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This paper presents a new method that uses distributed optical vibration sensing (DOVS) technology and a neural network, which can access the concrete pavement support condition with lower cost and higher efficiency. This method relies on the vibration properties of the concrete pavement slabs, which was captured by an embedded DOVS system and extracted using the wavelet packet transform. Based on the extracted properties, a grading method that using probabilistic neural network (PNN) to assess the support condition was proposed. Through field tests, the accuracy of this method can reach 92.8% for 2-grade assessment and 81.4% for 3-grade assessment, respectively.

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.

This paper aims to study the influences of temperature variations on airfield jointed plain concrete pavement (JPCP) deflections. The maximum deflection at the transverse joint ( D 0 j ), the maximum deflection at the corner of a slab ( D 0 c ), and the deflection basin at the centre of a slab were considered. The in-situ deflection measurements at three civil airports were conducted over a 24-hour period and numerical simulations for JPCP at a civil airport were performed as well. The results indicate that the temperature change slightly affects the deflection basin at the centre of a slab unless the positive temperature gradient in the slab increases to exceed a certain critical value. But both D 0 j and D 0 c are significantly affected by temperature variations. The results of in-situ tests show that D 0 j (or D 0 c ) is almost stable from 1 pm and 5 pm in a day. At other times of one day, there is a strong negative liner correlation between D 0 j (or D 0 c ) and the pavement surface temperature during the heating period and the cooling period, respectively. The results of numerical simulations reveal that both D 0 j and D 0 c gradually increase with the increase of the average temperature. The results of numerical simulations also suggest that a critical negative/positive temperature gradient exists at the transverse joint while there is a critical positive temperature gradient at the slab corner. Besides, all the critical temperature gradients are seldom affected by the average temperature. When the temperature gradient exceeds the critical value, D 0 j , D 0 c and all values of the deflection basin have a strong positive linear correlation with the temperature gradient.

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.

Asphalt-based composites have the ability to heal themselves. Under certain conditions, strength and stiffness modulus can be restored so that the fatigue life can be extended. However, without the aid of external influences (energy supply or material supplement), the self-healing ability of asphalt mixture is quite limited. In this paper, the efficiency of self-healing of asphalt mixture with Ni-Zn ferrite powders was analyzed based on the concept of microwave heating. The recovery rate of stiffness modulus and the fatigue life extension ratio were adopted to evaluate the self-healing efficiency of asphalt mixture. Different influence factors, such as heating temperature, healing time and damage level, were analyzed in this study. The analysis results proved that Ni-Zn ferrite powders can promote the self-healing ability of asphalt mixture significantly. It is found that when the asphalt mixture is filled with 80% ferrite powders (volume fraction of mineral powders), under the condition of healing for 3 h after heating to 55 °C by microwave, the fatigue life extension ratio of 50% damaged ferrite-filled asphalt mixture can reach 1.33.

The friction force for aircraft landing is mainly provided by the texture of runway surfaces. The mechanism underlying friction force generation is the energy dissipation of tire rubber materials during random excitation induced by asperities. However, the runway surface texture is deteriorated by cyclic loading and environmental effects during the service life of a runway, leading to loss of braking force and extension of landing distance. Additionally, when an aircraft lands on a wet runway at a high velocity, the hydrodynamic force causes the tires to detach from the runway surface, which is risky and may lead to the loss of aircraft control and runway excursion. Worn-out surfaces along with wet conditions increase the risk of poor control during aircraft landing. Accordingly, this study investigated three types of asphalt runways (SMA-13, AC-13, and OGFC-13). Surface texture deterioration was simulated using a surface texture wear algorithm. Kinematic friction models were established based on the viscoelastic property of rubber materials, power spectrum density, and statistics of surface textures. A finite element model was developed by considering a real rough runway surface and different water film depths (3, 7, and 10 mm). A comparison of hydroplaning speed was conducted between numerical simulation and former experiments. The effects of different factors, such as velocity, wear ratio, runway type, water film depth, and slip ratio, on the skid resistance of the runway were analyzed.

Many materials used as phononic crystals (PCs) are viscoelastic one. It is believed that viscosity results in damping to attenuate wave propagation, which may help to tune the defect modes or band gaps of viscoelastic phononic crystals. To investigate above phenomenon, firstly, we have extended the application of boundary element method (BEM) to the study of viscoelastic phononic crystals with and without a point defect. A new developed BEM within the framework of Bloch theory can easily deal with viscoelastic phononic crystals with arbitrary shapes of the scatterers. Experimental methods have been put forward based on the self-made viscoelastic phononic crystals. Verified by the experimental results, systematic comprehensive parametric studies on the band structure of viscoelastic phononic crystals with varying factors (final–initial value ratio, relaxation time, volume fraction of scatterers, shapes of scatterers) have been discussed by the numerical simulation. To further address the possibility to change the defect modes, the band structure of viscoelastic phononic crystals with a point defect has been studied based on the numerical and experimental methods. From present research work, it can be found that by adjusting the two viscous parameters combined with considering the effect of volume fraction and shapes, a wider and lower initial forbidden frequency or lower and higher quality factor resonant frequency can be obtained.

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.