Roadway Construction Research Articles

A flexible camera calibration method for pose vision measurement system of roadheader

Cameras used for visual measurement in underground roadway construction sites are difficult to calibrate. Therefore, this study proposed an on-site camera calibration method that does not require manual intervention. First, the virtual point and line features on the plane target are constructed using pole-polar constraints. Second, a homography model based on point-and-line features is established. Finally, a combined objective function based on the dynamic weight coefficient is proposed to optimise the calibration results further. Relevant simulations and experiments showed that the maximum internal parameter error obtained using the proposed method was 0.463 %, and the maximum position estimation error of the roadheader was 30 mm. In addition, the results show that this method is superior to other methods in terms of calibration accuracy and robustness, solving the difficulty of camera calibration in underground roadway construction sites and guaranteeing high-precision pose vision measurement.

Experimental study on the macroscopic and mesoscopic mechanical characteristics of deep damaged and fractured rock

Most of the rock surrounding deep roadways is in a fractured state; fractured rock has significant rheological properties, and the time-dependent mechanical properties of fractured rock affect excavation construction, support design, and long-term stability of deep roadways. Triaxial compression and mercury intrusion tests are conducted on the bearing characteristics of severely damaged and fractured rock samples, indicating the strength degradation properties of these samples. The evolution of the internal pore structure in damaged and fractured rock samples is analyzed in relation to changes in unloading points (pre-peak stage, peak point, and post-peak stage), leading to the establishment of a quantitative evaluation index for rock damage based on the porosity evolution. Short-term rheological testing is performed on rock samples with varying degrees of damage and fracture, demonstrating the evolution of creep and stress relaxation characteristics. The findings contribute to a deeper theoretical understanding of the post-peak mechanical properties of coal and rock masses, which hold significant theoretical implications and can inform research on long-term stability in underground engineering applications, such as deeply buried roadways, tunnels, and chambers.

Characteristics of debris flow development in Daxilada watershed and its hazard analysis on Lexi Expressway

The occurrence of frequent debris flow catastrophes in the mountainous regions of southwest China has necessitated the inclusion of debris flow disaster analysis and prevention as an essential component in the planning and construction of mountainous roadways. Daxilada watershed is located in the south of Mabian Yi Zuzizhixian, Leshan City, Sichuan Province, and the proposed Leshan-Xichang Expressway (Lexi Expressway) will pass through the upper reaches of Daxilada watershed. It is essential to consider that the presence of debris flows within the Daxilada watershed could have detrimental effects on the construction and functionality of the proposed Luoshanxi Bridge. This study examined the Daxilada watershed as a case study and analyzed the factors contributing to debris flow formation in the area. This analysis was based on field investigations, remote sensing interpretation, and experimental analysis. Additionally, the study utilized the Massflow software to simulate debris flow movement. It integrated the simulation results to determine the potential hazards the Daxilada Gully debris flow posed to the line project. This study found that Daxilada Gully meets debris flow formation conditions. The simulation results demonstrated that during the debris flow activity, there would be a maximum deposition depth of 2.1 m in the proposed Engineering Agency, which may lead to siltation and blocking disaster of the line project. Concerning the parameters related to the debris flow with a frequency of one in a hundred years, in conjunction with the outcomes obtained from numerical simulation, it would provide the design basis of the cross-flow cross-section of the proposed bridge. In a quantitative analysis of the blockage situation in the gully, debris flow deposits have the potential to cause damage to the line project. Debris flow deposits block the gully, but the risk of blockage is small. The study results have specific reference values for the debris flow prevention and control project of Lexi Expressway and offer valuable insights for the prevention and mitigation of similar disasters in relative projects.

Gaps in predicting water quality impacts of unbound air-cooled blast furnace slag utilized for roadway construction

Air-cooled blast furnace slag (ACBFS) is often used as road construction aggregate. Several incidences of adverse environmental effects have been reported in Indiana where unbound slag has been used. The aggregates that caused issues in the field had been previously approved for use by passing State of Indiana standard slag leaching procedures. The study goal was to test several hypotheses posed to the Indiana Department of Transportation and authors by the industry about slag leaching, and to better understand water quality impacts. Ten slags from two suppliers underwent leaching procedures adopted by two U.S. states, but additional test procedures and material and leachate chemical characterization were also conducted to better interpret results. Aggregates varied in size and age (24 h to 2 years old). Like prior literature reports, the chemical composition among the slag samples was similar. However, water quality impacts observed at the bench-scale in this study differed substantially across the slags. Results were consistent with those previously reported at Indiana field sites, but not with literature reported results from standardized leaching tests (i.e., TCLP, percolation, etc.). In the present study, no relationship was found between slag age and leachate composition. Leachate pH, conductivity, and color levels exceeded thresholds of regulatory and aquatic toxicity significance. For one slag, leachate pH reached 12.9, but the effluent was colorless. During both stagnation and rinsing tests, aqueous chloride, sulfate, and zinc concentrations sometimes exceeded regulatory water quality and aquatic toxicity levels. Repeated rinsing of the slag resulted in water conductivity and sulfate concentration differences. To better understand and predict the impacts of unbound ACBFS, additional fundamental studies and field investigations are recommended. Unbound ACBFS is not recommended for use near environmentally sensitive areas, drinking water sources, habituated areas, and where it may have water contact (i.e., waterways, wetlands, reservoirs, and groundwater).

Innovative Pavement Materials: Utilizing Corn Stover and Fly Ash in Geopolymers

The development of each nation is evaluated by its infrastructure, and each nation is competing with the others in infrastructure advancement, especially in the construction of roadways, since they play a vital role in the economic and social development of the nation. The conventional materials used for road construction are concrete and asphalt, which pose significant environmental challenges. This research gives insight into the potential of fly ash (FA) and corn stover (CS) in synthesizing geopolymer, as an alternative material for the construction of roads. This study examines the impact of three FA and CS mixture percentages and the particle size of CS on the compressive strength and porosity of geopolymer. The results indicate that incorporating larger amounts of CS in fly ash-based geopolymer may decrease the compressive strength of the geopolymer. Smaller CS particle sizes also tend to lead to lower compressive strength. Porosity of the geopolymer tended to increase with the incorporation of higher percentages of CS, particularly for smaller corn stover sizes. As a fine aggregate replacement for geopolymer, CS incorporation has the potential to reduce mined aggregate obtained from a process that harms the environment.

Fracture properties of ultra-thin friction course mixture containing reclaimed asphalt pavement and glass fiber under monotonic and cyclic loading

Ultra-thin friction courses (UTFC) have demonstrated exceptional efficacy in the preventive maintenance of asphalt pavements. Despite this, research into the influence of reclaimed asphalt pavement (RAP) and glass fiber on the fracture behavior of UTFC mixtures under cyclic loading is sparse. In response, this study conducted both monotonic loading tests and tension cyclic loading tests on notched semi-circular specimens at a temperature of 25 °C to elucidate the impact of RAP and glass fiber on UTFC’s fracture resistance. The findings revealed that, during monotonic testing, the introduction of RAP appeared to bolster mechanical performance by increasing peak load and tensile stiffness index (TSI). However, RAP diminished the fracture energy, with the concurrent addition of RAP and glass fiber resulting in further compromise to fracture resistance. Conversely, in the cyclic loading tests operated under load control, the integration of RAP positively influenced fatigue life. Furthermore, the addition of 0.1 % glass fiber (identified as H-25R-0.1F) also improved fatigue life, highlighting its beneficial role in augmenting fatigue endurance. When compared to the mixture devoid of RAP, the inclusion of 25 % and 50 % RAP led to substantial increases in cumulative dissipated energy by 101 % and 398 %, respectively. These results suggest that both RAP and glass fiber have nuanced effects on the fracture and fatigue properties of UTFC mixtures, with potential implications for their application in roadway construction and rehabilitation. Minimum rate of cumulative dissipated energy change (RCDEC_min) could be used to characterize the fatigue performance. The lower the RCDEC_min, the larger the fatigue life. There existed a power law relationship between RCDEC_min and fatigue life, which was independent of the mixture type. Compared to the cumulative dissipated energy method, the maximum displacement method may be more suitable to characterize the damage evolution during the fatigue test.

Identification of asphalt binder tests for detecting variations in binder cracking performance

Asphalt binders are vital components in the construction of roadways, and their quality significantly impacts the performance and durability of asphalt mixtures. However, it is possible for binders to exhibit different performance with identical Performance Grade (PG) due to variations in source, refining processes, and modifiers (if any). This paper presents a comprehensive study aimed at identifying candidate tests to detect variances in the quality of the binders in terms of cracking resistance. Eight PG 64–22 asphalt binders were selected and subjected to multiple laboratory tests, including X-ray fluorescence (XRF), Dynamic Shear Rheometer (DSR), Poker chip, and Bending Beam Rheometer (BBR) tests. The binders were then incorporated into asphalt mixtures, and their cracking resistance was evaluated using the IDEAL cracking test (IDEAL-CT) and Overlay test (OT). The study findings revealed that phase angle test, poker chip test, and Glover–Rowe (G–R) parameter test emerged as promising candidates to detect variations in the quality of binders of the same grade based on their cracking resistance. Notably, phase angle and G-R tests, both utilizing DSR, offered valuable supplementary assessments to the traditional PG grading system, proving crucial in evaluating cracking resistance. Furthermore, the poker chip test, an affordable alternative to DSR, demonstrated its effectiveness in evaluating binder quality for cracking performance. In conclusion, the identified candidate tests provide valuable insights into evaluating the quality of asphalt binders. By incorporating these tests into mix design and evaluation processes, engineers can make informed decisions to optimize the performance and durability of asphalt pavements.

Spalling Criterion of Hard Brittle Rock Mass Based on Dilatation Lateral Strain.

Spalling failure is a typical failure phenomenon after excavation and unloading of a deep, hard brittle rock mass, which seriously threatens the safe construction of deep roadways (tunnels) and other projects. From the engineering viewpoint, it is essential to accurately evaluate the range and depth of surrounding rock spalling failure. From the perspective of the laboratory and engineering site, the strength and formation mechanism of hard rock spalling failure were statistically summarized and analyzed. Under uniaxial and low confining pressure conditions, when the load reached the rock damage stress, cracks in the rock penetrated to form a failure plane approximately parallel to the axial loading direction, and the strength of rock mass spalling was much smaller than that of intact rock spalling. A triaxial compression test was conducted to analyze the dilatation axial strain and dilatation lateral strain characteristics of gneiss. The results showed that dilatation axial strain gradually increased with the increase of confining pressure, whereas dilatation lateral strain was almost unchanged. Therefore, a safety factor (FS) based on dilatation lateral strain was developed. Through comparison with other strain-based spalling criteria, the establishment and physical meaning of the method were described in detail. In addition, FS was applied to analyze the deep roadway of the Hongtoushan Copper Mine in China and the Rm415 test tunnel in Canada. The results showed that the spalling criterion could accurately indicate the range and depth of the surrounding rock spalling failure, which verified the rationality and applicability of the new spalling criterion. Thus, FS can be utilized as a new theory and analysis tool for the assessment and prevention of spalling failure in deep hard rock roadways.

Application of Greenroads Rating System and Life Cycle Assessment in Informing the State of the Practice in Sustainable Roadway Construction

This paper highlights the application of the Greenroads Rating System in collecting, measuring, and communicating sustainable best practice data in the context of roadway infrastructure construction. Once measured, meaningful comparisons between common practice and what goes above and beyond routine can be recognized, educated, advertised, spread, and finally, implemented. This study collected, organized, and analyzed data from 33 Greenroads-certified roadway construction projects completed between 2011 and 2018 with a total value of over 2 billion USD. We believe such a database is scarce within the literature and is worth exploring. Greenroads scorecards, which indicate the level of achievement in sustainable construction practices, were analyzed to show the frequency with which best practices are pursued. Findings show that projects typically perform activities that can be considered common practice and avoid activities that fall outside of their prior experience realm. Realizing that roadway surfaces including pavement structures often contribute to a high proportion of a roadway project’s sustainability efforts, the last piece of this study is dedicated to the life cycle assessment (LCA) of paving materials as conducted and reported by project teams. Integrating LCA results with financial information from pay item lists, correlation analyses between carbon and energy footprints and the price of major paving materials such as asphalt mixtures and portland cement concrete were carried out. Results show that the quantified environmental footprints of projects and the materials used to build them strongly correlate with the total price of projects and the price of constituent materials, respectively.

Roadway construction as a natural experiment to examine air pollution impacts on infant health

Traffic-related air pollution (TRAP) poses a significant public health risk that is associated with adverse birth outcomes. Large roadway infrastructure projects present a natural experiment to examine how resulting congestion change is associated with adverse birth outcomes for nearby populations. This study is designed to examine the influence of living close to a roadway before, during, and after a construction project using a difference-in-differences design. We integrated data on all large roadway construction projects (defined as widening of existing roads, building new roads, improving bridges, installing intelligent transportation systems, improving intersections, and installing or upgrading traffic signals) in Texas from 2007 to 2016 with Vital Statistic data for all births with residential addresses within 1 km of construction projects. Our outcomes included term low birth weight, term birth weight, preterm birth, and very preterm birth. Using a difference-in-differences design, we included births within 3 years of construction start and 2 years of construction end. In our main model, the exposed group is limited to pregnant individuals residing within 300 m of a construction project, and the control group includes those living within 300–1000 m from a project. We used regression models to estimate the influence of construction on infant health. We included 1,360 large roadway construction projects linked to 408,979 births. During construction, we found that the odds of term low birth weight increased by 19% (95% CI: 1.05, 1.36). However, we saw little evidence of an association for other birth outcomes. Contrary to our hypothesis of decreased TRAP after construction ends, we did not observe consistent improvements post-construction for pregnant individuals living within 300 m. Continued consideration of the influence of traffic congestion programs on birth outcomes is necessary to inform future policy decisions.

Dynamic and Energy Consumption Characteristics of Sandstone Ring Specimens under Dry and Wet Cycling

The aim of this study was to examine the effects of sandstone ring specimens with different inner diameters on dynamic compression mechanical characteristics after dry and wet circulation. To carry out our study, we subjected a sandstone ring specimen with a 50 mm outer diameter and a 0~25 mm inner diameter to 10 cycles of dry and wet circulation. Afterward, we recorded the specimen’s basic physical parameters and used a split-Hopkinson pressure bar (SHPB) test device to perform an impact compression test. Following dry and wet circulation, our results showed that the mass loss rate increased and the volume expansion rates and density decreased with the increase in the inner diameter of the sandstone ring sample. Simultaneously, with the increase in the inner diameter of the specimen ring, the dynamic compressive strength of the specimen presented an exponential negative correlation, the dynamic elastic modulus presented a quadratic negative correlation, and the dynamic peak strain presented a quadratic positive correlation. Concurrently, the average particle size of the specimen decreased, and the degree of breakage increased with the increase in the sandstone sample’s inner diameter. Regarding the energy analysis performed in this study, the sandstone ring sample’s energy dissipation increased, and its kinetic performance evidently weakened with the increase in the ring sample’s inner diameter. The results of this study have certain reference values for the construction and maintenance of natural cavity rock and underground hard rock roadways.

A Comparative Analysis of Traditional Roadways vs. Electric Vehicle (EV) Roads: Environmental, Infrastructure, And Technological Perspectives

As the global transportation sector seeks to address pressing environmental challenges and transition towards sustainable mobility solutions, the comparative analysis between Traditional roadways and Electric Vehicle (EV) roads emerges as a critical area of investigation. This paper presents a comprehensive comparative analysis of traditional road infrastructure and EV road infrastructure from environmental, infrastructure, and technological perspectives. From an environmental standpoint, the analysis evaluates the life cycle environmental impacts, including greenhouse gas emissions, air and noise pollution, and resource consumption associated with traditional roadways and EV roads. It examines the potential for EV roads to mitigate environmental impacts through reduced fossil fuel dependency, lower emissions, and integration with renewable energy sources. Infrastructure comparisons encompass the design, construction, maintenance, and operation of traditional roadways versus EV roads. Factors such as pavement materials, structural integrity, durability, and lifecycle costs are scrutinized to assess the performance and resilience of each infrastructure type. Additionally, the analysis explores the implications for urban planning, land use, and transportation networks in accommodating EV road infrastructure. Technological perspectives delve into the advancements and innovations driving both traditional roadways and EV roads. It examines the integration of smart technologies, intelligent traffic management systems, and renewable energy solutions in enhancing the functionality, efficiency, and sustainability of road infrastructure. Furthermore, the analysis explores the implications of EV road technologies, such as dynamic wireless charging systems and vehicle-to-grid communication, on future transportation systems. Through a systematic comparison of traditional roadways and EV roads, this study provides insights into the environmental, infrastructure, and technological implications of each infrastructure type. By elucidating the benefits, challenges, and opportunities associated with EV road adoption, policymakers, urban planners, and transportation stakeholders can make informed decisions to advance sustainable transportation solutions and mitigate environmental impacts in the transition to electric mobility.

Greenhouse Gas Emissions Inventory from Roadway Construction: Case Study for the Washington State Department of Transportation

Recent emphasis on actions to reduce greenhouse gas (GHG) emissions has pushed many state departments of transportation (DOTs) to develop carbon accounting practices compatible with their current standard data collection and storage guidelines. Once accurate and reliable accounting of GHG emissions is established, strategies can be formed that could help mitigate the adverse environmental impacts of materials used by state DOTs. To date, the Washington State Department of Transportation (WSDOT) has not conducted comprehensive research on the embodied carbon within its construction material usage (i.e., upstream Scope 3 emissions inventory of procured materials) with most previous carbon accounting practices being focused on Scope 1 and Scope 2 emissions (i.e., the carbon footprint of direct and indirect energy usage). This paper summarizes the results of a life cycle assessment on the agency-wide material procurements and construction operations that emit GHGs at WSDOT as a case study. This study uses several data sources from WSDOT in conjunction with publicly available life cycle emissions factor data to estimate GHG emissions attributed to the materials used to build and maintain roadways under WSDOT’s jurisdiction. Results indicate that upstream Scope 3 emissions for WSDOT as an agency is a significant contributor to its overall GHG emissions inventory. Specifically, between 2017 and 2022, this paper estimates an average annual upstream Scope 3 emissions of 310,000 metric tons of CO2 equivalents, which translates to 56% of the total annual GHG emissions including Scope 1 and 2 emissions.

Analyzing the Mechanical and Durability Characteristics of Steel Slag-Infused Asphalt Concrete in Roadway Construction

Steel slag is a solid byproduct of the steelmaking process, widely generated in the metallurgical industry. Due to its alkaline nature and excellent adhesive properties with asphalt, it represents a potential road construction material with outstanding road performance, making it well-suited for utilization in highway construction. This paper conducts a systematic analysis of the physical and chemical properties of steel slag, specifically South Steel Electric Furnace slag, and compares it with natural basalt and limestone aggregates. The aim is to establish a foundation for the application of steel slag in asphalt mixtures. Building upon this foundation, we carry out proportioning design for AC-13C and SMA-13 steel slag asphalt mixtures, followed by a comprehensive study of their high-temperature stability, low-temperature stability, water stability, and fatigue performance. Our research reveals variations in the chemical composition of different steel slags, with CaO, SiO2, and Fe2O3 being the primary components. The content of harmful elements varies depending on the steelmaking raw materials and additives used. Notably, the optimum asphalt-to-aggregate ratios for AC-13C and SMA-13 significantly surpass the specified requirements. The freeze–thaw splitting strength ratio and residual stability of steel slag AC-13C and SMA-13 asphalt mixtures exceed the specified requirements, with AC-13C demonstrating the highest water stability, boasting a freeze–thaw splitting strength ratio of 94.07%, and a residual stability of 93.8%. In terms of fatigue characteristics, SMA-13 exhibits a longer fatigue life than AC-13C, indicating superior fatigue performance for steel slag SMA-13. Steel slag enhances the abrasion resistance and rutting resistance of asphalt pavement surface layers, fully meeting the performance requirements for high-grade road surface layers.

A chance encounter in central Texas yields insights on the ecology of aestivating Siren nettingi (Caudata: Sirenidae)


 
 
 
 Siren spp. are often dominant vertebrates in the wetlands they occupy and are known to estivate when such wetlands dry up. Practical considerationslimit in-situ observations of estivating individuals. On 12 October 2021, we incidentally discovered an estivating aggregate of Siren nettingi in Bastrop County, Texas, USA. These salamanders were excavated from compact, rocky soil adjacent to a caliche road, at depths that ranged between ~0.2 to 1.5 m. The dominant vegetation at this site included Ulmus crassifolia, Persicaria sp., and various grass species. We recovered 140 individuals of which seven were salvaged and 133 were captured live. We measured 115 of these for snout–vent length (SVL) and observed the aggregate was predominated by juveniles. We estimated an estivation density of 2.33 sirens/m2 that is comparable to densities estimated for non-estivating populations. However, in-lieu of monitoring that was in place for this study, we expect a mass mortality event would have likely occurred. We therefore suggest that roadway construction in preferred habitat be considered as a threat to siren populations.
 
 
 

Identification of Geotechnical-Related Factors Impacting Cost, Schedule, and Claims on Roadway Construction Projects

Identification of Geotechnical-Related Factors Impacting Cost, Schedule, and Claims on Roadway Construction Projects

Evaluation of Millability and Recyclability of Asphalt with Paving Interlayers

Abstract Reclaimed asphalt pavement (RAP) has been widely incorporated into roadway base and surface courses, as they provide economic and environmental benefits that lead to sustainable construction practices. However, because of the increasing use of paving interlayers (e.g., geotextiles, geogrids, and geocomposites) during roadway rehabilitation, the likelihood of milling projects involving asphalt layers with paving interlayers (referred to as GRAP) has significantly increased. Consequently, the assessment of potential GRAP reuse in geotechnical and pavement applications becomes essential. This research study aims at evaluating the millability and recyclability of asphalt layers with paving interlayers. Specifically, sections with and without paving interlayers were first milled to evaluate the millability of asphalt layers with paving interlayers. Subsequently, the recyclability of GRAP for the base and surface course of pavements was assessed by quantifying the geotechnical characteristics of millings collected from asphalt layers with paving interlayers, referred herein as geosynthetic RAP or GRAP, and those without paving interlayers (RAP). The evaluation of RAP and GRAP materials for road base suitability included blending them with virgin aggregates and investigating these blends via determination of particle size distribution, binder content, compaction characteristics, abrasion resistance, hydraulic conductivity, and resilient modulus. The evaluation of RAP and GRAP materials for surface course suitability involved preparing asphalt mixtures that incorporated RAP and GRAP and quantifying their particle size distribution, indirect tensile strength, and moisture susceptibility. Comparison of the results obtained from five different base course blends and five different asphalt mixtures demonstrated that the base course blends and asphalt mixtures with GRAP exhibited properties similar to those with RAP. Also, the results of this investigation indicate that asphalt mixtures (surface course) and granular base courses can incorporate up to 30 % and 50 % GRAP, respectively, thus leading to sustainable roadway construction practices.

A Review of Beneficial Use and Management of Dredged Material

This study systematically examined dredged materials from various aspects, including their sources, the volume generated annually, beneficial uses, and the management processes currently practiced. In addition, this paper presents the relevant policies governing the dredging, reuse, and disposal of dredged materials in the United States. A summary of various sources, types/classifications, and the physical and chemical properties of dredged materials used by various researchers are presented. This paper also summarizes the innovative techniques for the beneficial reuse of dredged materials in a wide range of applications in concrete materials, construction products, roadway construction, habitat building, landfill liner/cap, agriculture soil reconstruction, and beach nourishment. Further, limitations and corresponding solutions related to the beneficial use and management of dredged materials were provided in the end.

Carbon Emission Evaluation of Roadway Construction at Contaminated Sites Based on Life Cycle Assessment Method

Greenhouse gas emissions induced by climate change have garnered global attention. Minimizing climate change can be achieved through the reduction of carbon emissions in transportation infrastructure construction and in the production of construction materials. This study aims to calculate carbon emissions in three hypothetical construction scenarios based on the life cycle assessment (LCA) method when a roadway passes across polluted soil at contaminated sites. Three methods are employed to remediate contaminated soil: off-site cement kiln co-processing, on-site ex-situ thermal desorption, and on-site ex-situ solidification/stabilization. Carbon emissions are calculated using the LCA method for each scenario. The baseline carbon emission is estimated for the scenario in which contaminated soil is remediated using the off-site cement kiln co-processing method, and the roadway subgrade is constructed using transported clean soil. In the other two scenarios, contaminated soils are remediated using the on-site ex-situ thermal desorption and solidification/stabilization methods, respectively, and then they are reused as roadway subgrade materials. The LCA analyses demonstrate that the total carbon emission reductions range from 1168.48 to 2379.62 tons per basic unit, corresponding to decreased of 19.31% to 39.33%, respectively, compared to baseline. The reuse of solid waste to replace sand and ordinary Portland cement (OPC) as raw materials in roadway construction reduces carbon emissions by 498.98 tons. Finally, a comparison of carbon emissions between the three scenarios indicates that reducing carbon emissions in the remediation of contaminated soil and reusing solid waste as construction materials are two important methods for achieving overall carbon emission reductions in roadway construction projects.

Developing materials and energy-related indicators and identifying barriers to their adoption in an adjustable urban road sustainable rating system

Materials and energy consumption contribute significantly to the carbon footprint of roadway construction and operation. Although material and energy-related indicators (MEIs) have been incorporated into existing sustainability rating systems in developed countries, their application to other countries/regions, especially developing countries, might be hindered because of varying local contexts. Given that no rating system is specified for urban roadway projects, this study aims to develop MEIs and their weighting system as a part of an adjustable urban road sustainable rating system (AUR-SRS) and investigate the important barriers to MEI adoption. To this end, the adaptive approach integrating top-down and bottom-up methods was employed. The top-down approach used the comprehensive literature review to derive potential MEIs and barriers. The bottom-up approach referred to expert opinions in a three-country context (i.e., Taiwan, Indonesia, and Vietnam) to finalize the five most suitable MEIs and 26 corresponding requirements. The study then applied the Analytical Hierarchy Process (AHP) and Weighted Sum Model (WSM) methods to assign a weighting system to proposed indicators/ requirements and investigate the three critical barriers. The proposed research framework would serve as a baseline for developing adaptable indicators for other categories and examining barriers to indicator implementation.