Scholarly Works, Civil and Environmental Engineering

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Testing and Microcracking Assessment of Cement-Treated Full-Depth Reclamation
Tong, Bilin; Amarh, Eugene; Diefenderfer, Brian K.; Brand, Alexander S.; Hasibul Hasan, Rahat; Katicha, Samer; Benavides Ruiz, Carolina; Flintsch, Gerardo W. (SAGE Publications, 2026-04-21)
Full-depth reclamation (FDR) has gained increasing recognition as an efficient and cost-effective pavement rehabilitation method by recycling up to 100% of existing materials on-site, with Portland cement-stabilized FDR (FDR–PC) providing enhanced structural integrity. A comprehensive understanding of the mechanical properties of FDR–PC is essential to optimize its design and improve implementation efficiency. This study investigated the mechanical characteristics of FDR–PC, the interrelationships among various tests, and assessed the use of microcracking on constructed accelerated pavement test sections. Tests conducted included compressive strength (CS), flexural strength, elastic modulus, and shrinkage behavior in the laboratory, and deflection testing using a falling weight deflectometer. Four constructed FDR–PC pavement sections, including 3.25% and 5.5% cement content (by weight), both with and without induced microcracking, were built to study the shrinkage concerns observed during practice associated with FDR–PC. In addition, the influence of the microcracking technique was evaluated. The findings include: (1) a correlation factor of 1.46 to account for specimen-size effects in FDR–PC CS testing; (2) a slower loading rate than that specified in ASTM C469 may be more appropriate for characterizing FDR–PC; (3) the American Concrete Institute-based modulus predictions tend to overestimate FDR–PC stiffness; (4) the American Association of State Highway and Transportation Officials model provided the most accurate 7-day modulus of rupture (MoR) estimates; (5) length change test results were influenced by density and cement content; (6) strong correlations were observed among all evaluated mechanical properties; and (7) microcracked mixtures gained stiffness over time, with greater initial reduction in the lower-stiffness FDR–PC and significant stiffness recovery in the high-stiffness FDR–PC.
Track Transition Performance: A Sensor-Centric Literature Review and Optical Sensing Advances
Gharizadehvarnosefaderani, Mahsa; Rabbi, Md. Fazle; Mishra, Debakanta (MDPI, 2026-03-04)
The structural and geotechnical characteristics of railroad tracks change abruptly at transition zones. At these locations, a change from ‘rigid’ to ‘flexible’ track conditions or the opposite leads to amplified dynamic responses, large deformations, accelerated track deterioration, and increased maintenance expenses. Researchers have conducted numerous field and numerical studies into track transitions’ behavior; however, their investigations are often limited by point-based and short-term measurements and assumptions that overlook critical mechanisms in track transitions. This review presents current sensor-centric knowledge achieved by integrating insights from field instrumentations and numerical modellings of transition zones. The objective is to expose the overlooked behavioral aspects of track transitions and identify the limitations of conventional monitoring systems. To address these gaps, this review introduces optical fiber sensors (OFSs) as an emerging technology for track condition monitoring. Focusing on recent OFS applications, this study demonstrates how OFSs can improve the quantity and quality of field data through spatial continuity, multiplexing, and higher sensitivity, thus marking a significant practical improvement. This review also outlines OFS-based monitoring challenges, such as sensor durability, measurement quality, temperature-strain cross-sensitivity, and lack of a standardized data interpretation framework. Altogether, this work’s novelty is in connecting transition zone behavior, monitoring limitations, and the inherent potential of OFS systems.
Transit time modeling framework for predicting freshwater salinization in urban catchments
Bhide, Shantanu V.; Grant, Stanley B.; McGuire, Kevin J.; Prestegaard, Karen; Kaushal, Sujay S.; Sekellick, Andrew J.; Rippy, Megan A.; Schenk, Todd; Curtis, Shannon; Gomez-Velez, Jesus D.; Hotchkiss, Erin R.; Vikesland, Peter J.; Saksena, Siddharth (Elsevier, 2026-03)
The salinity of inland freshwaters is rising globally, particularly in urban watersheds where winter road deicers are widely applied. Attributing stream salinity dynamics to specific sources and transport pathways remains challenging due to episodic salt inputs, engineered drainage, and strong coupling between hydrology and subsurface storage. We present a modeling framework that couples climate-driven deicer build-up and wash-off with transient transit time distribution theory to simulate salt transport through drainage, interflow, and groundwater pathways. Applied to an urban watershed in Northern Virginia (USA), the model reproduces ten years of high-frequency stream salinity measurements across daily-to-decadal timescales. The calibrated model implies an average deicer application of 206 tonnes Cl yr−1, or roughly one 20 kg bag of rock salt person−1 yr−1 when normalized by the 20,000 people living in the watershed. In winter months, higher infiltration routes a large fraction of snowmelt and deicers into shallow subsurface pathways, enhancing vadose-zone and interflow contributions to stream salinity. Limited subsurface storage capacity and seasonal hydrologic turnover flush excess chloride from the vadose zone and groundwater during subsequent summer storms. By linking climate-driven deicer inputs, hydrologic connectivity, and stream water age, the framework provides a transferable basis for diagnosing and managing freshwater salinization in urban watersheds.
From PFAS source attribution to collaborative management in a One Water system
Krauss, Lauren; Rashid, Md Redowan; Noble-Blair, Mishelle; Furst, Kirin; Spiesman, Anne; Kaushal, Sujay; Dadiala, Rhea; Bhide, Shantanu V.; Rippy, Megan A.; Curtis, Shannon; Grant, Stanley B. (2026)
A major barrier to preventing per- and polyfluoroalkyl substances (PFAS) from entering drinking water supplies is identifying and quantifying their upstream sources, particularly in One Water systems that integrate diverse water inputs. Here we combine high-frequency measurements with mass-balance analysis to quantify PFAS and major-ion loading to the Occoquan Reservoir, a drinkingwater supply serving one million people in Northern Virginia, USA. Mass-balance analysis at the confluence of watershed inflows and treated wastewater inputs reveals seasonally varying contributions from domestic wastewater, watershed runoff, and a single significant industrial user (SIU) of the sanitary sewer system. A one-month, system-scale diversion of SIU effluent confirms this source attribution for several short-chain PFAS and major ions, with concentration deficits closely matching withheld mass. These results demonstrate that traditional mass-balance approaches can inform collaborative management of PFAS contamination in One Water systems.
The short-term and long-term performance of biopolymer-remediated soils
Sasar, Mohammadhasan; Abdelaziz, Sherif L. (Springer, 2025-12)
This paper discusses the short- and long-term durability of biopolymer-treated coarse-grained soils. Despite their promise as an environmentally friendly alternative to traditional methods, the durability of biopolymer-treated soils has been a limiting factor in their widespread adoption. Therefore, we consider the durability of biopolymer-treated soils at two different stages after treatment: For short-term durability, the biopolymer gel is present in the pore structure of the soil, improving it through its finite yield stress and viscosity. In this case, our work focuses on assessing the durability against cyclic drying and wetting. The results show that, due to the pore-clogging effect of the biopolymer, rapid moisture variations and the majority of biological degradation are concentrated in a thin outer crust. Long-term durability is studied in terms of the synergistic effects of biopolymer and plant roots on soil shear strength. Biopolymer increased root diameter and, in the early stages, decreased total root length.
Mechanisms of compacted soil deterioration in biopolymer-treated sands under cyclic wetting and drying
Sasar, Mohammadhasan; Aryal, Rijan; Lamsal, Anish; Abdelaziz, Sherif L. (Springer, 2026-02-01)
Biopolymers have received research attention for improving the erosion resistance and strength of coarse-grained soils. Unlike cement-treated soils, however, no standardized tests have been developed to assess the durability of biopolymer-treated soils under cyclic drying and wetting conditions. Therefore, questions remain on their long-term stability. The main goal of this study is to examine the performance of biopolymer-treated sandy soils both over time and with cyclic drying and wetting. This work focuses on Xanthan Gum (XG) as a model biopolymer for treating sandy soils. Compacted biopolymer-treated specimens were subjected to cyclic drying/wetting according to the ASTM code designed for soil-cement mixtures. The specimens were dissected after each cycle to study the mechanism and progression of failure. Furthermore, the biopolymer pore fluid was extracted and studied using rheology and infrared spectroscopy (FTIR) to investigate the effects of drying and wetting on the physical and chemical properties of the biopolymer gel. It was found that the low hydraulic conductivity of the biopolymer-treated sand creates a unique distribution of moisture in the compacted specimens. Rheological investigations indicated a reduction in the yield stress of the pore fluid in the “crust” of the specimens, which played the main role in the failure of the specimens under cyclic drying and wetting. FTIR tests showed evidence of biological degradation of the biopolymer. Cyclic drying and wetting tests were also performed on pure biopolymer gels to further investigate the degradation of biopolymers independent of the soil.
Statistical Crushing of Hollow Calcareous Sediments
Zeppilli, Danilo; Beemer, Ryan D.; Riera, Rosine; Lebrec, Ulysse; Blazeski, Melissa; Cassidy, Mark J. (ASCE, 2024-11-13)
Whereas the crushing of solid soil particles has been studied for decades, there is very little research performed on the micro-mechanics of hollow particles crushing. In this paper a statistical model based on the principles of Weibull survival statistics is presented to analyze the particle size distribution and void ratio evolutions during one-dimensional (1D) crushing of hollow particles. It was found that 1D crushing of hollow particles tends to evolve toward gap grading. A theoretical Beta factor (β) is introduced and implemented to parametrically study impact of microscale exchange of intraparticle void space from within the hollow particles to the external void space on the macroscale behavior. These trends are compared with a calcareous sediment from the Browse Basin which is located on the North West Shelf (NWS) of Australia and contains hollow sand particles from biologic origins. Whereas the bulk void ratio tends to decrease in all cases when hollow particles are crushed, it appears that the extraparticle void ratio increases in most cases presented in this study. A more in depth understanding of the mechanisms of intraparticle voids exchange may lead to better analytical, finite element, and discrete element models of the unique shear and compression behaviors of hollow calcareous sediments through the work of this statistical model.
Investigation of the Combined Effects of Surface Roughness, Gradation, Mineralogy, and Effective Stress on the Large-Displacement Behavior of Sand-Structure Interfaces
Mondal, Sanchari; Disfani, Mahdi M.; Beemer, Ryan D.; Martinez, Alejandro (ASCE, 2025-11)
The interface friction angle is an important design parameter in geotechnical engineering applications, such as onshore and offshore foundations, retaining walls, and landfills, necessitating its accurate estimation. The influence of the surface roughness, particle shape and size, mineralogy, gradation, and breakage on the interface friction angle has been widely reported, mostly in isolation from each other. This study investigated the combined effects of surface roughness, gradation, mineralogy, and effective stress on the mobilized interface friction angle and particle breakage through large-displacement ring shear tests. Seven different sand types were sheared against two kinds of interfaces with different surface roughnesses and at varying effective stress levels. The critical state interface friction angle increased in conditions that produced greater particle breakage, including larger effective stress, surface roughness, and shear displacement. This effect was more apparent in the poorly graded sands than in the well-graded sands. With the increase in effective stress, the dependency of critical state interface friction angle on initial mean particle size decreased. The critical state interface friction angle ratio decreased with particle size, increased with angularity, and had mixed behavior with effective stress, gradation, and surface roughness, depending on the other parameters. The data presented in this paper provide insight into the coupled effects of particle size, surface roughness, and effective stress on the breakage of particles and how this influences the mobilization of strength.
Development of the MPAS-CMAQ coupled system (V1.0) for multiscale global air quality modeling
Wong, David C.; Willison, Jeff; Pleim, Jonathan E.; Sarwar, Golam; Beidler, James; Bullock, Russ; Herwehe, Jerold A.; Gilliam, Rob; Kang, Daiwen; Hogrefe, Christian; Pouliot, George; Foroutan, Hosein (Copernicus, 2024-11-07)
The Community Multiscale Air Quality (CMAQ) model has been used for regulatory purposes at the U.S. EPA and in the research community for decades. In 2012, we released the Weather Research and Forecasting (WRF)CMAQ coupled model that enables aerosol information from CMAQ to affect meteorological processes through direct effects on shortwave radiation. Both CMAQ and WRF-CMAQ are considered limited-area models. Recently, we have extended domain coverage to the global scale by linking the meteorological Model for Prediction Across Scales – Atmosphere (MPAS-A, hereafter referred simply to as MPAS) with CMAQ to form the MPAS-CMAQ global coupled model. To configure these three different models, i.e., CMAQ (offline), WRF-CMAQ, and MPAS-CMAQ, we have developed the Advanced Air Quality Modeling System (AAQMS) for constructing each of them effortlessly. We evaluate this newly built MPAS-CMAQ coupled model using two global configurations: a 120 km uniform mesh and a 92–25 km variable mesh with the finer area over North America. Preliminary computational tests show good scalability and model evaluation, when using a 3-year simulation (2014–2016) for the uniform mesh case and a monthly simulation of January and July 2016 for the variable mesh case, on ozone and PM2.5 and show reasonable performance with respect to observations. The 92–25 km configuration has a high bias in wintertime surface ozone across the United States, and this bias is consistent with the 120 km result. Summertime surface ozone in the 92–25 km configuration is less biased than the 120 km case. The MPAS-CMAQ system reasonably reproduces the daily variability of daily average PM from the Air Quality System (AQS) network.
Quantitative Evaluation of Regulatory Indicators for Brominated Haloacetic Acids in Drinking Water
Furst, Kirin E. (American Chemical Society, 2025-02-25)
Drinking water regulations often use indicators to represent risk associated with broader contaminant groups. To evaluate the efficacy of indicators, a quantitative approach is needed that aligns with the regulatory framework, in which a benchmark value represents an unacceptably high level of a contaminant or contaminant class. This policy microsimulation study develops such an approach in the context of potential regulatory revisions to address brominated HAAs, a class of disinfection byproducts. Likely scenarios include a limit on the sum of nine brominated and chlorinated HAAs (HAA9), on bromide, or on the sum of six brominated HAAs (HAA6Br). The probability of each potential regulatory indicator co-occurring with a high level of HAA6Br was quantified using logistic models. The HAA9 and bromide indicators both performed poorly, with no better than a ∼1 in 4 chance of identifying equivalently high levels of HAA6Br. Furthermore, high false positive rates (>75%) would implicate a substantial number of water systems that do not have high HAA6Br levels. This study reveals the trade-off implicit in the use of regulatory indicators, in which precision (fewer false positives) must be sacrificed to achieve greater coverage (more true positives). The methodology and findings have broad implications for evaluating indicator classes in drinking water policy and research.
Enhanced Formation of Brominated and Nitrogenous Disinfection Byproducts in Drinking Water Disinfection with Chlorocyanurates
Adusei, Kadmiel B.; Tanveer, Hafiz Usama; Kralles, Zachary T.; Furst, Kirin E. (American Chemical Society, 2026-01-13)
Disinfection of drinking water provides essential protection against microbial pathogens. However, disinfectants react with organic matter and other constituents in water to form disinfection byproducts (DBPs), which are of concern for human health. Chlorocyanurates are chlorine-based disinfectants that have been used for drinking water in point-of-use and emergency contexts. Little is known about chlorocyanurate DBP formation beyond the potential to form lower regulated trihalomethanes and haloacetic acids compared to chlorine. In this study, regulated and unregulated DBP formation was evaluated for multiple chlorocyanurate formulations to understand the effect of the chlorine-to-cyanuric acid ratio on DBP mixture composition and calculated toxicity by comparison to conventional chlorine. Chlorocyanurates produced lower regulated DBPs by ∼10-50% compared to chlorine but promoted bromine incorporation in most DBP classes by 50-200% and produced higher calculated toxicity than chlorine under most conditions. Enhanced dichloroacetonitrile formation by chlorocyanurates was partly attributed to trichloramine formation from the degradation of chlorocyanurates by hypochlorite. Thus, chlorocyanurates may promote multiple DBP toxicity drivers. Water quality and operational considerations are identified to minimize DBP toxicity while using chlorocyanurate disinfectants, which remain an important option for drinking water disinfection in low-resource settings.
Transit times link pollution sources to drinking water quality in a "One Water" system
Bhide, Shantanu V.; Grant, Stanley B.; Benettin, Paulo; Rippy, Megan A.; Monofy, Ahmed; Furst, Kirin E.; Shelton, Sydney; Kaushal, Sujay S.; Misra, Shalini; Vikesland, Peter J.; Hotchkiss, Erin R.; Spiesman, Anne; Prelewicz, Greg; Schenk, Todd; Post, Harold; Alvi, Dongemei; Steglitz, Brian; Husic, Admin (Pergamon-Elsevier, 2025-09-27)
Innovative approaches are needed to manage chronic and emerging water quality challenges in communities that rely on treated wastewater and urban stormwater as sources of raw water for drinking water treatment, or “One Water” systems. When amended to account explicitly for upstream versus distributed inflow to the reservoir, we show that unsteady transit time theory links pollution sources to water quality in the Occoquan Reservoir (Virginia, USA), one of the largest and oldest One Water systems in the United States. Using 11 years of hydrologic and water quality data, the model identified distinct sources and transformation rates for reactive (nitrate) and relatively non-reactive (sodium, chloride) solutes. High predictive skill was achieved with a strikingly small number of parameters: two for sodium and chloride (one for the upstream storage selection function, one for solute input from distributed sources; Nash–Sutcliffe Efficiency (NSE) = 0.65 and 0.76) and two additional for nitrate (capturing seasonal denitrification linked to summer stratification and hypolimnetic processes; NSE = 0.55). The simplicity of unsteady transit time theory supports rigorous parameter estimation (Bayesian Markov Chain Monte Carlo) and model structure evaluation (Bayesian Information Criterion). It also opens the door to real-time interactive simulations with stakeholders, supporting collaborative solutions to cascading water quality challenges.
Storm-Induced Solute Dynamics and Hysteresis Behaviour in an Eogenetic Karst Aquifer
Spellman, Patricia; Husic, Admin; Hasenmueller, Elizabeth A. (Wiley, 2025-04)
Eogenetic karst aquifers that maintain high carbonate bedrock permeability can have distinctive aquifer hydrodynamics that would be captured in hysteresis behaviour. Analysing the hysteresis behaviour of these systems can be a concise and efficient method to provide insight into the dominant recharge mechanisms, porosity integration and contributing land uses to spring discharge. The availability of deployable water quality sensors that can monitor spring water chemistry at high temporal resolution across multiple events allows us to capture delayed or attenuated signals that may occur in eogenetic karst. Additionally, analysing hysteresis across multiple events can identify patterns in the responses that occur. The Upper Floridan Aquifer (UFA) is an example of an eogenetic karst aquifer that has extensive phreatic conduits embedded in a high permeability carbonate matrix. We collected high temporal resolution (15 min) discharge, specific conductance and nitrate. We analysed storm-induced changes to nitrate and specific conductance and quantified hysteresis by calculating the hysteresis index (HI) and complementary flushing index (FI) at two major springs that drain agriculturally dense regions of the UFA. The combined analysis of HI and FI showed that 95% of all events had delayed connectivity of discrete feature recharge emerging at each spring. Mobilisation (FI > 0) of specific conductance occurred 95% of the time at both springs, but nitrate was diluted (FI < 0) 85% of the time at one spring and mobilised 95% of the time at the other. Changes to both specific conductance and nitrate were less than 15% of the pre-storm values, which illustrates how discrete recharged water mixes with substantial volumes of older, stored water in the aquifer. The hysteresis behaviour in the UFA was in contrast with a telogenetic setting, where higher variability in nitrate responses occurred between events, dilution was mostly observed for specific conductance and nitrate, and responses varied between delayed and rapid connectivity. Our work quantifies the storm-induced hydrodynamics of an eogenetic karst aquifer, which can help guide local water resource management decisions and advance our knowledge of karst aquifer hydrodynamics across a wide range of diagenetic and karstification stages.
Development and validation of a multi-modal contactless sensing system for surgical risk analysis in a real-world environment
Scarpa, Joseph R.; Kanchumarthi, Nidhi; Hussain, Iqram; Keswani, Aakash; Zeepvat, Julianna; Milewski, Andrew; Scarpa, Julia; Boyer, Richard; Sarlo, Rodrigo (Public Library of Science, 2025-11-14)
Gait measurements are a central component of functional assessments and risk stratification before surgery. Various sensors can measure gait metrics, but none are routinely integrated into surgical workflows because they are too challenging to implement at scale in clinical situations. In this manuscript, we report the development and validation of a rapidly-deployable, low footprint, entirely contactless sensing system, called GroundCode, that is explicitly integrated within a surgical workflow. GroundCode combines the Microsoft Kinect with seven floor-mounted single-axis accelerometers, overcoming the weaknesses of each individual sensor technology and providing both robust spatiotemporal resolution (Kinect) and high-fidelity footstep detection and quantification (floor accelerometers). We show that GroundCode-derived gait speed and cadence are highly precise measurements (>90%), and we validate them against two standard clinical gait measurements relevant to pre-surgical evaluations – stopwatch time and six-minute walk test distance. We show that GroundCode-derived gait metrics identify various surgical risk factors, like age, sex, and frailty. In addition, we show that preoperative gait is associated with postoperative quality of recovery. Importantly, we designed this system to be deployed by non-technical personnel and performed this study in a non-laboratory setting, providing proof-of-principle that GroundCode can be used in various real-world environments. We conclude that GroundCode provides highly robust gait measurements in real-world settings with possible applications spanning clinical diagnosis, risk stratification, and digital biomarker development.
Effects of digestate application depth on soil nitrogen volatilization and vertical distribution
Wang, Lili; Wenzhe, Li; Zhongjiang, Wang; Wang, Zhiwu; Sui Chao, Li Yan (Chinese Academy of Agricultural Engineering, 2016-09)
This study investigated the effect of the digestate application depth on soil nitrogen volatilization and vertical distribution in black loam soil and sandy loam column. The contents of soil moisture, TKN (total Kjeldahl nitrogen), ammonium nitrogen, nitrate nitrogen, and the extent of ammonia volatilization were tested by applying digestate at depths of 0 cm, 2 cm, 6 cm, 10 cm, 15 cm and 20 cm, respectively. The experimental results showed that ammonia volatilization mainly occurred in the first 10 days and reduced significantly when the application depth was deeper than 10 cm. At the same application depth, compared with the black loam, the nitrogen loss in sandy loam through ammonia volatilization was less, and the penetration depth of nitrate nitrogen and ammonium nitrogen were all deeper. In the same soil, nitrate nitrogen penetrated deeper than ammonium nitrogen at all application depths.
Salinity effect on production of PHA and EPS by Haloferax mediterranei
Cui, You-Wei; Gong, Xiao-Yu; Shi, Yun-Peng; Wang, Zhiwu (The Royal Society of Chemistry, 2017)
The halophilic archaeon, Haloferax mediterranei, is able to produce polyhydroxyalkanoates (PHAs) in large quantities. Along with the synthesis of PHAs by H. mediterranei, an extracellular polymeric substance (EPS) is excreted as a byproduct, lowering the efficiency of the production of PHAs. In this experiment, salinity effects on the carbon distribution to synthesis of PHAs and/or EPS were explored in order to control their production. It was found that high NaCl concentrations inhibited the productivity of EPS while encouraging the productivity of PHAs. The optimal salinity for the growth and proliferation of H. mediterranei was in the range of 150–200 g L⁻¹. EPS productivity decreased from 371.36 to 319.74 mg EPS per g CDW as the concentration of NaCl increased from 75 g L⁻¹ to 250 g L⁻¹. However, high salinity promoted the synthesis of PHAs. When the NaCl concentration was 250 g L⁻¹, the intracellular content of PHAs reached a maximum of 71.1%. This result indicated that a high NaCl concentration significantly stimulated the production of PHAs while depressing the production of EPS. This study provided a possible solution to adjust the carbon distribution to the synthesis of PHAs and EPS by H. mediterranei by controlling the concentration of NaCl.
Pivotal role of municipal wastewater resource recovery facilities in urban agriculture: A review
Wang, Jiefu; Sun, Yuepeng; Xia, Kang; Deines, Allison; Cooper, Ross; Pallansch, Karen; Wang, Zhiwu (Wiley, 2022-05-18)
Urban agriculture provides a promising, comprehensive solution to water, energy, and food scarcity challenges resulting from the population growth, urbanization, and the accelerating effects of anthropogenic climate change. Their close access to consumers, profitable business models, and important roles in educational, social, and physical entertainment benefit both developing and developed nations. In this sense, Urban Water Resource Reclamation Facilities (WRRFs) can play a pivotal role in the sustainable implementation of urban agriculture. Reclaimed water as a recovered resource has less supply variability and in certain cases can be of higher quality than other water sources used in agriculture. Another recovered resource, namely, biosolids, as byproduct from wastewater treatment can be put to beneficial use as fertilizers, soil amendments, and construction material additives. The renewable electricity, heat, CO₂, and bioplastics produced from WRRFs can also serve as essential resources in support of urban agriculture operation with enhanced sustainability. In short, this review exhibits a holistic picture of the state of-the-art of urban agriculture in which WRRFs can potentially play a pivotal role.
Environmental and Economic Analysis of Repurposed Wind Turbine Blades for Recreational Trail Bridges
Silverman, Aeva G.; Ackall, Gabriel P.; Johansen, G. Eric; Gentry, T. Russell; Bank, Lawrence C. (MDPI, 2026-02-01)
A two-parameter environmental (measured in CO2eq—CO₂ is used in this paper to represent the carbon dioxide molecule as opposed to the chemical formula CO₂ as is common practice in LCA studies; CO2eq is an abbreviation for CO₂ equivalent and may be written as CO2e in the literature) and economic (measured in USD) analysis using life cycle analysis (LCA) and techno-economic analysis (TEA) of repurposed wind turbine blades for structural use in recreational trail bridges (e.g., on hiking trails and golf courses) is described in this paper. The US Department of Energy’s TECHTEST TEA/LCA software (v1.0) platform was used to compare three commercially available trail bridges (a steel truss bridge, an FRP pultruded truss bridge, and a glulam stringer bridge) with a bridge made from retired wind turbine blades (known as a BladeBridge). All bridges had a 50 ft (15.24 m) long by 6 ft (1.83 m) wide deck and were designed for a 90 psf (4.3 kN/m²) live load. The LCA functional unit was the assembled bridge, which was made ready to be shipped from the fabricator. Cradle-to-gate (A1–A3, i.e., raw material extraction, transportation, and manufacturing) system boundaries were used. For the BladeBridge, no embodied carbon was attributed to the blade itself (cut-off system allocation). For the TEA, a USD 660/tonne credit was attributed to the blade. The raw materials for each bridge were determined from detailed construction documents. Manufacturing and transportation energy were determined based on the equipment used for fabrication and geographical location. Direct labor for fabrication was calculated based on a weighted average of salaries taken from the US Bureau of Labor Statistics. The results indicate that raw materials had the biggest effect on embodied CO2eq and that labor had the largest impact on cost for all bridges. The results indicate that the BladeBridge is significantly less expensive to produce and releases less CO2eq into the environment (less Global Warming Potential (GWP)) than the three commercially available bridges. Additional TEA metrics for the BladeBridge, including Technology Readiness Level (TRL) and future market potential, were also evaluated and found to be positive for the BladeBridge technology.
Fracture Initiation Pressure as a Measure of Cemented Paste Backfill Strength
Frimpong, James A.; Shabab, Basel Ahmad; Pandey, Rohit; Chatterjee, Snehamoy; Walton, Gabriel; Brand, Alexander S. (Springer, 2025-06)
This laboratory-scale study presents the development and validation of a hydraulic fracturing technique to directly measure the tensile strength of cemented paste backfill (CPB), providing an alternative to traditional strength testing methods. Fracture initiation pressure (FIP) was used as the primary measure of CPB strength. Experimental results were compared with traditional benchmark measures such as uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), and critical Mode-I fracture toughness (KIc). Regression analysis of experimental results revealed a strong linear relationship between FIP and these benchmark strength measures, indicating that FIP can be used as a reliable predictor of CPB strength. However, traditional linear elastic failure models did not adequately explain the observed FIP values, as they significantly over-predicted the CPB tensile strength. To address this, the Point Stress (PS) model was applied, which provided a more accurate prediction of tensile strength, especially in cases involving small boreholes. The PS model explained observed effects of borehole size on the material’s response to hydraulic pressurization. This study confirms that hydraulic fracturing, interpreted through the PS model, is an effective method for determining CPB strength and provides a practical alternative measure to conventional testing methods.
Modelling earthquake-triggered landslide runout with the Material Point Method
Alsardi, Abdelrahman; Copana, Julio; Yerro Colom, Alba (2021-10)
Landslides triggered by earthquakes cause devastating consequences to downstream infrastructure. The simulation and prediction of these large-strain events remain challenging. The objectives of this paper are i) to validate the Material Point Method (MPM) framework for the study of coseismic landslides, and ii) to compare the capabilities of MPM with mesh-based methods and simplified Newmark-type methods to simulate post-failure runouts. To achieve these objectives, the MPM framework is presented whereby nodal kinematic boundary condition is employed with a moving mesh. Secondly, the framework is validated with a shaking-table laboratory test of a saturated clay slope. Thirdly, a parametric analysis is conducted using 25 real ground motions on a simple theoretical slope. The MPM results are compared to those obtained with mesh-based methods and three state-of-the-art Newmarktype approaches. It is concluded that mesh-based methods are consistent with MPM predictions for small-strain instabilities associated with low energy ground motions (i.e. Arias intensity lower than 4 m/s). When using ground motions with energy above this threshold, mesh-based methods accumulate significant errors associated with bad geometry. MPM results consistently matched permanent displacements predicted with the Newmark-type methods employed in this analysis.

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