Recent Submissions

  • Transportation Equity for RITI Communities in Autonomous and Connected Vehicle Environment: Opportunities and Barriers

    Sorour, Sameh; Abdel-Rahim, Ahmed; Swoboda-Colberg, Skye (2020-08)
    This report summarizes the results of a study conducted to document the safety and mobility needs of Rural, Isolated, Tribal, or Indigenous (RITI) communities and to identify autonomous and connected vehicle technology that have the potential of addressing these needs. A review of the administrative structure for the five Native American Tribes in Idaho revealed that none of the tribes has a department dedicated to transportation services. Two of the five tribes, however, have a department dedicated to Information Technology (IT) services. Based on the results of focus group discussions and the follow up in-depth interviews, some of the major transportation safety and mobility problems and need areas for RITI communities include: safety of school-age children walking to school, lack of safety pedestrians facilities (sidewalks) in the community, inefficient emergency response services, issues with paratransit scheduling and reliability of service, roadway maintenance issues, aggressive driving in community roadways, struggle of low-income families with no car ownership, snow removal and clean up especially for local roads, and not having enough driver education programs available for the community. In terms of major barriers to Autonomous and Connected Vehicle implementation in RITI communities, the interviewed citizens believe that lack of communication infrastructures, cost of smart phone use, difficulties to use internet and/or smart phones, lack of electrical power coverage in some roadway areas, privacy and safety issues in car sharing operations, cost of expanding communication and power networks, and the lack of human resources in the community to support these technologies are some of the major barriers to the wide-spread implementation of such advanced technology.
  • RESULTS OF A SURVEY ON TRANSPORTATION SAFETY EQUITY IN HAWAII

    Duque de Medeiros, Flavia; Barros, Rafaela De Melo; Prevedourous, Panos (2020-07)
    Five transportation equity questions were developed for this assessment. Question 1 addressed EMS response in urban and rural areas. People with a bachelor’s degree or higher thought slightly more that rural response is worse. Rural residents believed it is worse and half of urban residents agreed. CSET minority respondents thought that rural response is slightly worse. These groups have a perception that reflects reality, according to FARS data, but the overall response to the question “Compared to urban areas, in rural areas emergency response is?” is “about the same.” Every demographic group did not support the proposal of question 2 for the government to increase gasoline taxes to collect money to invest in EMS response improvements in rural areas of Hawaii. The overall result for question 3 is that respondents were divided when it comes to converting rural roads into high standard roads in Hawaii. No demographic group had a majority response, pro, against or neutral. The response to question 4 was much clearer: all demographic groups disagreed with the proposition that the government should raise gasoline taxes to collect funds for the purpose of making rural roads safer by converting them to high standard roads. Question 5 addressed the urban-rural road funding balance: “Should more money, less money or about the same amount of money be provided to support urban road and highway improvements?” The response was mostly divided between same amount and more money, suggesting that an equal share should be allocated between urban and rural roads. Overall, the results suggest a lack of awareness of conditions on rural roads.
  • DOCUMENTING THE CHARACTERISTICS OF TRAFFIC CRASHES FOR RITI COMMUNITIES IN IDAHO

    Abdel-Rahim, Ahmed; Swoboda-Colberg, Skye; Mohamed, Mohamed; Gonzalez, Angel (2020-08)
    This project documents the characteristics of traffic crashes in rural, isolated, tribal, and indigenous (RITI) communities in Idaho and establishes an in-depth understanding of the baseline traffic safety conditions in RITI communities. Different sources of crash data for RITI communities in Idaho was used to conduct an in-depth ten-year crash analysis (2007-2016) to document the characteristics of traffic crashes in rural roads that serve RITI communities in Idaho. The results of analysis of fatal and severe injury crashes on unpaved roads clearly shows that ATVs and pickup trucks and the two most common vehicle types involved in crashes in these roads. The results also showed that the majority of fatal and severe injury crashes on unpaved roads involved male drivers and occupants 24 years or younger with considerable number involving occupants younger than 14 years old. A comparative safety analysis was conducted to identify and document the differences in characteristics between crashes that occurred on unpaved and paved rural roads in Idaho. The results of the analysis show that the percent of fatal and severe injury crashes where no restraining device was used is much higher in unpaved roads (50.4% and 38.3% in unpaved roads compared to 37.9 and 22.8 on paved roads). The same trend also exists in helmet use which shows the critical need for a much more aggressive seat belt and helmet use enforcement among communities who use rural unpaved roads in Idaho. The results also show a substantial difference in ATV crashes on unpaved versus paved. Teenagers or children that are 14 years or younger are more susceptible to fatal and severe injuries on unpaved roads compared to paved roads. Crash injuries for age groups from 15 to 44 are also higher on unpaved roadways. The results also clearly highlight the fact that unpaved roads have higher percentages of crashes where alcohol impairment was a major contributing circumstance. The same is true for speeding and inattention related crashes. A proportion statistical test results show that many of these results have a calculated p-value less than 0.05, indicating that these results are statistically significant at the 95% confidence level.
  • Effects of Reading Text While Driving: A Driving Simulator Study

    Prevedouros, Panos; Miah, M. Mintu; Nathanail, Eftihia (2020-02)
    Although 47 US states make the use of a mobile phone while driving illegal, many people use their phone for texting and other tasks while driving. This research project summarized the large literature on distracted driving and compared major outcomes with those of our study. We focused on distraction due to reading text because this activity is most common. For this research project, we collected simulator observations of 203 professional taxi drivers (175 male, and 28 female) working at the same Honolulu taxi company, using the mid-range driving simulator VS500M by Virage. After a familiarization period, drivers were asked to read realistic text content relating to passenger pick up displayed on a 7-inch tablet affixed to the dashboard. The experimental scenario was simulated on a two-lane rural highway having a speed limit of 60 mph and medium traffic. Drivers needed to follow the lead vehicle under regular and text-reading conditions. The large sample size of this study provided a strong statistical base for driving distraction investigation on a driving simulator. The comparison between regular and text-reading conditions revealed that the drivers significantly increased their headway (20.7%), lane deviations (354%), total time of driving blind (352%), maximum duration of driving blind (87.6% per glance), driving blind incidents (170%), driving blind distance (337%) and significantly decreased lane change frequency (35.1%). There was no significant effect on braking aggressiveness while reading text. The outcomes indicate that driving performance degrades significantly by reading text while driving. Additional analysis revealed that important predictors for maximum driving blind time changes are sociodemographic characteristics, such as age and race, and past behavior attributes.
  • Operational Safety of Gravel Roads in Rural and Tribal Communities: Vulnerability to Structural Failures and GeoHazards

    Ibrahim, Ahmed; Sharma, Sunil; Kassem, Emad; Nielsen, Richard; Nasrin, Sabreena (2020-04-20)
    Of the 4.1 million miles of federal and state highways in the U.S., 2.2 million miles (or 54%) are unpaved, gravel roads. In the Pacific Northwest and Alaska, unpaved gravel roads provide critical transportation access, with some communities relying on just a single highway for access into and out of town. In such cases, these highways become a critical component of the infrastructure, and there is a need to ensure that safe access is always available to the communities. The Idaho highway database has been used to identify unpaved, gravel roads in Idaho that are critical for access to rural communities. Once identified, information regarding their existing condition has been used to assess their vulnerability and other impacts. The results of this study are considered an initial evaluation that relies on information that is readily available in the database. The project outcomes include a comprehensive literature review of unpaved roads including data produced from field visits. In addition, a questionnaire survey was sent to local jurisdictions authorities for investigating locations, reasons of road closures, and population size of the affected communities. Finally, 37 responses have been received by the research team indicating five rural communities that have experienced closures and isolation. The reasons for the closure of the unpaved roads were due to the lack of funding for snow removal, excessive dirt, unstable gravel roads, tornados, and heavy rains. The location of those communities was spread across the state of Idaho with corresponding populations range from 25 to 8,500 people.
  • DRONES FOR IMPROVING TRAFFIC SAFETY IN RITI COMMUNITIES IN WASHINGTON STATE

    Ban, Xuegang (Jeff); Abramson, Daniel; Zhang, Yiran (2020-04-04)
    Transportation and traffic safety is a primary concern in Rural, Isolated, Tribal, or Indigenous (RITI) communities in Washington (WA) State. Parallel to this, while emerging technologies (e.g., connected/autonomous vehicles, drones) have been developed and tested in addressing traffic safety issues, they are often not widely shared in RITI communities for various reasons. Compared with other technological advances, drone technologies have been rapidly improved and can be flexibly applied to multiple fields, including engineering, agriculture and disaster managements. The goal of this study is to explore and synthesize the opportunities, challenges and scenarios that drone technologies can assist to resolve traffic safety related issues and concerns in RITI communities. Through the outreach activities with the outer Pacific Coast in WA state, it is found that the principal concern within these communities are disaster management and mitigation since they are facing the threat of coastal erosion, earthquake and tsunami. Thus, the emergency management and hazard mitigation becomes the major way to further explore drone applications in the selected communities. To achieve this, we reviewed the current state of the drone technologies, conducted surveys from National Guard and coastal communities in WA, including City of Westport, South Beach Region, Grays Harbor County, Shoalwater Bay Tribe, and Quinault Indian Nation, to better understand their current needs, challenges and issues. Ultimately, recommendations of drone applications under specific scenarios are provided based upon the integration of drone technologies with community safety needs.
  • Enabling Data-Driven Transportation Safety Improvements in Rural Alaska

    Bennett, F. Lawrence; Metzgar, Jonathan B.; Perkins, Robert A. (2019-12)
    Safety improvements require funding. A clear need must be demonstrated to secure funding. For transportation safety, data, especially data about past crashes, is the usual method of demonstrating need. However, in rural locations, such data is often not available, or is not in a form amenable to use in funding applications. This research aids rural entities, often federally recognized tribes and small villages acquire data needed for funding applications. Two aspects of work product are the development of a traffic counting application for an iPad or similar device, and a review of the data requirements of the major transportation funding agencies. The traffic-counting app, UAF Traffic, demonstrated its ability to count traffic and turning movements for cars and trucks, as well as ATVs, snow machines, pedestrians, bicycles, and dog sleds. The review of the major agencies demonstrated that all the likely funders would accept qualitative data and Road Safety Audits. However, quantitative data, if it was available, was helpful.
  • Development of Landslide Warning System

    Riad, Beshoy; Zhang, Xiong (2019-11)
    Landslides cause approximately 25 to 50 deaths and US$1 - 2 billion worth of damage in the United States annually. They can be triggered by humans or by nature. It has been widely recognized that rainfall is one of the major causes of slope instability and failure. Slope remediation and stabilization efforts can be costly. An early warning system is a suitable alternative and can save human lives. In this project, an early warning system was developed for a 40-foot-high cut slope on the island of Hawaii. To achieve the objective, subsurface investigations were performed and undisturbed samples were collected. For the purpose of unsaturated soil testing, new testing apparatuses were developed by modifying the conventional oedometer and direct shear cells. The unsaturated soil was characterized using two separate approaches and, later, the results were discussed and compared. The slope site was instrumented for the measurement of suction, water content, displacement, and precipitation. The collected climatic data along with the calibrated hydraulic parameters were used to build an infiltration-evapotranspiration numerical model. The model estimations were compared with the field measurements and showed good agreement. The verified model was used to determine the pore-water pressure distribution during and after a 500-years return storm. Later, the pore-water pressure distribution was transferred to a slope stability software and used to study the slope stability during and after the storm. Based on a 2D slope stability analysis, the slope can survive the 500-year storm with a factor of safety of 1.20. Instrument threshold values were established for water content sensors and tensiometers using a traffic-light-based trigger criterion.
  • Development of a Computer Vision-Based Three-Dimensional Reconstruction Method for Volume-Change Measurement of Unsaturated Soils during Triaxial Testing

    Zhang, Xiong; Xia, Xiaolong (2019-10)
    Problems associated with unsaturated soils are ubiquitous in the U.S., where expansive and collapsible soils are some of the most widely distributed and costly geologic hazards. Solving these widespread geohazards requires a fundamental understanding of the constitutive behavior of unsaturated soils. In the past six decades, the suction-controlled triaxial test has been established as a standard approach to characterizing constitutive behavior for unsaturated soils. However, this type of test requires costly test equipment and time-consuming testing processes. To overcome these limitations, a photogrammetry-based method has been developed recently to measure the global and localized volume-changes of unsaturated soils during triaxial test. However, this method relies on software to detect coded targets, which often requires tedious manual correction of incorrectly coded target detection information. To address the limitation of the photogrammetry-based method, this study developed a photogrammetric computer vision-based approach for automatic target recognition and 3D reconstruction for volume-changes measurement of unsaturated soils in triaxial tests. Deep learning method was used to improve the accuracy and efficiency of coded target recognition. A photogrammetric computer vision method and ray tracing technique were then developed and validated to reconstruct the three-dimensional models of soil specimen.
  • Laboratory and Field Evaluation of Modified Asphalt Binders and Mixes for Alaskan Pavements

    Liu, Jenny; Liu, Jun (2019-08)
    In order to properly characterize modified asphalt binders and mixes for Alaskan pavements, this study evaluated properties of 13 asphalt binders typically used in Alaska from three different suppliers, and 10 hot mix asphalt (HMA) mixtures which were either produced in the lab or collected from existing paving projects in Alaska. Various binder and mixture engineering properties were determined, including true high binder grades, complex modulus (G*), and phase angle (δ) at high performance temperatures, multiple stress creep recovery rate and compliance, bending beam rheometer stiffness and m-value, Glover-Rowe parameter, ΔT, rheological index, and crossover frequency for binders, and rut depth, critical strain energy release rate (Jc), Indirect tensile (IDT) creep stiffness and strength for mixtures. Binder cracking temperatures were determined using asphalt binder cracking device. Mixture cracking temperatures were determined with IDT creep compliance and strength data. It was found that rutting and cracking resistances of the mixtures with highly modified binders were better than the mixture with unmodified asphalt binder (PG 52-28). Future recommendations for highly modified asphalt binders applications and research were provided based on laboratory testing results and field survey evaluation.
  • Reaching Out to Tribal Communities: Lessons Learned and Approaches to Consider

    Awwad-Rafferty, Rula; Chang, Kevin; Brown, Helen (2019-12-31)
    When transportation safety decision-making is desired, the involvement and engagement with a community is essential. A streamlined delivery of a project or program is more likely to occur when active dialogue and an exchange of ideas occurs in advance and occurs frequently. This is particularly important in tribal communities, who value sustained relationships and represent the focus population of this study. The research team, on six separate occasions, met with local and regional tribal leaders to explore and discuss transportation safety needs within and outside tribal communities, as well as discern the recommended approaches to foster ongoing dialogue about these needs. In all cases these discussions closely correlated with existing research studies or activities; transportation safety and equity is not seen as separate from other tribal foci and community needs. Specific recommendations to consider, in no particular order, included the following: invest respectfully enough time for people to talk; tribes think long-term and consider the impact of any decision from a long-term viewpoint so an iterative process and re-sharing of ideas is critical; the power of decision is in the hands of the tribe and its members; do not lump tribes together as each tribe is sovereign and unique and every community should be expected to think differently; all tribes are unique as is the environmental and social context; to disseminate information widely and iteratively, do so when there is a large group or event; be sure to understand the Tribal governance, decision making, and organizational structure; know who is the tribal Chairman or Chairwoman; and develop an emic and etic understanding of the community.
  • Highly Abrasion-resistant and Long-lasting Concrete

    Liu, Jenny; Murph, Diane (2019-08)
    Studded tire usage in Alaska contributes to rutting damage on pavements resulting in high maintenance costs and safety issues. In this study binary, ternary, and quaternary highly-abrasion resistant concrete mix designs, using supplementary cementitious materials (SCMs), were developed. The fresh, mechanical and durability properties of these mix designs were then tested to determine an optimum highly-abrasion resistant concrete mix that could be placed in cold climates to reduce rutting damage. SCMs used included silica fume, ground granulated blast furnace slag, and type F fly ash. Tests conducted measured workability, air content, drying shrinkage, compressive strength, flexural strength, and chloride ion permeability. Resistance to freeze-thaw cycles, scaling due to deicers, and abrasion resistance were also measured. A survey and literature review on concrete pavement practices in Alaska and other cold climates was also conducted. A preliminary construction cost analysis comparing the concrete mix designs developed was also completed.
  • A Bio-Wicking System to Prevent Frost Heave in Alaskan Pavements: Phase II Implementation

    Galinmoghadan, Javad; Zhang, Xiong; Lin, Chang (2019-11)
    Water within pavement layers is the major cause of pavement deterioration. High water content results in significant reduction in soil’s resilient behavior and an increase in permanent deformation. Especially in cold regions, frost heave and thaw weakening cause extensive damage to roads and airfields. Conventional drainage systems can only drain gravity water not capillary water. Both preliminary lab and field tests have proven the drainage efficiency of a newly developed H2Ri geotextile with wicking fabrics. In this report, continuous research was conducted to verify the effectiveness of the wicking fabric in mitigating frost boil issues in Alaskan pavemnets. Two test sections were selected at two low volume roads on the campus of the University of Alaska Fairbanks. Soil moisture and temperature sensors were installed within the road embankments. The monitored data was used to analyze the soil migrations and evaluate the drainage performance of the wicking fabric. Preliminary monitoring results showed that the wicking fabric was effective in mitigating the frost boil problem.
  • Use of Cellular Concrete for Air Convection Embankment to Protect Permafrost Foundations in Cold Regions: Feasibility Study

    Liu, Jenny; Wu, Hanli (2019-08-15)
    The air convection embankment (ACE) is a technique used to protect permafrost from thawing in road construction in cold regions. However, the desired materials needed for ACE are not readily available, which prevents its extensive use in Alaska. To overcome the limitation of traditional ACE, and further improve the cooling effect of ACE, this study investigated the feasibility of using cellular concrete as an alternative material for ACE in cold regions. The heat transfer patterns of the cellular concrete ACE, the crushed-rock ACE, and the sand/gravel embankment were studied using the numerical simulation. The results of the present study show that the cooling performance of both cellular concrete ACE and crushed-rock ACE are superior to the traditional sand/gravel embankment. The cellular concrete ACE has better heat insulation property in the summer, and the crushed-rock ACE has stronger natural convection in winter. For the annual cooling efficiency of the two different ACE techniques, the proposed cellular concrete ACE has a better cooling effect on the foundation soil than the crushed-rock ACE. These results indicate that the thermal conductivity and specific heat capacity of construction materials have significant impacts on the performance of the ACE.
  • The Impact of Snowfall on Airport Operations and Delays

    Lee, Jukwan; Yan, Jia (2019-03-31)
    Flight delays or cancelations due to snowfall are a costly inconvenience, not only to airports but also to airlines, passengers and society as a whole. However, no quantitative research has ever been done to provide an analytical explanation about the issue. Though being a reliable alternative to melt snow on the runway and mitigate flight delays, the Heated Pavement System is not adopted in any US airports because of concerns over the initial investments and maintenance costs being higher than the economic loss from delays during unpredictable snowfall days. Combining weather and domestic flight data in Boston and Los Angeles regions, we analyze the benefits and costs associated with installing the Heated Pavement System. Using two advanced econometric methods, the Difference in Difference in Difference (DDD) and the nearest neighbor matching, we first develop a Delay Analysis model to evaluate the exact effect of snowfall on flight delays, and then we calculate the delay costs. Based on the empirical findings, we conduct cost-benefit analysis of installing HPS at the three airports in Boston area. Our results indicate that HPS is feasible for airports with a great number of flights and passengers, such as Boston Logan airport.
  • Examination of the Variability in Grout Test Results

    Ahn, Il-Sang; Friend, Trenton (2019-08-31)
    Keyway grouting is an operation that connects decked bulb-tee girders into one system. The quality of grout should be well maintained through reliable material test procedures. Due to the issues of discrepancy and variability, there have been several cases in which grout materials did not satisfy the compressive strength standard specified in the DOT&PF Standard Specifications for Highway Construction. This research examined the causes of such issues. Six factors – grout material, mix consistency, workmanship, initial curing/storing, curing method, and test equipment – were identified as the causes of strength variation. Their effects on strength variation were investigated by testing compressive strength of cube and cylinder specimens made from 5 grout materials that were used or considered to be used in DOT&PF projects. Grout material characteristics such as grout material and mix consistency have significant effect on strength variation. Workability and consolidation can be different from one material to another. Consequently, they affect compressive strength and its variation. Workmanship and test equipment were evaluated in this research to have moderate effect on strength variation. Especially, strength variation can increase when the workmanship factor combines with the grout material characteristics factor.
  • Pre-Stress Loss Due to Creep in Precast Concrete Decked Bulb-Tee Girders Under Cold Climate Conditions

    Vandermeer, Drew; Ahn, Il-Sang (2019-07-31)
    Accurate estimation of pre-stress losses is one of the important issues for the design of precast, pre-stressed concrete bridge girders. While this subject has been long studied by many researchers, studies on pre-stress losses in cold climates are minimal. In the present research, long-term pre-stress loss due to concrete creep was studied based on concrete creep test. Two concrete creep test frames were fabricated and placed indoors and outdoors. Concrete strains were measured by Demountable Mechanical Strain Gauge (DEMEC) from two 612 high-strength concrete cylinders in each frame. The concrete strains were collected for 11 months (7/26/2017 – 6/21/2018) after loading, and outdoor ambient temperature dropped below 0C between 100 and 250 days. Between 50 and 100 days, two curves from the two frames are similar in their patterns and values. After 100 days, the total strain from the indoor frame slowly increased reaching 1,600 and 1,700 after 250 days. However, the total strain from the outdoor frame varied between 1,000 and 1,500 and the averaged total strain was 1,300 after 250 days. In cold temperature, the occurrence of concrete creep and shrinkage was suppressed.
  • Developing an Interactive Baseline Data Platform for Visualizing and Analyzing Rural Crash Characteristics in RITI Communities

    Zhang, Guohui; Prevedouros, Panos; Ma, David T.; Yu, Hao; Li, Zhenning; Yuan, Runze (2019-10-01)
    This project focused on developing an interactive baseline crash data platform, termed as Rural Crash Visualization Tool System (RCVTS), to visualize and analyze rural crash characteristics in RITI communities. More than 975 thousand crash records were collected in the state of Alaska, Idaho, and Washington, from 2010 to 2016. Data fusion is applied to unify the collected data. In the proposed RCVTS platform, three main functions are defined: crash data visualization, data analysis, and data retrieval. Crash data visualization includes an on-street map based crash location tool and a graphic query tool. Data analysis involves a number of visualization approaches, including static charts— i.e., the scatter chart—the line chart, the area chart, the bar chart, and interactive graph— i.e., the sunburst chart. Users are allowed to generate customized analytical graphs by specifying the parameters and scale. The three types of authorized users are defined to download crash information in the data retrieval section following corresponding limitations. The proposed RCVTS was illustrated using a sample case with crash records of the State of Alaska. It showed that the proposed RCVTS functions well. Recommendations on future research are provided as well.
  • Developing a Data-Driven Safety Assessment Framework for RITI Communities in Washington State

    Wang, Yinhai; Sun, Wei; Yang, Hao; Gottsacker, Christopher; Ricord, Sam; Yin, Shuyi (2019-10-03)
    In the history of this country, rural, isolated, indigenous, and tribal (RITI) communities were commonly overlooked with regards to social infrastructure and support. This issue is evident in the development of the transportation networks of these areas and the distinct lack of road safety in these types of communities. RITI communities carry a significantly disproportionate amount of traffic collisions and fatalities compared to urban areas. In order to improve the traffic safety conditions of the RITI communities in Washington State, it is necessary to build a traffic safety management system. A baseline data platform was developed by integrating the collected safety related data for the RITI communities in Washington State in the Year 1 Center for Safety Equity in Transportation (CSET) project. Besides the baseline data, the traffic safety management also requires the safety assessment framework, which is the corner stone of the traffic safety management system. Therefore, this project aims to develop a data-driven safety assessment framework to enable an effective roadway safety management system and improve the traffic safety conditions for RITI communities. The framework is based on an effective and efficient database management system for traffic and crash-related data of the RITI communities. In addition, in order to assist transportation agencies in practices such as the identification of high-risk roadway segments, the developed database management system has powerful visualization functions. Besides the database management and visualization platform, this project also develops roadway safety performance indices and traffic safety assessment methods in the safety assessment framework. This project also provides guidance on how to utilize these safety performance indices and results of safety assessment methods for visualization and analysis.
  • A Novel Systematic Strategy Towards Air-Purifying, Corrosion Resistant and Self-Healing Concrete Infrastructure

    Yang, Zhengxian (2019-09-15)
    Transportation causes major emissions of harmful gases (NOx, CO, VOCs). These pollutants also travel long distances to produce secondary pollution such as acid rain. The most popularly used photocatalytic cementitious composites based on TiO2 achieve the air purification function under ultraviolet sunlight, significantly impeding a broader application of photocatalytic cementitious composites. This study focused on developing an environmentally friendly and durable cementitious system based on the multifunctional photocatalytic Graphitic carbon nitride (g-C3N4). The photocatalytic cementitious composites (PCC) were prepared in three manners: (1) incorporating g-C3N4 nanosheets (CNNs) in cement at three mixing dosages (0.5%, 1% and 2% by weight of cement), (2) applying CNNs at various concentration levels as the coating on recycled asphalt pavement aggregate, (3) applying CCNs s with vinyl chloride/vinyl ester/ethylene copolymer (as a binder) as the coating on cement mortar. The photocatalytic performance and durability of the newly developed cementitious composites were evaluated systematically and the results showed that the PCC hold marked efficiency in terms of NOx removal and self-cleaning when the CNNs were applied in a proper way. The obtained knowledge sheds light on a future perspective of developing a novel systematic strategy towards air-purifying, corrosion resistant, and self-healing concrete infrastructure.

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