In this paper, an interlayer contact bonding model according to the Coulomb friction model was developed by contact element and target element to accurately simulate the bonding condition between the adjacent layers of semi-rigid base asphalt pavement. The interlayer contact bonding model can be used to not only simulate the partial bond condition between adjacent layers but also imitate the phenomenon of bonding failure between adjacent layers. Semi-rigid base asphalt pavement structure, finite element mesh, material property with temperature, kinds of interlayer bonding failure, and moving load were explained in detail, and the responses of the semi-rigid base asphalt pavement structure were calculated and analyzed by this model at the room temperature and the higher temperature. The results indicated that the disengaging area between the asphalt concrete layer and the base layer can negatively affect the strain responses of asphalt pavement, especially at the higher temperature, and it can also weaken the asphalt pavement performance with the increase of the disengaging area. The deformation of semi-rigid base asphalt pavement is intensified under the action of the high temperature and the overloads, which would be easy to result in potential pavement structural deficiency. At the higher temperature, the adverse effect of moving loads on asphalt pavement is greater than that of roadbed, and the responses of the asphalt pavement decrease with the increase of the vehicle speed.

Random surface roughness of bridge deck pavement just like random road surface roughness was simulated by the harmony superposition method in this paper. e dynamic load of vehicle was calculated by the random surface roughness of the deck pavement and the quarter-car model. A finite element model of a box girder bridge and its deck pavement was established, and the bonding condition between the adjacent layers was assumed to be contact bonding condition. e stress values of the asphalt concrete layer were calculated and analyzed when surface roughness condition, vehicle speed, and disengaging area changed. Results show that random surface roughness of deck pavement affected the stress trend of the asphalt concrete layer obviously. e appearance of disengaging area would increase the stress values of the asphalt concrete layer and the normal tensile stress value between the asphalt concrete layer and the waterproof layer. is would speed up the damage of the asphalt concrete layer and enlarge further the disengaging area.

In this research the interlayer contact condition was considered between the adjacent layers of orthotropic steel deck pavement, and an interface contact bonding model was applied to simulate the interlayer bonding condition and evaluate the response of deck pavement under vehicle loads. An advantage of this model is that it can simulate not only the full-bond condition but also the debonding condition at somewhere between adjacent layers. The responses of the orthotropic steel deck pavement were calculated and analyzed by the model, and it found that this model is reasonable and credible to evaluate the responses of the deck pavement comparing with the previous researches. The full-bond condition was an ideal condition between adjacent layers, which was prone to underestimate the responses and deformation of the deck pavement. Moreover, the position and size of the disengaging area have a notable influence on the tensile strain at the top of SMA layer and the bottom of GA layer, and the tensile strain of them also increase with the increase of the disengaging area. Finally, the responses of the steel deck pavement changed obviously when the vehicle speed increase, so the suitable speed limit may reduce the responses and deformation for prolonging the service life of the orthotropic steel deck pavement.

A cold-resistant bacterium (strain QL) that can degrade 2,2',3,3',4,4',5,5',6,6'-decachlorobiphenyl (PCB209) was isolated from Wei-he River sediment. Strain QL was identified as a rod-shaped gram-negative bacterial strain, which was further identified as Comamonas testosteroni. C. testosteroni has never been reported to be capable of degrading PCB209 at low temperatures. In this study, the degradation characteristics showed that strain QL could grow with PCB209 as the sole carbon source at low temperatures (10 ± 0.5 °C). More significantly, strain QL of 40% inoculation volume was able to completely degrade PCB209 in 140 h (initial concentration of PCB209 was 100-500 µg L(-1) at 10 ± 0.5 °C and pH 7-8). The degradation process proceeded with zero-order reaction kinetics. Moreover, both laboratory simulation and real-world field experiments demonstrated that strain QL was effective in practical applications of PCB209 biodegradation in contaminated soil.

A three-dimensional finite element steel bridge and its deck pavement were established by ANSYS software to simulate the influence of different model and bonding failure between adjacent layers on stress values of asphalt concrete deck pavement. The stress values of asphalt concrete deck pavement were calculated and analyzed with consideration of the characteristic of asphalt concrete and interlayer bonding condition. The influence of the disengaging area between the upper layer and lower layer of asphalt concrete on the stress values of asphalt concrete deck pavement was computed and analyzed. At the same time, the influence of the disengaging area between the lower layer of asphalt concrete and the waterproof layer on the stress values of asphalt concrete deck pavement was calculated and analyzed.