Tran-SET 2021

Rockfall is a hazard in mountainous areas threatening infrastructure and human lives. A major method that is adopted for this issue is inspecting rock surfaces using pry bars. The inspector reaches to rock blocks, hits the rock surface, detect and remove the loose rocks. This method is very labor demanding, unsafe, and challenging. This research presents a method that automatize the inspection of the areas and rock blocks that are prone to rockfall events. A tap testing system on a robot is proposed which collects the sound of the hammer taps on the surface and classifies them using principal component analysis (PCA) scores of each tap sound’s signal. This research enables the inspectors to collect data remotely, detect loose rocks, and save data for future references.

As the number and proportion of older adults (65 years and above) as well as older licensed drivers grows in North America, their susceptibility to fatal and injury traffic crashes increases due to natural aging. So, it is vital to study the determinants of older drivers’ involvement in traffic collisions. The main objective of this study is to identify the most significant contributing factors affecting the severity of traffic crashes involving older drivers. The data used in the analysis includes a 2014–2018 crash dataset that was obtained from Louisiana Department of Transportation and Development (LA DOTD). The logistic regression approach including interaction terms was used to investigate the impact of roads, vehicle, environment, and drivers’ factors. The interaction between these variables was also studied to identify potential contributors influencing the dependent variable. Crash severity measured in two classes of no injury, and injury/fatality. The findings of this study suggest that the significant factors affecting crash severity of older drivers in Louisiana are road characteristics (location of accident, road type, road alignment, and highway type), driving maneuvers (prior movement and lane departure), and drivers’ characteristics (driver condition and gender). Also, three significant interaction terms (alignment*lane, highway type*gender, and location type*driver condition) were identified among the above variables.

Mental health issues are increasingly affecting the performance of workers in many different industries, including the transportation construction industry. Depression, anxiety, etc. are the most prevalent health issues in the construction industry today, and identifying the major causes of these issues can help significantly in lessening their consequences. In this study, a selective literature review was conducted through which the major causes of mental health issues and their impact on the productivity of workers were identified and analyzed. The top-three factors leading to mental health issues were identified as work pressure, emotional and physical demands, and bullying and harassment. The results also demonstrated that the support of supervisors is an effective strategy for alleviating the rate of mental health issues and its negative impacts. Communication among the co-workers can also lead to stress relief and consequently prevent the corresponding adverse results. This information will help transportation construction project managers understand the main causes of mental and psychological problems among their workers, and they can use the outputs of this study to determine how each mental issue affects productivity and what strategies can be implemented to alleviate the adverse consequences.

As one important component of bridge inspection, bridge deck inspection ensures the serviceability and safety of everything above, on, and in bridge decks. Traditionally, bridge deck inspection is performed on the ground by having inspectors either visually inspect surface conditions or interpret the acoustic feedback from hammer sounding or chain dragging to determine subsurface conditions. These traditional methods have many limitations, including but not limited to, expensive, labor-intensive, time-consuming, requiring specialized staff on a regular basis, and unsafe. Recent advancements in remote sensing, especially small-unmanned aircraft systems (S-UAS) based airborne imaging techniques and object based image analysis techniques, have shown promise in improving bridge deck inspection. This project explored the utility of S-UAS based airborne imaging techniques and structure-from-motion techniques in developing a data acquisition system to accurately and rapidly collect bridge deck wearing surface and subsurface distress condition data at a low cost.

The success of a transportation project to some extent depends on the health condition of the workforce working in the field. The short- and long-term physical and mental health of field workers in the construction of transportation infrastructure are mostly overlooked by employers. Therefore, the aim of this study was to analyze the impact of heat stress and cold weather (two extreme weather conditions) on the health of transportation projects’ workforce. To this end, a comprehensive study of the literature in this area was conducted focusing on the effects of extreme weather conditions on the transportation project workers with regard to their age, gender, and race. In addition, proper strategies to manage the negative effects of extreme weather on workers’ health were established. The results indicated that workers over 50 years old are significantly more affected by extreme weather conditions. In addition, female workers and pregnant women are at a higher risk of a cardiac strain than male workers. Furthermore, Hispanic workers are found to have more heat disorders compared to non-Hispanics. Timely breaks and increased workforce are the most cited management strategies that reduce the effects of heat load and help in increasing the project’s productivity. This study helps project managers identify the workers at the highest risks of health problems. In addition, the findings of this study will assist employers to adopt strategies that prevent and/or reduce the physical and mental health issues in the transportation field workforce.

The number of electric vehicles (EV) has increased significantly in the past decades due to its advantages including emission reduction and improved energy efficiency. However, the adoption of EV could lead to overloading the grid and degrading the power quality of the distribution system. It also demands an increase in the number of EV charging stations. To meet the charging needs of 15 million EVs by the year 2030 with limited charging stations, prediction of charging needs, and reallocating charging resources are in emerging needs. In this study, long short-term memory (LSTM) and autoregressive and moving average models (ARMA) models were applied to predict charging loads with temporal profiles from 3 charging stations. Prediction accuracy was applied to evaluate the performance of the models. The LSTM models demonstrated a significant performance improvement compared to ARMA models. The results from this study lay a foundation to efficiently manage charge resources.

Gender-related factors that impact job promotions in engineering fields have not been widely studied. In an attempt to remedy that, a descriptive analysis was performed on the workforce of the U.S. Department of Transportation (USDOT) from the years 2011–2017 to determine the gender-related factors, including education, age, and years of service, that make an employee eligible for a promotion. The results indicated that females are elevated to high-level positions less often than males, primarily because of their lower level of education, age, and fewer years in service. The outputs of this study will provide guidance to DOTs as they develop policies that motivate females to become eligible for higher level positions and will assist employers in private and public engineering organizations as they move toward a more diverse working environment.

A concrete pavement test area containing 12 different typical sections was constructed on Interstate 30 in 1996 by the Arkansas Department of Transportation. The test area was part of the FHWA’s long term pavement performance (LTPP) program’s Specific Pavement Studies of concrete pavement (SPS-2). Performance data of the test sites was carefully collected by the Arkansas Department of Transportation (ARDOT) and FHWA periodically. Performance measures included roughness (IRI), faulting, cracking, and drainage. Data collected under the LTTP program served as a critical resource in developing the American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical Pavement Design Guide (MEPDG). The performance of the Arkansas SPS-2 site was carefully evaluated each year until its reconstruction in 2014. The predicted versus actual performance of the test sections are reported herein using the mechanistic empirical pavement design guide (MEPDG). It was found that the MEPDG was more conservative than the actual performance for the Arkansas test sections. The MEPDG also placed greater value on widened slabs and concrete strength than was seen in the field.

Laboratory direct tension (pull-off) tests were conducted to supplement field implementation of a non-proprietary ultra-high performance concrete (UHPC) overlay on an existing normal strength concrete (NSC) bridge deck in Socorro, New Mexico, USA. A mock placement of the UHPC overlay prior to construction revealed that improper surface preparation of the substrate concrete resulted in lack of bond. To demonstrate the importance of surface preparation to the contractor, a series of pull-off tests were performed on overlaid laboratory slabs. The NSC laboratory slabs had surface moisture conditions that included pre-wetted and dried prior to overlay application. Pre-wetted slab specimens had a tined, tined-light sand blasted, or tined-medium sand blasted substrate surface texture. The dried slab specimens had either a tined or an exposed aggregate substrate surface texture. Pre-wetted specimens with tined, tined-light sand blasted, and tined-medium sand blasted surface textures achieved average direct tension bond strengths of 134 psi (0.924 MPa), 211 psi (1.45 MPa), and 283 (1.95 MPa), respectively. Specimens with dried substrate surface conditions prior to overlay placement had zero bond strength. Results from this study showed that pre-wetting was essential for achieving adequate overlay bond. Tined-light sand blasted specimens with proper pre-wetting achieved adequate bond strengths, and properly pre-wetted, tined-medium sand blasted specimens produced excellent bond strengths. This type of information allows specific guidance to be provided to contractors and communicates the consequences of not following best practices.

Local, state, and federal highway agencies run some form of maintenance and rehabilitation program during the design life of highways. Due to budgetary restrictions, maintenance and rehabilitation actions must be prioritized based on the future condition of the highway section. There are important factors that affect the performance of highways. To properly assess the condition of the pavement and operate maintenance, prediction models with significant condition variables are essential. Mississippi Department of Transportation (MDOT) utilizes probability-based prediction models to determine which sections of the highway and when they need rehabilitation. The current probability models predict the performance without the section-specific parameters. The goal of this study is to develop a new set of performance prediction models for the jointed concrete pavements (JCP) in Mississippi by using the artificial neural networks (ANNs) approach. The best performing ANN model integrated into a Microsoft Excel spreadsheet to generate an application that is simple, user-friendly, and allows the user to visualize the future projections of the pavement section. MDOT personnel can employ this application to predict the condition of the JCP section and prioritize the maintenance and rehabilitation schedule.

In the greater Houston area, mobile sources (on- and off-road vehicles) contribute to the highest share of NO_x emissions and the second-highest share of VOC emissions. The Houston METRO system that operates public buses in Houston is a key element in Houston’s infrastructure that can target lower emissions of criteria air pollutants (CAPs) and greenhouse gases (GHGs), thus improving the regional air quality. We used life cycle assessment (LCA) to evaluate the environmental sustainability of electric buses and compared it to the baseline of diesel buses. The LCA simulations using the GREET model demonstrate that the life cycle emissions of GHGs, VOCs, and NO_x associated with electric buses are lower than conventional diesel and diesel hybrid buses. These lower emissions are mainly attributed to the fact that natural gas takes about 50% of the current resource share of electricity generation in Texas. However, other emissions such as PM₁₀, PM_2.5, SO_x, and N₂O of electric buses are higher, and they are mainly caused by the coal use up to 20% in the resource share of electricity generation. These emissions would be reduced by 2040, and more significantly for electric buses.

Pavement markings play a significant role in the highway system by providing guidance and conveying regulations and warnings to road users. In Region 6, specifically in Louisiana, thermoplastic pavement markings are commonly used on construction projects. Yet, the field performance of thermoplastic markings is not well-documented, specifically in hot and wet climates experienced in Region 6. Hence, the objective of this paper was to quantify the field performance of thermoplastic pavement markings. To achieve this objective, retroreflectivity data for several thermoplastic pavement markings from the 2012 and 2015 national transportation product evaluation program (NTPEP) Florida test decks were retrieved. Retrieved data were analyzed to determine the service life of these markings using three different techniques: linear interpolation, linear regression, and piecewise linear regression. Results indicated that the predicted service life of thermoplastic pavement markings ranged between 0.3 and 8.1 years, with an average value of 3.6 years. This large variation in the service life could be attributed to the line color, traffic level, surface type, weather conditions, etc. The results of this study could be utilized in future research to develop pavement marking performance models that could predict the performance of pavement markings based on the project conditions without the need for monitoring the retroreflectivity of pavement markings.

This study evaluates the multimodal linkages to and opportunities for proposed terminal sites for a potential future passenger rail connection between Baton Rouge and New Orleans, Louisiana. The project included a comprehensive analysis of recent planning processes and documents and distribution of a statewide survey aimed at understanding ridership potential (including non-work trips) and the needs of likely users, the results of which were modeled to illuminate key considerations for service design and station area planning. This study finds a strong foundation for, and support of, the proposed rail service, but distinct deficiencies in the current multimodal transportation environment connecting to and from proposed stations, with most survey respondents indicating poor walkability, bikeability, and transit access in their communities. In response to these deficiencies, we find that the majority of residents interested in rail service strongly prefer to access stations by driving. In addition, previous analyses include potentially faulty assumptions about likely rail passenger trip purposes, which have critical implications for service design. We find that while intraregional travel is very common within the study area, with most respondents making frequent interparish trips, work trips are not the primary driver of this travel. Rather, weekend trips focusing on recreation, entertainment, and/or social activities appear to be the trips for which respondents are most inclined to utilize the proposed rail service. The findings of this study reflect the priorities of likely rail passengers and advance efforts to plan for successful passenger rail service operation in Southeast Louisiana, by providing insight into where, when, how, and why potential passengers will take the proposed train.

Injection of powder activated carbon (PAC) into the flue gases is one of the useful absorption-based techniques to lower the emission of mercury vapor released from coal-fired power plants. This PAC then settles in the electrostatic precipitator along with the fly ash, which has been used as a supplementary cementitious material in the concrete industry for years. Currently, contractors routinely use class C fly ash (CFA) as a partial replacement of ordinary Portland cement that may have an adverse effect on the long-term durability of concrete for containing PAC. The objective of this study is to examine the influence of PAC in CFA on the alkali-silica reactivity (ASR) and scaling resistance of concrete. This study will also propose an optimum amount of PAC to be used in mitigating the effect caused by ASR and scaling of concrete. To this end, test samples were produced with PAC (0%, 0.25%, 0.50%, and 0.75% by weight of CFA) in the laboratory to the CFA obtained from two different sources. The results of the ASR tests had been analyzed based on the expansion rate with time. The concrete mix with a higher amount of PAC (0.75% by weight of CFA) showed more ASR expansion than the mix with no PAC. In addition to that, on the 20^th day, all the samples exhibited a 20%–60% reduced expansion than the non-PAC and non-CFA concrete mix. On the other hand, the visual inspection of the scaling resistance tested samples suggested that the PAC-containing fly ash had no impact on the scaling resistance of concrete.

Cement stabilized crushed stone base course (CSCSBC) is a subbase alternative that is usually provided to prevent loss of subbase support over time. Often, CSCSBC is designed based on prescribed strength values, regardless of the range of cement contents used. CSCSBC can have varying strength properties that are often not accounted for. The goal of this research was to provide a subbase structural layer coefficient (a) based on the actual strength of CSCSBC for use in Arkansas Department of Transportation (ARDOT) projects. A range of tests were performed to characterize the strength and stiffness of a test strip located in central Arkansas and on laboratory samples. This paper shares results relevant to the structural layer coefficient of CSCSBC. The recommended minimum design value for the structural coefficient, a, was 0.21. A layer coefficient of 0.21–0.30 was determined to be appropriate, based on the 7-day compression strengths measured and based on values used in other states.

Bacterial concrete has become one of the most promising self-healing alternatives due to its capability to seal crack widths through microbial-induced calcite precipitation. Due to concrete’s harsh environment, bacterial protection is essential to ensure the viability of this technology. This can be achieved by encapsulating bacteria with polymer-based microcapsules, hydrogel beads, or vacuum-impregnating porous aggregates that are then added into the concrete mixture. The main objective of this study, was to develop a novel technique to protect Bacillus pseudofirmus bacteria using chitin nanofibers for future impregnation into the concrete. To achieve this objective, extraction of chitin nanofibers from crab shell was conducted followed by characterization with fourier-transform infrared spectroscopy (FTIR), zeta potential, and transmission electron microscopy (TEM). Zeta potential indicated a negative surface charge for the bacteria and nanofibers. Yet, TEM showed significant adhesion between the bacteria and nanofibers resulting from hydrophobic forces. The results indicated the bacteria can be successfully protected by chitin nanofibers.

The presence of powder activated carbon (PAC) in the Class C Fly Ash (CFA) is a concern to some transportation agencies and concrete producers. The main goal of this study is to investigate the influence, if any, of PAC in CFA on the properties of fresh concrete. The fresh concrete properties (e.g., air content, workability, and unit weight) were estimated in the laboratory. Moreover, the electrical resistivity and the air-void quality of the fresh concrete mixes were measured. Two CFAs containing different PAC contents (i.e., 0%, 0.25%, 0.50%, and 0.75% by the mass of CFA) were used to prepare a total of 14 mixes (12 laboratory and two plant mixes). The results showed that the PAC content had notable effects on some of the fresh concrete properties. The findings of this study can help to better understand the effect of PAC content in CFAs in producing durable concrete.

Microbial induced calcite precipitation (MICP) is a promising pathway in self-healing concrete due to its capability to seal cracks. In the present research study, Bacillus pseudiformus was selected as the bacterial strain and encapsulated with nutrients in hydrogel beads that were further added to a mortar mix. A combination of magnesium acetate and yeast extract were implemented as the nutrients and evaluated at different dosages. Flexural strength tests were performed on the specimens 28 days after casting in order to induce cracking. Once the crack was induced the specimens were subjected to 28 days of wet/dry cycles and the corresponding crack width was monitored. A second flexural strength test was performed in order to determine the strength recovery at the end of the cycles. Furthermore, the self-healing efficiency was obtained from the crack widths, revealing that the specimens with a larger nutrient and cell concentration displayed the best results.

This study investigated the use of alternative sources of supplementary cementitious materials (SCMs), namely landfilled reclaimed fly ash (RFA) and reclaimed ground bottom ash (GBA), for its beneficial use in concrete. The study characterized RFA and GBA along with conventional Class F fly ash (FA), as control. Furthermore, the influence of the three ashes on the fresh and hardened properties of concrete was investigated (when used to replace 10% of cement by mass). Experimental results revealed that all the ashes were classified as class F fly ash according to ASTM C618. Yet, in contrast to FA, RFA and GBA presented an increased water requirement, which was attributed to the differences in micro-morphology. Furthermore, RFA exhibited a lower strength activity index (SAI), while GBA presented a higher SAI, in contrast to FA. This was attributed to the CaO contents of the ashes, which was lowest for RFA and highest for GBA. RFA admixed concrete exhibited a slight decrease in workability, while GBA admixed concrete exhibited a significant decrease. This was attributed to the irregular shape of GBA particles. The control concrete mixture (with no ashes) exhibited the highest air content among all concrete mixtures, while GBA admixed concrete exhibited the lowest air content. Notably, while RFA exhibited the highest loss on ignition (LOI), RFA admixed concrete presented the highest amount of air from all concrete mixtures implementing ashes, including FA. In terms of hardened properties, all coal ashes had a minimal influence on the compressive strength of concrete, producing marginal decrements in strength. Furthermore, all concrete mixtures with ashes exhibited a slight increase in surface resistivity compared to control.

The objective this study was to evaluate the compositional space of high-performance cementitious matrices using mostly readily available ingredients in region 6 for the development of ultra-high performance engineered cementitious composites (UHP-ECCs). Specifically, the present study evaluated the effects of supplementary cementitious materials (SCMs) to cement ratio (i.e., SCMs/C), silica fume to fly ash ratio (i.e., SF/FA), and ordinary sand to microsilica sand ratio (i.e., OS/MS) on the compressive strength (f’c) of cementitious matrices reinforced with 1 vol.% ultra-high-molecular-weight polyethylene (UHMWPE) fiber. The ratios of water to binder and sand to binder were kept constant at 0.24 and 0.3, respectively. A total of 36 mixtures were evaluated by compressive strength test. Experimental results showed that: (1) the increase in SF/FA enhanced f’c and SF/FA had the greatest impact on f’c; (2) the increase in SCMs/C produced a decrease in f’c; (3) the increase in OS/MS had a minor negative impact in f’c and OS/MS had the least impact in f’c from the variables studied.

One of the challenges in applying 3D-printing in the construction industry is the concrete mix design. This paper is a preliminary study on the design of a printable engineered cementitious composite (ECC). The cement was replaced with a combination of different contents of fly ash, slag, and silica fume, in two replacement levels, 50% and 75%, and their compressive strength and setting time were evaluated. To assure the flowability of the mixtures, the flow table results were set in a constant range of 19–20 cm. The results indicate that 50% cement-substitution by slag/fly ash resulted in the largest strength. The incorporation of slag shortened the setting time and improved the strength of ECC mixtures. The cement substitution by fly ash lowered the water demand, enhanced workability, and up to 50% cement replacement improved the compressive strength. The addition of 10% silica fume reduced compressive strength and extended the setting time.

In this research tensile characteristics of roller-compacted geopolymer concrete (RCGPC) using 100% recycled concrete aggregate (RCA) and reclaimed asphalt pavement (RAP) were investigated and compared with similar mixtures using ordinary Portland cement (OPC). The formation of chemical compounds in the geopolymer composite mixtures was also analyzed using X-Ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). It was revealed from the investigation that the roller compacted geopolymer concrete using 100% RCA and RAP exhibited satisfactory tensile properties. The results showed that flexural, split tensile, and semi-circular bending beam strengths were around 2.8 MPa, 2.4 MPa, 1.1 MPa, and 3.56 MPa, 2.5 MPa, 0.9 MPa for RCGPC using RCA and RAP, respectively. XRD and FTIR analysis also proved the formation of the geopolymer compounds. Similar concrete mixtures using OPC containing RCA and RAP were also tested. The tensile strengths of those mixtures were also compared with the geopolymer mixtures. The results showed that roller-compacted geopolymer concrete using RCA and RAP performed better than similar mixtures using Portland cement concrete in terms of tensile properties. This also proved that geopolymer binder created better bonding with recycled aggregates (RCA) and reclaimed asphalt pavement (RAP) than OPC binder. It is believed that the developed RCA and RAP based roller-compacted geopolymer concrete could be used as an alternative material for pavement construction.

The utilization of traditional calcium-based stabilizers, such as lime or cement, for the treatment of sulfate-rich expansive soil, is a cause of concern for geotechnical engineering practitioners. The major problem associated with the application of such stabilizers is that when calcium ions from the stabilizers are exposed to soluble sulfate in the presence of sufficient soil moisture, they form a highly expansive mineral ettringite. This study aims to investigate the feasibility of stabilizing sulfate-rich expansive soils using a novel eco-friendly metakaolin (MK)-based geopolymer (GP) for the long-term durability of transportation infrastructure. Laboratory studies were undertaken to understand the influence of the geopolymer composition and dosage percentage for different curing periods in stabilizing the sulfate-rich expansive soils. Engineering tests such as the linear shrinkage and unconfined compressive strength tests were performed to compare the behavior of natural, lime-stabilized, and geopolymer-stabilized soils over different curing periods. Microstructural characterization using field emission scanning electron microscopy (FESEM) with energy-dispersive x-ray spectroscopy (EDXS) was performed to compare the morphological and chemical changes between geopolymer-treated and untreated natural soil. The results indicated that the geopolymer treatment of sulfate-rich expansive soils could result in significant reductions in shrinkage and subsequently help in a greater strength gain than lime-treated high-sulfate soil.

Northeast Arkansas (NEA) lies within the Mississippi Embayment (ME), and it has a deep deposition of soil (ranging from 200m~1000m) overlying the bedrock. The code based design approaches such as the American Association of State Highway and Transportation Officials (AASHTO) do not consider the impact of deep deposition of soil while designing structures like bridges. As a result, short period spectral accelerations are overestimated at significant cost and long period spectral accelerations are underestimated at significant risk. The purpose of this study is to bring out importance of performing site specific ground motion response analysis (SSGMRA) over code-based design procedures and predict seismic site factors for the NEA region by ground response analyses. After the analyses, it has been found that short period spectral accelerations get deamplified and long-period spectral accelerations get amplified compared to that of the AASHTO method. This study strengthens the demand for performing SSGMRA over code-based approaches in the case of deep deposition of soil.

A field-testing program was conducted to estimate the modulus of subgrade from the falling weight deflectometer (FWD) tests at three asphalt pavement sections in South Carolina. Three backcalculation software packages were used to interpret FWD deflections: BAKFAA, SCDOT Program, and AASHTOWare. To verify these tools for South Carolina conditions, the back-calculated layer modulus is compared to results from Finite Element Models (FEM) that were developed for the pavement sections using ABAQUS. This study aimed to validate the back-calculated subgrade modulus from FWD testing through numerical analysis. The predicted surface deflections at different radial distances were compared with the field FWD deflection values. The results show that FEM predicted surface deflection profiles are closely aligned with the field measured values.

Poor subgrade soils require stabilization to provide a stable platform during the earthwork construction operation. Arkansas Department of Transportation (ARDOT) often faces problematic soils that do not possess sufficient strength to support wheel loads imposed upon them during construction. Thus, it is necessary to stabilize these soils to provide a stable subgrade or a working platform for the construction of pavements. The main objective of this research was to establish useful guidelines for subgrade stabilization and create standard rehabilitation techniques for selected geological regions of the state. The research team conducted a review and evaluation of the current ARDOT soil stabilization procedure along with the existing procedures of the nearby states. Interviews of ARDOT district and construction personnel were conducted to gain insight into their soil stabilization experience in their respective districts. An evaluation of the state geological conditions, in terms of surficial soil types, was conducted. Three different stabilizing agents (Portland cement, Lime, and Class C Fly Ash) were evaluated through laboratory experiments and field demonstration in three ARDOT’s construction projects. The post-construction performance of these test sections was evaluated by measuring their surface roughness (international roughness index). Based on the findings of laboratory test results and performance of the test sites, subgrade stabilization guidelines for future ARDOT projects have been established.

The surface deflection bowl data collected through Non-Destructive Testing (NDT) has been widely utilized by various Department of Transportation (DOTs) in the South Central States and other places. The primary purpose of using deflection-based NDTs in network-level assessment is to identify a weak pavement section that requires further analysis at the project level. The falling weight deflectometer (FWD) test is one of the common NDT based tests utilized by highway agencies in assessing the performance of the flexible pavement. This study focuses on simulating the deflection obtained from FWD devices with the help of a simple yet comprehensive software 3-D Move Analysis. The need for extensive FWD testing in the field will be reduced with software-based simulations. Ninety-seven pavement sections from the state of Arkansas, Louisiana, New Mexico, Oklahoma, and Texas are utilized in the study for the simulation, analysis, and verification of FWD testing. 3D-Move Analysis was utilized to simulate the surface deflection obtained from the FWD test. It was found that the deflection values obtained through the software simulations were highly correlated with the field test results. Furthermore, the simulated deflection values can be utilized efficiently in future analyses to monitor the pavement conditions.

Incompatible and poor quality aggregates used in pavement construction result in different types of distresses and pavement failure which has been recognized as one of the major problems to most state Departments of Transportations (DOTs) and highway agencies. It is believed that the use of good quality aggregates can exhibit a good bonding with asphalt binders and minimize this problem significantly. This study aims to identify suitable aggregates used in Arkansas for durable pavement construction. The Arkansas Department of Transportation (ARDOT) approved four types of aggregates (sandstone, limestone, gravel, and dolomite) from four different sources have been evaluated in this study. The physical, mechanical, and chemical properties of aggregates have been determined by performing a series of laboratory tests. Also, the work of adhesion and boiling resistance tests have been conducted to predict the performance of the asphalt mixtures made of these aggregates and binder. The findings of this study are expected to help pavement researchers and highway professionals to find appropriate aggregates in constructing the durable pavements.

Ultra-Thin hot-mix asphalt concrete overlay (UTO) is a pavement maintenance treatment that is becoming increasingly popular among transportation agencies due to the resulting improved ride quality and reduction in noise. However, there is limited literature related to the long-term field performance of UTO treatments in hot and humid climates. The objective of this study was to assess the short- and long-term field performance of UTO treatments over asphalt pavements in Louisiana. To achieve this objective, Louisiana Department of Transportation and Development (LaDOTD) was contacted to identify all the UTO projects that were constructed over asphalt pavements in Louisiana before 2010. A total of seven projects were identified, and relevant pavement performance data and project information were retrieved from LaDOTD Pavement Management System (PMS) over a monitoring period of at least 14 years. The retrieved data were analyzed to determine the short- and long-term field performance in terms of the Performance Jump (PJ) and increase in Pavement Service Life (∆PSL), respectively. The results indicated that the UTO had a significant immediate impact on all the surface distresses, restoring them to like-new conditions. The results also indicated that the UTO extended the pavement service life of asphalt pavements by 0.7 to 21.5 (average of 8.8±3.6) years according to the pre-treatment pavement condition and truck volume. It was concluded that benefits of UTO are maximized when applied to pavements with Pavement Condition Index (PCI) in the range of 60 to 70. It was also concluded that the benefits are maximized when UTO is applied to pavements subjected to lower truck volume (in range of 0–500).

Toward assessing the reduction in production temperatures, this study evaluated the viscosity of three Performance Grade (PG) binders, (PG 64-22, PG 70-22, and PG 76-22) modified by three selected warm mix asphalt (WMA) additives (Sasobit, Advera, and Rediset). These three PG binders are approved by the Arkansas Department of Transportation (ARDOT). The corresponding dosages of Sasobit, Advera, and Rediset were 1.0, 1.5, and 2.0 %; 4.0, 6.0, and 8.0 %; and 0.5, 0.75, and 1.0 % by the weight of binder; respectively. Penetration and viscosity tests were performed on 30 blended binder samples following the respective specifications. The study showed that these WMA technologies were able to reduce the binders’ viscosity to some extent. However, the mixing and compaction temperatures estimated from the viscosity data could not truly reflect the advent of WMA technologies. The viscosity temperature susceptibility (VTS) relationship analysis showed that PG 64-22 showed the highest temperature susceptibility when mixed with 1.0 % Sasobit and the same binder showed the least susceptibility when it contained 6.0 % Advera.

Transportation infrastructure construction quality control and quality assurance demand construction monitoring by field inspectors. Currently, these inspectors monitor the infrastructure by measuring and photographing structures. These tasks allow them to assess any correction decision during construction or to inform about the quality of the construction process for the future. In order to promote and objective decisions obtained during infrastructure construction, the proposed paper developed and implemented a methodology to measure construction progress and compared it with the designed 3D shape, quantifying the difference. This paper includes an implementation for the development of Department of Transportation (DOT) standards that could be added in near future bridge construction documents. The research results outline recommendations about standards for implementation of technology in specifications for DOTs.

Finite element analysis of fluid-structure interaction in bridge structures under waive impact is an important research technique given the scale and cost limitations associated with flume tests. Recent advances in computational mechanics have introduced multi-physics methods such as coupled Eulerian–Lagrangian (CEL) analysis into commercially available analysis software like Abaqus. The CEL method can lead to important advances because it allows researchers to evaluate the effect of important parameters such as foundation and substructure flexibility on the dynamic response of bridge structures under wave impact. Although advantageous, the CEL method presents significant challenges establishing the validity of simulation results given the paucity of experimental results, and the difficulty of obtaining accurate results at a reasonable computational cost. This paper presents numerical simulations of wave impact trials on a 1:5 scale concrete bridge model of the I-10 costal bridge over Escambia Bay tested in the flume at O. H. Hinsdale Wave Research Laboratory at Oregon State University. The implementation of the CEL method in Abaqus permits only the use of explicit analysis, so the parametric study presented is focused on this specific. Parameters related to the maximum stable increment were varied and the results of simulations are presented. Computed forces and displacements induced by wave impact were found to be very sensitive to Eulerian and Lagrangian domain mesh size in the region where fluid-structure interaction took place, time increment size, and the flexibility of the connection between the superstructure and the substructure. Because reducing element size was found to decrease the stable time increment, and element size was critical to the accuracy of the simulation results, establishing a balance between maximum element size, maximum time increment, and computational cost was found to be critical for reliable simulation results.

Corrosion of corrugated metal pipes (CMP) is a significant problem facing all U.S. Departments of Transportations. There is an urgent need to provide an efficient solution, that is corrosion-resistant, to retrofit thousands of corroded CMP across the country. High specific strength, high strength-to-weight ratio, and corrosion resistance made fiber-reinforced polymers (FRP) the engineer’s choice material where corrosion is a problem. This paper discusses the design method for using glass fiber-reinforced polymer (GFRP) slip liner to retrofit CMP culvert. The structural aspects, such as wall thrust, buckling, deflection, and bending strains, along with hydraulic design, are considered. The proposed method is used to design a GFRP retrofit slip liner for a 25 ft corroded steel CMP. The retrofitting system is modeled using the finite element method to predict the magnitude and location of maximum stresses under service conditions and ensure the retrofitted culvert's safety under traffic loads.

The objective of this study was to investigate the effect of fine aggregate type (i.e., natural river sand and manufactured microsilica sand) and ultra-high-molecular-weight polyethylene (UHMWPE) fiber length (i.e., short and long) on the mechanical properties of metakaolin (MK) based Engineered Geopolymer Composites (EGCs) with 0.8 vol.% fiber cured at room temperature. EGCs produced were evaluated by compressive strength test and uniaxial tensile test. Experimental results showed that the compressive strength of the EGCs exceeded that of conventional concrete by ~44–47%, while exhibiting ~19–22% lower densities. However, the compressive strength was not significantly affected by the different types of sand or fibers evaluated. On the other hand, the tensile properties of the EGCs were significantly affected by the type of sand used. The use of natural river sand (RS) in specimens using long UHMWPE fiber, produced a dramatic increase in the tensile strain capacity (i.e., 129%) and a reduction in the tensile strength (i.e., 41%) in contrast to specimens manufactured using microsilica sand (MS). Nevertheless, the different types of fiber evaluated did not produce a substantial effect in the tensile properties of the composites. Notably, the EGC material using natural river sand and long UHMWPE fiber at 0.8 vol.%, presented an exceptional tensile strain capacity of 8.6%, which is comparable to that of some metals. It was concluded that metakaolin-based geopolymers matrices with UHMWPE fibers are highly promising for the manufacture of EGC materials.

This study investigated the feasibility of using post-processed bagasse ash (PBA) in combination with class F fly ash to replace a high quantity of cement (i.e., 75% by mass) in ECC mixtures. PBA was prepared by drying, sieving, burning, and grinding raw sugarcane bagasse ash (SCBA) collected from a sugar mill. Combinations of fly ash with PBA evaluated as SCMs included: (1) 25% PBA and 75% FA; (2) 50% PBA and 50% FA; (3) 75% PBA and 25% FA; and (4) 100% FA as control. ECC materials prepared were evaluated by compressive strength test, surface resistivity test, and uniaxial tensile test. Experimental results revealed that the replacement of fly ash with PBA produces a minor decrease in the compressive strength (i.e., up to 13.3% compared to control) while increasing the surface resistivity (i.e., up to 81.8% compared to control). Furthermore, a progressive decrease in tensile strain capacity was observed with the increase in PBA content (i.e., up to 68.5% compared to control). However, ECCs implementing PBA exhibited higher first-cracking and tensile strength compared to the control (i.e., up to 28.2 and 27.0% and, respectively). It was hypothesized that, compared to class F fly ash, PBA is less effective at reducing the fiber/matrix chemical bond and the matrix fracture toughness, thus explaining the increase in first-cracking and tensile strength as well as the decrease in tensile ductility observed when partially replacing fly ash with PBA. Nevertheless, using combinations of PBA and class F fly ash as SCMs in the manufacture of ECC materials can be feasible as the replacement of 25% of fly ash with PBA minorly affected the compressive strength and tensile ductility of the composites while increasing the tensile strength and surface resistivity.

Bacterial concrete is one of the most promising self-healing alternatives due to its ability to seal crack widths through microbial induced calcite precipitation (MICP). In this process, alkali-resistant Bacillus pseudofirmus bacteria are embedded in concrete to precipitate calcium carbonate to seal the cracks. Due to concrete’s harsh environment, it is critical to protect the bacteria to ensure the viability of this technology. One of the key protection techniques is vacuum impregnation into porous aggregates. The objective of this study was to evaluate the impregnation efficiency of Bacillus pseudofirmus into fine lightweight aggregate by using three different nutrients, namely, magnesium acetate, calcium lactate, and sodium lactate by using a vacuum impregnation chamber. To achieve this objective, a vacuum impregnation chamber was used to impregnate Bacillus pseudofirmus bacteria at a concentration of 10⁸ cells/ml into three fine lightweight aggregate samples. In these samples, three different nutrients namely, magnesium acetate; calcium lactate; and sodium lactate were added to yeast extract and impregnated at a concentration of 75 mM/l along with the bacteria. Eventually, Scanning Electron Microscope with Energy Dispersive Spectroscopy analysis (SEM-EDS analysis) was conducted to evaluate the impregnation efficiency of the bacteria into the three aggregate samples. The results indicated that the bacteria were successfully impregnated into all the aggregate samples. Future work will be conducted in this study to evaluate the pre-cracking strength recovery and crack sealing efficiency for the different nutrients.

Geopolymers (GP) are aluminosilicate network polymers that have gained interest in recent years as an eco-friendly alterative to ordinary Portland cement (OPC) in transportation infrastructure. This novel material can be processed from waste and/or widely available natural materials under ambient conditions. In this study, a set of rebar-reinforced metakaolin-based geopolymer concrete samples were prepared by mixing aggregate with geopolymer binders having different alkali activators (Na⁺ and K⁺), SiO₂/Al₂O₃ ratios, water/solid ratios, and alkali/aluminum ratios. The concrete samples with rebars were then cured for 14 days before they were exposed to simulated marine environment and monitored with electrochemical methods such as open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). The results show that the composition of GPs strongly affects their corrosion-inhibiting performance.