George C . Wang | East Carolina University (original) (raw)

Papers by George C . Wang

Drones

Small unmanned aerial systems (UAS) have been increasingly popular in surveying and mapping tasks... more Small unmanned aerial systems (UAS) have been increasingly popular in surveying and mapping tasks. While photogrammetry has been the primary UAS sensing technology in other industries, construction activities can also benefit from accurate surveying measurements from airborne LIDAR. This paper discusses a custom-designed low-cost UAS-based LIDAR system that can effectively measure construction excavation and bulk piles. The system is designed with open interfaces that can be easily upgraded and expanded. An error model was developed to predict the horizontal and vertical errors of single point geo-registration for a generic UAS-LIDAR. This model was validated for the proposed UAS-LIDAR system using calibration targets and real-world measurements from different scenarios. The results indicated random errors from LIDAR at approximately 0.1 m and systematic errors at or below centimeter level. Additional pre-processing of the raw point cloud can further reduce the random errors in LIDA...

Drones

Coastal environments are some of the most dynamic environments in the world. As they are constant... more Coastal environments are some of the most dynamic environments in the world. As they are constantly changing, so are the technologies and techniques we use to map and monitor them. The rapid advancement of sUAS-based remote sensing calls for rigorous field and processing workflows so that more reliable and consistent sUAS projects of coastal environments are carried out. Here, we synthesize the best practices to create sUAS photo-based surveying and processing workflows that can be used and modified by coastal scientists, depending on their project objective. While we aim to simplify the complexity of these workflows, we note that the nature of this work is a craft that carefully combines art, science, and technology. sUAS LiDAR is the next advancement in mapping and monitoring coastal environments. Therefore, future work should consider synthesizing best practices to develop rigorous field and data processing workflows used for sUAS LiDAR-based projects of coastal environments.

Drones

UAV-based technologies are evolving and improving at a rapid pace. The abundance of solutions and... more UAV-based technologies are evolving and improving at a rapid pace. The abundance of solutions and systems available today can make it difficult to identify the best option for construction and civil projects. The purpose of this literature review is to examine the benefits and limitations of UAV-based sensing systems in the context of construction management and civil engineering, with a focus on camera-based and laser-based systems. The risk factors associated with UAV operations at construction sites are also considered.

To investigate the suitability of using recycled concrete aggregate (RCA) as an aggregate in nons... more To investigate the suitability of using recycled concrete aggregate (RCA) as an aggregate in nonstructural concrete for the bridge and highway rehabilitation projects in eastern North Carolina, Concrete slabs were selected from demolished concrete bridges in three counties in this region. The concrete bridge panels were crushed, separated from reinforcing steel, sieved, and examined in laboratory for making non-structural concrete to investigate strength related properties comparing with natural aggregate concrete (control mix). For the recycled concrete aggregate, LA Abrasion, bulk specific gravity, absorption, and alkaline-silica reaction were examined. Percentage of fine particles and impurities incorporated in the RCA generated during the crushing were also measured. Normal concrete design method was used to make concrete mixes containing 0%, 15%, 30%, 50%, and 100% RCA according to the requirements of the Standard Specifications for Class B (nonstructural concrete) by the North...

Nonferrous metals are extensively used for various industrial purposes. When smelting nonferrous ... more Nonferrous metals are extensively used for various industrial purposes. When smelting nonferrous metal-bearing ore concentrates with fluxes and converting matte into pure metal in reverberatory, blast, flash, and electric furnaces, molten slag is formed to separate the metal and unwanted elements in the raw materials. It is normally returned to the smelter or converter to recover the base metals, and then discharged. Nonferrous slag possesses a number of favorable physical, mechanical, and hydraulic activity properties and has the potential to be used for construction purposes. The pyrometallurgical production of copper, nickel, lead, zinc, and tin, and the formation and basic properties of their slags, are discussed in this chapter.

As the coproduct of steelmaking, steelmaking slag, volumetrically expansive-prone without treatme... more As the coproduct of steelmaking, steelmaking slag, volumetrically expansive-prone without treatment, has been satisfactorily used as an aggregate base course material in highway construction. Although numerous technical reports and papers have revealed that steel slag aggreged using in rigid matrixes, the end product, paving block, non-structural concrete, for example, possesses superb strength and durability properties, the application of steel slag aggregate as a concrete aggregate is currently prohibited in highway construction. Naturally, researchers explore the practicality of use of steel slag, how to connect the laboratory experiment results to the end-product behavior, and further convert the research results into real construction? For all nontraditional or secondary materials utilization, the procedure of laboratory material examination, lab and field trial test are critical. To generalize the utilization, usability criteria establishment is necessary. This paper tries to ...

Construction Research Congress 2016, May 24, 2016

Steel slag is the molten byproduct from steelmaking operations that is subsequently air-cooled fo... more Steel slag is the molten byproduct from steelmaking operations that is subsequently air-cooled for use. It has been used in cement manufacture and as unbound granular materials in construction. While numerous studies have revealed that concrete containing steel slag aggregate possesses good mechanical properties, and slag, as a byproduct, is cheaper than virgin aggregates, its practical use in portland cement concrete is currently a forbidden area in the construction practices. What is the practicality, where is the crux of converting research results into to real production, and how to build the bridge between the laboratory experiment and the end products? Based on the philosophy of slag utilization, i.e., laboratory testing, field demonstration, and criteria establishment, the questions to be answered includes (i) two distinct laboratory test methods to determine the expansion force generated by slag particles; (ii) conversion of the expansion force of mass slag aggregate to the expansion force of single slag particle; (iii) mechanical disruption model of slag failure; and (iv) usability criteria for the use of steel slag in a rigid or restrained matrices. The paper introduced the answers for the first two questions; and provides the mechanical model and criterion deduction to answer the other two questions that lead to criteria and specification establishment.

Journal of Risk Analysis and Crisis Response, 2012

Construction is one of the high-risk industries. Constructed facilities are becoming more sophist... more Construction is one of the high-risk industries. Constructed facilities are becoming more sophisticated and complex and risk management in construction is imperative. I would like to thank the Journal of Risk Analysis and Crisis Response (JRACR) for providing the platform for construction professionals and educators to interact and exchange research experience and results on risk management in construction. The Special Issue contains seven papers. The topics cover the development of new models, methods, and framework of risk management in construction; dispute analysis based on numerous data, and the impact of climate on property values. The first paper titled 'Analysis of Disputes in Transportation Projects' by M. Emre Bayraktar, Cagri Cinkilic and Farrukh Arif presents an analysis of the disputes for transportation projects and the related lessons learned. It was found that majority of disputes in the 262 cases studied were due to unforeseen conditions. The analysis is based on the data stored in the Dispute Resolution Board (DRB) database of the Florida Department of Transportation (FDOT). The second paper by Payam Bakhshi and Ali Touran proposes a new approach for contingency determination in a portfolio of construction projects. A Bayesian approach is employed to modify a model on regular intervals that helps an agency find the level of confidence needed for individual projects to ensure that the portfolio budget will meet the minimum level of confidence based on available funding and the agency's policy goals. The third paper contributed by Dean Kashiwagi and Jacob Kashiwagi presents a new risk management model designed by using deductive logic. The new model identifies risk, mitigates risk by use of transparency and dominant information which has been used by the expert contractor to minimize the risk they do not control. The fourth paper contributed by Lingguang Song, Sang-Hoon Lee and Fitria H. Rachmat deals with a new method for scheduling repetitive construction operations with stochastic simulation to incorporate uncertainty in activity performance during field operations. The proposed Stochastic Linear Scheduling Method (SLSM)

Journal of Risk Analysis and Crisis Response, 2016

The use of unmanned aerial vehicles (UAVs) in the construction industry is swiftly growing worldw... more The use of unmanned aerial vehicles (UAVs) in the construction industry is swiftly growing worldwide. UAVs are changing the way construction companies do business. Contractors are increasingly using camera-mounted UAVs to monitor the full range of activities. Rapid advances in camera, sensing, aeronautics, battery and autopilot navigation technologies have helped make UAVs affordable, reliable and easy to operate. The US Federal Aviation Administration predicts that UAVs hold tremendous promise and commercial drone sales could increase from 600,000 to 2.7 million over the next four years. On the one hand, UAVs are extremely cost-effective in conducting aerial surveys, worksite surveillance, real-time inspections, and monitoring jobsite safety. On the other hand, with UAV ownership rapidly rising, the number of reported UAV safety, risk, and liability incidents is increasing. With this new technology use in the construction industry, construction companies must be aware of all regulations, legislations, privacy liability, and risks for construction related businesses. Operating a drone or hiring a subcontractor to operate it is not something to do on the spur of the moment. Emphasis and effort should be placed on safety, risk control, training and education. The goal of this paper is to provide construction professionals with timely and pertinent information on UAV use with a focus on risk management based on current industry practice, experience and literature review.

Journal of Risk Analysis and Crisis Response, 2017

In large public infrastructure projects, political risks due to the power imbalance between centr... more In large public infrastructure projects, political risks due to the power imbalance between central and delivery agencies are often overlooked or underestimated. The primary motive of the delivery agency in distorting information for political gains should be deemed a risk that creates uncertainty for large projects planning the outcome. In this study, seven large infrastructure projects in the state of Victoria, Australia are examined through a workshop involving key stakeholders who had played active roles in these projects. The findings revealed that power asymmetry between central and delivery agencies exist and would lead to optimism bias, which in turn creates uncertainty and risk of overpromising in the business case. Power asymmetry exist in large infrastructure projects because the central agencies usually only have the responsibility but not the skill set needed to measure the robustness of the business case. These types of political risks are difficult to quantify and even detect. This paper recommends a few managerial strategies that have referential values and/or can be used to mitigate and circumvent this risk.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Laboratory testing, field trialing, and property and performance quantifying are equally importan... more Laboratory testing, field trialing, and property and performance quantifying are equally important steps in research on the comprehensive utilization of slags in construction. It is imperative to establish quantified properties and criteria to guide the extensive use of slags and remove the main inhibiting factors contributing to low utilization rate. Pertinent specifications and quality requirements supported by quantified characterization will guide rational and sustainable use of slag. In view of energy, natural resources, and environment conservation, latent energy value invested in slag should receive a higher priority of attention and be fully utilized. It is essential to inclusively understand the compositional and physical properties of slag, the conventional materials, end products, and final uses in which slag is involved. This chapter enunciates the methodology that should be followed for slag research and the extensive utilization of slag in civil infrastructure construction.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Portland cement, as a binder, when mixed with water, can set, harden, and bind fine and coarse ag... more Portland cement, as a binder, when mixed with water, can set, harden, and bind fine and coarse aggregate to make concrete. The source of raw materials used in the manufacture of Portland cement include lime, iron, silica, alumina, and magnesia. High energy is required and emissions are released during cement production. Ferrous slags and nonferrous slags contain some mineral sources that are needed in cement. Great potential exists for some slags to be used as mineral sources in cement manufacture, either as blended cement making or as a raw material in cement clinker and other cementitious applications. This chapter deals with the basic quality requirements of cement, the hydraulic properties of slags of different kinds, and their use in cement manufacture. The use of slag in other cementitious applications is also discussed.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Air-cooled slag can be used as a granular material in a broad range of applications such as pavem... more Air-cooled slag can be used as a granular material in a broad range of applications such as pavement subbase and base, railroad ballast, port and harbor construction stone, dam and embankment construction stone, and soft soil stabilization stone. The similarity of these applications is that no binding agent is used, that is to say that the bulk granular material is in an unbound condition. It is critical to understand the effect of volumetric properties of some slags, typically steel slag, on the stability of the bulk stability of the bulk mass slag materials and establish usability criteria to guide the slag use in unbound conditions. This chapter enunciates the nature of volumetric instability of some slags using steel slag as an example, the theoretical expansion modeling and laboratory experiments, and the deduction of the usability criteria for expansive slag use in nonrestrained conditions.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Unbound aggregate is the bulk particulate material providing bearing capacity and other functions... more Unbound aggregate is the bulk particulate material providing bearing capacity and other functions by the compacted particles without binding agent. The use of slag in construction as unbound bulk applications has a long history and made important contributions to natural aggregate resource conservation. Slag aggregates have good engineering properties that meet or exceed the technical requirements for virgin aggregates. Current technical specifications along with relevant test methods for natural materials and slag can be used for unbound slag materials while modification or addition may be needed with the development of research on the utilization. This chapter introduces the basic technical requirements for unbound granular materials and end products, practical uses for slag as an unbound material, and recent research development.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Steel slag is the molten by-product from steelmaking operations that is subsequently air-cooled f... more Steel slag is the molten by-product from steelmaking operations that is subsequently air-cooled for use. It has been used in cement manufacture and as unbound granular materials in construction. While numerous studies have revealed that concrete containing steel slag aggregate possesses good mechanical properties, its practical use in Portland cement concrete is currently a forbidden area in construction practices. What is the practicality, where is the crux of converting research results into real production, and how to build the bridge between laboratory experiment and end products? Based on the philosophy of slag utilization (ie, laboratory testing, field demonstration, and criteria establishment), the questions to be answered include (i) two distinct laboratory test methods to determine the expansion force generated by slag particles; (ii) conversion of the expansion force of mass slag aggregate to the expansion force of single slag particle; (iii) mechanical disruption model of slag failure; and (iv) usability criteria for the use of steel slag in rigid or restrained matrices. This chapter introduces the answers to the first two questions and provides the mechanical model and criterion deduction to answer the other two questions that lead to criteria and specification establishment.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Asphalt mixtures contain asphalt binder and graded aggregates. Since the early stage of using bla... more Asphalt mixtures contain asphalt binder and graded aggregates. Since the early stage of using blast furnace slag and steel slag in hot-mix asphalt considerable experience has been accumulated through mix design, production, and construction. Quality control and technical specifications have been well developed to ensure the quality of steel slag asphalt concrete, minimize potential expansion, and take advantage of the positive features of high stability, skid and rutting resistance, and antistripping. In recent years new materials and construction techniques have been developed, such as warm-mix asphalt, cold in-place recycling, and various surface treatment methods that provide a broad platform to develop novel uses of ferrous, nonferrous, and nonmetallurgical slag aggregate products. This chapter introduces the basic technical requirements for aggregates, asphalt mixes, and pavement, and summarizes the experience of using slag in asphalt mixes and paving.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Utilizing slag in infrastructure construction is to practice and realize sustainability principle... more Utilizing slag in infrastructure construction is to practice and realize sustainability principles to improve the quality of life for society indefinitely without degrading the quantity, quality, or availability of natural, economic, and social resources. This utilization must produce environmentally acceptable end products. Regulations and guidance must strike the right balance between promoting a wide variety of applications and protecting the environment. Environmental regulations governing slag utilization should be clear, pertinent, and have efficacy to actual environmental performance outcomes. This chapter reviews relevant policies and regulations related to secondary material utilization and leaching tests, the main measure to evaluate potential environmental impact of slag use in construction, and special substances in certain slags that have been addressed during utilization.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Three case studies concerning steel slag and nickel slag use in highway construction and foundati... more Three case studies concerning steel slag and nickel slag use in highway construction and foundation construction are presented. In the Egnatia Odos highway project, electric arc furnace (EAF) slag aggregate was used as an aggregate of 25 mm open-graded hot-mix asphalt (HMA). In Saudi Arabia, EAF slag aggregate was used in stone column ground stylization to strengthen bearing capacity of local soils. In the Dominican Republic, ferronickel slag aggregate was used in granular base and HMA paving.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Slag is regarded as a by-product after it is separated from base metal or element in smelting fur... more Slag is regarded as a by-product after it is separated from base metal or element in smelting furnaces or discharged from coal-firing boilers or municipal solid waste incinerators. Unlike normal primary product production in which the final required properties are carefully designed and adjusted during the production to meet the final products’ specifications, slag is produced with less consideration about its further use in construction applications. Its property is most likely to fluctuate. The inherent nature of slag and variation in chemical and mineral composition lead to variation of physical and mechanical properties of slag. To convert slag into useful and quality slag products for selective uses, processing and special treating are critical and inevitable. This chapter outlines the intrinsic properties of slag, and the evaluation and processing of slag.

Philosophy of Engineering and Technology, 2015

Ethical decision-making is central to the practice of construction engineering and management. Th... more Ethical decision-making is central to the practice of construction engineering and management. This is no more evident than in the twenty-first century, when the construction industry must function in very diverse organizational contexts. Whilst construction companies pursue projects in international markets, many investors are buying or forming joint ventures with domestic companies. New and varied professional attitudes have recently arrived in western markets such as the United States and Australia because construction companies are increasingly employing managers from developing nations to undertake commercial and infrastructure engineering projects. In many developing countries the construction industry is vulnerable to unethical behavior or corruption – vulnerability in part because of differences in culture and managerial systems across countries; and this diversity is manifest in the different perspectives of professional ethics and professional practice. Importantly, professionals in construction engineering must be aware of these differences; however current ethics education for engineering professionals generally lacks global components. In this chapter, emphasis is placed upon professional registration, including mandatory awareness of professional ethics, as an imperative for the welfare of world citizens; discussion on the nature of the construction industry and globalized trends emphasizes why ethics and professional education must be integrated within civil and construction engineering and management curricula. Only then we can anticipate an appropriate educational foundation for professional registration of the international engineer.

Drones

Small unmanned aerial systems (UAS) have been increasingly popular in surveying and mapping tasks... more Small unmanned aerial systems (UAS) have been increasingly popular in surveying and mapping tasks. While photogrammetry has been the primary UAS sensing technology in other industries, construction activities can also benefit from accurate surveying measurements from airborne LIDAR. This paper discusses a custom-designed low-cost UAS-based LIDAR system that can effectively measure construction excavation and bulk piles. The system is designed with open interfaces that can be easily upgraded and expanded. An error model was developed to predict the horizontal and vertical errors of single point geo-registration for a generic UAS-LIDAR. This model was validated for the proposed UAS-LIDAR system using calibration targets and real-world measurements from different scenarios. The results indicated random errors from LIDAR at approximately 0.1 m and systematic errors at or below centimeter level. Additional pre-processing of the raw point cloud can further reduce the random errors in LIDA...

Drones

Coastal environments are some of the most dynamic environments in the world. As they are constant... more Coastal environments are some of the most dynamic environments in the world. As they are constantly changing, so are the technologies and techniques we use to map and monitor them. The rapid advancement of sUAS-based remote sensing calls for rigorous field and processing workflows so that more reliable and consistent sUAS projects of coastal environments are carried out. Here, we synthesize the best practices to create sUAS photo-based surveying and processing workflows that can be used and modified by coastal scientists, depending on their project objective. While we aim to simplify the complexity of these workflows, we note that the nature of this work is a craft that carefully combines art, science, and technology. sUAS LiDAR is the next advancement in mapping and monitoring coastal environments. Therefore, future work should consider synthesizing best practices to develop rigorous field and data processing workflows used for sUAS LiDAR-based projects of coastal environments.

Drones

UAV-based technologies are evolving and improving at a rapid pace. The abundance of solutions and... more UAV-based technologies are evolving and improving at a rapid pace. The abundance of solutions and systems available today can make it difficult to identify the best option for construction and civil projects. The purpose of this literature review is to examine the benefits and limitations of UAV-based sensing systems in the context of construction management and civil engineering, with a focus on camera-based and laser-based systems. The risk factors associated with UAV operations at construction sites are also considered.

To investigate the suitability of using recycled concrete aggregate (RCA) as an aggregate in nons... more To investigate the suitability of using recycled concrete aggregate (RCA) as an aggregate in nonstructural concrete for the bridge and highway rehabilitation projects in eastern North Carolina, Concrete slabs were selected from demolished concrete bridges in three counties in this region. The concrete bridge panels were crushed, separated from reinforcing steel, sieved, and examined in laboratory for making non-structural concrete to investigate strength related properties comparing with natural aggregate concrete (control mix). For the recycled concrete aggregate, LA Abrasion, bulk specific gravity, absorption, and alkaline-silica reaction were examined. Percentage of fine particles and impurities incorporated in the RCA generated during the crushing were also measured. Normal concrete design method was used to make concrete mixes containing 0%, 15%, 30%, 50%, and 100% RCA according to the requirements of the Standard Specifications for Class B (nonstructural concrete) by the North...

Nonferrous metals are extensively used for various industrial purposes. When smelting nonferrous ... more Nonferrous metals are extensively used for various industrial purposes. When smelting nonferrous metal-bearing ore concentrates with fluxes and converting matte into pure metal in reverberatory, blast, flash, and electric furnaces, molten slag is formed to separate the metal and unwanted elements in the raw materials. It is normally returned to the smelter or converter to recover the base metals, and then discharged. Nonferrous slag possesses a number of favorable physical, mechanical, and hydraulic activity properties and has the potential to be used for construction purposes. The pyrometallurgical production of copper, nickel, lead, zinc, and tin, and the formation and basic properties of their slags, are discussed in this chapter.

As the coproduct of steelmaking, steelmaking slag, volumetrically expansive-prone without treatme... more As the coproduct of steelmaking, steelmaking slag, volumetrically expansive-prone without treatment, has been satisfactorily used as an aggregate base course material in highway construction. Although numerous technical reports and papers have revealed that steel slag aggreged using in rigid matrixes, the end product, paving block, non-structural concrete, for example, possesses superb strength and durability properties, the application of steel slag aggregate as a concrete aggregate is currently prohibited in highway construction. Naturally, researchers explore the practicality of use of steel slag, how to connect the laboratory experiment results to the end-product behavior, and further convert the research results into real construction? For all nontraditional or secondary materials utilization, the procedure of laboratory material examination, lab and field trial test are critical. To generalize the utilization, usability criteria establishment is necessary. This paper tries to ...

Construction Research Congress 2016, May 24, 2016

Steel slag is the molten byproduct from steelmaking operations that is subsequently air-cooled fo... more Steel slag is the molten byproduct from steelmaking operations that is subsequently air-cooled for use. It has been used in cement manufacture and as unbound granular materials in construction. While numerous studies have revealed that concrete containing steel slag aggregate possesses good mechanical properties, and slag, as a byproduct, is cheaper than virgin aggregates, its practical use in portland cement concrete is currently a forbidden area in the construction practices. What is the practicality, where is the crux of converting research results into to real production, and how to build the bridge between the laboratory experiment and the end products? Based on the philosophy of slag utilization, i.e., laboratory testing, field demonstration, and criteria establishment, the questions to be answered includes (i) two distinct laboratory test methods to determine the expansion force generated by slag particles; (ii) conversion of the expansion force of mass slag aggregate to the expansion force of single slag particle; (iii) mechanical disruption model of slag failure; and (iv) usability criteria for the use of steel slag in a rigid or restrained matrices. The paper introduced the answers for the first two questions; and provides the mechanical model and criterion deduction to answer the other two questions that lead to criteria and specification establishment.

Journal of Risk Analysis and Crisis Response, 2012

Construction is one of the high-risk industries. Constructed facilities are becoming more sophist... more Construction is one of the high-risk industries. Constructed facilities are becoming more sophisticated and complex and risk management in construction is imperative. I would like to thank the Journal of Risk Analysis and Crisis Response (JRACR) for providing the platform for construction professionals and educators to interact and exchange research experience and results on risk management in construction. The Special Issue contains seven papers. The topics cover the development of new models, methods, and framework of risk management in construction; dispute analysis based on numerous data, and the impact of climate on property values. The first paper titled 'Analysis of Disputes in Transportation Projects' by M. Emre Bayraktar, Cagri Cinkilic and Farrukh Arif presents an analysis of the disputes for transportation projects and the related lessons learned. It was found that majority of disputes in the 262 cases studied were due to unforeseen conditions. The analysis is based on the data stored in the Dispute Resolution Board (DRB) database of the Florida Department of Transportation (FDOT). The second paper by Payam Bakhshi and Ali Touran proposes a new approach for contingency determination in a portfolio of construction projects. A Bayesian approach is employed to modify a model on regular intervals that helps an agency find the level of confidence needed for individual projects to ensure that the portfolio budget will meet the minimum level of confidence based on available funding and the agency's policy goals. The third paper contributed by Dean Kashiwagi and Jacob Kashiwagi presents a new risk management model designed by using deductive logic. The new model identifies risk, mitigates risk by use of transparency and dominant information which has been used by the expert contractor to minimize the risk they do not control. The fourth paper contributed by Lingguang Song, Sang-Hoon Lee and Fitria H. Rachmat deals with a new method for scheduling repetitive construction operations with stochastic simulation to incorporate uncertainty in activity performance during field operations. The proposed Stochastic Linear Scheduling Method (SLSM)

Journal of Risk Analysis and Crisis Response, 2016

The use of unmanned aerial vehicles (UAVs) in the construction industry is swiftly growing worldw... more The use of unmanned aerial vehicles (UAVs) in the construction industry is swiftly growing worldwide. UAVs are changing the way construction companies do business. Contractors are increasingly using camera-mounted UAVs to monitor the full range of activities. Rapid advances in camera, sensing, aeronautics, battery and autopilot navigation technologies have helped make UAVs affordable, reliable and easy to operate. The US Federal Aviation Administration predicts that UAVs hold tremendous promise and commercial drone sales could increase from 600,000 to 2.7 million over the next four years. On the one hand, UAVs are extremely cost-effective in conducting aerial surveys, worksite surveillance, real-time inspections, and monitoring jobsite safety. On the other hand, with UAV ownership rapidly rising, the number of reported UAV safety, risk, and liability incidents is increasing. With this new technology use in the construction industry, construction companies must be aware of all regulations, legislations, privacy liability, and risks for construction related businesses. Operating a drone or hiring a subcontractor to operate it is not something to do on the spur of the moment. Emphasis and effort should be placed on safety, risk control, training and education. The goal of this paper is to provide construction professionals with timely and pertinent information on UAV use with a focus on risk management based on current industry practice, experience and literature review.

Journal of Risk Analysis and Crisis Response, 2017

In large public infrastructure projects, political risks due to the power imbalance between centr... more In large public infrastructure projects, political risks due to the power imbalance between central and delivery agencies are often overlooked or underestimated. The primary motive of the delivery agency in distorting information for political gains should be deemed a risk that creates uncertainty for large projects planning the outcome. In this study, seven large infrastructure projects in the state of Victoria, Australia are examined through a workshop involving key stakeholders who had played active roles in these projects. The findings revealed that power asymmetry between central and delivery agencies exist and would lead to optimism bias, which in turn creates uncertainty and risk of overpromising in the business case. Power asymmetry exist in large infrastructure projects because the central agencies usually only have the responsibility but not the skill set needed to measure the robustness of the business case. These types of political risks are difficult to quantify and even detect. This paper recommends a few managerial strategies that have referential values and/or can be used to mitigate and circumvent this risk.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Laboratory testing, field trialing, and property and performance quantifying are equally importan... more Laboratory testing, field trialing, and property and performance quantifying are equally important steps in research on the comprehensive utilization of slags in construction. It is imperative to establish quantified properties and criteria to guide the extensive use of slags and remove the main inhibiting factors contributing to low utilization rate. Pertinent specifications and quality requirements supported by quantified characterization will guide rational and sustainable use of slag. In view of energy, natural resources, and environment conservation, latent energy value invested in slag should receive a higher priority of attention and be fully utilized. It is essential to inclusively understand the compositional and physical properties of slag, the conventional materials, end products, and final uses in which slag is involved. This chapter enunciates the methodology that should be followed for slag research and the extensive utilization of slag in civil infrastructure construction.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Portland cement, as a binder, when mixed with water, can set, harden, and bind fine and coarse ag... more Portland cement, as a binder, when mixed with water, can set, harden, and bind fine and coarse aggregate to make concrete. The source of raw materials used in the manufacture of Portland cement include lime, iron, silica, alumina, and magnesia. High energy is required and emissions are released during cement production. Ferrous slags and nonferrous slags contain some mineral sources that are needed in cement. Great potential exists for some slags to be used as mineral sources in cement manufacture, either as blended cement making or as a raw material in cement clinker and other cementitious applications. This chapter deals with the basic quality requirements of cement, the hydraulic properties of slags of different kinds, and their use in cement manufacture. The use of slag in other cementitious applications is also discussed.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Air-cooled slag can be used as a granular material in a broad range of applications such as pavem... more Air-cooled slag can be used as a granular material in a broad range of applications such as pavement subbase and base, railroad ballast, port and harbor construction stone, dam and embankment construction stone, and soft soil stabilization stone. The similarity of these applications is that no binding agent is used, that is to say that the bulk granular material is in an unbound condition. It is critical to understand the effect of volumetric properties of some slags, typically steel slag, on the stability of the bulk stability of the bulk mass slag materials and establish usability criteria to guide the slag use in unbound conditions. This chapter enunciates the nature of volumetric instability of some slags using steel slag as an example, the theoretical expansion modeling and laboratory experiments, and the deduction of the usability criteria for expansive slag use in nonrestrained conditions.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Unbound aggregate is the bulk particulate material providing bearing capacity and other functions... more Unbound aggregate is the bulk particulate material providing bearing capacity and other functions by the compacted particles without binding agent. The use of slag in construction as unbound bulk applications has a long history and made important contributions to natural aggregate resource conservation. Slag aggregates have good engineering properties that meet or exceed the technical requirements for virgin aggregates. Current technical specifications along with relevant test methods for natural materials and slag can be used for unbound slag materials while modification or addition may be needed with the development of research on the utilization. This chapter introduces the basic technical requirements for unbound granular materials and end products, practical uses for slag as an unbound material, and recent research development.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Steel slag is the molten by-product from steelmaking operations that is subsequently air-cooled f... more Steel slag is the molten by-product from steelmaking operations that is subsequently air-cooled for use. It has been used in cement manufacture and as unbound granular materials in construction. While numerous studies have revealed that concrete containing steel slag aggregate possesses good mechanical properties, its practical use in Portland cement concrete is currently a forbidden area in construction practices. What is the practicality, where is the crux of converting research results into real production, and how to build the bridge between laboratory experiment and end products? Based on the philosophy of slag utilization (ie, laboratory testing, field demonstration, and criteria establishment), the questions to be answered include (i) two distinct laboratory test methods to determine the expansion force generated by slag particles; (ii) conversion of the expansion force of mass slag aggregate to the expansion force of single slag particle; (iii) mechanical disruption model of slag failure; and (iv) usability criteria for the use of steel slag in rigid or restrained matrices. This chapter introduces the answers to the first two questions and provides the mechanical model and criterion deduction to answer the other two questions that lead to criteria and specification establishment.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Asphalt mixtures contain asphalt binder and graded aggregates. Since the early stage of using bla... more Asphalt mixtures contain asphalt binder and graded aggregates. Since the early stage of using blast furnace slag and steel slag in hot-mix asphalt considerable experience has been accumulated through mix design, production, and construction. Quality control and technical specifications have been well developed to ensure the quality of steel slag asphalt concrete, minimize potential expansion, and take advantage of the positive features of high stability, skid and rutting resistance, and antistripping. In recent years new materials and construction techniques have been developed, such as warm-mix asphalt, cold in-place recycling, and various surface treatment methods that provide a broad platform to develop novel uses of ferrous, nonferrous, and nonmetallurgical slag aggregate products. This chapter introduces the basic technical requirements for aggregates, asphalt mixes, and pavement, and summarizes the experience of using slag in asphalt mixes and paving.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Utilizing slag in infrastructure construction is to practice and realize sustainability principle... more Utilizing slag in infrastructure construction is to practice and realize sustainability principles to improve the quality of life for society indefinitely without degrading the quantity, quality, or availability of natural, economic, and social resources. This utilization must produce environmentally acceptable end products. Regulations and guidance must strike the right balance between promoting a wide variety of applications and protecting the environment. Environmental regulations governing slag utilization should be clear, pertinent, and have efficacy to actual environmental performance outcomes. This chapter reviews relevant policies and regulations related to secondary material utilization and leaching tests, the main measure to evaluate potential environmental impact of slag use in construction, and special substances in certain slags that have been addressed during utilization.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Three case studies concerning steel slag and nickel slag use in highway construction and foundati... more Three case studies concerning steel slag and nickel slag use in highway construction and foundation construction are presented. In the Egnatia Odos highway project, electric arc furnace (EAF) slag aggregate was used as an aggregate of 25 mm open-graded hot-mix asphalt (HMA). In Saudi Arabia, EAF slag aggregate was used in stone column ground stylization to strengthen bearing capacity of local soils. In the Dominican Republic, ferronickel slag aggregate was used in granular base and HMA paving.

The Utilization of Slag in Civil Infrastructure Construction, 2016

Slag is regarded as a by-product after it is separated from base metal or element in smelting fur... more Slag is regarded as a by-product after it is separated from base metal or element in smelting furnaces or discharged from coal-firing boilers or municipal solid waste incinerators. Unlike normal primary product production in which the final required properties are carefully designed and adjusted during the production to meet the final products’ specifications, slag is produced with less consideration about its further use in construction applications. Its property is most likely to fluctuate. The inherent nature of slag and variation in chemical and mineral composition lead to variation of physical and mechanical properties of slag. To convert slag into useful and quality slag products for selective uses, processing and special treating are critical and inevitable. This chapter outlines the intrinsic properties of slag, and the evaluation and processing of slag.

Philosophy of Engineering and Technology, 2015

Ethical decision-making is central to the practice of construction engineering and management. Th... more Ethical decision-making is central to the practice of construction engineering and management. This is no more evident than in the twenty-first century, when the construction industry must function in very diverse organizational contexts. Whilst construction companies pursue projects in international markets, many investors are buying or forming joint ventures with domestic companies. New and varied professional attitudes have recently arrived in western markets such as the United States and Australia because construction companies are increasingly employing managers from developing nations to undertake commercial and infrastructure engineering projects. In many developing countries the construction industry is vulnerable to unethical behavior or corruption – vulnerability in part because of differences in culture and managerial systems across countries; and this diversity is manifest in the different perspectives of professional ethics and professional practice. Importantly, professionals in construction engineering must be aware of these differences; however current ethics education for engineering professionals generally lacks global components. In this chapter, emphasis is placed upon professional registration, including mandatory awareness of professional ethics, as an imperative for the welfare of world citizens; discussion on the nature of the construction industry and globalized trends emphasizes why ethics and professional education must be integrated within civil and construction engineering and management curricula. Only then we can anticipate an appropriate educational foundation for professional registration of the international engineer.