influence of cover depth to tunnel diameter ratio (C/D), internal friction of the soil (

φ

), and cohesion (c) on normalized support pressure (

p_{u} / γ D

) for each model. To verify the accuracy of the selected models, a comparison of the results of seven tunnel stability models with the results of the physical models is carried out. In a ground composed of two layers, a comparison of the required tunnel face pressure is presented. The results show that the wedge–silo models provide higher support pressure than the conical block models. Moreover, the support pressure using the conical block models is only dependent on the friction angle and not on the C/D ratio. Finally, the results of wedge-silo models indicate more significant dependence of the required support pressure on the C/D ratio especially for the lower friction angle. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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29 pages, 1999 KiB

Open AccessReview

Use of Fibre-Optic Sensors for Pipe Condition and Hydraulics Measurements: A Review

by Jevgenija Prisutova, Anton Krynkin, Simon Tait and Kirill Horoshenkov

CivilEng 2022, 3(1), 85-113; https://doi.org/10.3390/civileng3010006 - 27 Jan 2022

Cited by 17 | Viewed by 6303

Abstract

The combined length of the sewerage and clean water pipe infrastructure in the UK is estimated to be about 800,000 km. It is prone to failure due to its age and the inadequacies of the current pipe inspection methods. Fibre-optic cable sensing is [...] Read more.

The combined length of the sewerage and clean water pipe infrastructure in the UK is estimated to be about 800,000 km. It is prone to failure due to its age and the inadequacies of the current pipe inspection methods. Fibre-optic cable sensing is an attractive way to continuously monitor this infrastructure to detect critical changes. This paper reviews the existing fibre-optic sensor (FOS) technologies to suggest that these technologies have better sensing potential than traditional inspection and performance monitoring methods. This review also discusses the requirements for retrofitting an existing pipeline with an FOS. It also demonstrates that there is a need for further research into methods applicable to non-pressurised pipelines, as there is very little existing literature that focuses on partially filled pipes and pipes with gravity fed flows. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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14 pages, 797 KiB

Open AccessReview

Literature Review on the Response of Concrete Structures Subjected to Underwater Explosions

by Jacob Sanders, Girum Urgessa and Rainald Löhner

CivilEng 2021, 2(4), 895-908; https://doi.org/10.3390/civileng2040048 - 11 Oct 2021

Cited by 2 | Viewed by 3323

Abstract

This paper presents a review of research on underwater explosions (UNDEX) with a focus on the structural response of concrete or reinforced concrete (RC) structures. First, the physical phenomena of UNDEX and its effects are discussed describing both the theory and considerations of [...] Read more.

This paper presents a review of research on underwater explosions (UNDEX) with a focus on the structural response of concrete or reinforced concrete (RC) structures. First, the physical phenomena of UNDEX and its effects are discussed describing both the theory and considerations of the event. Then a brief description of the standard UNDEX experiment is followed by computational methods that employ governing equations that are used for verification of those methods. Lastly, a discussion on structural response for UNDEX is presented with a particular focus on concrete structures. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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22 pages, 4385 KiB

Open AccessReview

Review of Energy Harvesting for Buildings Based on Solar Energy and Thermal Materials

by Luciana Sucupira and João Castro-Gomes

CivilEng 2021, 2(4), 852-873; https://doi.org/10.3390/civileng2040046 - 30 Sep 2021

Cited by 8 | Viewed by 7212

Abstract

Reducing the use of fossil fuels and the generation of renewable energy have become extremely important in today. A climatic emergency is being experienced and society is suffering due to a high incidence of pollutants. For these reasons, energy harvesting emerges as an [...] Read more.

Reducing the use of fossil fuels and the generation of renewable energy have become extremely important in today. A climatic emergency is being experienced and society is suffering due to a high incidence of pollutants. For these reasons, energy harvesting emerges as an essential source of renewable energy, and it benefits from the advancement in the scope of solar and thermal energy which are widely abundant and usually wasted. It is an option to obtain energy without damaging the environment. Recently, energy harvesting devices, which produce electricity, have been attracting more and more attention due to the availability of new sources of energy, such as solar, thermal, wind and mechanical. This article looks at recent developments in capturing energy from the sun. This literature review was performed on research platforms and analyzes studies on solar and thermal energy capture carried out in the last four years. The methods of capturing solar energy were divided according to how they were applied in civil engineering works. The types of experiments carried out were the most diverse, and several options for capturing solar energy were obtained. The advantages and disadvantages of each method were demonstrated, as well as the need for further studies. The results showed that the materials added to the components obtained have a lot of advantages and could be used in different energy capture types, such as photovoltaic, thermoelectric generators, pyroelectricity and thermometrical. This demonstrates that the capture of solar energy is quite viable, and greater importance should be given to it, as the number of research is still small when compared to other renewable energies. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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13 pages, 587 KiB

Open AccessReview

Bituminous Pavement Reinforcement with Fiber: A Review

by Nuha Mashaan, Mohamed Karim, Farag Khodary, Nikhil Saboo and Abdalrhman Milad

CivilEng 2021, 2(3), 599-611; https://doi.org/10.3390/civileng2030033 - 23 Jul 2021

Cited by 19 | Viewed by 8102

Abstract

This paper attempts to display, analyze and discuss the literature affiliated to the previous research data on road surfacing in pavement engineering reinforcement. In this paper, a review of the background and present status of road surfacing is also provided for supportive explanation [...] Read more.

This paper attempts to display, analyze and discuss the literature affiliated to the previous research data on road surfacing in pavement engineering reinforcement. In this paper, a review of the background and present status of road surfacing is also provided for supportive explanation of the significance of fiber-reinforced asphalt pavement HMA and its role in providing effective and durable surfacing for heavy-trafficked roads. The paper attempts to clarify some of the terms and notions related to the discussions to give the readers the needed background, to be able to actively understand the experiments and discussions. Results from many studies confirm that fiber specifically enhances the optimum bitumen content in the design of the mixture and halts the bitumen leakage due to its asphalt absorbing susceptibility. Fiber modifies the visco-elastic response, susceptibility against moisture, increase resistance to rutting, as well as lowers the pavement fatigue cracking. Full article

(This article belongs to the Special Issue Early Career Stars in Civil Engineering)

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