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Prestress force loss is crucial to the structural performance of cross-tensioned concrete pavement (CTCP). Severe loss in prestress force will reduce the constricting-cracking capacity of the CTCP, resulting in damage with load and temperature applied. Vibration-based methods are commonly used in prestress force monitoring, but few relative studies are reported into CTCP and the relationship between prestress force and CTCP vibration is still unclear. The purpose of this paper is to investigate the effect of prestress force on CTCP vibration. The vibration characteristics of CTCP subjected to different prestress forces were studied through field testing and finite element (FE) analysis. Impulse load was applied as excitation at the anchorage zone and dynamic responses were measured in the time domain. A signal processing method was employed to obtain short-time power spectral from original vibration signals, which was utilized to extract vibration characteristics in time and frequency. As shown in both the field testing and the FE analysis, the prestress force has a more significant effect on frequency spectral distribution, rather than the dominant frequency. Integrated frequency is proved to be a reliable index for describing frequency spectral distribution and has a good correlation with prestress force, which suggests it can be used to reflect the change in prestress force. Overall, these findings indicate that vibration testing has potential in prestress force monitoring in CTCP, though the practicality of this method requires further demonstration.

This study focuses on the critical responses of airfield composite pavements that are composed of hot-mix asphalt (HMA) overlay and Portland cement concrete (PCC) pavement. Accelerated pavement testing (APT) and a finite element (FE) method were employed to investigate the effects of three influential factors: temperature, interface bonding, and load level. A full-scale test field was constructed for this study and instrumented with 20 strain gauges and 32 temperature sensors. A finite element model was developed based on the parameters derived from laboratory and field tests and the model was then validated through measurements. The results indicate that longitudinal strain is more critical than transverse strain in an HMA overlay when subjected to moving loads. Moreover, the results underscore that temperature significantly affects the responses of HMA overlays and that the relationship between temperature and pavement responses is sigmoidal. Furthermore, a good interface bonding is able to significantly reduce the critical strain in an HMA overlay and the interface bonding strength is very sensitive to the amount of tack coat. The positive strain near to the surface of HMA overlay is due to high compressive stress, which is different from the tensile strain used in fatigue testing.

The deformation of piezoelectric transducer and asphalt pavement differs because of their different stiffness. As the piezoelectric transducer is embedded in asphalt pavement, the differential deformation may cause a non-uniform stress and degrade their performance. In this paper, the synergistic performance of piezoelectric transducer and asphalt pavement is studied through finite element analysis. Results show that the energy conversion efficiency of the transducers decreases with increasing burial depth and modulus of surface course. Under the vehicle loading, the piezoelectric transducer and asphalt pavement are easily separated by shear stress. For the asphalt pavement, the change in the stress of pavement structure and surface deflection is very small, which means that the differential deformation has no effect on fatigue cracking. Furthermore, an energy harvesting system composed of transducers array and asphalt plate is made and evaluated in a laboratory. Results show that the transducers within asphalt pavement have acceptable efficiency and high durability. Keywords: Synergistic performance, Piezoelectric transducer, Asphalt pavement, Energy harvesting, Cymbal, Differential deformation

This paper proposes a novel method to detect and localize debonding beneath the concrete pavement using transmissibility function (TF) analysis. The layout of the measurement node array, the signal processing approach, and the testing procedures are proposed. Two matrices of transmissibility damage indicator (TDI) are proposed to describe the distribution of debonding. This method is a response-only approach and can offer advantages in easy and low-cost implementation. The theoretical deduction, finite element analysis (FEA), and field tests are conducted to demonstrate and verify detection and localization performance. It is first observed that the arrangement of measurement nodes and the frequency range are crucial to TF analysis. TFs at higher frequencies range are more sensitive to the debonding but may result in higher errors. The density of the measurement node array and the noise’s effect are investigated in the FEA. Using a denser node array and maintaining a lower noise level helps localize the debonding more precisely. Field tests are conducted on a precast concrete pavement plate using a specially designed accelerometer array. The test results demonstrate the feasibility of the TF-based method for debonding detection and localization.

The aim of this paper is to propose a simple empirical prediction model for temperature gradients within concrete slabs of jointed plain concrete pavements (JPCPs) based on data collected b...

Part of energies in asphalt pavement caused by vehicle can be converted into electric energy by piezoelectric transducer. A bridge-shaped transducer is selected to harvest energy because of its reasonable efficiency and moderate stiffness close to asphalt pavement. This paper is to compare the performance of Bridge transducers with trapezoidal, arc and arch structure through finite element analysis (FEA) and laboratory test. Results show that the arch Bridge has higher energy conversion efficiency and the trapezoidal Bridge has stronger ability to resist pressure. For arc and trapezoidal Bridge, the maximum tensile stress and shear stress are both in the inner corner of contact area between cap and PZT (lead zirconate titanate) disk. They were broken because of the cracking of PZT at the stress concentrations area. For arch Bridge, the maximum tensile stress increases with thickness of metal cap but decrease with modulus, and maximum shear stress decreases first and increases later with increasing thickness and modulus of metal cap. In laboratory test, its cracking area is shifted from edge to inner corner of contact area between cap and PZT disk with increasing thickness of metal cap. The electric potential generated by arch Bridge decreased with increasing thickness and modulus of metal cap. Under the load of 0.7 MPa, the electric potential is about 286 V for an arch Bridge transducer with 0.4mm thickness of stainless steel cap, and its storage electric energy is 0.6 mJ. The designed arch Bridge transducer is suggested as the optimum one for harvesting energy from asphalt pavement.

This paper presents the way to harvest mechanical energy from asphalt pavement by piezoelectric generator. Results show that the potential energy in asphalt pavement can be up to 150 kW/h per lane per kilometre. Part of the mechanical energy can be harvested by piezoelectric transducers. The performance of seven typical transducers is examined through finite element analysis. Results show that PZT piles and multilayer, cymbal and bridge can work in asphalt pavement environment. PZT piles and multilayer have higher energy converting rate. However, the total harvested energy is small if these transducers are embedded directly in pavement. A prototype pavement generator is developed using PZT piles to increase the harvested energy. The generator can harvest more than 50 kW/h energy from the pavement under heavy traffic. 8–16 PZT piles are recommended for one generator. Round shape is suggested for the PZT piles to reduce the concentration of stress. And multilayer structure is recommended for PZT piles to decrease the electric potential of generator. The generator can be extended as sensor in the asphalt pavement, which can be used to monitor the traffic, pavement stress and temperature.

This paper presents a pavement structure segmentation method based on the results derived from ground-penetrating radar (GPR) data. Surface type, layer thickness, base/sub-base type, shortest segment and outlier point criteria are developed to perform the segmentation. A boundary comparing method using t-tests is developed to perform layer thickness criteria. The value t = 4 is suggested for the HMA (hot mix asphalt) or aggregate layer; and t = 6 is suggested for Portland cement concrete and cement-treated base. During segmentation, segments that are shorter than the minimum length of 100 m are merged into adjacent segments. Furthermore, the flow charts of pavement structure segmentation as well as a procedure for automated segmentation are detailed. Proposed rules for fixing segment boundaries between GPR observations are also presented. Several segmentation examples are calculated by the automated procedure using the data from a pilot project in California. The results show that the method presented in ...

An online monitoring system was recently built to acquire the inner condition and response of the runway pavement at Shanghai Pudong International Airport. Seven sections were instrumented to detect the responses of pavement when aircrafts were taking off, landing, and taxing. Sensors used in the system include strain gauges, multi-depth deflectometers, temperature sensors, earth pressure cells, moisture sensors and three laser distance sensors for aircraft position. Most of the sensors are fiber bragg grating based sensors, and some are electronic signal based sensors used to improve the reliability and variety of the data. Instruments are divided into dynamic and static parts, which are aimed at measuring pavement responses caused by aircraft load and environmental influence. The instruments are all fiber optic cable connected within the airport area for radio frequency control. This paper presents the (1) layout of sensors; (2) verification tests of the instruments; (3) process of installation; (4) method of data collection; and (5) initial responses test of pavement.

The purpose of this paper is to explore the vibration characteristic of asphalt pavement with various structures for harvesting mechanical energy via finite element analysis (FEA) and analytic model. Part of energies in asphalt pavement caused by mechanical vibration can be harvested by piezoelectric transducers. In order to get more energy from pavement, the sensitivity of structure parameters such as thickness, modulus, mass and stiffness are analyzed by using semi-rigid asphalt pavement as an example. Finite element model and analytic model are established in the analysis, which are calibrated by field measurement and laboratory test. The results show that the vibration frequency of typical semi-rigid asphalt pavement is between 10 Hz and 20 Hz, which is far lower than frequency of typical piezoelectric transducers. The fundamental frequency of asphalt pavement decreases with increasing thickness and mass of surface, base and subbase. However, the fundamental frequency is increase with the modulus and stiffness of subgrade, the increment is about 23 Hz/10 MPa and 0.7 Hz/10⁶ (N/m).

Superposition effects of runway asphalt pavement under multiple aircraft tires load are discussed in this paper. 30 x 20 x 10 m (Full Size Model), 15 x 20 x 10 m (1/2 Model) and 15 x 15 x 10m (1/4 Model) size models are established on ABAQUS 3D numerical analysis platform. Using those models, asphalt pavement responses under single tire, double tires, single tandem, dual tandem, dual triple, and compound landing gear are studied. Results show that multiple superposition effects are apparent. The pavement surface deflection under full landing gear is larger than any other tire groups; the maximum vertical strain on the top of the sub-grade and the horizontal stress at the bottom of the base appear in 6 tires group for A 380 and rear 8 tires group for B-777; the largest strain or stress can reach 1.15 times of the full landing gear’s value. Based on the pavement responses under multiple tires load, the fatigue life of pavement is analyzed. Functions developed by LEDFAA, APSDSR and UC Berkeley are used in the fatigue analysis. The results of flexible and semi-rigid pavements show that the allowed load repetitions of runway asphalt pavement under full landing gear are 20∼30% higher than 6 or 4 tires group. Therefore, the full landing gear is recommended to be used in asphalt pavement structure design.

Coverage is an important parameter in the airport pavement design. Coverage calculating method in CBR pavement design method of FAA and UFC are detailed. In those methods the load repetitions can be considered using pass-to-coverage ratio. The ration is calculated base on the wheel-path distribution on pavement surface, which is not corresponding to the damage caused by the stress or strain within pavement depth. The calculating position is moved from surface to the top of subgrade in LEDFAA 1.3, while the lateral distribution of strain is considered as uniform not a normal distribution. There are no specific definitions of coverage in the specifications for asphalt concrete pavement design in China. For a pavement design method which can satisfy the New Generation Large Aircraft, such as A380, the coverage should be considered base on pavement spatial responses. The general pavement design concept advanced by Monismith gives a good idea to develop coverage calculation method.