To harmonize the conflict between the durability and drainability of porous asphalt mixtures, the coarse aggregate void filling (CAVF) method is introduced to the design of a porous asphalt mixture. Bulk volume relative density is used as a measure to evaluate the compaction effect, and the temperature at which the compacting specimen reaches the maximum bulk volume relative density is selected as the optimum compacting temperature. At this temperature, a porous asphalt mixture specimen is modeled, and its properties, such as water stability, high-temperature stability, permeability, and skid resistance, are tested. Test results show that adopting the temperature at which the compacting specimen reaches the maximum bulk volume relative density as the optimum compacting temperature is reasonable. Moreover, the water stability, high-temperature stability, permeability, and skid resistance of the designed porous asphalt mixture exceed the specification requirements. The designed mixture shows good stability even at a high temperature of 70℃. This finding proves that the CAVF method presents advantages when used to design asphalt mixtures with a skeleton interdocking structure.

The principle of fracture energy was put forward to evaluate the anti-cracking performance of high viscoelastic tar sands. To effectively reconstruct the anti-cracking performance of high viscoelastic tar sands, a semi-circular bending test was performed to measure the maximum load and fracture energy. The test results show that when the test temperature remains constant, the maximum failure load of the specimen increases along with loading rate, while the fracture energy of the specimen decreases along with increasing loading rate. Meanwhile, when the loading rate remains constant, the maximum failure load of the specimen decreases along with increasing temperature, while the fracture energy increases along with temperature. The test device is simple and cheap, while the test specimen is easy to manufacture. Therefore, the semi-circular bending test can be used as a standard method for testing the crack resistance design of asphalt mixture. A parameter sensitivity analysis is also conducted by using the ABAQUS finite element numerical simulation method. The experiment and numerical simulation results are compared to verify whether fracture energy can be used to evaluate the anti-cracking performance of high viscoelastic tar sands.

To improve the performance of recycled low-density polyethylene (LDPE_R), this paper describes the polymer modification of bitumen with gamma-irradiated recycled low-density polyethylene (γ-LDPE_R). The effects of the γ-LDPE_R on bitumen were investigated by means of morphological and chemical analyses, including Fourier-transform infrared spectroscopy and multiple stress creep recovery (MSCR) test. The results showed that the surface of the LDPE_R treated by gamma beam irradiation led to the formation of free radicals and some functional groups that may contribute to the creation of strong chemical bonds between the polymer modifier and bitumen, thus improving the compatibility of the modified asphalt. With the increased use of γ-LDPE_R, the modified asphalt rutting resistance also increased. However, due to the high γ-LDPE_R content of the modified asphalt, undertaking the high-temperature performance evaluation of the applicability of MSCR deserves further study.

Joints are weak links in the structure of cement pavements, and heavy traffic sections must be set up to maintain the transmission capacity of the board and to ensure the long-term use of pavements. However, with the advancement of force transferring rod construction technology, concrete with ratio and construction control of the influence of the force transmission rod actual spatial location and design of the location will inevitably produce some deviations. Given that such deviation will rapidly reduce the transfer capability of the board, the deviation of the transmission rod must be controlled in the construction process. However, basic data on the transmission rod are lacking. To this end, this paper conducts an experiment in the Beihei Expressway in Heilongjiang Province using MITSCAN2, and the test results are compared with the actual test data of two highways in the US and Canada. Some technical measures for improving the deviation of the transmission rod in the construction process are then proposed based on the detection and analysis results.

The second and third types of boundary conditions were mixed to simulate the change rule for the subgrade temperature field under the actual climate condition in a seasonal frozen region. The temperature difference between sunny and shady slopes was also analyzed. The freezing and thawing coefficients were introduced to compute the subgrade deformation caused by temperature differences considering the location and shape of the freezing fringe. Then, the mechanism of subgrade deformation was discussed. Results show the following conditions. (1) When groundwater exists, an uneven horizontal deformation is strongly affected by the temperature difference caused by slopes. (2) The deformations of the shoulder and bottom of the northern slope are greater during the freezing process than during the thawing process, and maximum deformation occurs at the top of the northern slope during the thawing process. Meanwhile, tension damage is likely to appear on both sides of the slope and at the top of the subgrade near the northern slope. Thus, for subgrade design and maintenance in a seasonal frozen region, the northern slope and the shoulder near the northern slope can be treated separately. Different designs and maintenance procedures can be applied to decrease temperature difference.

The failure mechanisms of backfill with limited width that is subjected to a co-application of earthquake force and surcharge formed by single and double wedges, respectively, were introduced to address the active earth pressure acting on gravity walls. An analytic model that is applicable to general cases of tilt walls with frictional backs and inclined ground surfaces was established by incorporating the quasi-static Mononobe-Okabe method and upper bound limit analysis. The reasonability and effectiveness of this technique were verified and supported by a comparison with results from reported laboratory model tests. A sample case analysis revealed a nonlinear distribution of active earth pressure on a gravity wall with limited backfill width. Coulomb's solution and three other published methods tended to overestimate the earth pressure measured in the laboratory more significantly than the proposed method did when the width of the backfill was reduced to a critical threshold. The superiority of this suggested technique increased with the shrinkage of backfill width. Moreover, the ascending horizon seismic coefficient k and surcharge q mobilized an increasing active thrust on the wall while easing and enlarging the crack angle of the slip surface, respectively.

A new numerical calculation method for slope stability is proposed to analyze the effect of the seepage force of a coarse-grained soil embankment slope on the distribution of the plastic zone and the change in safety factor under rainfall condition. The framework of coarse-grained soil was analyzed, and the SEEP/W module of software Geo-studio was used to calculate the change in matrix suction, underground water table line, and seepage gradient. Then, the calculation result for seepage was imported into FLAC3D using FISH language, considering the change in underground water table line, matrix suction, and seepage force. The influence of seepage force on the stability of the slope was also analyzed. Results showed that rainfall affected the spatial distribution of the underground water table line, matrix suction, and seepage gradient. The underground water table line lifted gradually from the foot of the embankment slope and developed into a deep slope. After a rainfall, the underground water table line decreased rapidly and the height of the final line near the embankment center was higher than the initial state. The matrix suction dissipated gradually because of the change in the underground water table line but recovered slowly when the rainfall stopped. At the beginning of a rainfall, the positive values of X-direction seepage gradients turned to negative and the negative areas expanded gradually. The plastic zone of the slope extended gradually from the foot to the inside of the slope as the rainfall continued. After the rainfall, the plastic zone mainly occurred at the foot of the slope. The slope safety factor increased gradually at the beginning of the 24 h period. The safety factor decreased rapidly and reached the minimum after 72 h. Then, the rainfall safety factor was gradually restored, but the recovery of the safety factor was delayed and smaller than during the initial state.

The Zhijiang River Bridge was used as a test model to study the mechanical behavior of long-span arch-shaped steel tower cable-stayed bridge. The test model was designed and simulated with a finite element method,which was confirmed to reflect the actual behavior of a structure. An experimental model was assembled, and a load test was performed under four conditions. The test results of the stress of the main tower and the deformation of the main beam were analyzed, and the working condition of the maximum bending moment in the middle span was used as an example. Results showed that the measured data and the converted value of the actual results of bridge calculation were relatively close. The actual structure had high safety reserves. Our research provided a reference for similar bridge and test model designs.

This work revealed the flood damage rule of road-bridge binding sites in highway bridge engineering according to the F_r similarity criterion by adopting the orthogonal test design method and emphasizing, exploring, and analyzing the influence degree of flood damage on the model while considering the length into fluid of the model, the included angle between the model and the fluid direction, the slope ratio of the model, and the existence of protective measures for the model. According to a comparison and an analysis, ADINA finite element numerical calculation and model test results coincided perfectly. Findings suggested that when the length of the fluid into the model is long, the extent of the damage of the model structure body is serious. After water scouring the model, and when the included angle between the model and the fluid direction was set at 135 degrees, the deposits was enlarged and dispersed, the scouring depth was significant, and the model was nearly completely destroyed. The slope surface could effectively decompose the fluid velocity with its strong anti-scouring capability given a certain slope ratio of the model. The protective measures of grouting layers or cofferdams could fully protect the model structure body. These results provide important references for enriching the flood damage mechanism of road-bridge binding sites and the safety operation of related highway bridge engineering.

The design of a gradient structural concrete component was investigated to improve the durability of concrete structures under harsh environments. On the basis of the theory of functionally graded materials with high crack resistance, low transmission, and good self-repairing capability of the cement-based material without a mesoscopic interface transition zone, the reinforcement on performance of protective layer could be achieved. Given the differences in construction situation, structural shape, inner, and outer layer among materials, the gradient structural concrete member (GSCM) and general single-layer concrete member would be prepared. The Deformation coordination capacity, chloride transport properties, and preparation method were investigated, through simulation of stress and deformation, interface bond strength test, and accelerated corrosion test. Results showed that the consistent volume deformation of GSCM did not cause failure, and the surface layer strength of GSCM improved by up to 30%. Only 0.02-0.05 mm cracks were observed without the aid of instruments, and 0.2-0.5 mm cracks were observed in general single-layer members. Moreover, the GSCM had a depth of penetration and chloride diffusion coefficient of 0mm and 6.3×10^-13m²/s, respectively. These values indicated that the GSCM exhibited good tricyclic assemble performance and satisfied the construction requirement. Meanwhile, the values obtained for the general single components were 15mm and 12.8×10^-13 m²/s.

The cellular automaton model is an effective tool for studying the dynamic characteristics of urban road traffic flow. To improve the lane changing behavior of vehicles in a microscopic traffic simulation by using the cellular automaton model, the interaction between the following and the lane changing vehicles was analyzed. The following vehicle on the target lane was taken as the research object during the lane changing process, and the lane changing rules of three lane changing models, namely, the free, forced, and cooperative lane changing models, were adopted. These three types of models were simulated and compared by changing the traffic flow density. The average velocity of the cooperative lane changing model was higher than that of the other models. The information exchange between the vehicles improves the lane change success rate and ensures that the road resources are fully utilized. The cooperative lane changing model is better than the original STCA model in improving traffic flow and reducing traffic jams.

This study mainly discusses the construction of the driving cycle within passenger cars in representative districts in Harbin, China. It conducts a comparative analysis of the New European Driving Cycle (NEDC) and Japan 10-15. This study selects passenger cars in Harbin as study objects and uses GPS to analyze the data of their driving cycle and divide the collected data curves into several short segments. Then, 11 of the most representative parameters are identified to reduce and classify data by conducting principal component analysis and cluster analysis. The relative coefficient is used to extract representative driving segments. The analysis shows that the average speed of passenger cars in Harbin is approximately 15 km/h, which is lower than the conditions set in NEDC and Japan 10-15, with acceleration and deceleration speed parameters at 33.57% and 29.70%, respectively, but higher than the relative parameters in NEDC and Japan 10-15. Comparative results of characteristic parameters show that existing road parameter conditions in Europe and Japan evidently differ from those in Harbin. Driving conditions based on running data can accurately reflect local operating characteristics. This study can serve as an important reference for the design optimization, matching calculation, and control strategy optimization of new energy automobile power systems.

To improve the forecasting accuracy of short-term traffic flow and provide precise and reliable traffic information for traffic management units and travelers, this study proposes a hybrid prediction model that is based on the characteristics of K-nearest neighbor (KNN) method and support vector regression (SVR). The proposed hybrid model, i.e. KNN-SVR, mimics the search mechanism of the KNN method to reconstruct a time series of historical traffic flow that is similar to the current traffic flow. Then, the SVR is used for short-term traffic flow forecasting. Using actual traffic flow data, we study the effect of the traffic flows on target and adjacent section roads and analyze the forecasting accuracy of the proposed model. Results show that the KNN-SVR model that considers the target and adjacent section roads has the best performance, having a mean absolute percentage error (MAPE) of 8.29%. The forecasting error of the KNN-SVR model that considers only the target section road is slightly large, having an average MAPE of 9.16%. Furthermore, the forecasting accuracy of the KNN-SVR model is better than that of traditional prediction models, such as the KNN method, SVR, and neural networks.

Carbon trading policy, as an important¹ approach to energy conservation and emission reduction, is being applied by an increasing number of cities at home and abroad with a certain effect. Meanwhile, traffic is a major source of energy consumption and carbon emission in cities and thus a main field of energy conservation and carbon emission and a carbon emission trading object in cities. Globally, the carbon trading policy is rarely adopted in the traffic sector. Emission monitoring and quota allocation are challenging tasks due to several characteristics, such as the mobility and dispersibility of vehicles and non-profitability of certain sectors. Therefore, the inclusion of the transportation sector in the carbon emission trading policy framework remains an issue. On the basis of the definition of the carbon emission trading policy framework, this study draws certain elements of applicability of carbon emission trading policy and conducts an empirical analysis of the applicability of the participation of the transportation sector in carbon emission trading.

Under the operation service problem of public transit in China, this work studied the impacts of the operating efficiency and service effectiveness of public transit based on stochastic frontier analysis (SFA) and the trans-log function with the annual data from 2010 to 2013 of 36 cities in China. Results indicated that the operating efficiency of public transit exhibited a downward trend, i.e., from 0.854 to 0.847. Meanwhile, service effectiveness demonstrated an improvement from 0.615 in 2010 to 0.625 in 2013. The level of urbanization had a positive effect on improving the operating efficiency of public transit, whereas the rail passenger share rate had a negative impact on service effectiveness. Cities with a population of 10 million exhibited high operating efficiency. The operating efficiency of the central region was higher than those of the western and eastern regions.