2024 Onward

Permanent URI for this collectionhttps://hdl.handle.net/1807/137421

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  • ItemOpen Access
    Geometric Design and Safety Outcomes of Roundabouts in the Canadian Context: A Case Study in the Region of Waterloo
    (Canadian Science Publishing, 2024-11-19) Miyake, Ryoto; Fu, Liping
    Road safety remains a critical concern in Canada and worldwide. In response, roundabouts have emerged as a safer intersection design under certain road, traffic and environmental conditions, with extensive research highlighting the critical role of geometric design in their safety effect. However, such geometric effects remain relatively unexplored in Canada, where roundabouts are a recent addition. Moreover, it is unknown whether the underlying relationship varies over time due to the evolution in driver behaviour. This study attempts to address these questions by utilizing data from the Region of Waterloo and constructing negative binomial models. Results indicate that geometric design significantly impacts collision frequency, with effects generally consistent but showing some temporal variability. The study also highlights unique relationships between geometries and safety in Canada, advocating for tailored roundabout designs and cautioning against direct application of findings from other regions.
  • ItemOpen Access
    Finite element study on seismic performance of reinforced concrete bridge pier with kinked rebars
    (Canadian Science Publishing, 2024-10-03) WANG, Chengquan; XIE, Changgen; WU, Xi; Zhuang, Yizhou; QIAN, Haimin; WANG, Xinquan; SUN, Miaomiao
    This paper presents a new design for cost-effective and easily constructed kinked rebar reinforced concrete bridge piers to improve their deformation capacity and energy dissipation during earthquakes, addressing issues of uneven concrete damage and challenging post-disaster repairs. Based on uniaxial tensile tests, mechanical properties of kinked rebars are determined, focusing on steel bar diameter (d) and kinked ratio .In ABAQUS simulations, three pier models are created: a regular RC-B(reinforced concrete bridge pier ) pier and two RC-KB (concrete bridge piers with kinked rebars) piers with kinked rebars, varying the kink ratio. Under 0.1 axial compression ratio, these piers undergo low-cycle reciprocating loading; their seismic performance is assessed through hysteresis curves, skeleton curves, residual displacements, and energy dissipation capacities. Results demonstrate that kinked rebars effectively concentrate concrete damage and enhance ductility and energy absorption. Piers exhibit increased post-yield stiffness and gradual capacity growth in later loading stages, providing robustness throughout the loading process. This validates the use of kinked steel bars in bridge piers.
  • ItemOpen Access
    Time-dependent Mechanical Properties and Structural Behaviour of Graphene Nanoplatelet-reinforced Concrete
    (Canadian Science Publishing, 2024-11-24) Yager, Jacob; Haridas, Haritha; Woods, Joshua; Kontopoulou, Marianna
    Concrete with high volumes of supplementary cementitious materials often have lower early age compressive strength and slower strength gain with time. It has been reported that the addition of graphene nanoplatelets (GNPs) enhances concrete compressive strength. However, the ability of GNPs to increase the early age concrete compressive strength has not been investigated, and there has been limited testing of structural elements of GNP-containing concrete. This study examines the mechanical properties of low cement concrete between 1- and 28-days of curing with varying GNP concentrations. Furthermore, reinforced concrete beams with GNPs were tested at 3 and 28 days to investigate their structural behaviour. The results show compressive strength increases of up to 31% at early ages for a GNP concentration of 0.15 wt% of cement, but no overall changes in the structural behaviour.
  • ItemOpen Access
    Effect of Aquatic Worms and Straw Amendments on the Geotechnical and Biogeochemical Properties of Oil Sands Tailings
    (Canadian Science Publishing, 2024-09-20) Kuznetsov, Petr; Balaberda, Amy-lynne; Pardo, Miguel de Lucas; Ulrich, Ania
    Aquatic Oliogochaete worms (Lumbriculus variegatus) combined with straw led to improved geotechnical properties of fluid fine tailings (FFT) and thickened tailings (TT) in large-scale column studies. Gravity settling caused 19.9% and 20.6% consolidation of FFT and TT over 125 and 127 days, while the addition of straw and worms increased consolidation to 22.0 – 24.3% for FFT and 28.1 – 28.9% for TT. Solids content and peak undrained shear strength were up to 1.1x and 6.6x higher in straw and worm columns, with greatest improvements seen in the top tailings layers where worm tunnels were visually observed. Surviving worms were only found in one column, suggesting the worms provide benefits extending past their depth of penetration and lifespan. The addition of straw stimulated methanogenic activity, decreasing pH, increasing alkalinity, and creating strictly anaerobic conditions (-300 mV), which may have impacted the survivability of the worms but provided another bio-consolidation pathway.
  • ItemOpen Access
    The Universal Classification system for assessing the embodied carbon of concrete in Canada
    (Canadian Science Publishing, 2024-11-16) Kanavaris, Fragkoulis; Munro, Matthew; Giotis, Georgios
    Concrete is known to be the most prevalent human-made material globally owing to its durability, versatility and affordability which; however, contributes significantly to global CO2 emissions. Consequently, efforts have intensified to reduce concrete's embodied carbon, with emerging or conventional alternative technologies aiming to mitigate emissions and produce "sustainable" and "low carbon" concrete; a set of terms which have been used inconsistently leading to potential greenwashing and confusion in the industry. Simultaneously, there is a pressing need for tools and policies to guide the design of low-carbon concrete structures and infrastructure. This paper introduces an embodied carbon classification system as a practical solution to address industry confusion and facilitate sustainable practices in the concrete construction sector. It consists of a universally applicable tool that can be used by designers, manufacturers, asset owners and policy makers to enable a robust evaluation of the embodied carbon concrete, develop pathways to concrete decarbonisation.
  • ItemOpen Access
    Effects of Antifreeze Admixtures on Masonry Performance at Subfreezing Temperatures
    (Canadian Science Publishing, 2024-11-25) Alfarra, Jawdat; Wegner, Leon D.; Boulfiza, Mohamed
    Concrete brick prisms prepared with Type S masonry mortar that included sodium nitrite and/or nanocellulose as potential antifreeze admixtures were cured for 28 days at -10°C before measuring compressive and flexural bond strengths. Addition of sodium nitrite allowed masonry prisms cured at -10°C to reach 88% and 86% of the compressive and flexural bond strengths, respectively, of control specimens cured at room temperature. Nanocellulose was only effective when used in combination with sodium nitrite, improving the compressive and flexural bond strengths by an additional 3% and 27%, respectively. Results are primarily attributed to the ability of the sodium nitrite to lower the freezing point, allowing hydration to continue in subfreezing conditions, as confirmed by results of companion tests on mortar samples. Both additives also reduced the required w/c ratio and porosity. The findings offer a sustainable alternative to energy-intensive protective heating methods, potentially lengthening the construction season into colder periods.
  • ItemOpen Access
    Effect of Oligochaete worms on the permeability of Fluid Fine Tailings and Thickened Tailings under operational parameters: consequences for dewatering and strengthening
    (Canadian Science Publishing, 2024-10-22) Pardo, Miguel de Lucas; Sittoni , Luca; van Kessel, Thijs; Herman, Peter; Hanssen, Jill; van Rees, Floris; Buffarini, Lorenzo; Le Galeze, Simon; Kuznetsov, Petr; Ulrich, Ania
    Oligochaete worms enhance dewatering of Mature Fine Tailings (MFT). In this context, the research team has investigated the beneficial effects of Oligochaete worms in dewatering and strengthening of fresh samples of Fluid Fine Tailings (FFT) and Thickened Tailings (TT), including cold temperatures. Applying Oligochaete worms to FFT and TT resulted in enhanced permeability leading to faster Sc increases which are twice as large as in controls, up to final Solids Content Sc of 37% for FFT and 61% for TT, and shear strengths that are twice as large in their absolute value as in controls too.
  • ItemOpen Access
    Sustainable application of recycled plastics in asphalt pavement: Case study of a trial in Newtonville, Ontario, Canada
    (Canadian Science Publishing, 2024-10-30) Ma, Jianmin; Yuan, Hai; Nawarathna, Hanwalle M.C.; Hesp, Simon
    Global research on using plastic waste in asphalt roads highlights its benefits: recycling waste, reducing greenhouse gas emissions, and providing an alternative to non-renewable asphalt binders. This study aims to bridge the gap between laboratory results and field performance of recycled plastic-modified asphalt in cold regions, promoting broader adoption. Laboratory analysis of core samples was performed as part of a quality assurance program. High-temperature rutting resistance was evaluated using the Hamburg wheel tracking test, while low-temperature cracking resistance was assessed through semi-circular bending testing. Results show that the impact of recycled plastics and fibers on rutting resistance varies with temperature, with the greatest benefit at the highest temperatures. For low-temperature cracking resistance, polyethylene terephthalate (PET) fibers outperform mixed plastics by delaying crack propagation. Low-temperature conditioning can induce thermal shrinkage in the asphalt mixture, slightly moderating the effects of recycled plastics and fibers.
  • ItemOpen Access
    INTEGRATING SMART CITY TECHNOLOGIES FOR SUSTAINABLE PAVEMENT INFRASTRUCTURE
    (Canadian Science Publishing, 2024-11-29) Furtado, Lara; Bessa, Iuri; Gurjão, Nayara; Soares, Jorge Barbosa
    This article explores the connection between Smart City advancements and the development of materials and strategies for asphalt pavements. It highlights the synergy between Smart Cities and Industry 4.0 through current technological advancements using connectivity, artificial intelligence, and big data analysis. The relationships between Smart Cities and Industry 4.0 are examined with an emphasis on five major areas: (i) Internet of Things and integrated systems; (ii) Robotics and additive manufacturing; (iii) Augmented reality for modeling and simulations; (iv) Data driven analysis: Big data, Artificial Intelligence; and (v) Citizen participation. We also point to the importance of smart infrastructure, with the integration of nanomaterials and materials into the structure to reduce energy consumption, optimize resources, and assist automation in construction and maintenance strategies, contributing to the efficiency and longevity of pavement infrastructure. We conclude by envisioning how Generative Artificial Intelligence is integrated into pavement research, opening new avenues for innovation.
  • ItemOpen Access
    Effect of Aquatic Worms and Straw Amendments on the Geotechnical and Biogeochemical Properties of Oil Sands Tailings
    (Canadian Science Publishing, 2024-09-20) Kuznetsov, Petr; Balaberda, Amy-lynne; Pardo, Miguel de Lucas; Ulrich, Ania
    Aquatic Oliogochaete worms (Lumbriculus variegatus) combined with straw led to improved geotechnical properties of fluid fine tailings (FFT) and thickened tailings (TT) in large-scale column studies. Gravity settling caused 19.9% and 20.6% consolidation of FFT and TT over 125 and 127 days, while the addition of straw and worms increased consolidation to 22.0 – 24.3% for FFT and 28.1 – 28.9% for TT. Solids content and peak undrained shear strength were up to 1.1x and 6.6x higher in straw and worm columns, with greatest improvements seen in the top tailings layers where worm tunnels were visually observed. Surviving worms were only found in one column, suggesting the worms provide benefits extending past their depth of penetration and lifespan. The addition of straw stimulated methanogenic activity, decreasing pH, increasing alkalinity, and creating strictly anaerobic conditions (-300 mV), which may have impacted the survivability of the worms but provided another bio-consolidation pathway.
  • ItemOpen Access
    Development of Conflict-Based Safety Performance Function for Safety Evaluation of Urban Roundabouts in India
    (Canadian Science Publishing, 2024-10-29) Maji, Abhijnan; Ghosh, Indrajit; Chandra, Satish
    This study evaluates the safety performance of urban roundabouts in India using conflict-based Safety Performance Functions (SPFs). High-resolution aerial videos were utilized to extract vehicle trajectories, and the Surrogate Safety Assessment Model (SSAM) was employed for conflict identification. Data were collected from 27 roundabouts across various Indian cities, focusing on non-lane-based heterogeneous traffic conditions. Four SPFs were developed utilizing a Generalized Linear Model with Negative Binomial (NB) distribution and log link function for different proximity levels based on Time-to-Collision (TTC) and Post-Encroachment Time (PET) values. Key factors influencing conflict frequency included conflicting traffic volume, occupancy time, ratio of approaching and conflicting traffic volume, percentage of cars and motorcycles, inscribed circle diameter, roundabout symmetry, and number of legs. The developed conflict frequency prediction models fitted well and demonstrated robust predictive performance. This proactive framework for roundabout safety assessment can be followed to enhance road safety in developing nations.
  • ItemOpen Access
    New Rotating Coanda-Type Intake for Sediment-Laden Flows
    (Canadian Science Publishing, 2024-10-23) Hazar, Oğuz; Civelek, Sercan; Sagir, Cem Ali; Elçi, Sebnem
    Tyrolean and Coanda types of water intake structures are the most widely preferred bottom intake structures used to divert water from channels and river systems for various purposes, such as energy production, irrigation, and domestic use. Estimation of withdrawal water and filtered sediment amounts are important to obtain maximum efficiency from an intake structure. The purpose of this study is to numerically analyze a newly patented rotating Coanda-type intake system to achieve the highest Water Capturing Efficiency and Sediment Release Efficiency. The newly patented system (patent no: TR2021011306B) presented here incorporates Coanda screens with variable void ratios, autonomously selected based on the sediment characteristics of the inflowing water. The process of selecting and positioning the appropriate screen is fully automated, requiring no human intervention. The system rotates under motor control to place the suitable screen at the operational point based on the specific requirements of the incoming sediment-laden flow.
  • ItemOpen Access
    Field Performance of Asphalt Mixture Modified with Reactive Isocyanate Based Modifier
    (Canadian Science Publishing, 2024-09-04) Tran, Nam; Moraes, Raquel; Taylor, Adam; Timm, David
    The reactive isocyanate-based modifier chemically reacts with asphalt components, overcoming the issues of increased viscosity and phase separation encountered with conventional modified binders. It can be used to modify binders to meet the highest performance grades currently specified by state highway agencies. This project aimed to demonstrate the constructability of an asphalt mixture modified with the reactive isocyanate-based modifier in the field and compare its performance with that of a control mixture. The project involved milling an approximately 5.0-cm (2-in) thick surface layer of two 30.5-m (100-foot) sections with similar foundation support. One section was resurfaced with a reactive isocyanate-modified mixture and the other with a conventional SBS-modified mix. The mixtures have shown no significant difference in field performance and laboratory performance test results. This study has provided insights into the field applicability of reactive isocyanate-based modifiers in asphalt mixtures, facilitating the ongoing efforts to develop durable road surfaces.
  • ItemOpen Access
    EXPERIMENTAL AND NUMERICAL STUDIES ON THE PROPOSED STIFFENER DETAILING OF INTEGRAL BRIDGE STEEL H PILES TO ALLEVIATE THE COMBINED ADVERSE EFFECTS OF AXIAL LOAD AND CYCLIC THERMAL DISPLACEMENTS
    (Canadian Science Publishing, 2024-10-14) Karalar, Memduh; Dicleli, Murat
    Past research studies demonstrated that local buckling may be observed when the steel H piles (SHPs) at the abutments of integral bridges (IB) are simultaneously subjected to axial load and lateral plastic displacements. The large curvatures and strains associated with local buckling may lead to earlier low cycle fatigue (LCF) failure of the pile under cyclic thermal displacements. Accordingly, first, the detrimental effect of axial load combined with lateral plastic displacements leading to local buckling and accelerated LCF failure of the SHP is demonstrated through experimental testing and finite element modeling and analysis. Then preventive measures to eliminate or delay local buckling are developed and assessed numerically as well as by experimental testing. Numerical simulation and experimental test results revealed that welding longitudinal stiffeners on the flanges successfully prevent the local buckling of the flanges and improve the fatigue life of the pile.
  • ItemOpen Access
    Characterising the permanent deformation of subgrade soils under seasonal variation
    (Canadian Science Publishing, 2024-10-11) Carvalho Everton, José Henrique; Erlingsson, Sigurdur
    Rutting, a prevalent failure mode in flexible pavements, largely stems from subgrade issues. Despite this, there is a lack of standard protocols to evaluate subgrade rutting or permanent deformation (PD). This study attempted to characterise PD in subgrades, focusing on a poorly graded sand and two silty sands. Moisture contents above and below optimum levels were considered to account for seasonal variations. The research involved adapting a test to assess the PD by determining typical stresses on the subgrade. Moreover, given these soils' unsaturated state and medium- to fine-grained nature, suction is an important factor. Suction-controlled multi-stage Repeated Load Triaxial tests were conducted, and the results were fitted by a PD model modified to account for suction. The characterisation was compared with the subgrade strain criterion used in pavement design solutions. Results indicated discrepancies between the PD characterisation and strain criteria predictions, with the silty sands performing better than the poorly graded sand, consistent with the shakedown theory.
  • ItemOpen Access
    THE IMPACT OF EXTREME WEATHER EVENTS OF PROJECTED CANADIAN REGIONAL CLIMATE MODEL DATA ON FLEXIBLE PAVEMENT
    (Canadian Science Publishing, 2024-09-22) Maadani, Omran; Shafiee, Mohammad; Shirkhani, Hamidreza; Hiedra Cobo, Juan
    This paper presents findings about the influence of projected data from the Canadian regional climate model on the performance of flexible pavement, building upon the results from previous work where the data was generated and published, in which a general trend of decreasing the design life was observed. Projected temperature is the most important extreme climate impact on flexible roads. Adopting a conservative approach demonstrated that two extreme events of Maximum Mean Annual Air Temperature (MMAAT) and Maximum Summer Average Air Temperature (MSAAT) resulted in significant reduction of 25 years road design life. The observed trend indicates a severity range of 7% to 15% in terms of design service life loss when considering events every year compared to every five years. The findings revealed a reduction in pavement design life by 34%, 50%, 73%, and 90% for historical, short, intermediate, and long-term life cycles in the city of Windsor, respectively.
  • ItemOpen Access
    Climate Change in Canadian Civil Engineering Curricula: Gaps and Best Practices
    (Canadian Science Publishing, 2024-07-17) Liu, Paris; Lovegrove, Gordon Richard; Nehdi, Moncef L.
    This study examines the state of curricula, knowledge, and practices in Canada’s civil engineering programs with respect to climate change, identifies best practices, and formulates recommendations on ways to improve climate change knowledge and skills training for Canadian civil engineering programs. A survey based on the Climate Framework was distributed to 856 civil engineering instructors across all 25 accredited engineering schools listed by Engineers Canada and gathered data on 55 civil engineering climate change related courses, with representation from 20 out of the 25 accredited programs across the country. The results of this study provide important benchmarks to help instructors incorporate most relevant climate change topics and resources into their courses for equipping civil engineering students with the necessary skills to tackle emerging challenges related to the mitigation of climate change and adaptation to wildfires, droughts, sea level rise, increased precipitation, storms, heat domes, floods, earthquakes, and biodiversity loss.
  • ItemOpen Access
    Impact of Refuge Island in Two-Lane Roads on Pedestrian Crossing Behavior: A Virtual Reality Study
    (Canadian Science Publishing, 2024-09-19) Haq, Muhammad Faizan ul; Iryo-Asano, Miho; Alhajyaseen, Wael; Samson, Christian J. R.; Zhu , Hong
    Crashes involving pedestrians are particularly common at unsignalized mid-block crosswalks, where, sometimes, vehicles do not yield to pedestrians. A refuge island (RI) is a countermeasure at mid-block crosswalks on two-lane roads to improve safety in pedestrian–vehicle conflicts. This study investigates the impact of RI at unsignalized mid-block crosswalks on pedestrian crossing behavior and conflict severity, considering vehicle approach speed and approach direction. A virtual reality experiment was designed to compare pedestrian crossing behaviors in different scenarios. Results revealed that at higher vehicle approaching speeds, pedestrians tended to accept shorter gaps, leading to a higher rate of unsafe crossings. Generally, in RI setting, pedestrians accepted significantly shorter gaps, which increases the operational efficiency of the crosswalk without significantly affecting the severity of conflicts with vehicles. Furthermore, the subjective evaluation of the pedestrians after the experiment clearly indicated their preference for the RI setting, as they reported a safer crossing experience.
  • ItemOpen Access
    Quantifying changes in floods under different bathymetry conditions for a lake setting
    (Canadian Science Publishing, 2024-06-13) Redondo Tilano, Sergio Andrés; Boucher, Marie-Amélie; Lacey, Jay; Parent, Jérémy
    Floods can cause extensive damage proportional to their magnitude, depending on the watershed hydrology and terrain characteristics. Flood studies generally assume bathymetry as steady, while in reality it is constantly changing due to sediment transport. This study seeks to quantify the impact of different lake bathymetry conditions on flood dynamics. The Hydrotel and Telemac2D models are used to simulate floods for a lake with bathymetries from multiple year surveys. The bathymetries differ in bed elevation due to sediment accumulation and/or remobilisation. Results show that bathymetric differences produce a more noticeable effect for moderate flows than for maximum flows. During moderate flows, shallower bathymetries induce higher water levels and larger water extents. For peak flows, differences in water levels and extent are practically negligible for the different bathymetries tested. Higher water levels during moderate flows could produce longer flooding times and affect the community’s perception of flood impacts.
  • ItemOpen Access
    Application of Reliability Models for Crash Frequency Analysis: Implications for Network-wide Safety Performance
    (Canadian Science Publishing, 2024-06-28) Deljouyi, Nasim; Patnala, Phani Kumar; Mehran, Babak; Regehr, Jonathan D
    The present study demonstrated the potential applications of reliability models for crash analysis of a large highway network. Specifically, three major outcomes of reliability models were investigated: temporal distributions of crashes, reliability score, and expected number of crashes, using 20-year data (2001-2020) of crashes recorded on the Saskatchewan highway network. A series of reliability models were developed for crashes by crash severity, vehicle involvement, and highway type. First, the temporal distributions of crashes on each segment were fit to a statistical distribution. Second, the reliability scores were used to rank the high crash risk segments. Third, the mean expected crash frequency was used to develop network-wide safety performance functions for total and fatal crashes in urban and rural highway segments using Poisson-Tweedie regression models. The developed PTw models showed that the presence of trucks in the traffic composition has a significant effect on crash frequency, especially for urban highway segments.