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Recycled gypsum powder from waste drywalls is a new alternative that has been recently introduced for partial cement replacement in concrete for construction applications. It has been shown that the recycled gypsum, alongside fly ash, can partially replace cement in concrete to some extent without hurting the required properties of concrete. In this paper, the impact of recycled gypsum content on the durability of concrete (hereafter called gypsum concrete) exposed to different environmental exposures is evaluated. A total of 153 concrete cylinders (100×200 mm) with different recycled gypsum contents (0%, 10%, and 20% of cement replacement) were considered. Each mix was exposed to air-dry, freshwater, seawater, freshwater–air dry cyclic, and seawater–air dry cyclic conditions. The specimens were tested in compression loading after 1,000, 3,000, and 6,000 h of exposure. Recycled gypsum used in this research was in two types of a powder with fine particles only (hereafter called fine gypsum) and in the form of mixed fine, coarse, and paper particles (hereafter called whole gypsum). Other mechanical and physical properties of concrete such as absorption, volume change, and ultrasonic pulse velocity were analyzed. It was observed that the compressive strength of the specimens with 10% and 20% fine gypsum content at Day 28 was about 36% and 40% lower than that of the control specimens, respectively. However, the strength gap was reduced to about 16% and 7% at the end of 6,000 h in the air-dry condition. The specimens submerged in freshwater and seawater showed a rate of strength gain higher than that of the control specimens, bringing the compressive strength of the gypsum concrete specimens slightly higher than that of the control specimens after 6,000 h exposure. Overall, recycled gypsum in combination with fly ash not only does not hurt the long-term strength of concrete but also can enhance the strength under certain conditions, mostly those exposures involving water exposure. [ABSTRACT FROM AUTHOR]

Corporations develop, own, operate, and direct a majority of all assets in the built environment (BE), and the development and operation of these assets is a significant component of global sustainability. In recent years corporate sustainability action for large companies has trended toward becoming embedded within corporate environmental, social, and governance (ESG) programs. However, ESG strategies and their impacts are only beginning to be understood by large corporations, with little definition for how to apply, measure, and assess the effectiveness of ESG practices. Every industry sector has some connection to the BE, and construction engineering, and management (CEM) professionals contribute to all phases of the BE life cycle, including development, design, construction, and operations. As such, CEM professionals are vital in developing and implementing sustainability practices specifically for corporations with large footprints in the BE. The purpose of this research was to assess the extent to which the BE is impacted by corporate sustainability practice through ESG programs. The research utilized a grounded theory approach to explore sustainability practices directly associated with the BE from companies within all 11 Global Industry Classification Standard (GICS) sectors. It presents a representative model that encapsulates current organizational ESG strategy, through the development of ESG action categories. A total of 24 different ESG action categories are presented and defined. The research further identifies those ESG actions commonly applied by large corporations and how these actions differ by GICS sector. This research indicates that over half of corporate ESG actions are related to the BE. Ultimately, this paper demonstrates the necessary role that CEM professionals should play in influencing sustainability practice through ESG strategy and action within the BE. Practical Applications: ESG is a rising topic in corporate sustainability and is becoming increasingly tied to financial instruments such as sustainable investment indexes or green bonds. The rise of ESG presents both a challenge and an opportunity for CEM professionals. Large entities are expected to publish ESG reports sharing their sustainability progress, including entities in which CEM professionals are key figures, such as power utilities. The advent of ESG reporting presents a challenge to CEM professionals because they need to learn to navigate ESG reporting or risk losing access to valuable funding opportunities when subject to ESG measurement and evaluation. It also presents an opportunity for CEM professionals because they are uniquely qualified to lead ESG efforts as BE experts. ESG and the BE are strongly related, with most ESG work being environmental in nature. CEM professionals have been actively involved in improving the sustainability of BE assets as they relate to the environment for many years. To leverage this experience, CEM professionals need to take an active part in recommending improvements to corporate ESG strategy. Corporations themselves must also actively seek to engage CEM professionals in their ESG decision making processes and advisory boards. [ABSTRACT FROM AUTHOR]

Quantifying recycled asphalt binder availability in recycled asphalt pavement (RAP) mix design is very essential, as the widely adopted 100% RAP binder availability assumption in RAP mix design never holds correct. Depending on the mix production condition, recycled binder stiffness, and virgin binder properties, the degree of binder availability in the mix is always partial. The present study proposes a simple procedure to estimate the degree of recycled binder availability in RAP mix design. In the proposed methodology, the designer needs to compare optimum binder content of bituminous mixes prepared using white rock aggregate gradation and virgin aggregates, along with mixes designed by blending black rock gradation and virgin aggregates blended in proportion to achieve the target white rock gradation. The binder content in the RAP fraction used in the blending exercise was determined using ignition oven method. RAP mix designs were performed for RAP material collected from two different sources, and design was performed for three mixing durations in a laboratory pug mill—60, 120, and 180s. The mixes were prepared with 50% RAP incorporation level. RAP material was conditioned at 110°C for 2 h, whereas virgin aggregates were superheated to 175°C. Using the methodology proposed, RAP binder availability was found to vary between 92.5% and 96.6% for softer RAP material, 75.9% to 91.5% for mixes incorporating stiffer RAP. With increasing mixing time, even though the total active binder content did not change significantly, a mixture performance test quantified the implication of increased RAP binder availability in mixes. A higher degree of binder activation resulted in mixes being rut resistant, while the same mixes exhibited relatively higher cracking susceptibility. Recycling of bituminous mixes has been considered as one of the sustainable practices in the highway construction industry. In a recycled bituminous mix, the milled material contributes good quality aggregates, and aged bituminous binder. The amount of aged bituminous binder that can be mobilized in the recycling process largely depends on mix production condition, milled, and virgin material property. The paper presents a simple methodology to quantify the degree of bituminous binder which becomes available in recycled mix design. The methodology can be used by mix designers to account for appropriate adjustment in virgin binder grade selection. The knowledge of degree of binder availability would also enable, if one targets to synthesize recycled mixes of a definite binder content. The paper also investigated the implication of different degree of binder availability on mix performance, arising due to different mixing time (production condition) and milled material property. [ABSTRACT FROM AUTHOR]

To adequately facilitate project digital responsibility implementation (PDRI), a solid comprehension of the influencing factors and effective strategies that influence project digital responsibility implementation are necessary. Surprisingly, despite the increased interest in digital responsibility over the last few years, there still is a significant dearth of digital responsibility implementation. In practice, the factors that influence project digital responsibility implementation are complex and interconnected, not simple and isolated. Due to the omission of the causal relationship between these influencing factors, the project digital responsibility is not implemented effectively. This paper describes the process of identifying and classifying the factors influencing the project digital responsibility implementation, taking into account the network of interconnected factors. Four primary data sources and methodologies yielded new insights into the nature of these influential factors: a systematic literature review, semistructured interviews, fuzzy interpretative structural modeling, and cross-impact matrix multiplication applied to classification. Our analysis demonstrates that the 26 factors influencing project digital responsibility implementation interact and form a 9-level hierarchy. The 26 factors can be subdivided further into four dimensions: project dimension, stakeholder dimension, market environment dimension, and government dimension. Notably, the influencing factors in the government dimension have the most driving force, and adjusting the influencing factor in this dimension can enhance the influencing factors in the other dimensions. Finally, 11 policy proposals are proposed along 4 dimensions. This study bridges the knowledge gap of PDRI by providing new insights targeting the factors influencing PDRI. The findings provide valuable information for policy makers and practitioners to adopt effective measures to promote the implementation of PDRI. [ABSTRACT FROM AUTHOR]

Mixed multiple seismic systems (MMSSs) are ideally suited for sustainable seismic design (SSD). MMSSs are combinations of two or more different earthquake-resisting structures (ERSs) that provide lateral support for gravity frameworks. Same-system combinations have been demonstrated to not be suitable for SSD. Regardless of the carbon footprint reduction, unless a structure has been designed for seismic sustainability it would be disposable with greater harm to the environment. Here, design means planning for both seismic resistance as well as post-earthquake realignment and repair (PERR). Earthquakes are random, natural, and dynamic events, whereas PERR is a deliberate, manual, and static process. In SSD the practicality of PERR is as important as the relevance of the theoretical assumptions. In SSD the non-lateral-resisting items are designed not to partake in seismic resistance, nor hinder the realignment process. Additionally, efforts are made to mitigate the P -delta effects that undermine the global strength of the system and oppose the recentering effort. The purpose of this paper is to identify and remedy design flaws and physical issues that prevent MMSSs from achieving seismic sustainability as cost-effectively as possible. Two newly developed technologies, the ladder moment frame (LMF), and the fail-safe (FS) system, as well as a capacity distribution rule together with six simple axioms are introduced. Brief descriptions of LMF and FS are presented in the text. Any structure designed to survive earthquakes is expected to either remain elastic and stable or be capable of post-earthquake realignment and repairs. Sustainable seismic design is a new field of research that promises improved environmental conditions and innovative developments in structural engineering. Regardless of the carbon footprint reduction, unless a structure has been designed for the purpose, it would be disposable with greater harm to the environment. Here, design implies planning for seismic resistance as well as post-earthquake realignment and repairs. The difference between conventional and sustainable seismic design is in the modes of behavior during and after the event. In conventional seismic design, the object is to satisfy code-specified requirements; in sustainable seismic design, the post-earthquake attributes of the system are as important as those during the event. The paper shows that seismic sustainability can be achieved without resorting to untenable costs and technologies. In light of current findings, it is suggested to include post-earthquake realignment and repairs in seismic design guidelines for new construction. [ABSTRACT FROM AUTHOR]

This paper evaluated the effect of a biobased polyurethane modifier on the moisture resistance of asphalt binder. Biomodifiers with high acid values have been implicated in moisture damage to asphalt. Here, castor oil with a relatively high acid value of 190 mg KOH·g−1 was used to produce biobased polyurethane. Biobased polyurethane was produced by combining castor oil, toluene diisocyanate (TDI), and diethylene glycol (DEG) at a molar ratio of 1∶2∶1. Asphalt binder was modified with 3%, 6%, or 9% of the biobased polyurethane (by weight of asphalt binder), and the moisture susceptibility of the modified asphalt was evaluated with a comprehensive laboratory experiment plan using the boiling water test, the indirect tensile strength test, the bitumen bond strength test, the water contact-angle moisture-susceptibility test, and the moisture-induced shear-thinning index test. Study results showed that the introduction of biobased polyurethane enhanced the bond between the aggregate and asphalt, thereby increasing the asphalt mixture's resistance to moisture damage. Consequently, the resistance of asphalt binders to cohesive failure and adhesive failure was enhanced in biobased polyurethane, as evidenced by respective increases of 19%, 40%, and 49% in tensile strength ratio for dosages of 3%, 6%, and 9% biobased polyurethane. Compared with neat asphalt, the asphalt blend containing 9% polyurethane had the highest bond-strength increases, 55.73% and 37.93%, for dry and wet conditions, respectively. This improvement is attributable to the phenol and amide components in biobased polyurethane, which increase the polarity of asphalt binder and increase the affinity of asphalt binder to siliceous aggregate. In addition, the moisture-induced shear-thinning index and the contact-angle moisture-susceptibility index showed that increased doses of biobased polyurethane resulted in increased resistance of asphalt to moisture damage. The study outcomes promote the sustainability of asphalt construction by introducing biobased polyurethane as a sustainable modifier for asphalt. [ABSTRACT FROM AUTHOR]

This paper presents the development, testing, and characterization of an innovative low-cost fail-safe sustainable energydissipation device in which the material surrounding the moving piston and enclosed within the damper housing is pressurized sand. The proposed sand damper does not suffer from the challenge of viscous heating and failure of its end seals, and it can be implemented in harsh environments with either high or low temperatures. Its symmetric force output is velocity-independent, and it can be continuously monitored and adjusted at will with standard commercially available strain gauges installed along the post-tensioned rods that exert the pressure on the sand. Component testing at various levels of pressure, stroke amplitude, and cycling frequency show that the proposed pressurized sand damper exhibits stable hysteretic cyclic behavior with increasing pinching at larger strokes. The paper examines the fidelity of an eight-parameter Bouc-Wen hysteretic model capable to model pinching and concludes that the proposed hysteretic model is able to capture the pronounced pinching of the hysteretic behavior at larger stroke amplitudes. Four of the eight parameters of the proposed hysteretic model can be determined a priori from physical arguments; therefore, only the remaining four parameters need to be determined from nonlinear regression analysis. [ABSTRACT FROM AUTHOR]

The disposal of waste face masks (FM) caused by COVID-19 has become an increasingly severe problem. In order to alleviate this issue, this paper proposes an approach of adding face mask waste as modifiers to asphalt. Extensive performance tests evaluated the feasibility of FM in asphalt binders, including rotational viscosity and rheological behaviors at different temperatures, aging performance, separation tendency, and modification mechanism. Based on this, the road performance of FM-modified asphalt mixtures were also investigated. The results showed that FM increased the rotational viscosity, high-temperature performance, and anticreep performance, whereas it had a negative effect on the stress change sensitivity, low-temperature performance, aging performance, and storage stability of asphalt binder. Based on the linear amplitude sweep test results, the incorporation of FM contributed to the material integrity and load resistance capacity of asphalt binder, whereas it was not conducive to its antideformation performance. According to Fourier transform infrared spectroscopy and fluorescence images, the modification process of FM with a chemical composition of polypropylene was mainly a physical blend, and 5% FM had the best compatibility with asphalt. The addition of FM could improve Marshall stability, rutting resistance, low-temperature cracking resistance, and moisture susceptibility of an AC-13 mixture. The 5% FM-modified asphalt and asphalt mixture met the specific road requirements. The experiment results could provide a new way to deal with waste FM by recycling. [ABSTRACT FROM AUTHOR]

Hot in-place recycling (HIR) technology, 100% recycling reclaimed asphalt pavement (RAP), has been widely used as a sustainable maintenance treatment. However, the inhomogeneity of RAP makes it impossible to securely assume that the produced mixture properties will match the laboratory design. For HIR projects, a virgin asphalt mixture (VAM) is added to modify the gradation of the existing rutted pavement. However, once the quantities of VAM added to areas of rutting are varied along the driving direction, the desired construction quality cannot be maintained. In this paper, a method to estimate the quantities of VAM needed for areas with rutting along the driving direction is proposed. To verify the feasibility of the proposed method and explore the effects of varying VAM content caused by rutting depth (RD) distribution variation on construction quality, performance tests of all samples, including two gradation types of virgin aggregates and five VAM contents, were conducted in the laboratory. Test results indicate that the pavement performance of the recycled mixture with continuously graded virgin aggregates is more stable due to the similar gradation of RAP, while the performance of the recycled mixture with gap-graded virgin aggregates possesses substantial fluctuation. Specifically, when the required VAM content is lower than 15%, namely, all monitored RDs less than 10 mm, gap-graded virgin aggregates are more highly recommended from a high-temperature stability perspective. When the required VAM content ranges from 10% to 15%, namely, all monitored RDs ranging from 5.9 to 10 mm, the continuously graded virgin aggregates should be considered first with respect to low-temperature performance. To improve moisture susceptibility, the continuously graded virgin aggregates are more appropriate. [ABSTRACT FROM AUTHOR]

The architecture, engineering, and construction (AEC) industry globally has a long history of prudently adopting novel technologies to improve products and services. Yet the rapid development of digital technology currently taking place is threatening to produce a more disruptive inflection, or substantial jolt. This paper explores the state of readiness of the AEC industry for such anticipated transformation. We illustrate our conceptual arguments with evidence from an explorative study across a sample of AEC organizations in Australia. At the core of this paper, we offer six provocations that highlight what we consider major challenges for the AEC industry—across multiple levels of analysis—related to the increasing role of digital technology. We then turn to lessons learned from other industries in order to propose a framework consisting of four leadership thinking schemas to enable digital transformation readiness: future thinking, strategic thinking, capability thinking, and experimental thinking. For these four schemas, we present practices and initiatives that may help AEC firms to better adapt—or to proactively create and shape a sustainable future. [ABSTRACT FROM AUTHOR]

Cold in-place recycling (CIR) is a pavement rehabilitation technique that has been used for decades. During this time, singlecomponent binder (SCB) systems have governed the market. Single-component binders are defined as those with one binder or two if the secondary binder dosage is 1% or less (e.g., 3% asphalt emulsion with 1% hydrated lime). In contrast, this paper investigates multiplecomponent binder (MCB) systems (e.g., 2.5% emulsion with 2% portland cement). This paper's objective is threefold: (1) present a universal CIR design framework applicable to any cementitious and/or bituminous material; (2) demonstrate MCB sustainability advantages; and (3) conduct an extensive SCB and MCB characterization. Universal design framework components include specimen preparation, curing, and testing protocols. Nine binder combinations were tested for wheel tracking, permeability, modulus, strength, and cracking response. Cement SCBs yielded low cracking resistance, high rutting resistance, and favorable economics; emulsion SCBs yielded the opposite. Multiple-component binders balanced cracking, rutting, and economics. The work presented in this paper could benefit agencies in many ways, for example, by promoting informed decisions regarding CIR performance and economics. [ABSTRACT FROM AUTHOR]

Production of alkali-activated binders is a developing research field that utilizes industrial/agricultural by-products and solid waste for the development of sustainable concrete. This paper comprehensively reviews the literature relating to rice husk ash (RHA)–based alkali-activated binders incorporating fly ash (low/high calcium) and blast furnace slag. The literature demonstrates that the properties of raw material significantly influence the formation of the alkali-activated gel matrix. Every precursor (low/high calcium fly ash and slag) that is used to develop alkali-activated binders with RHA have their own reaction mechanism dependant on their specific chemical composition. Hence the incorporation of RHA influences each binder in a unique way depending upon the alkali activation process and reaction mechanisms. The incorporation of RHA, in the range 5%–15%, with blended slag alkali activated binders, yields better compressive strength, when compared with RHA blended with fly ash (low/high calcium). The review presented in this paper is very useful to understand the behavior of alkali-activated binders incorporating RHA and in advancing the research into the successful application of RHA as a binder for alkali-activated materials. [ABSTRACT FROM AUTHOR]

Production strategies and parameters control the efficiency of geothermal energy extraction related to the thermal stability and economic benefits of a geothermal system. The optimization strategies of geothermal energy extraction play a critical role in engineering and are generally determined through a numerical simulation approach. Considering the correlation among production parameters, numerical simulation requires numerous runs and manual adjustments, resulting in lower calculation efficiency and limited or local optimizations. This study proposes a high-efficiency network based on a three-dimensional heterogeneity model in the Gonghe Basin in China to achieve a high-efficiency and high-precision production strategy. The neural network was successfully established as a surrogate of the numerical model for the repetitive forward simulation. Meanwhile, the neural network is integrated with the Harris Hawks algorithm to optimize extraction strategies for sustainable heat extraction. This paper focuses on the effects of human-controlled operational parameters on geothermal systems. Results indicated that the maximum electrical power can be guaranteed 5.2 MW during a 50-year production period at an injection temperature of 60°C, an injection rate of 39 kg/s , and a well spacing of 380 m. The study provides important operational guidance for sustainable utilization in the Gonghe Basin. This simulation-optimization approach can be applied to other geothermal sites for sustainable energy production. [ABSTRACT FROM AUTHOR]

Most geopolymer research claims a substantial reduction in carbon dioxide emissions compared with ordinary portland cement concrete. However, geopolymer concretes are not all equally eco-friendly. The environmental benefits of geopolymer concrete cannot be taken for granted. Modeling emissions is necessary to assess the environmental impact of each geopolymer mix. Unfortunately, only studies concerned with carbon dioxide emissions care to provide sophisticated emissions modeling. Such modeling is practically nonexistent for other geopolymer studies; because function-oriented geopolymer research tends to assume the environmental eminence of their designed mixes. This research reviews the last 7 years of geopolymer concrete research to assess the sustainability of the mixes designed by researchers worldwide and to highlight any bad environmental practices in the mix design. The nominal CO2-e equivalent emissions for geopolymer concrete mixes varied from 56 to 661 kg-CO2/m3 for the surveyed mixes. SOx and NOx emissions reached 1,865 g-SOx/m3 and 1,161 g-NOx/m3 , respectively. Finally, this paper recommends a simple method for estimating a nominal carbon dioxide emissions value, which can be easily implemented in future geopolymer research. [ABSTRACT FROM AUTHOR]

Design teams must make numerous decisions in building design, including choosing materials. Lately, they have become more concerned about the social and environmental effects of their choices, in addition to the economic constraints. These concerns, in addition to the increasing offerings of construction materials and products and the engagement of more stakeholders, make decisions more complex. As decision complexity increases, so does the need to systematically use sound decision-making methods. However, in practice many decisions are made without a formal method or discussion, thereby often generating conflict and waste in the design process. Further, even if practitioners are looking for better decision-making methods, the literature does not provide enough support for them to choose the best method for this context. This research fills the literature gap and provides a systematic approach as well as practical advice for decision makers by demonstrating the application of a method, called choosing by advantages (CBA). CBA creates transparent and collaborative environments in which to make decisions. To illustrate the use of CBA, this paper provides a detailed example of choosing materials, in this case ceiling tiles, in a commercial interior design project considering global supply chain issues. This paper contributes to the body of knowledge by illustrating how to use CBA for (1) integrating multiple perspectives, (2) identifying relevant sustainability factors, (3) making transparent trade-offs, (4) documenting a decision rationale, (5) separating value from cost, (6) organizing location-dependent factors, and (7) incorporating supply chain issues. CBA is a method worth adding to the toolbox of design teams determined to chose globally sustainable materials. [ABSTRACT FROM AUTHOR]

The construction industry has grown significantly to fulfill the expanding need for accommodation, facilities, welfare, and services resulting from the rapid increase in the global population. Infrastructure projects in particular facilitate transportation and services for both new and existing areas, yet they are also one of the primary producers of construction waste, which is harmful to both society and the environment. Hence, the objective of this paper is to identify the factors affecting construction waste management in infrastructure projects (CWMIIP) and study their respective impacts on construction waste management (CWM) performance. This study makes a unique contribution by not only addressing the factors that influence the development of construction wastes and their importance, but also by giving quantifiable solutions and action plans to reduce the waste. Using a literature review, 26 factors were selected as the major contributors to construction waste in infrastructure projects. An online questionnaire was then developed to collect data on the respective impacts of these factors. A total of 167 complete responses to the questionnaire were collected, and a structural equation model (SEM) was developed to quantitatively measure the impact of each factor on waste management performance. The model was validated using goodness of fit (GOF), multivariate normality, construct validity, reliability, and hypotheses analyses. The results indicate that the most significant factors affecting the generation of construction wastes are "quantity take-off error by contractor," "unforeseen incidents damaging site and/or completed works," "design errors," and "extreme weather conditions damaging completed works." The model results showed that all predefined hypotheses were supported, except for the positive effect of the logistics group, which was dropped during model development. Individual factors were also divided into groups, and the total impact of each group was assessed; the "management" group had the greatest impact, followed by "execution," "others," and "procurement." Based on these findings, we make several recommendations to construction industry professionals to reduce waste and mitigate its harmful effects, such as requiring a construction waste management implementation plan before awarding a project to a contractor; engaging with project suppliers to provide execution training for contractor staff; ensuring proper implementation of health, safety, and environmental plans; and purchasing locally available materials. This research built a model based on structural equation modeling that will help researchers better understand the links between building waste management parameters. To examine the impact of each waste component on construction waste management performance, a quantitative model is built based on the data obtained. This quantitative waste management model could be used to track construction waste management performance. The findings of this study are not limited to infrastructure projects because they may be tailored to fit any project. As a result, it is recommended that project contractors and supervision consultants rely on the factors responsible for construction waste generation identified in this study to capture their actual construction waste factors. Also, having a record and log of all construction wastes generated during a project, as well as the reasons for these wastes, would help the organization improve its waste management learning curve for future projects. [ABSTRACT FROM AUTHOR]

Improvement of poor engineering properties for very high-moisture content fine-grained soils (VHMS) is important for several industries, including dredging. This paper focuses on improving engineering properties of VHMS by way of adding low dosages of portlandlimestone cement (PLC) such as ASTM C595 Type IL, which is a more sustainable alternative to ordinary portland cement (OPC) such as ASTM C150 Type I. A key goal was to determine if PLC can satisfactorily enhance the properties of lightly cemented (LC) VHMS (LC-VHMS), defined as having 5% or less cement by total mass. This paper focuses exclusively on the behavior of PLC versus OPC by making use of five matched pairs of OPCs and PLCs from four different cement manufacturing facilities. A series of index property, unconfined compression (UC), and unconsolidated undrained (UU) triaxial tests were performed on LC-VHMS samples collected from a dredged disposal facility near the port of Mobile, Alabama. Overall, the results suggested that using PLC in LC-VHMS can provide a sustainable alternative to OPC while leading to comparable engineering properties (5% stronger to 8% weaker overall depending on the test type). [ABSTRACT FROM AUTHOR]

Building sustainable green cities for the future can be difficult or highly challenging as such cities need to reduce their environmental footprint through eco-friendly materials, resource and energy conservation, as well as renewable energy generation. A recent paper by the first author has proposed sustainable concrete with 80% ground granulated blast furnace slag (GGBFS) to build Masdar City in the UAE with a 153 kg/m³ carbon footprint. This paper proposes three new types of sustainable concretes in an attempt to further reduce the carbon footprint. In Type I, a total of 4 concrete mixes were made with a high volume GGBFS with 60, 70, 80, and 90% replacement of ordinary portland cement (OPC), 100% recycled water (RW), and 100% recycled aggregate (RA). The same replacement ratios were used in Type II but with only 100% RA. In Type III, a total of four concrete mixes made with a high volume fly ash (FA) cement with 40, 50, 60, and 70% replacement of OPC. The paper provides information on the mix design, full justification of CO2 footprint, and the cost for each concrete mix. The hardened and plastic properties and durability test parameters for each mix are presented. The results showed that the fly ash and slag significantly reduced the carbon footprint and meet the requirements of future sustainable cities. An economical mix with 90% GGBFS and 10% OPC was nominated for use in the future construction of sustainable cities with 125 kg/m³ emissions. [ABSTRACT FROM AUTHOR]

This paper aims to highlight the critical problems associated with the construction supply chain (CSC) by analyzing the literature and shedding light on the existing research limitations and gaps. Moreover, this research aims to explore the applications of emerging blockchain technology in addressing the identified CSC issues and initiating the process of bridging the body of knowledge gap by proposing future research directions. The review demonstrates that the critical problems in the CSC are related to sustainability, collaboration, and information sharing. Existing CSC studies focus on each individual issue, and they have not yet tackled these key intertwined issues through a holistic system view approach. This research put into context the intertwined relationship of these key issues and proposes a supply chain management system coupled with emerging blockchain technology to enhance sustainability, promote collaboration, and facilitate information sharing. These findings are synthesized with different reviews of the literature on the use of blockchain applications in supply chains to propose a blockchain-enabled CSC that can fill the research gaps. The proposed blockchain applications in the CSC involve establishing a blockchain-enabled supplier selection and assessment, blockchain-assisted claims auditing, forensic analysis and dispute resolution, and smart contract-based governance to enforce a reward and punishment system that can facilitate information sharing, and thus promote collaboration. The integration of the two different literature reviews contributes to the body of knowledge by highlighting the research gaps in the existing CSC studies and providing opportunities for improvement through the use of an emerging state-of-art technology: blockchain. Furthermore, the construction industry can enhance its sustainability and promote collaboration and information sharing in its supply chains by leveraging the proposed applications. [ABSTRACT FROM AUTHOR]

Designing urban water infrastructure systems for environmental sustainability requires consideration of hydrologic performance design criteria and results from life cycle assessment (LCA). The objective of this paper is to present a study of merging hydrologic and LCA criteria into the evaluation of the environmental sustainability of rainwater harvesting (RWH) to control combined sewer overflows (CSOs). A case study of the City of Toledo, Ohio combined sewer system serves as the platform to investigate the two approaches and to compare RWH with centralized gray infrastructure strategies for controlling CSOs. Results show that the four RWH scenarios studied (two RWH-only: one to supply toilet flushing demand and the other to serve as extended detention; and two hybrids based on combining the two previous with gray infrastructure) delivered higher combined sewage volumes to wastewater treatment facilities compared to a gray infrastructure-only scenario. This resulted in elevated life cycle global warming potential (GWP) impacts (1.10 kg CO2e per 1 m² of reduced CSOs) on average for the four RWH scenarios. The gray infrastructure-only scenario reduced GWP impacts because it included sewer separation leading to lowered amounts of combined sewage volume treated (-1.89 kgCO2e per 1 m² of reduced CSOs). But, due to the untreated stormwater discharges to receiving waters, the gray infrastructure-only scenario led to a higher ecotoxicity water (ETW) impact [-12.11 comparative toxic unit for ecotoxicity (CTU eco) per 1 m² of reduced CSOs] compared to the RWH scenarios (-19.62 CTU eco per 1 m² of reduced CSOs on average). In conclusion, the new watershed-scale LCA framework led to more information on the CSO control strategies compared to hydrologic-only analysis, but it created a more complicated decision. Information from Toledo water stakeholders must be taken into account before nominating a scenario as the one that globally outperforms the others according the multi-hydrologic-LCA criteria. [ABSTRACT FROM AUTHOR]

The replacement rates of portland cement by ceramic waste powder (CWP) are generally limited to few percentages (i.e., less than 10%), as increased additions lead to inferior concrete strength and durability. This paper assesses the importance of blending CWP with blast furnace slag (BFS) to foster synergistic pozzolanic reactions and reinstate strength development despite increased cement replacement rates. Tested binders contained different cement-CWP-BFS proportions, while the evaluated properties included the compressive, splitting tensile, and flexural strengths in addition to the modulus of elasticity, freeze/thaw resistance, and thermal transmittance. Test results showed that concrete strength and durability gradually degraded when the cement was partially replaced by 10%–20% CWP, given the dilution effect that alters hydration reactions and overall porosity. Yet, the concrete properties significantly improved when the CWP and BFS materials were both incorporated in the same binder, indicating the occurrence of synergistic pozzolanic reactions that refined the matrix microstructure. Hence, concrete prepared with ternary binder containing 50% cement, 15% CWP, and 35% BFS exhibited durability and strength properties at 56 days comparable to the control mix made with 100% cement. [ABSTRACT FROM AUTHOR]

Although post-occupancy evaluation (POE) is an old tool with hundreds of studies, it is yet to become routine in the housing industry. The growing complexity of buildings and emerging trends in the industry further reinforces the need to carry out more POE studies. Though some studies exist, a holistic approach is yet to be given priority in the industry. This paper presents an overview of POE; it presents a broad introduction, levels of investigation, POE methods, performance elements related to the housing context, and POE tools and frameworks. It also highlights key benefits to be derived from a POE and barriers forestalling its adoption in the industry. The goal of this paper is to provide a foundation and source of reference for current research in housing evaluation studies. [ABSTRACT FROM AUTHOR]

There is an urgent need for policies to close the existing financing gap for civil infrastructure. However, identification of the desired scenarios for the closure of the financing gap is complex because there are many factors that affect investment in infrastructure. Thus, comprehensive models are required to (1) simulate the impacts of policies, and (2) identify the highly likely scenarios for desired policy outcomes. The objective of this paper is to create a simulation model for ex-ante analysis of financing policies in highway transportation infrastructure in the United States. Using the agent-based technique, this model simulates the microbehaviors of state Departments of Transportation, private institutional investors, and the public. Using the output of the simulation model, financing landscapes of the U.S. transportation infrastructure are developed. The simulated landscape is shown to be helpful in identifying the highly likely scenarios leading to a high level of investment in highway transportation infrastructure under the existing infrastructure investment structures and budget constraints in the United States. The study presented in this paper is novel with respect to (1) the application of the system-of-systems modeling in the analysis of transportation infrastructure financing policies, (2) identification of the desired policy scenarios and their likelihoods for closure of the financing gap in the presence of uncertainties and adaptive behaviors, and (3) simulation and visualization of the impacts of financing policies at the state and national levels. The model promotes a data-driven policy analysis and provides policymakers with a tool to simultaneously account for the impacts of several factors and uncertainties. [ABSTRACT FROM AUTHOR]

Currently, foundation piles for inhabited areas are often constructed using a continuous flight auger, which is a cost- and time-efficient technology that does not require stabilization of the borehole wall; the steel bar reinforcement is embedded after the concrete has been poured. However, this reinforcement operation can lead to severe construction and structural issues. Thus, several improvements to this technology have been proposed since its first application in the 20th century, such as the use of more fluid concretes. Nevertheless, steel and polymers are emerging as a potential replacement for steel bars in concrete reinforcement for several types of structures and building components, with identified and quantified benefits from a sustainability perspective. Accordingly, this paper proposes and validates a multicriteria decision-making approach designed with multidisciplinary experts within the construction field to assess the sustainability index of concrete pile foundations. The results of a case study enable us to conclude that polymeric fiber-reinforced concrete piles are the most sustainable due to their cost–structural efficiency ratio, high durability, and minimal risks during construction. Steel fiber-reinforced concrete alternatives were also found to be more sustainable than traditional reinforced concrete. Nonetheless, these results are unrepresentative of the current practice as direct costs were found to be the main driver in the decision-making processes, while other costs and both environmental and social indicators are disregarded. This justifies the urgency to provide sustainability-driven decision-making approaches capable of objectively quantifying the satisfaction degree of economic, environmental, and social indicators involved in the analysis. [ABSTRACT FROM AUTHOR]

Water distribution networks (WDNs) confront momentous challenges, including the need to meet continuously increased demand, combat unforeseen disruptions, and reduce carbon emissions. Developing efficient plans for resilience enhancement of WDNs thus is essential recognizing the ubiquitous nature of WDNs and increased frequency and destructive severity of hazardous events. This paper presents a resilience-driven multiobjective optimization model to maximize the resilience of WDNs while minimizing the life-cycle cost and carbon emissions. Enhancement actions first are determined and clustered into work packages, and then an optimized schedule is generated considering various operational and managerial factors. A real WDN in the city of London, Ontario, was utilized to demonstrate the proposed model's practicality. The resilience increased by 24% with CAD 1.6 million investment. Additionally, cost saving of about 33% is achievable if the proposed model is employed instead of a currently utilized practice. The developed model is expected to help city managers establish optimal resilience enhancement plans, considering tight available budgets and limited workforce. [ABSTRACT FROM AUTHOR]

The durability and sustainability of concrete structures is a prime socioeconomic concern of contemporary society. The lifecycle of these structures is typically determined by the rate of moisture ingress, in which dissolved and unwanted substances are transported into the structure. Therefore finding a sufficient means to measure these rates is of utmost importance. A sorptivity testing scheme as outlined by a commonly used standard can be a useful means of measuring how quickly liquid can be transported unidirectionally through concrete samples in the laboratory. Currently the standard prescribes that disc specimens 100 mm in diameter and 50-mm thick be sealed in such a manner to ensure unidirectional flow through one, unsealed face of the sample, while all other surfaces are appropriately sealed. However the standard does not specify how this seal is to be achieved. Furthermore, differing methods have yielded a likewise array of varied results, which may not be representative of the true sorptivity. The objective of this paper is to propose a simple but effective means of sealing the specimens that will yield more consistent results, which are more representative of the actual absorption properties of the concrete. This was accomplished by studying the performance of electrical insulation tape and cellophane (as suggested in the standard) against paraffin wax using three different mixture designs, as follows: (1) involving normal strength concrete without air entrainment, (2) a normal strength concrete mixture with air entrapment, and (3) self-consolidating concrete without air entrapment. The prepared specimens were subjected to various freeze-thaw cycling periods, conditioned, and then tested for sorptivity. Batches of samples were exposed to freeze-thaw cycling periods of 0, 50, 100, 150, 200, and 300 cycles. Within each group of samples, half of the specimens were sealed with electrical tape and cellophane, and the other half were sealed with paraffin wax in order to conduct sorptivity testing. Specimens coated in wax typically exhibited lower absorption values than those wrapped in tape. Furthermore, the tape would not adhere perfectly with the concrete at the edge formed by the cylindrical wall and the exposed surface, resulting in increased sorptivity values. Statistical analysis was done on the rates of early-age (0-6 h) and late-age (1-8 days) sorptivity by using the F-test to examine variability (with an 80% confidence interval) and the student-t test was used to evaluate the significance of differences in sample means. Generally, sorptivity rates were higher for taped samples than those for waxed samples. These results further reinforced visual observations. The waxed samples yielded more reliable results primarily because they did not absorb moisture artificially along the sides in the manner as observed in the taped specimens. Moreover, the paraffin wax sealant method also resulted in less variability within test results. Therefore it was believed that the wax facilitated more representative results of the true sorptivity. It was suggested that the procedures of the common standard discussed in this paper should be refined such that the sealing of test specimens should be done with the use of paraffin wax, or some other similar substance, such as silicone, which is impermeable and readily available commercially. [ABSTRACT FROM AUTHOR]

Nevertheless, several challenges have prevented the success of green bidding implementation in current practice, including difficulty in establishing a powerful bidding preference that has the capability to effectively encourage every construction-oriented party toward sustainability. This paper developed a novel, sustainable bidding model to identify a potential environmental weight for evaluating the environmental impacts using the amount of CO2 emission generated from construction equipment fleet operations. A highway construction project case study in Thailand was used to evaluate the performance and capabilities of the developed model in specifying possible environmental weights toward sustainable bidding. The model facilitated the quantification of different construction equipment mixes and their impact on the environment, based on the cost per kilogram of CO2 equivalent for inclusion in the bidding award preference. The model was validated to investigate the green bidding preference awarded to a contractor. The validation results confirmed the benefit of including the environmental weight in the bidder evaluation to provide better opportunities for contractors pursuing sustainability in bid winning under an impartial and more practicable environment. The developed model contributes to (1) promoting greater practicality in the existing confined green bidding mechanism by incorporating an effective sustainability weight for green performance evaluation of construction bidders and (2) reducing the substantial environmental impacts of construction equipment by offering incentives in the primitive bidding approach to create sustainable initiatives for public works contractors. [ABSTRACT FROM AUTHOR]

A holistic evaluation of a building's environmental impact must include a thorough accounting of both its operating and embodied energies, inclusive of the influence of hazard-induced damage and repairs. Unfortunately, these considerations are notoriously absent in today's practice owing to a traditionally segmented approach to the design process that has perpetuated interoperability challenges between existing commercial tools. In response to this and other limitations of existing approaches, this paper offers an integrated life-cycle assessment (iLCA) that (1) considers the effects of site-specific climate and exposure to wind and seismic hazards on a building's embodied and operating energy, (2) adopts an assembly-based approach to reveal the specific components influencing performance outcomes, (3) accommodates both risk-neutral and risk-adverse perspectives, and (4) addresses interoperability challenges that limit access to the data stored within commercial building information models. The resulting iLCA is partitioned into a sustainability workflow, with modules dedicated to embodied and operating energy, and a resilience workflow, sequencing modules for hazard characterization, structural response, damage, and repair/loss. A custom parser leverages semantic technologies to efficiently extract geometry and material information from the underlying data structures of Revit building information models; this parser ultimately supplies the required building data to each module. A unifying probabilistic framework is then adopted to quantify life-cycle performance, in terms of repair costs and total (embodied and operating) energy, with emphasis placed on expanding the statistical descriptions of performance to support both risk-neutral and risk-averse decision-making. The iLCA is applied to a case study office building at two sites to demonstrate the effects of climate and wind and seismic hazards on the performance of specific components over different service lives, inclusive of potential performance variability due to hazard exposure. The framework is further leveraged to examine how different sources of uncertainty, or assumptions surrounding the quantification of this uncertainty, impact life-cycle performance estimates. [ABSTRACT FROM AUTHOR]

Despite the efforts of governments to promote sustainable construction practices, the decision to adopt sustainability practices largely falls upon the firms involved in construction projects. This paper presents an econometric model that describes the relationship between the level of sustainability experience a firm possesses and its characteristics and behavioral attributes. Data for this research were collected in Qatar by means of a survey as part of a study that aimed to analyze the triggers of sustainability adoption in the Qatari construction market. The presented model showed that a number of behavioral attributes of firms, besides their origin and the average size of projects they undertake, determine the level of sustainability experience these firms might have. Examples include firms’ risk-taking tendencies, their claimed competitive advantages, and their previous history of introducing changes to their modus operandi. This research adds to the body of knowledge on sustainable construction by studying its adoption from an organizational behavior perspective that focuses on factors internal to the firms. This complements existing literature that studies external triggers such as governmental policies. [ABSTRACT FROM AUTHOR]

The present paper reports on the analysis performed over a set of 44 final designs projected in the period 2000 to 2007, and is aimed at performing a quantitative and qualitative analysis on the prevalence of project deficiencies in flat roofs in construction building projects. The methodology is based on the study of a set of control parameters to point out the most frequent deficiencies in flat-roof designs. Out of the total number of sample projects, only eight (18.18% of total number of projects) were categorized as high-quality projects, while 17 (38.63%) and 19 (43.18%) were finally regarded as intermediate and low-quality, respectively. The use of accurate methodologies at former project stages to identify potential failures or construction deficiencies in advance is a successful predictive strategy, which directly enhances infrastructure sustainability. It provided they might prevent between 70 and 80% of the standard pathologies addressed for flat roofs, and might moreover achieve annual saving rates as high as €10-12=m2 during building use. [ABSTRACT FROM AUTHOR]

This paper reports the results of an initial attempt of using iron ore tailings (IOTs) to develop greener engineered cementitious composites (ECCs). ECC is a unique class of high-performance fiber-reinforced cementitious composites featuring high tensile ductility and durability. However, the high cement usage in ECC limits the material greenness and increases the material cost compared with normal concrete. In this paper, IOTs in powder form are used to partially replace cement to enhance the environmental sustainability of ECC. Mechanical properties and material greenness of ECC containing various proportions of IOTs are investigated. The newly developed versions of ECC in this paper, with a cement content of , exhibit a tensile ductility of 2.3-3.3%, tensile strength of 5.1-6.0 MPa, and compressive strength of 46-57 MPa at 28 days. The replacement of cement with IOTs results in 10-32% reduction in energy consumption and 29-63% reduction in carbon dioxide emissions in green ECC compared with typical ECC. Thus, the feasibility of producing greener ECC with significantly reduced environmental impact using IOTs, and maintaining the mechanical properties of typical ECC, is experimentally demonstrated in this paper. [ABSTRACT FROM AUTHOR]

This paper presents a holistic postoccupancy evaluation (POE) framework and its application to a campus residential facility. The development of a framework was based on an extensive review of literature and an identification of a comprehensive set of performance indicators. Multiple evaluation techniques were employed, including the review of existing documents, interviews, walkthroughs, questionnaire surveys, and spot measurements. The importance-satisfaction (IS) matrix was utilized to identify building performance successes and failures. The study shows that occupants are moderately satisfied with their residential environment. Specific issues identified were related to HVAC and lighting systems, among others. The holistic POE framework will help to derive more qualitative feedback in housing evaluation studies for more reliable decision making. This study bridges the research gap for the need for more holistic forms of POE in the facilities management sector. The recommendations provided in this paper will serve as feedback and feedforward for the building and construction industry. [ABSTRACT FROM AUTHOR]

Many people lose their homes around the world every year because of natural disasters, such as earthquakes, tsunamis, and hurricanes. In the aftermath of a natural disaster, the displaced people (DP) have to move to temporary housing (TH) and do not have the ability to choose the settlement dimensions, distributions, neighborhood, or other characteristics of their TH. Additionally, post-disaster settlement construction causes neighborhood changes, environmental degradation, and large-scale public expenditures. This paper presents a new model to support decision makers in choosing site locations for TH. The model is capable of determining the optimal site location based on the integration of economic, social, and environmental aspects into the whole life cycle of these houses. The integrated value model for sustainable assessment (MIVES), a multicriteria decision making (MCDM) model, is used to assess the sustainability of the aforementioned aspects, and MIVES includes the value function concept, which permits indicator homogenization by taking into account the satisfaction of the involved stakeholders. [ABSTRACT FROM AUTHOR]

This paper presents practical guidance and resources for use during the construction phase developed by the Construction Industry Institute (CII) Research Team (RT) 304, Sustainability Practices and Metrics for the Construction Phase of Capital Projects. It introduces 54 construction phase sustainability actions (CPSAs) that project teams can use during project execution to prioritize and carry out sustainability solutions. Further, it discusses the results of the sustainability survey on current and future capital project implementation of CPSAs, with a focus on frequency of use and barriers to deployment. By following the guidance provided here for adopting these CPSAs, owners and contractors will be better prepared to implement sustainability actions during the construction phase of their capital projects. This paper's primary contributions are the identification of construction-related decisions and actions to advance sustainability implementation, the provision of detailed practical guidance for effective application, and the validation of the 54 CPSAs in the catalog based on the frequency of current and likely future application. [ABSTRACT FROM AUTHOR]

Geopolymers are used for several applications due to their sustainability, low density, low cost, excellent thermal properties, and fire resistance. Geopolymer concrete (GC) may possess superior fire resistance compared to conventional concretes with ordinary portland cement (OPC). The proper understanding of the effects of elevated temperatures on the properties of GC is essential. In the research reported in this paper, relationships are proven for normal and high-strength GCs at elevated temperatures to establish efficient modeling and specify the fire-performance criteria for concrete structures. They are developed for unconfined GC specimens that consist of compressive strength, modulus of elasticity, flexural strength, thermal strain, prestressed thermal strain, and the compressive stress-strain relationships at elevated temperatures. The proposed relationships at elevated temperature are compared with experimental results and available OPC relationships. These results are used to establish more accurate and general compressive stress-strain relationships. [ABSTRACT FROM AUTHOR]

Building façade elements should have aesthetically pleasing geometrical shapes made up of sustainable materials with energy-efficient designs. The low mass-to-high strength ratio of glass fiber–reinforced concrete (GFRC) has the potential to be adopted as a façade material and has been used in the manufacturing of façade elements. The workability of GFRC mixes is comparatively low; therefore, commercial polymer admixtures are used to improve it. The application of commercial polymers may reduce the fire resistance of GFRC mixes due to their easy combustibility. This study investigated the possible application of waste paint to completely replace commercial polymer admixtures in GFRC. It explored the optimum dosage of waste paint to achieve the required strength of a GFRC mix to be used as a façade material. First, characterization of the waste paint was carried out using its rheological properties and solid content, which were compared with commercially available polymer and paint. Subsequently, the effect of different dosages of waste paint (i.e., 0.5%, 1%, and 2% by mass) on the workability and mechanical properties of GFRC mixes (e.g., compressive and flexural strength) was evaluated. Water absorption and porosity were also evaluated. Finally, the combustibility of GFRC mixes with waste paint was evaluated to qualitatively assess fire performance when compared with polymer GFRC mixes. The experimental results demonstrated that the addition of waste paint to the GFRC mixes improved workability. Furthermore, the mixes with a waste paint dosage of less than 1% showed no significant variation in compressive strength compared with the commercial polymer mix. However, the mix with 1% waste paint enhanced flexural strength by 34% whereas a further increase in waste paint content was observed to reduce flexural capacity due to an increase in porosity. Finally, the fire performance of the mixes showed that waste paint is a noncombustible material and can be used as a potential substitute for polymer admixtures in façade applications. [ABSTRACT FROM AUTHOR]

Given the urgent need for decarbonization of the construction industry due to its pivotal role in global greenhouse gas emissions, industrialized construction (IC) has emerged as a promising technique to change the productivity, quality, and sustainability of construction. Although some evidence and case studies reveal that IC has distinct decarbonization advantages compared with traditional construction, there still is a need to analyze best practices, opportunities, and challenges in order to guide industry practitioners and to define key knowledge gaps. A systematic review was conducted following the three core steps: database search; research gap identification, analysis according to key lifecycle stages, and decarbonization themes. This synthesized existing academic works at the intersection of industrialized construction and decarbonization to provide a comprehensive understanding of decarbonization in IC. The findings show that although a significant amount of research focused on emissions during project stages A1–A3, there is a noticeable research gap in evaluating the carbon emissions associated with transportation, operations, and end-of-life attributes of IC. Moreover, the absence of real-time assessments during the B6–B7 operational stages impedes optimal carbon emission assessment. The verbosity of carbon estimation and tracking methodologies also adds challenges to ensuring that additional carbon impacts of IC are adequately offset by improved efficiency and lower onsite emissions. The potential of decarbonization of IC can be explored further by future research on the standardization of life-cycle assessments, development of continuous carbon-tracking methodologies, and application of alternative materials and new technologies. Practical Applications: The effectiveness of IC practices in reducing carbon emissions may vary, as deduced from the reviewed literature. However, the conscientious selection of materials characterized by low embodied emissions can contribute to a reduction in carbon emissions, applicable to both IC and non-IC projects. IC projects are uniquely positioned to achieve an even greater reduction in carbon emissions because of a unique process that innately offers waste reduction and product quality improvements. Although a considerable volume of research has focused on estimating carbon emissions, there appears to be a gap in tracking the precise quantity of emissions across various life-cycle phases within IC. Although there is considerable research on decarbonization in prefabricated components, research on specific life-cycle phases still is lagging. Furthermore, future research should prioritize investigating similar opportunities for three-dimensional (3D) volumetric systems. [ABSTRACT FROM AUTHOR]

Fly ash (FA) increases the performance of cement concrete through pozzolanic reaction and microstructure development at later ages. FA is usually associated with lower early age compressive strength especially at higher replacement levels. This study attempts at improving the early age strength of FA portland pozzolana cement with limestone calcined clay pozzolan (LC2). Different proportions of limestone and calcined clay (1∶1 , 1∶2 , and 2∶1) in tandem with FA at various replacements of cement clinker (30%, 40%, and 50%) were tested. The combined effect of using LC2 with FA has shown to enhance the early age hydration of cement along with improved compressive strength. Heat of hydration results showed increased heat release in FA mixes blended with LC2. Thermodynamic modeling analysis was used to study the change in phase assemblage of these mixtures. A higher solid volume observed in the thermodynamic simulations in the combined blends of FA and LC2 is hypothesized to be the cause of improved performance compared with only FA blended cement. Mercury intrusion porosimetry (MIP) results further confirmed an improvement in pore structure characteristics of FA cement blended with LC2. The possibility of reducing associated carbon emissions without compromising in strength are highlighted by using FA and LC2. [ABSTRACT FROM AUTHOR]

Engineering design and construction teams commonly use decision tools, such as rating systems, to manage the complexity of infrastructure projects. However, these systems often focus predominantly on environmental dimensions, potentially overlooking the holistic economic and social aspects of sustainability. This can hinder decision-makers from recognizing the benefits, thereby inadvertently impeding optimal sustainability performance. This research explores a potential solution: reframing the goals of credits on rating systems to explicitly highlight the interconnectedness of environmental, social, and financial dimensions. The aim was to amplify engineers' motivation towards higher levels of sustainability performance. The study examined the effect of the goal-framed credits by comparing the sustainability scores between engineering professionals (n=42) who used the original Envision system and the reframed version when evaluating a case project. The control group participants averaged a score of 95.4 Envision points (37%), while the intervention group averaged 121.8 Envision points (48%). The reframed credits significantly increased engineering professionals' sustainability goal setting. Emphasizing financial and social objectives on credits from the Envision rating system, rather than solely focusing on the existing environmental goals, had a favorable influence on professionals' sustainable design choices. This reframing, by emphasizing the interconnectedness of environmental, social, and financial dimensions of each decision, appears to amplify the awareness, motivation, and selection of higher levels of sustainability achievement, thereby increasing their perceived value and leading to a shift in sustainability-oriented decision-making. The findings suggest that reframing rating systems to better emphasize the interconnectedness of the environmental, social, and financial dimensions of each decision can serve to help engineering teams set higher goals for sustainable performance. Practical Applications: For infrastructure project managers, architects, and designers, this research highlights the significance of considering economic and social aspects alongside environmental concerns. By doing so, it can further empower stakeholders to make more well-rounded and sustainable decisions that benefit both their projects and the communities they serve. Small changes in how decision tools are worded, or framed, can have a significant effect on project goal setting. A better understanding of how framing affects design cognition can also help inform how project managers, architects, and designers present information to their clients. Subtle changes in the decision tools and the way information about projects is expressed cost little compared to the actual cost of infrastructure, offering inexpensive and easy to implement strategies to influence and nudge project teams toward setting higher sustainability goals during the design and construction of infrastructure projects. [ABSTRACT FROM AUTHOR]

This paper describes a modification to the layered-sectional analysis approach, which provides the engineer with a tool to assess structural behavior of concrete beams with localized damage, a problem not well suited to classical, closed-form solutions. The modified layered-sectional analysis (MLSA) framework is applied to a forensic investigation case study in which two prestressed double-tee beams are exposed to a short duration, intense fire in a parking structure. The results of the MLSA are within 1% of the case study load test, which indicates that the MLSA could be a useful, computationally efficient tool for the investigating engineer to predict the postfire serviceability and strength of damaged beams, and potentially eliminate the need for expensive load testing. A short parametric study is included for the research engineer interested in the MLSA for predicting the postdamage behavior of non-standard materials such as enhanced sustainability concrete (ESC). [ABSTRACT FROM AUTHOR]

This paper investigates the use of glass cullet as a 100% sand replacement in Portland cement concrete (glasscrete) systems. Specifically, this paper evaluates the fresh and hardened properties of these systems in comparison with conventional natural sand concretes on the basis of similar 28-day design compressive strength, or the same w/cm. The results show that glasscrete mixtures need a lower w/cm to match the 28-day compressive strength of conventional concrete. In addition, glasscrete mixtures have greater elastic modulus, less drying shrinkage, less water sorptivity, and greater resistance against chloride ion penetration. Empirical curves are developed to provide material engineers and suppliers with necessary design specifications on the proper w/cm to implement when proportioning glasscrete mixtures. This study concludes that glasscrete mixtures are producible with adequate consistency and mechanical and durability performance, as long as the alkali-silicate reaction is properly controlled using pozzolanic materials. [ABSTRACT FROM AUTHOR]

This paper presents ongoing research aimed at improving building sustainability education through the use of serious games. With the growth of the population worldwide and the increased demand on resources, there has been a growing emphasis on sustainable buildings. As architects, engineers and construction professionals are educated for the future, the complex area of building sustainability must be included in the curriculum; however, the literature shows no clear consensus on teaching methods or curriculum design. Growing evidence suggests that computer games could be effective tools in construction education as they can provide students with both theoretical and applied knowledge. In this paper we describe the development and initial evaluation of a serious game for learning sustainable building design principles and practices. The game is aimed at undergraduate students enrolled in Civil Engineering, Architecture and Building Construction Management programs. Findings from a formative study with 17 students and three faculty show that the game was perceived as usable, engaging and useful for learning/teaching building sustainability. Results of a summative study with 42 undergraduate students show that playing the game led to an increase in subjects' declarative knowledge by 22% and procedural knowledge by 37%. Compared with traditional learning methods, playing the game led to significantly higher procedural knowledge gains, whereas gains in declarative knowledge were not significantly higher. [ABSTRACT FROM AUTHOR]

This paper examines effects of a new biobased modifier, 'biobinder,' on low-temperature properties of asphalt binder and compares the results with those of conventional modifiers: crumb rubber, Gilsonite, styrene-butadiene-styrene (SBS), and polyphosphoric acid (PPA). Low-temperature characteristics of modified and nonmodified asphalts were studied using experimental and modeling approaches. A three-point bending beam rheometer was used to measure the stress-strain response of each specimen. A theoretical approach was used to determine stiffness and stress release rate; in addition, the Burgers model was implemented to predict the stored and dissipated energy ratio and quantity of derivation of creep compliance in each of modified and nonmodified asphalt specimens. Effects of various modifications were compared based on both the calculated stored and dissipated energy ratio and quantity of derivation of creep compliance. The proposed biobinder is produced from the thermochemical conversion of biomass (including animal waste, switch grass, and woody biomass). Biobinder is then blended with virgin binder to produce biomodified binder (BMB). This paper argues that the improved low-temperature rheological properties in biomodified binder is reflected in the enhancement in energy dissipation ratio and quantity of derivation of creep compliance. [ABSTRACT FROM AUTHOR]

Numerous ecofeedback systems have been built around the proven principle that providing feedback to individuals about their energy use can lead to increased conservation through behavior change. This paper presents a novel ecofeedback system called Watt's Watts, which is designed to leverage the impacts of individual and social feedback to influence energy consumption behavior. Watt's Watts is one of the first ecofeedback systems that integrates individual-level, near-real-time energy consumption feedback within a social network environment and simultaneously collects network data that can be used to quantify social network effects on energy consumption. It was designed around two main goals: (1) to create a hardware/software integrated system that maximizes potential energy savings through behavior-based energy use reduction in residential buildings; (2) to collect data that will allow the validation of the user interface design and the examination of how social network dynamics impact energy consumption behavior. The objective of this paper is to introduce the concepts driving the design of the front and back ends of the novel Watt's Watts system to inform the design and development of future socially oriented ecofeedback systems. It explains the principles that directly informed the design of the system's interface, the methods by which the system's design is validated in numerous studies, how the back end system design enabled the robust analysis undertaken in the validation studies, and the future research avenues enabled by the development of this system. [ABSTRACT FROM AUTHOR]

Efficient management of irrigation/drainage systems relies to a large extent on the ability to predict a priori the response of the system to a proposed management plan. However, such numerical prediction of system response (e.g., root-zone hydrosalinity conditions and crop yield) are dependent on several parameters that are spatially and/or temporally variable and are related to soil properties, atmospheric conditions, crop type, and the amount and salinity of water application. This paper presents enhancements to the Colorado State University Irrigation And Drainage (CSUID) model that expand its capacity to fully simulate the dynamics of variably saturated flow and transport in a three-dimensional (3D) variably saturated porous media and to account for spatial and temporal heterogeneity in input parameters. The CSUID model has the ability to simulate irrigation/drainage activities and their impact on the soil and underlying groundwater, as well as on crop yield, taking into account the spatial and temporal variability in available soil moisture, including matric stress, waterlogging, and osmotic stress due to salinity. Having a model with these capabilities is an important step towards understanding the influence of heterogeneous inputs and parameter uncertainty on the design and management of field-scale irrigation/drainage systems. Four benchmark problems are used in this paper to test the CSUID model and the model performs well. In addition, an example is presented to demonstrate model capabilities in representing a 3D time-varying irrigated field with and without subsurface drainage. [ABSTRACT FROM AUTHOR]

The widely-utilized multispan simply-supported adjacent (side-by-side) box girder bridges often suffer from problems of deterioration attributable to transverse cracking in link slabs between spans, malfunctioning expansion joints, and longitudinal cracks between adjacent girders. Such problems can degrade the functionality, durability or even safety of the bridge over time, depending on the environmental exposure conditions. This paper discusses an approach taken to rehabilitate the Shili Bridge by eliminating expansion joints and retrofitting the structure from simply-supported box girders into a continuous bridge. Condition assessments were performed before retrofitting. In addition, several design options and construction procedures were considered and analyzed. Static and dynamic load tests were carried out after the completion of rehabilitation. The lessons learned in this project are presented and discussed. This practical and novel methodology is a step forward toward improving safety, sustainability, reliability, and quality of such existing bridges in China and elsewhere. [ABSTRACT FROM AUTHOR]

In the recent times, rejuvenators have been investigated as a potential solution to incorporate higher amounts of recycled asphalt (RA) in hot-mix asphalt (HMA). In this study, waste cooking oil (WCO) was used as rejuvenator to assess the performance of RA mixtures. A method was proposed to optimize WCO content in HMA with high RA content (>45%), balancing the performance in the high and intermediate temperatures. The optimized mixtures with high RA content depicted rut depth and cracking properties similar to HMA. Simultaneously, the recycled mixtures utilizing WCO dosages derived from a blending equation exhibited pronounced rutting, implying that the blending equations yielded WCO dosages that exceeded the necessary dosages. A life cycle assessment (LCA) study considering a cradle-to-gate approach indicated that incorporating 45%, 60%, and 75% RA would decrease total embodied energy (TEE) by 25.08%, 33.30%, and 41.17% compared with HMA. Further, a sensitivity study with distance as the parameter indicated that the permissible distance of RA source for 45%, 60%, and 75% was 500, 300, and 300 km, beyond which RA mixtures showed higher TEE than HMA. Practical Applications: The incorporation of reclaimed asphalt pavements (RAP) using waste cooking oil as a rejuvenator presents significant practical implications for the asphalt industry and sustainability initiatives. By enabling the use of higher RAP content while maintaining the performance of traditional mixtures, this research offers a more environmentally friendly and cost-effective approach to road construction. Moreover, the life cycle assessment findings reveal substantial reductions in environmental impacts when including different RAP proportions, making a strong case for improved environmental sustainability. The sensitivity analysis regarding the distance between RAP sources and construction sites provides valuable insights for location-based decision-making, ensuring that the benefits of RAP utilization remain maximized. In summary, the potential application of the study emphasizes a greener and durable road infrastructure, with a focus on increasing RAP content using waste cooking oil as a rejuvenator in asphalt mixtures. [ABSTRACT FROM AUTHOR]

Following recommendations for replacing center pivots and center-pivot sprinkler packages can help farmers improve water application efficiency and optimize crop production. Little information exists on the frequency with which farmers are replacing center pivots and sprinkler packages. To help address this issue, this study evaluated an industry database of center pivot (n=654) and sprinkler package (n=5,131) replacements in the western United States. On average, pivot systems were oldest in Montana, Idaho, and Utah, with an average age of 18, 16, and 16 years, respectively. Oregon had the lowest average pivot age (9 years). Average pivot age also varied by brand: Reinke systems were the oldest (16 years) and Valley were the youngest (11 years), on average. Across the database, 92% of the pivots were 25 years old or younger. Utah also had the oldest average sprinkler package age (10 years). Oregon and California changed sprinkler packages most frequently (≤4 years). Sprinkler package replacement frequency varied among center-pivot manufacturers, with Valley pivots having the highest frequency of sprinkler package changes (5 years) and Zimmatic pivots having the lowest frequency (8 years). Across the database, 50% of the sprinkler packages were replaced within 2 to 5 years, and 81% were replaced within 10 years. Most farmers in the region generally follow recommendations on replacing pivots and pivot sprinkler packages, but a sizeable number of farmers do not. Therefore, an opportunity exists to improve center-pivot and sprinkler package maintenance, thereby helping to make center-pivot irrigation more water efficient and crop production more sustainable. This study contributes to industry knowledge and awareness by providing data and insights on center-pivot and sprinkler package replacement trends. The authors evaluated an industry database of center-pivot (n=654) and sprinkler package (n=5,131) replacements in the western United States. Insights on the frequency of replacement can help farmers make informed decisions about when to replace their equipment, and can raise awareness on the importance of equipment maintenance. Farmers may therefore be encouraged to follow equipment maintenance recommendations and replace outdated or inefficient equipment. By so doing, farmers can irrigate more efficiently and optimize crop production, leading to improved yields and more sustainable crop production. The study revealed that equipment replacement trends vary by manufacturer. This reinforces the need for irrigators to consult with irrigation experts, manufacturers, or equipment dealers to obtain specific recommendations tailored to their specific circumstances and equipment. Irrigation equipment manufacturers and distributors can also use the study findings to improve their equipment and farmer support systems. Policy makers may use the findings in structuring and implementing farmer support programs and related policies and laws. The study, therefore, can provide insights that contribute to the nation's goals of sustainable agricultural water use and crop production. [ABSTRACT FROM AUTHOR]

The present study aimed to examine the relationship between canopy air temperature difference and vapor pressure deficit (VPD) in wheat crops under normal or nonstressfull conditions. The treatments were undertaken on five plots, having randomized block design (RBD), each maintained at different levels of soil moisture having full irrigation; no irrigation; and 10%, 30%, and 50% soil moisture. Then canopy air temperature difference was regressed against VPD to generate non-water stress and maximum water stress baselines, and the crop water stress index (CWSI) was computed using empirical approach-baseline methods at different soil moisture deficits. It was found that irrigation treatment at 30% soil moisture deficit yielded the maximum water use efficiency. The canopy air temperature difference and VPD resulted in linear relationships, and the slope (m) and intercept (c) for lower baseline of preheading and postheading stages of wheat crop were found as m=−2.371 , c=−1.659 ; and m=−1.8952 , c=−2.32 , for the crop season of 2018–2019. Similarly, the non-water stress baseline equation in the season of 2019–2020 had m=−1.7184 , c=−2.3009 ; and m=−1.8137 , c=−1.9176 for preflowering and postflowering stages of wheat, respectively. The CWSI was determined by using the developed empirical equations for three irrigation schedules of different maximum allowable depletion (MAD) of available soil water (ASW). The developed CWSI may have the potential to improve irrigation scheduling of wheat in India. The study shows practical applications for enhancing wheat cultivation under varying soil moisture conditions. First, it recommends irrigating at 30% soil moisture deficit to maximize water use efficiency, aiding farmers in balancing crop yield and water conservation. Second, established relationships between canopy air temperature difference and VPD allow for the assessment of water stress. By utilizing regression equations, farmers can estimate the CWSI across soil moisture levels, guiding irrigation scheduling during critical growth stages. Third, the developed empirical equations enable real-time prediction of water stress. Monitoring the canopy air temperature difference and VPD offers insights into plant health, helping with informed decisions on irrigation and fertilization. Last, the findings are relevant for water-scarce regions like India, where tailored CWSI equations can be integrated into irrigation systems, promoting sustainable practices under a changing climate. This study may help farmers with practical tools for water-efficient wheat cultivation, fostering informed choices for sustainable agriculture, particularly in water-scarce regions. [ABSTRACT FROM AUTHOR]

Sticky rice–lime mortar, a representative ancient binding material widely employed in construction applications across Asian countries, has been a subject of substantial academic research and development efforts for its restoration. However, conventional sticky rice–lime mortar is characterized by suboptimal strength and limited toughness, necessitating further enhancements to expand its practical utility. This study presents the formulation of a high-performance sticky rice–lime mortar by incorporating metakaolin and hemp fibers. A comprehensive investigation of various parameters influencing the compressive and flexural properties of the resulting composite was undertaken, encompassing the volume content of hemp fibers, the mass content of sticky rice paste, and the mass content of metakaolin. The experimental outcomes demonstrate the efficacy of metakaolin and sticky rice paste in significantly elevating the compressive strength of the sticky rice–lime composite. Notably, the presented sticky rice–lime mortar attains a remarkable compressive strength of up to 3.5 MPa, exceeding that of conventional sticky rice–lime mortar by more than threefold. Moreover, the introduction of hemp fibers effectively enhances the flexural strength of the sticky rice–lime composite through fiber bridging mechanisms. The research culminates by proposing a relationship equation, derived from the empirical data, to characterize the compressive and flexural strength of the high-performance sticky rice–lime composite. Overall, these findings emphasize the importance of optimizing sticky rice–lime mortar through the integration of advanced constituents, thus highlighting its potential as a durable and versatile binding material for historical preservation and sustainable construction practices within Asian contexts and beyond. [ABSTRACT FROM AUTHOR]