Airport Pavement Research Articles

Planar Distribution Model of Airport Pavement Traffic Volume

The current specification of airport pavement design and evaluation had seldom pointed out the longitudinal distribution of airport pavement traffic volume (APTV) except the wheel offset at the edge or the central section of the runway. In this study, the characteristics of APTV were pointed out, which revealed that every point of the pavement had a different traffic volume. Then using the longitudinal traffic factors, the planar distribution model was established. At last, influence factors of APTV including take-off probability ratio at one side, runway length, take-off running distance and lateral distribution were analyzed. Examples and analysis showed that only considering the lateral distribution of APTV would make the pavement design more conservative.

Research on the Causes and Prevention of Airport Pavement Diseases

The structure of airport runway has changed the balance of water movement between the original surface and the atmosphere, resulting in the accumulation of water under the base of airport runway surface, forming a “pot-cover effect”, aggravating the uneven settlement of the foundation under aircraft load, resulting in the destruction of the structure of the runway surface, frequent diseases, and seriously affecting the airworthiness of the runway. In order to solve the problem of water enrichment under the base of the runway surface, this paper proposes a specific layout scheme of diversion canals. In the runway overhaul project of Shenyang Taoxian International Airport, the water diversion canal was excavated on the spot, and it was found that the water level at the site was comparatively consistent with the water level at the scheme analysis. The layout scheme of the water diversion canal was reasonable and effective, and could well solve the problem of “pot-cover effect”.

Instrumented flexible pavement responses under aircraft loading

ABSTRACT The FAA National Airport Pavement Test Facility (NAPTF) is a full-scale accelerated pavement testing facility located in Atlantic City International Airport, New Jersey. Six flexible and three rigid test sections were built, instrumented and trafficked by Boeing 777 and 747 gears as part of construction cycle one. One flexible test section with an asphalt-stabilised base over a low-strength subgrade was considered in this study. All dynamic sensors, including pressure cells, strain gauges and multi-depth deflectometers were evaluated. A multistep procedure for evaluating the dynamic sensors was developed, and it included data reliability, repeatability, changes in the pavement responses under the Boeing 777 and 747 gears, and comparison with a three-dimensional (3D) finite element (FE) mechanistic model. The mechanistic model was found to predict the pavement responses with good reliability, whenever representative layer moduli are used. The study also found that 60% of the sensors produced acceptable or marginal responses and 40% produced unacceptable responses; therefore, it is recommended to consider this sensor survival rate when instrumenting future test sections. The rutting performance and pavement responses over time were evaluated; the test section was shown to have relatively similar performance and pavement responses under the Boeing 777 and 747 gears.

Analysis and Load Rating of Corrugated Steel Arch Culverts

ABSTRACTCulverts are typically used as short span bridge substitutes for spans less 50 ft (15 m). The corrugated metal arch culvert (CMAC) is one of the most popular types, which is frequently installed under highways, airport pavements and railroad tracks. For the purpose of validating the service conditions of CMAC, a load rating method is developed in this study based on AASHTO Manual for Bridge Evaluation. The rating factors (RFs) for culverts are derived to verify the capacity of the culverts to carry current standard truck loads. In order to carry out the load rating, a finite element model of the CMAC is developed for analysing the axial thrust of the culvert wall when subjected to static and dynamic moving truck loads. A method to calculate the CMAC wall thrust capacity is derived by summarizing existing capacity calculation approaches for arch culvert and corrugated metal plates.

The Durability and Performance Test methods of the New Type of Pavement Filling Material - An Holistic Review

Airport pavement joint weaknesses are one of the important factors that affect airport performance and threaten flight safety. The traditional pavement caulking materials are mainly asphalt-based materials of heating construction type, which are prone to aging, loss of adhesion and other shortcomings in natural environment. Based on the shortcomings of traditional pavement caulking materials, this paper introduces the research and application status of new type of filling caulking materials represented by high-performance elastic polymer materials, with emphasis on its durability, performance testing methods. Finally, it summarizes the existing problems and prospects of the new type of pavement filling caulking materials.

Usage of power plant waste for airport pavement surface

A research has been conducted to analyze usage of power plant waste and characteristics of asphalt concrete mixture for airport pavement using artificial aggregate. The artificial aggregate was made of power plant wasted related to waste energy that has not been fully utilized. This testing method used to determine the marshall stability and flow values of asphalt concrete, and to measure how much fly ash from power plant waste can be reduce to utilized as airport pavement surface. The result of marshall testing provides the new material that made of power plant wasted was eligible to used as a replacement material for airport pavement surface and the mixed compositions can be applied for airport runway pavement which is using artificial aggregate was expected to reduce power plant wasted.

Airport concrete pavement design by environmental and double dual tandem gear loadings

A method for designing an airport concrete pavement (ACP) that can withstand environmental loads as well as traffic loads is presented. Information on ACPs for which double dual tandem landing gears were used for design aircrafts was collected and the stresses induced on the slabs when environmental loads and traffic loads were simultaneously applied were predicted with the finite-element analysis program FeaFaa. In addition, a maximum tensile stress regression model of ACP slabs was developed using the statistical analysis program SPSS. When environmental and traffic loads were simultaneously applied, the maximum tensile stress obtained with the finite-element method was significantly different from that obtained using Westergaard's equation of edge loading only in traffic loads. Therefore, the fatigue model in the US Federal Aviation Administration's AC 150/5320-6E design method was corrected to be appropriate for this study. Using the stress regression model developed in this study and the corrected fatigue model, the thickness and joint spacing of existing ACP slabs were redesigned and compared with existing airport pavements. Previously, only the thickness of a slab was designed and the joint spacing was empirically determined. However, from the results of this study, a slab's thickness and joint spacing can be designed mechanistically.

Airport asphalt pavement health monitoring system for mechanical model updating and distress evaluation under realistic random aircraft loads

The performance of airport asphalt pavement gradually deteriorates under aircraft load repetitions. In this study, a framework of airport asphalt pavement health monitoring system was developed to evaluate pavement performance under realistic random aircraft loads. The taxiway of the Beijing Capital International Airport was used as an example, and sensor layout was designed to obtain pavement mechanical responses and identify random aircraft loads. Multi-layered system theory was selected as the mechanical model to simulate airport asphalt pavement structure considering its computational efficiency. Mechanical model updating and distress evaluation based on airport asphalt pavement health monitoring system were discussed. First, in accordance with the theoretical relationship between mechanical responses and moduli derived from the mechanical model, the moduli of the pavement structure layers were back-calculated using measured mechanical responses. The Kalman filtering method was developed to identify modulus parameters that can be used to update the mechanical model. Second, full-field pavement mechanical responses under each load were reconstructed from the mechanical responses of a single point acquired by the sensors based on the updated mechanical model with knowledge of random aircraft loads and modulus parameters. Finally, real-time deterministic pavement distress calculation (cumulative damage from fatigue cracking and rutting) at any point were realized based on transfer functions between mechanical responses and performance. The strategy and process for short-term non-deterministic distress prediction were developed, and non-deterministic pavement distress at any point after multiple random aircraft loads can then be obtained. This study is beneficial for the understanding of airport pavement behavior and decision-making regarding pavement maintenance.

Resetting dense graded airport asphalt production and construction tolerances

All elements of pavement material supply and construction are variable in nature and some specifications recognize this variability via statistically based specification limits and pay rates that are related to the percentage of complying quality assurance test results. It was perceived that the traditional and prescriptive airport asphalt specification in Australia included some tolerances that were unreasonably tight and this was preliminarily addressed in conjunction with the development of a more performance-based specification in 2017. However, the reasonableness of the current tolerances required verification based on data generated by actual airport pavement resurfacing works. The quality testing results from three well-constructed and adequately performing recent runway resurfacing projects were statistically analyzed to review, verify and where necessary reset, the tolerances relating to raw material manufacture, asphalt production and surface layer construction. The majority of the current tolerances were appropriate. However, the tolerances associated with the Marshall Stability and Marshall Flow, as well as some compacted field air void limits were recommended to be tightened. It was also recommended that the tolerances for surface cross fall deviation from design be widened and that new tolerances be added for asphalt maximum density and Marshall bulk density. The recommended tolerances aim to allow an average compliance failure rate of approximately 5%, which is consistent with other statistical approaches to infrastructure material specification in Australia.

Validation of the subgrade shear strength parameters estimation methodology using light weight deflectometer: Numerical simulation and measured testing data

Abstract Shear strength parameters (angle of internal friction, ϕ, and cohesion, c) of a soil medium are the key properties for the bearing capacity and stability analyses. The strength parameters have been recognized as one of the most reliable mechanical properties of pavement subgrade that can be used to estimate its permanent deformation behavior under repeated loading. In addition, when a pavement structure is subjected to a non-standard superheavy vehicle load (i.e., gross vehicle weight in excess of a few million pounds), investigation of instantaneous shear failure or onset of yielding in the pavement subgrade layer requires the knowledge of the strength parameters. Light Weight Deflectometer (LWD) has been commonly used as a Non-Destructive Test (NDT) method for in-situ determination of stiffness properties of pavement layers, unpaved roads, and subgrade layer during the construction process. In this study, the validity of a recently developed LWD-based methodology for estimating the in-situ shear strength parameters of the pavement subgrade layer has been further investigated. In this methodology, the commonly accepted hyperbolic stress-strain constitutive soil model along with the consideration of stress dependency of subgrade materials under multiple LWD load levels have been incorporated. The methodology was validated using numerically simulated LWD testing at multiple load levels for two different subgrade materials. In addition, the LWD data collected from large-scale experiments conducted at University of Nevada, Reno testing facility and National Airport Pavement Test Facility were also utilized to verify the methodology. It was found that the proposed LWD-based methodology provides a reasonable estimate for the in-situ shear strength parameters of the compacted soil subgrade.

Prediction of the California bearing ratio (CBR) of compacted soils by using GMDH-type neural network

The California bearing ratio (CBR) is an important parameter in defining the bearing capacity of various soil structures, such as earth dams, road fillings and airport pavements. However, determination of the CBR value of compacted soils from tests takes a relatively long time and leads to a demanding experimental working program in the laboratory. This study is aimed to predict the CBR value of compacted soils by using the group method of data handling (GMDH) model with a type of artificial neural networks (ANN). The results were also compared with multiple linear regression (MLR) analysis and different ANN models. The selected variables for the developed models are gravel content (GC), sand content (SC) fine content (FC), liquid limit (LL), plasticity index (PI), optimum moisture content (OMC) and maximum dry density (MDD) of compacted soils. Many trials were carried out with different numbers of layers and different numbers of neurons in the hidden layer in GMDH model and with different training algorithms in ANN models. The results indicate that the GMDH model has better success in the estimation of the CBR value compared to both the MLR and the different types of ANN models.

Study of the Influence of Fibres Type and Dosage on Properties of Concrete for Airport Pavements

Abstract The paper follows the potential practice of fiber reinforced concrete (FRC) as a solution for airport`s runway pavements, in order to increase the bearing strength, resulting in decreasing the height of the concrete layer that is currently used. Experimentally, the study focuses on the properties of fiber reinforced Portland cement concrete using 3 different percentages (0.5%, 1% and 1.5% of the concrete volume) and 4 different types of fiber (for 1% percentage – hooked steel fiber 50 mm length, hooked steel fiber 30 mm length, crimped steel fiber 30 mm length and polypropylene fiber 50 mm lenght), using as reference a plain concrete with 5 MPa flexural strength. More exactly, the study presents the change in compressive and flexural strength, shrinkage, thermal expansion factor, elastic modulus and Poisson`s ratio over fiber type and dosage. For the highest performance concrete (7 MPa flexural strength), it has been made a study using two methods for rigid airport pavements design (general method and optimized method), and one method for evaluation of bearing strength (ACN – PCN method), which is compared to a plain 5 MPa concrete. Furthermore, the decrease in the slab`s thickness proportionally to the growth of the flexural strength is emphasized by evaluating the slab`s height for a high performance 9 MPa concrete using both design methods.

Non-Linear Analysis of Precast Concrete Element for Airport Pavement

The paper focuses on structural design of a precast concrete element used for an innovative precast concrete pavement system for airports which is being developed within an ongoing project at Faculty of Civil Engineering CTU in Prague. The object of the structural design consists in designing reinforcement for the selected element with respect to crack width, tensile stress limitation in reinforcement and compressive stress limitation in concrete. The amount of reinforcement is highly affected by both applied load and the presence of imperfection in pavement bedding. In order to examine the behavior of the element subject to the load from Airbus A380800F, a three-dimensional model was created and analyzed by using Newton-Raphson's method and FEM. The data obtained from the numerical simulation served for the optimization of the element reinforcement.

Temperature Control Planning Tool for Multi-Lift Resurfacing of Airport Pavements

Overnight repairs and resurfacing of runway or taxiway pavements are common in busy airports. The time window available for such repair and resurfacing works is often limited. A common problem encountered is to ensure that the newly compacted asphalt mixture has cooled down sufficiently before receiving aircraft loadings, so as to avoid premature deformation and failure of the asphalt mixture. In this regard, a simulation model that provides a prediction of the temperature–time variation trend of each compacted pavement lift in a multi-lift asphalt course laying would be a valuable planning tool for temperature control. Information on the temperature cooling trend of an asphalt layer helps to estimate the time duration available for effective compaction during laying, as well as the time lapse needed before the pavement is sufficiently stable to receive traffic. A finite element simulation model is presented in this study to predict the temperature–time variation trends of successive asphalt lifts in a multi-lift asphalt mixture laying operation. The numerical model was developed based on the theory of thermodynamics taking into account the heat transfer effects of solar radiation, convection, and conduction. The model was calibrated and validated using data from a field trial involving a two-lift and a three-lift laying of asphalt mixtures. Illustrative examples are presented to demonstrate the applications of the simulation model as a temperature control planning tool for repair and resurfacing operations of airport pavements.

Evaluation of Pavement Surface Conditions for Luxor International Airport

Egypt has many airports which include millions of square meters of paved runways, taxiways and aprons. These pavements serve a great mix of different aircrafts. Aviation community has a large investment in airport pavements. The main purpose of airfield pavements is to carry aircraft loads conveniently, economically, and safely during its design life. In addition, good ride-quality which permit safe operation of aircraft under all weather conditions is essential for runway and taxiway pavements. Immediately upon completion of construction, airport pavements begin a gradual deterioration which is attributed to several factors. These factors include traffic loads, climate, and others causes due to faulty construction techniques. In addition, inferior materials properties and differential movement of the underlying layers can fasten pavement deterioration and effect pavement performance. Consequently, failure to perform routine maintenance during the early stages of deterioration may result in extensive repairs at a later date. The decision to conduct maintenance works depends mainly on the evaluation of the pavement surface conditions. Some pavement distresses as raveling and weathering could produce loose aggregate particles on the runway surface which cause a serious safety problem. This study aims to evaluate the condition of the pavement surface of Luxor International Airport, Egypt. Field inspection includes determination of the type, severity and extent of all surface distresses and defects. Distresses were observed, assessed and tabulated. The Pavement Condition Index (PCI) technique for airport pavement and contribution of the different distress types were calculated. The computer software Micro PAVER 5.2 was then used to analyse the collected data. The results show that the most effective distresses were depression, raveling and weathering, and longitudinal and transverse cracking. Other less effective distresses affecting the studied features were bleeding and oil spillage. The results of this study emphasis the importance of conducting periodic evaluation of airfield pavement surface condition upon which a maintenance decision could be taken.

Effectiveness of Dowels in Concrete Pavement.

Dowels are located in transverse joints of Jointed Plain Concrete Pavements (JPCP) and they are used to provide load transfer between individual slabs, reduce faulting and improve performance. Dowels and the concrete itself are under the highest stress in the vicinity of joints; thus, in terms of pavement design, the joints are the weakest points of the whole structure. This study dealt with the drawbacks of JPCP with dowels. The evaluation was based on direct measurements on real airport and motorway pavements and highlights insufficient efficiency of load transfer and its possible causes. The authors present a successful outcome with validation by using the finite element method where high tensile stress values of the surrounding concrete were found.

Implementation of a pavement management system for maintenance and rehabilitation of airport surfaces

Airport pavements should satisfy safe and regular aircraft operations; thus, it is necessary to monitor these surfaces and implement expensive maintenance and rehabilitation works. The Airport Pavement Management System (APMS) is an approach to monitor the pavement condition and to determine the priorities for intervention, to plan, and to allocate resources through procedures. The method for monitoring pavement conditions is currently adopted by the airport management company because it is necessary to the airport operability. The study focuses on the paved network of an Italian airport that is composed of a runway, a parallel taxiway and five exit taxiways. Measures of load bearing capacity, transversal and longitudinal evenness, pavement-tire adherence, and pavement distresses were collected and merged to identify the needed maintenance and rehabilitation works. The results revealed the presence of critical sections, where several structural and functional distresses were. The needed structural and functional works involved the greater parts of the runway and the parallel taxiway, and two exit taxiways. Given the high operational impact of the needed works, they were scheduled to be conducted within three phases in order to minimize the impact on the traffic, reducing the closure period to 15 consecutive days. In general, the results summarized approaches typical of different conditions: the article has highlighted that the Pavement Management System (PMS) requires multiple analyses to consider various indices and correctly manage existing pavements having different competences to conduct comprehensive and appropriate analyses.

Iterative Framework for Performance and Environmental Impacts of Airfields

The main goal of a durable and sustainable airfield is to withstand repeated aircraft traffic loading while minimizing the environmental impact. The objective of this study is to develop a design-life cycle assessment (LCA) framework considering a balanced evaluation of structural adequacy, minimizing emission, and optimizing total energy demand. To achieve this objective, three steps are introduced: an evaluation of the structural adequacy of the design using the Federal Aviation Administration (FAA) pavement design software FAA rigid and flexible iterative elastic layered design; a preliminary performance check using field instrumentation responses; and a LCA of airfield sections using both deterministic and probabilistic approaches. In addition to presenting the design-LCA methodology, this paper offers a comparative evaluation that covers two perpetual designs (LFP1-N and LFP4-N) and one conventional section (LFC5-N). These pavement sections were built and tested at the National Airport Pavement Test Facility as part of construction cycle 7, funded by the FAA. Responses collected from instrumentation were used to compute field-based coverages to failure. Moreover, life cycle inventories from secondary sources were used to quantify the greenhouse gas emissions and energy demand associated with the construction of these sections. Results show inconsistencies between the field-predicted and theoretically predicted performance. This suggests the need for the additional calibration of the currently used performance models. Moreover, this study shows that under a specific asphalt concrete (AC) thickness limit, conventional AC may be more eco-friendly than a perpetual design.

Optimization of Structure Parameters of Airfield Jointed Concrete Pavements under Temperature Gradient and Aircraft Loads

Daily changing temperature causes significant thermal stress in concrete pavement. Tensile stress obtained can exceed flexural tensile strength when the concrete slabs are subjected to large temperature gradient and traffic loads, resulting in pavement damages. In this paper, maximum tensile stresses in concrete slabs with different slab sizes, thicknesses, and length to width (L/W) ratios were investigated by using the finite element (FE) method. The important parameters in the design of concrete pavement are the flexural tensile strength and the fatigue limit. By analyzing the comparison results between the maximum tensile stress and the fatigue limit, the optimum slab size and the critical thickness were determined. The results indicate that the maximum tensile stress obtained is higher for larger slab size with thin thickness. Furthermore, to reduce cutting work and the amount of dowel bars, the optimum slab sizes of the regional airport concrete pavement are recommended as 4 m × 4 m to 6 m × 6 m. The critical thicknesses of 4 m × 4 m slab and 6 m × 6 m slab are determined as 28.2 cm and 34.7 cm, respectively, based on the most unfavorable coupling between positive and negative temperature gradients and the Boeing 737–800 aircraft load. Moreover, the maximum tensile stress increases as the L/W ratio increases. When the slab length is less than 6 m, it is better to use square slab in airport jointed concrete pavement (JCP).

Turning Maneuver Effect on Near-Surface Airfield Pavement Responses

Airport pavement structures experience heavy aircraft tire loading through a localized contact area. Distributed three-dimensionally and non-uniformly, tire-pavement contact stresses directly influence the near-surface behavior of flexible airfield pavements. The resulting high shear stress levels induced by aircraft tire loading may lead to instability through shoving or slippage cracking. As the tire turns during taxiing, the risk of near-surface damage is exacerbated. In this study, numerical modeling of an inverted pavement system and a conventional flexible pavement structure loaded with a single tire from the A-380 landing gear was developed. The analysis matrix included two tire-inflation pressures, two speeds, and rolling conditions that varied from free-rolling to two turning maneuvers. Two analysis approaches were performed: 1) use of traditional critical point strains, and 2) domain analysis, which characterizes bulk pavement behavior using multiaxial stresses and strains. The critical strains, which are used as inputs for airfield pavement design, changed negligibly under varying tire turning conditions despite the asymmetric contact stress distribution. On the other hand, domain analysis not only captured the asymmetric pavement behavior, but also identified that altering the tire movement from a free-rolling condition to turning could induce a significant increase in the potential damage.