Airfield and Highway Pavements 2019: Innovation and Sustainability in Highway and Airfield Pavement Technology

Pavement distress data has been widely collected through pavement survey to evaluate roadway condition. Despite rapid advancements in automated pavement distress data collection, the implementation of the widely used pavement condition index (PCI) still requires extensive manual labor either in tradition manual survey or image-based PCI inspections. This paper proposes a deep-learning (DL) based automatic pavement cracking detection algorithm and further evaluates a potential for automatic PCI survey with the obtained cracking results on asphalt pavement. The pavement two- and three-dimensional (2D and 3D) images are collected via the state-of-the-art PaveVision3D imaging system on two asphalt sites in Maryland. The automatic lane marking detection is performed on the 2D images to define the lane width for the following cracking detection. The DL based CrackNet automates the detection of the cracking information from the 3D images. Cracking information for alligator, longitudinal, and transverse cracking are summarized to automatically calculate the PCI numbers. The high correlations between the fully automated PCI results and the historical PCI results indicate the DL based automatic PCI calculation method produces reasonable PCI numbers with minimum human intervention.

Pavement performance indicators, such as the international roughness index, rutting, and fatigue cracking, are usually employed to evaluate the effectiveness of pavement rehabilitation treatments and maintenance strategies. Although the short-term effect of these strategies can be evaluated using the performance indices, estimation of long-term performance could help the pavement management systems to optimize the maintenance operations and minimize the costs. The long-term pavement performance (LTPP) database is a valuable resource for studying the performance of different pavement structure under various environmental and traffic conditions. The database could be employed in developing performance prediction models and help to prioritize the maintenance strategies. In this study, a set of LTPP data was employed to develop a pavement roughness prediction model using traffic data, pavement age, and structural number as input variables. The performance of the prediction models was reasonably satisfactory. The results of this study could be extended to a wider range of pavement structures from the LTPP database and can be calibrated for the specific traffic data and pavement properties for state departments of transportation.

This paper presents a framework for using an artificial intelligence (AI) based computational approach for accelerating pavement mix design. The experimentation work in pavement engineering can be optimized significantly if the designer can start the work with materials or mixes that are known to be good performers, with a certain degree of accuracy. Unfortunately, the state of the art in pavement engineering has not yet reached a point where the properties that are known to be correlated to pavement performance can be computed from first principles. However, a variation of the approach mentioned above can still be adopted, as long as there is a set of known material properties and their performance. The predictors can be isolated and then used for building classification models, and the model with the highest accuracy can be selected. Once the model is verified it can be inverted to predict which combinations of properties are desirable. These identified sets of properties will then become the basis for the starting of experimentation in the mix design procedure. The suggested framework is illustrated with an example of designing HMA mixes for adequate resistance against moisture damage.

The long-term pavement performance (LTPP) database is a valuable resource for studying the performance of different pavement structures under various environmental and traffic conditions. The database could be employed in developing performance prediction models and help to prioritize the maintenance strategies. Soft computing techniques can be utilized to evaluate the performance of quality control programs (QCP) during the material production and construction processes. These data techniques can provide relationships between QCP parameters and the corresponding long-term performance indicators such as permanent deformation, roughness, and cracking. This paper employs the LTPP database, comprised of the measured quality control parameters, such as voids in mineral aggregates (VMA), air voids of the mixture (VA), in-place density of asphalt concrete, and the age of pavement structure, as well as deterioration indices. A hybrid machine learning (ML) method that combines random forest (RF) and artificial neural network (ANN) was developed for the prediction of alligator deterioration index (ADI). The model was then used to conduct a parametric study using a wide range of independent variables to investigate how they affect the ADI. The results showed that the hybrid ML technique is capable of predicting pavement deterioration rigorously.

Asphalt healing is directly related to the endurance limit strain and if the pavement experiences this value of strain, or lower, no fatigue damage would develop. The purpose of this paper is to extract the beam fatigue tests data that was collected under the NCHRP Project 9-44A and utilize it to create an artificial neural network predictive model (ANN) to determine the endurance limit values for conventional asphalt concrete pavements. The paper demonstrates the created ANN model architecture as well as how to utilize it to predict the endurance limit. Also, a stand-alone equation that is capable to predict the strain values, separate from the ANN model environment, was derived. The model training and validation data included 934 beam fatigue laboratory data points conducted under NCHRP Project 9-44A. The developed model is able to determine the endurance limit (strain) as a function of the stiffness ratio, number of cycles to failure, initial stiffness, and rest period. The created model had a reasonable R2 and significance values indicating the reliability of both the developed ANN model and the stand-alone equation.

This study investigates the effects of temperature changes on the electrical resistivity characterization of electrically conductive concrete (ECON) heated pavement systems (HPS). ECON is commonly characterized in terms of its electrical resistivity, the reciprocal of electrical conductivity. Compared to that of normal concrete, the electrical resistivity of ECON HPS is lower (or inversely, its electrical conductivity is higher), enabling it to allow passage of electric current and consequently generate heat to prevent ice and snow accumulation on paved surfaces. In this study, the electrical resistivity of the ECON HPS was calculated using applied voltage and electrical current measurements during ECON HPS operations under various weather conditions. Since the ECON behaves as a semiconductor, the electrical resistivity of ECON is temperature-dependent; as the temperature increases, the electrical resistivity decreases, helping to accelerate heat generation. The electrical resistivity values at different ages and weather conditions exhibited a very similar trend; these values were very stable and only slightly different with increase in ECON age and decrease in temperature. This study provides an essential understanding of the electrical resistivity of ECON HPS with respect to achieving sufficient heat to melt ice and snow for airport application.

Recent research studies at Iowa State University (ISU) have led to the development of electrically conductive concrete (ECON) heated pavement systems (HPS) whose primary goal is to prevent ice and snow accumulation on paved surfaces in an airport setting—a setting where radio frequency (RF) communication, such as in telecommunication and radio navigation systems, is also heavily utilized. The current loops created during the operation of ECON HPS, connected to a power source via electrode bars, can emit electromagnetic (EM) radiation. If the radiation lies in or near the radio frequency bandwidth, the RF communication and radio navigation systems in the airport can be affected, creating safety concerns such as disruption in connectivity, temporary loss of signal, declining signal quality, or preventing reception altogether. This study investigates the RF interference potential of ECON HPS. EM emissions from ECON samples were examined and tested for their emission frequencies. This study includes design parameters such as ECON sample size, power source magnitude, location, and sample dampness. Results from the study were examined and analyzed to determine the properties of the EM radiation emitted from ECON, and these properties were then compared to the operating frequencies of telecommunication and radio navigation devices used in the airports to determine whether ECON HPS exhibits unacceptable RF interference.

This study examined the feasibility of total replacement of asphalt binder in hot mix asphalt using biobinder produced from waste cooking oil (WCO). First, non-destructive rheological tests were conducted to evaluate the complex shear modulus and rutting resistance of biobinder. The WCO-based biobinder outperformed asphalt binder at high frequencies (low temperature performance). The WCO-based biobinder was then utilized to produce hot mix biobinder (HMB), and its performance in terms of fatigue, thermal cracking, rutting, and moisture susceptibility was evaluated through laboratory tests. The indirect tensile (IDT) test results showed that HMB yielded acceptable tensile strength and crack resistance at intermediate temperatures. In addition, the results of Hamburg wheel tracking test (HWTT) indicated that HMB was prone to high rut depth and stripping. The results of IDT tests conducted to evaluate the thermal cracking resistance of HMB at low temperature showed it had high thermal cracking resistance compared to HMA.

Incorporation of RAP in HMA increases the stiffness of the mix because of the presence of highly aged binder in RAP and consequently escalates the potential of cracking susceptibility. Two options, either a softer grade binder or a rejuvenator can be introduced with RAP to obtain a desired performance grade of the binder. In this study, these two options were compared with respect to their performances. In one case, a softer PG 58-34 binder was blended with RAP binder with RAP-binder ratio of 0.356 and the high temperature binder grade was determined. In the other case, two commercially available rejuvenators were used and were blended with PG 67-34 binder. Percentages of rejuvenators were selected to achieve the same binder grade of the softer binder with RAP binder. Rheological and mechanical properties of unaged and laboratory aged blended binders were investigated by multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS) tests and the results were compared with the properties of virgin PG 67-34 binder. Low-temperature cracking potential of RAP mixes were evaluated by semi-circular bending (SCB) test. It was observed that although both the softer binder with RAP binder and rejuvenated regular binder with RAP binder have the same high temperature grade, rejuvenators have more potential of improving low temperature grade and fatigue life. SCB test results show that the plant-based bio oil rejuvenator performs much better by showing higher fracture energy at low temperature.

Nanotechnology has been increasingly used in asphalt modification for its remarkable effect in improving the binder and mix performance. Rheological properties of binder play major roles in rutting, fatigue cracking, and low-temperature cracking resistance of hot mix asphalt (HMA) pavement. Rolling thin film oven (RTFO) and pressure aging vessel (PAV) were used to simulate short-term and long-term aging, respectively. Rheological properties of asphalt binders (un-aged, RTFO-aged, and PAV-aged from each binder) were tested using dynamic shear rheometer (DSR). The results were published in a different paper. This study was conducted to investigate the effect of nanomaterials (NMs) on the rutting, fatigue cracking, and low-temperature cracking resistance of HMA mixes. Two types of NMs, nanoclay and nanoalumina, were mixed separately into performance grade (PG) 58-28 and 64-28 asphalt binders at 0% NM (control), 1, 5, and 7% by binder weight. Hot mix asphalt specimens (150 mm diameter and 75 mm high) were compacted with 6.5–7.5% air voids using superpave gyratory compactor. Asphalt pavement analyzer (APA), semi-circular bending (SCB), and disc-shaped compact tension (DCT) were used to determine the rutting, fatigue cracking, and low-temperature cracking resistance of the mixes, respectively. Cracking of mixes was measured in terms of fracture energy. The results showed that NMs increased the rutting resistance of the mixes, but the mixes could be more susceptible to cracking due to increased stiffness.

According to recent research, the addition of graphene nano-platelets (GNPs) to bitumen can lead to a considerable improvement of the compactability of bituminous mixtures, without reducing the viscosity of the binder, meaning that other mechanisms are responsible for this phenomenon. In this regard, the present study focuses on the characterization of the lubricating behaviour of GNP binders obtained by adding 3% and 6% GNPs to a plain PG 58-28 bitumen, through a novel tribological approach recently proposed in literature. In addition, the experimental program is completed by viscosity tests. Results show that GNP addition leads to an increase in both viscosity and friction, which in general is greater for higher GNP contents, for all testing temperatures. A good correlation between viscosity and minimum friction exists in the elasto-hydrodynamic regime of lubrication, whereas the results obtained in the boundary and mixed regimes may be significantly affected by the testing conditions considered. Specifically, the use of different substrates is suggested for future work, in order to achieve a better understanding of the mechanisms that govern the compaction behaviour of bituminous mixtures.

Real-time density monitoring during pavement compaction process is crucial to ensure asphalt concrete (AC) construction quality. Ground penetrating radar (GPR) may be used for continuous real-time AC density estimation using AC and its components dielectric constants. However, the effect of surface moisture, resulted from roller water sprays, jeopardizes the predicted AC density accuracy. While algorithms were developed to remove the surface moisture effect, they are only applicable to 2 GHz GPR antenna. This study proposed a novel algorithm to remove surface moisture effect based on “frequency-select effect.” This algorithm is applicable to most of the GPR antenna central frequencies. The Al-Qadi, Lahouar, Leng (ALL) density prediction model was used in this study. Static field tests were performed using both 2 GHz and 1 GHz air-coupled antenna at the Illinois Center for Transportation (ICT) of UIUC. The GPR signals were processed through proposed algorithm using power spectrum of the surface reflections. There is a high correlation between AC dielectric constant and density; hence, the dielectric constant ground-truth values were used to estimate the errors using the proposed algorithm. The proposed algorithm was found to be efficient and accurate; errors of dielectric constant are less than 3% for the 2 GHz case and 5% for the 1 GHz case, respectively.

This study proposes a transfer function that relates the surface displacement under a lightweight deflectometer (LWD) with the surface displacement under a vibratory roller. LWD is a practical tool that is used for assessing the modulus of the compacted sections at randomly selected locations. One advantage of intelligent compaction (IC) technology over the spot tests is the assessment of uniformity and consistency of compaction over the entire compacted section. This study utilizes a database containing a comprehensive range of soils with diverse nonlinear parameters. Both single-layer (subgrade only) and dual-layer (base and subgrade) geosystems with different base thicknesses subjected to LWD and IC roller were included in the database. The deflections obtained from the LWD and IC roller were then related to one another using a genetic programming (GP) algorithm. The results show that the proposed relationship effectively relates the surface displacements from the two devices.

In the recent ASCE infrastructure report card, it is reported that one out of every five miles of highway is in poor condition that indicates the enormity of rehabilitation works needed across the country. Previous studies conducted all over the world have mentioned that lagging behind the schedule is a frequent problem within the pavement construction projects. This study identified the need for devising a methodology using the available advanced technologies that offer safe, quick, and efficient construction site monitoring opportunities, thereby, reducing the construction delays. Unmanned aerial vehicles coupled with close range photogrammetry (UAV-CRP) technology has been demonstrated to estimate the volume of construction material stockpiles and pavement characteristics such as transverse and longitudinal slopes. Accurately and efficiently estimating the inventory volumetrics information, thereby identifying timely needs for procuring additional resources for construction purposes will curb some of the construction delays. Also, determination of pavement characteristics during the construction will aid in quality control checks related to construction such that pavements are constructed as per design slope requirements. Accuracy analyses of the models generated from UAV-CRP data have been comprehensively analyzed and results are compared with ground truth measurements. Results indicated an excellent match thus proving that this UAV-CRP technology can be a valuable tool for infrastructure construction works, thereby reducing the delays associated.

This study discusses a methodology for developing a performance-based quality control system for flexible pavement works. The procedure relies on linking measures of quality at production and construction stages of the work with the in-service performance of flexible pavements. For this purpose, different elements of data from flexible pavement sections of 30 Wisconsin projects are compiled in a single relational database to demonstrate the potential of this methodology. From the compiled database, seven projects are selected for the in-depth analysis of the pavement. The effects of production and construction quality variation on performance are investigated in this study by using two performance prediction models that are based on the mechanistic-empirical method and statistical regression method. The prediction results of these models compared with the actual field performance measurements. The falling weight deflectometer (FWD) tests results improved the certainty of this comparison. The study shows the limitations associated with the use of current modeling programs in predicting long-term field performance, particularly in incorporating the quality variations inherent with flexible pavements. The analysis proposes a path to developing performance-based specifications for pavement materials based on understanding the relationship between quality measures and recorded performance of existing pavements. The findings suggest implementing a georeferenced relational database architecture for the Department of Transportations would magnify the impacts of current quality control programs.

Application of recycled materials has considerable advantages in reduction of virgin materials consumption and greenhouse gas emissions. In spite of these encouraging benefits, the utilization of recycled materials, based on limited factors such as emissions reduction or material consumption reduction, may not be advisable to key decision makers since the recycled materials promotion requires a thorough evaluation of this technology as well as the consideration of all critical environmental factors. This paper presents a comparative life cycle assessment (LCA) and cost analysis for asphalt mixtures containing recycled materials including glass and recycled construction aggregate (RCA). The composition of asphalt mixtures selected for this study are determined through a comprehensive laboratory investigation. In order to obtain more realistic results in this LCA, it is assumed that asphalt mixtures are produced in two different asphalt plants located in NSW, Australia, which are the largest asphalt plants in Australia. Accordingly, the process parameters and the transport distances are considered as close as possible to real situation. The results of these analyses indicate that the replacement of glass and RCA in asphalt mixtures at optimum content results in a significant reduction in adverse environmental impacts as well as a substantial cost saving in asphalt mixture production.

In 2009, the United States cement and concrete industries established the Concrete Sustainability Hub at the Massachusetts Institute of Technology to develop more sustainable and durable pavement infrastructure and buildings. With respect to pavements, two areas of focus have been on how the economic practices used in the pavement type selection process can be improved and how inter-industry competition (competition between industries) can lower agency pavement costs. With regard to the economic practices, MIT has focused on how the life cycle cost analysis (LCCA) process can be improved so that the results are more representative of the agency’s cost. With regard to competition, MIT has shown that sustained and viable competition between paving industries can lower bid prices. The goal of this paper is to summarize the relevant MIT CSHub pavement economic and competition research to date.

In pavement network improvement projects, construction time, cost, and value are some of the major parameters assessed when considering which treatment to use on a transportation network. Some treatments require less construction time, but they can incur a number of costs as well as result in a variety of performance impacts. In Alberta, there is not a large knowledge-base or overall understanding of the construction impacts of preservation methods—microsurfacing—in comparison to traditional paving practices—like mill and overlay. To evaluate and understand the differences between preservation methods and traditional paving methods, the city of St. Albert constructed a test section containing three different paving materials. Prior to construction, the city considered the current condition of the roadway, the process of which was followed by the placement of microsurfacing, stone mastic asphalt (SMA), and high traffic (HT) asphalts at specified locations along the 1.5 km stretch of urban arterial roadway. To review the test section, the city used AASHTO 1993 to determine the potential additional pavement life achieved with the use of each material. During construction, the costs, timelines, and placement of materials were carefully tracked and compared. Post-construction test results reveal that microsurfacing is both faster to install and has a lower upfront construction unit cost for application in comparison to conventional materials; while the SMA and HT may have the longer output of added life to the roadway.

Introduction of connected vehicles (CVs) and automated vehicles (AVs) are anticipated to have significant impacts on transportation operation, including its infrastructure. The autonomous and connected trucks (ACT) can result in significant cost savings for the freight industry. The cooperative cruise control (CACC) and vehicle-to-vehicle (V2V) technologies allow a string of trucks travel in series that may increase road capacity and improve traffic flow. Shorter distance between trucks would save in fuel consumption due to reduced aerodynamic drag forces. This would result in emission reduction. In addition, an optimized and control truck wheel location can lead to a longer pavement service life would result in minimizing work-zone traffic delays. Connected and autonomous vehicle (CAV) technology also contributes to improving safety by reducing crash and injury rate. However, retrofitting existing trucks with CAV technologies or new trucks with CAV may be costly; therefore, a benefit cost analysis (BCA) of ACTs is proposed to determine net benefits of CAV technology implementation. An economic assessment of CAV technology is conducted using BCA for one of the busiest corridors in Illinois at various market penetrations of CAV.

With the excess of sulfur by-product in many oil and gas producing countries, engineers must find new markets that can successfully use this by-product. One application of using excess sulfur by-product has emerged in the use of sulfur as a partial substitute for bitumen in roadways. This sulfur-extend asphalt (SEA) can be used to replace 20–40% by mass of bitumen in dense-graded and warm-mix asphalt concrete mixtures, acting as an asphalt extender and mix stabilizer. The primary objective of this research is to evaluate the environmental impact of using SEA mixtures in pavements compared to that of other asphalt concrete mixes used in the Kingdom of Saudi Arabia (KSA). A comprehensive life-cycle assessment (LCA) was conducted in this study. The assessment considered the entire life-cycle of the pavement from production, use, maintenance and rehabilitation, end-of-life treatment, recycling, and final disposal (i.e., cradle to grave), using guidelines from the International Organization for Standardization (ISO 14040). The inventory databases and LCA framework developed were incorporated into a software developed as part of the study, sulfur extended asphalt life cycle tool (SEL²ECT 1.0). A series of case studies were investigated as a part of this study. Four different pavement designs and life-cycle scenarios were evaluated using SEL²ECT 1.0. The case studies showed that the use of SEA modified mixture can result in some reduction in environmental impacts over similar conventional mixture depending on the performance and future rehabilitations of pavement.

In 2009, the U.S. cement and concrete industries established the Concrete Sustainability Hub at the Massachusetts Institute of Technology. A primary thrust of MIT’s activities has been improving the life cycle assessment practices to better quantify the environmental impacts over the life of a pavement. In their research, the MIT CSHub determined that the “use phase” can dominate the materials, construction, and maintenance phases of a pavement LCA and that two of the important factors in the use phase are pavement vehicle interaction (PVI) and Albedo. PVI describes the excess fuel emissions/energy from vehicles due to excess rolling resistance between the pavement and the vehicle. Albedo is the fraction of solar energy reflected by the Earth’s surface, with lighter color, higher albedo surfaces reflecting more energy than lower albedo, darker surfaces. This paper will summarize the CSHub use phase research findings to date.

One of the primary causes of the urban heat island (UHI) effect is the use of construction materials that absorb and store more heat than natural vegetation. Additional heating and temperature rise occurs because of the coupling between man-made surfaces and the air in urban areas. A coupled pavement-urban canyon model has been developed and applied to a hypothetical urban domain with 12 urban canyons in order to quantify the microscale UHI intensity for the statistically warmest hour of the year in Chicago, USA. The control pavement with low albedo and diffusivity had a microscale UHI intensity of 4.2–5.1°C as compared to the mesoscale intensity of 4°C. When the control pavement was replaced by a cool pavement of higher albedo and diffusivity, the microscale UHI intensity decreased in all the canyons to 4.0–4.4°C as compared to the control. The decrease in UHI magnitude ranged from 0.1–0.7°C with an average decrease of 0.4°C.

The structural rolling resistance (SRR) is the component of rolling resistance that occurs due to the viscoelastic deformation of the pavement structure. In this paper, a simple model to calculate the energy dissipation due to the SRR on flexible pavements is developed for use in applications such as life cycle cost analysis and life cycle assessment. First, the energy dissipated by different vehicles was calculated on ten flexible pavement sections using a fully mechanistic approach. Using the program ViscoWave II-M to simulate the vehicles moving along the pavement sections, the energy dissipation was calculated as the work done by the vehicle to overcome the slope seen by the wheels due to the pavement deformation. The results were then used to develop a simple and rapid-to-use model to predict the energy dissipation on any flexible pavement. The model consists of a predictive function that can provide the value of the SRR energy dissipation given the loading conditions (speed, loads, tire pressure, and pavement temperature), and information on the pavement structure (phase angle of the HMA layer at specific temperatures and loading frequencies, and pavement deflection under a specific static load).

Flexible airport pavements in Australia have traditionally been surfaced with Marshall-designed dense graded asphalt (DGA). Grooving is undertaken to avoid aircraft skidding incidents during wet weather conditions, as well as satisfying regulatory surface texture requirements. Groove closure is a common distress experienced at airports surfaced with DGA in Australia and has led to the investigation of stone mastic asphalt (SMA) as an alternate runway surfacing. Due to the gap-graded nature of SMA, and therefore coarse surface texture, grooving can be avoided. To facilitate the use of SMA on Australian runways, a performance-based specification was developed in line with the latest advances of airport technology. This paper describes the development of a performance-based specification for Australian airport SMA, focusing on constituent materials and mixture design.

The Federal Aviation Administration (FAA) Office of Airport Safety and Standards has sponsored the development of methodologies to extend the design life of runways at large and medium hub airports beyond the current standard of 20 years. As part of this effort, various data are being collected from both old and new runways at large and medium hub airports, and are stored in a modified version of FAA PAVEAIR that allows for multi-variable data analysis. Collected data are used to develop preliminary performance prediction models and curves incorporating both structural and functional factors. These prediction models can be used to determine intervention timing or the end of pavement service life. This paper includes a review of the FAA’s working definition of pavement service life and a high level illustration of the data collected to date. It also presents the methodology proposed for the development of the performance indicators as well as a new mega index, called the serviceability level that incorporates the performance models through logistic regression analysis.

Reducing the cooling period of newly laid asphalt overlays could help airport authorities to quickly open remediated pavements to traffic. This paper reviews four strategies for a reduced cooling period, prior to trafficking, of newly-placed asphalt overlays: (1) defining and selecting the warmest permissible asphalt temperature at opening to traffic, (2) reducing the cooling time by using warm mix asphalt (WMA), (3) increasing the cooling rate of asphalt by using high thermal conductivity material, and (4) decreasing the pavement temperature by spraying water onto the freshly paved asphalt. A one-dimensional (1D) heat-transfer model using a finite element (FE) solution is developed as a function of weather conditions to simulate the effect of each strategy on asphalt cooling time. The analysis shows that each strategy significantly contributes to the rapid cooling of newly laid asphalt. However, there are some concerns over the performance of the pavements when some strategies are adopted.

Highway strip/airstrip is the concept of using part of a road as an airstrip during exigencies. These airstrips are of extreme importance for rescue operations at times of war, natural calamities, and critical accidents. This paper focuses on the design of an airstrip for a stretch of 3200 m on the proposed Samajwadi Purvanchal Expressway connecting Agra and Lucknow in Uttar Pradesh, India, for emergency landing of combat jets of the Indian Air Force (IAF). FAARFIELD software was used for the designing of this road runway. Both flexible and rigid pavements were designed as per the FAA advisory circular (AC) guidelines “Airport Pavement Design & Evaluation (150/5320-6E),” for a design life of 20 years. Single Wheel-75 was selected as the design aircraft with a gross weight of 40,000 kg (40 ton) and tire pressure of 973 kPa. From the resultant thicknesses, it was observed that the designed pavement thicknesses were less than that required for the road pavement, for the given stretch, for both flexible and rigid pavements using similar materials. Hence, it was concluded that the expressway was structurally adequate to be considered as the airstrip in case of an emergency. However, it was proposed to construct the surface layer with stone matrix asphalt (SMA) to reduce rutting along the wheel path of the trucks.

Airfield pavements are known to be critical transportation infrastructure assets and their ability to provide adequate load-carrying capacity for anticipated aircraft is one of their primary functions, thus helping to ensure both passenger safety and uninterrupted operation of the airport facilities. In order to assess a runway pavement's load-carrying capacity, the structural condition of the pavement must be systematically monitored and evaluated. With this in mind and based on recent developments concerning globally utilized evaluation techniques, new challenges have been created in the field of airfield pavement evaluation. The present investigation aims to highlight the impact of the evolution of the Federal Aviation Administration (FAA) evaluation techniques on airfield pavement evaluation. For this reason, an assessment of the structural condition of a runway’s flexible pavement structure is performed, implementing a range of techniques that are both accepted and utilized worldwide, including the incorporation of the most recent developments of the FAA (FAARFIELD). The analysis results indicate that the latest assumptions considered within the FAA methodology may significantly impact evaluation results. The paper presents both the overall procedure followed and the related critical results obtained from the implemented airfield pavement structural evaluation.

Rigid and flexible aircraft pavement were designed using the software FAARFIELD v1.4, FAARFIELD v1.3, COMFAA (rigid only), and APSDS (flexible only). The designs included a range of subgrade conditions, as well as commercial aircraft with two, four, and six wheeled landing gear. Comparison of the results indicated that FAARFIELD v1.4 returns flexible pavement sub-base thicknesses 20% less than FAARFIELD v1.3, but 13% greater than APSDS. FAARFIELD v1.4 also returned rigid pavement concrete thicknesses that were generally less than FAARFIELD v1.3 and COMFAA, except for the six wheeled gear. It is recommended that further research consider whether the significant increase in rigid pavement thickness associated with the six wheeled landing gear applies to other aircraft with similar wheel configurations and whether the increased rigid pavement thicknesses for six wheeled landing gear, compared to FAARFIELD v1.3, are justified.

To consider top-down cracking failure in current airport rigid pavement design practices, a multiple-slab pavement structure’s three-dimensional finite element (3D FE) model should be analyzed for determining critical responses associated with such failures, and artificial neural networks (ANNs) can be considered a robust and computationally efficient alternative for 3D FE analysis. This study compares the effects of airport rigid pavement’s most important properties on the critical tensile stresses predicted by the ANN models relative to those for 3D-FE solutions. Sensitivity evaluation of both the 3D-FE solutions and the ANN model predictions for two new large and heavy aircraft (B777-300 ER and B787-8) have been conducted and are discussed in this study. The normalized sensitivity index (NSI) has been utilized to quantify the levels of sensitivity of the critical tensile stresses to changes in PCC slab thickness, base layer thickness, PCC slab modulus, subgrade elastic modulus, temperature gradients, and thermal coefficient. The results demonstrate that the developed ANN model is able to determine top-down critical tensile stress sensitivity similarly to the 3D-FE model.

Falling weight deflectometer (FWD) tests back-analysis consists of a process in which a calculated deflection bowl is gradually approximated to its test measured counterpart by adjusting the pavement layer moduli. This approximation is achieved via a numerical method in which the criterion is the minimization of the root mean square error between measured and calculated deflections at transducer positions. The set of elastic moduli that is obtained by performing FWD tests back-analysis is the main variable of this procedure. However, the calculated layer moduli are also dependent on the assumed thicknesses of the pavement layers. This work describes the use of the Levenberg-Marquardt nonlinear optimization method in the FWD tests back-analysis of an airfield runway for which preparatory coring tests presented a very large variation in layer geometry, hence making it impossible to select a fully representative pavement structure for the entire runway or even for limited in length pavement sections. The Levenberg-Marquardt numerical optimization was applied considering pavement layer moduli and thicknesses as interlinked variables, and by not fixing the latter. This approach allowed obtaining a closer fit between the calculated and test collected deflection bowls, and also to determine the poorest performing pavement section as a whole (factoring both calculated layer moduli and thicknesses), in order to use said section in the determination of the runways pavement classification number (PCN).

In a mechanistic-empirical pavement design framework, critical pavement responses are the most important input parameters for empirical damage models. Any mechanistic model developed to predict such responses should be validated in terms of measured responses. Pavement instrumentation such as earth pressure cells, asphalt strain gages, and temperature probes have long been used to determine such responses and develop damage algorithms for airfield flexible pavements. This paper summarizes the instrumentation effort and subsequent measurement of pavement responses during accelerated pavement tests under high tire pressure and temperature, conducted at the FAA’s National Airport Pavement and Materials Research Center (NAPMRC). A total of six test lanes were constructed with hot and warm mix asphalt materials at two different binder grades. Each of the test lanes had three different test sections. Respective test sections were instrumented with asphalt strain gages at the bottom of the asphalt concrete layer, earth pressure cells at the layer interfaces and multiple temperature probes within the asphalt concrete layer. Using the sixth generation heavy vehicle simulator for airport, the constructed test sections were trafficked with a bi-directional wheel load of 273 kN exerting two different tire pressures of 1.45 and 1.75 MPa. Rutting susceptibility of these sections was studied at the pavement temperature of 32 and 49°C at a depth of 5.1 cm from the surface. For both of the mix types, asphalt concrete with neat performance grade binder exhibited higher magnitude of tensile strain compared to polymer modified asphalt concrete layer.

Until the 1990s, flexible airfield pavement design was mainly based on the U.S. Army Corps of Engineers California bearing ratio (CBR) design procedure. The emergence of a new pavement design procedure, the linear-elastic analysis (LEA), which is now widely used, enables a more comprehensive analysis of the effect of an aircraft mix on the pavement structural life. It also provides a tool for airport managers to monitor continuously their pavement and anticipate usual maintenance, and for aircraft landing gear designers to optimize aircraft operations on airfield pavement. This paper discusses how airfield pavements behave when they are subject to an aircraft mix, including new-generation aircraft (777-9, A350-1000), and underlines how the design features of a very large aircraft such as the A380 make it the most pavement friendly aircraft when it is mixed with other wide body aircraft.

The rapid growth in transportation sector demands compatible infrastructure for its sustenance. This is offered by a long-lasting highway and airfield pavement network. However, these pavements start deteriorating soon after their construction, the degree of which depends on the rate of application of loading and prevailing climatic conditions. This calls for a need for continual assessment of their structural and functional capacity, to plan for their repair or rehabilitation alternatives. In this work, a case study on pavement condition evaluation of runway located at an international airport is conducted. The runway pavement being in deteriorated condition has been divided into six sections which are rated and prioritized for maintenance and repair (M&R) needs. Their condition has been evaluated on the basis of four decision criteria, using the opinion of experts. This task has been fulfilled by using two multi-criteria decision-making techniques, namely analytic hierarchy process and fuzzy inference tool. A combination of visual surveys, heavy weight deflectometer tests, and ground-penetrating radar scans provide the essential structural capacity data for carrying out the analyses. The ranking obtained from both the techniques slightly varies due to the inherent difference in their approaches. However, the sections with least and maximum priority are concluded to be similar from both the analyses. This prioritization methodology offers a systematic approach to planners and decision authorities for selecting optimum M&R strategies.

More than 200 communities in Alaska are not connected to the road system and rely upon the local airport for transportation outside the community. This is true for most communities above the Arctic Circle where the airport provides the lifeblood of goods, transportation, and emergency medical services. Alaska’s rural airports must function year round and support air traffic ranging from the smaller Cessna 208 Caravans to the occasional large cargo plane. Temperatures in this region vary from a record high of greater than 26 degrees Celsius (80 degrees Fahrenheit) to lower than minus 50 degrees Celsius (minus 60 degrees Fahrenheit). Resurfacing these runways presents a unique set of challenges that includes permafrost soil conditions, a short (less than 100 day) construction season where the temperature rarely gets above 10 degrees Celsius (50 degrees Fahrenheit), gravel costs that can exceed $620 per ton, and lack of cross-wind runways. This paper discusses some of the most common challenges of resurfacing runways in the desert, wetland, and tundra landscape north of the Brooks Range Mountains, and solutions addressing those challenges. Techniques discussed include insulated embankment sections and culverts, aggregate blending, soil additives, and half-width construction.

As part of the airport improvement program at Dallas Fort Worth International Airport (DFW), a new airfield concrete ramp was designed and constructed to increase gate capacity to serve wide- and narrow-body aircraft. The ramp is approximately 1,450 feet long by 690 feet wide constructed on a partially developed area that included access and service roads, a partial taxiway entrance, and several staging areas. Aircraft movement simulations were conducted to establish the optimum aircraft parking layout and separation between taxiways, taxilanes, vehicle service roads, and hardstand parking positions. The field investigation for pavement design revealed existing soils consisted of lean clays near saturation with low amounts of sulfates. The soil investigation concluded lime stabilization was a feasible alternative for the construction of the cement treated base and the concrete pavement. During the initial construction stages, verification sulfate tests indicated adverse sulfates contents to those obtained during design. The findings jeopardized the lime stabilization approach and a potentially substantial change order would be required if a subgrade replacement approach was conducted. After additional tests conducted by the contractor’s quality control and the airport’s quality assurance laboratories, it was concluded that most of the existing soils were adequate for lime stabilization and that only a few localized areas had elevated amounts of sulfate. A modified lime stabilization approach was conducted to address any potential issues with lime stabilization of elevated sulfate contents in soils. Construction of the base and concrete pavement were successful, and no major issues were encountered. This project was carefully phased to allow construction of the ramp to be predominately outside of the airport operations area (AOA) and completely removed from movement areas by installing temporary AOA fencing. This allowed the contractor to finish in 18 months; four (4) months ahead of schedule. This paper will present the planning, design, and construction considerations conducted for the successful completion of this project.

Deicing and anti-icing operations are frequently carried out on aircrafts at their current parking stand after completion of ground operations. Use of individual stands can be often challenging as this may also considerably affect operations, especially in highly-trafficked airports at winter-critical areas. Hence, a lack of or an incorrect location of these stations may have tremendous economic and operational impact. This research reports a multi-stage design method for construction of a 29,000 m² deicing station in a critical soil site. The main aim of the project is to identify sustainable interventions in order to avoid short- and long-term economic, environmental, and operational issues. An assessment based on the use of fundamental geotechnical parameters is first implemented to create thematic maps of the identified construction area, followed by a comparative analysis of potential intervention scenarios. A combination of lightweight filling and advanced materials has been proposed to ensure homogeneity and suitable bearing capacity of the laying ground.

Kannur International Airport is a green field airport project with airside development on a hilly terrain plateau. The airside infrastructure development works involved earthworks of 45.5 million cum in cutting and filling. To accommodate the desired runway length and runway end safety area (RESA), the plateau was extended along the runway centreline, beyond the plateau, and therefore requiring a high embankment filling with height ranging from 66 m to 87 m. Since the available land was insufficient to accommodate the construction of embankment with a free slope; a reinforced soil slope (RSS), with maximum slope of 65 degrees, was designed and constructed. An RSS of this magnitude in the runway alignment for an airport is a unique feature of this project, located in high rainfall area. The geometry of the RSS itself was challenging being asymmetrical with curves and bends. The airport operational perimeter (AOP) road is positioned at approximately mid height of the high embankment. The slope was reinforced with high strength uniaxial geogrids and the complete system was designed using finite element analysis. Slip circle failure and wedge failure cases were considered in both static and seismic analysis for local and global failure cases. Considering the high annual rainfall received at the airport site, an elaborate drainage system was also designed for the RSS embankment. The paper presents a case study detailing the concept to design development of the high RSS system constructed for providing the planned runway length and RESA.

Full-scale tests of unbonded concrete overlays were completed in February 2018 at the Federal Aviation Administration’s (FAA) National Airport Pavement Testing Facility (NAPTF). The objective was to gain full-scale data to improve the FAA’s FAARFIELD design procedure for PCC-on-rigid airport pavement overlays. The overlay experiment of Construction Cycle 8 (CC8) included two test items, each consisting of ten slabs. The north test item was trafficked by a four-wheel (2D) gear configuration, and the south test item by a six-wheel (3D) gear. Underlying slabs had existing damage, but still retained significant structural integrity. A thin asphalt interlayer was used as a bond breaker between two concrete layers. Both concrete layers were instrumented with embedded sensors to measure dynamic (strain and deflection), and static (temperature) pavement responses during trafficking. In contrast to previous Construction Cycle 4 (CC4) test results at the NAPTF, the 2D loaded test item failed earlier than the companion 3D item. The dominant distress types in both test items were corner breaks and linear reflection cracks. Longitudinal cracks were reflected from the doweled longitudinal joints of the underlying PCC slabs. In addition, the observed crack pattern suggests that some transverse cracks may have initiated from the instrumentation channels in the asphalt interlay; however, this remains to be confirmed by post-traffic forensic investigations. Pavement deterioration was characterized using the structural condition index (SCI) and crack density (CD). The rate of SCI deterioration remained nearly constant with coverages, confirming results from previous CC4 tests.

This paper presents findings from an ongoing research study focused on the permanent deformation behavior of full-scale airport pavements investigated through accelerated pavement testing at the Federal Aviation Administration’s (FAA) National Airport Pavement Testing Facility (NAPTF) located in Atlantic City, New Jersey. Six instrumented airfield pavement sections built with two different subbase materials and tested under various landing gear configurations were selected from NAPTF Construction Cycle 5 (CC5) test section database and an in-depth analysis of the rutting performance due to the use of different subbase materials was conducted. Different pavement deformation trends were observed due to the effects of load wander, landing gear configurations, gear/wheel load magnitudes and sequences, and trafficking direction. In addition, deflections measured using the installed multi-depth deflectometer (MDD) gages were analyzed to determine that most of the surface rutting had occurred due to permanent deformations observed in the granular base and subbase layers. The airfield pavement rutting trends explained in this paper help to establish a better understanding of granular layer rutting damage mechanisms which will eventually result in safer designs and improved performance predictions of airport pavements.

To reduce the aircraft hydroplaning potential of a pavement during wet weather, the Federal Aviation Administration (FAA) has provided a standard specification of airport groove configuration for runway construction and during service. To evaluate the pavement groove construction quality and operational performance, the National Airport Pavement Test Facility (NAPTF) made a series of full scale tests of airport pavement grooves on both flexible and rigid pavements in recent years. FAA has also developed a computer program, ProGroove for groove identification and analysis. During Construction Circle 7 (CC7) testing at NAPTF, several areas of trapezoidal and rectangular grooves with different asphalt concrete pavement structures under aircraft tire loading were tested. The groove geometry data was scanned and collected on each structural location using a high performance laser system during the loading test period. Groove performance service life of trapezoidal and rectangular grooves with different pavement structures under aircraft tire loading was evaluated and compared. Two types of groove deformations under aircraft loading were also simulated by using finite element models. The test results and analysis demonstrate the service life shape changes of trapezoidal and rectangular grooves in asphalt concrete pavements. The relationships between the asphalt pavement groove life and the aircraft traffic loading effect are discussed in the paper.

Early-age cracking is a major issue in design and construction of concrete pavements. This occurrence depends upon various factors i.e., design features, concrete mixture materials, jointing techniques, and environmental circumstances. This may however occur despite adequate design, construction, and jointing operations are correctly followed. Interactions of the above key factors are assessed using comprehensive analytical methods which are demanding in terms of data input and computational requirements. This research presents a streamlined probabilistic methodology for probabilistic risk assessment of early cracking in airfield concrete pavement design. The method provides a strength-to-stress ratio (SSR) index for identification of critical cracking conditions. A risk chart is presented with reference to the designed SSR value, and the required reliability level of the design process.

Spherical glass beads embedded within paint aid in visibility of pavement markings at night. Retroreflectivity measurements on roadways are based on ASTM E1710, a standard using parameters for an automobile 30 meters from the point of interest on the pavement. Various manufacturers’ equipment replicate this geometry and conveniently conduct measurements on pavement markings. However, aircraft geometry varies widely, and entrance and observation angles differ significantly from those of a passenger car. Literature suggests that the higher refractive index of Type III beads (1.9) over Type I beads (1.5) provides a higher peak reflectance but returns light at a narrower range of angles than Type I. A complete angle scatter instrument measured the bidirectional reflectance distribution function of beads of both types embedded in white paint. Results are reported for angles more appropriate for large-aircraft geometries. Limited results from this study confirm the higher retroreflective peak of Type III beads, but also suggest that Type I may beads provide marginally higher retroreflectivity for large aircraft with observation angles exceeding ±7°, as encountered during taxiing.

Strategic asset management optimises the asset performance in the most cost-effective manner. To deliver the optimum investment solution, a decision support tool was developed to generate investment and maintenance plans over a 20-year period optimising the performance of airfield pavements. The strength of the model is to plan in advance strategic, targeted maintenance treatments or replacement at section level. This planned approach can generate capital savings arising from optimising construction costs, minimising operational disruption, and targeting appropriate treatments. This paper presents two case studies of two major airport airports in the U.K.: Heathrow Airport Limited (HAL) and Manchester Airport (MAN). In all cases, savings up to 50% on a 20-year maintenance plan have been identified. Also, this performance-targeted, airfield pavement asset replacement strategy derived from the DST has identified savings of CO₂ in the next 20-year capital investment period; the sustainable aspects of DST are not covered in this paper.

A runway reconstruction project at John F. Kennedy airport was recently completed, and with the help of the Port Authority of New York and New Jersey (PANYNJ) the goal for the case study was defined to perform a standalone/benchmark study to quantify the environmental impacts from the life cycle stages (materials stage and construction stage) of the different layers of the erosion and shoulder pavements. Several runway reconstruction project-related documents were shared by PANYNJ from which data and information relevant to the case study were extracted. Environmental impacts that are considered and reported include primary energy (spilt by consumed and used as a material), greenhouse gas emissions, particulate matter, and ozone depletion. The shoulder pavement had a higher set of environmental impact contributions than the erosion pavement due to the difference in pavement thicknesses. Among materials stage, construction stage, and transportation, the materials stage had the highest environmental impacts followed by the transportation of materials.