In order to study the strength forming mechanism and influencing factors of half-warm mix asphalt (HWMA), the stability of Marshall samples is tested under different test conditions such as gradations, asphalt quantities, forming methods, number of compaction passes, maintenance period, and forms of maintenance. The results show that (1) the suspension dense gradation is satisfactory for early strength of HWMA, and its strength varies with asphalt quantity; (2) the number of compaction passes and maintenance period are two major external factors influencing strength forming, and the increase in strength reduces significantly when the number of compaction passes on both sides increases above 130. (The Marshall samples acquire final strength in 49 days of maintenance.); and (3) both loading and maintenance time significantly affect the strength forming process. Moreover, the cohesion of the material and internal friction increase, and the Marshall samples gain strength more rapidly with both the factors. Loading and maintenance time affect the internal friction and cohesion of the material, respectively. The results of this study provide guidance for design and construction of HWMA.

Compared with flat slope sections of asphalt pavement, the loading time of low-speed vehicle load to uphill sections with long and large longitudinal slope is much longer, under the comprehensive combination of heavy load and high temperature. Developing and forming speed of rutting on uphill sections with long and large longitudinal slope is faster. Rutting factor and dynamic modulus of asphalt and asphalt mixture under different loading time will be calculated and analyzed in this paper. The results show that rutting factor and dynamic modulus were substantially reduced. Using the new rutting test equipments with the changing wheel speed and load to simulate the influences of overload and temperature (loading time) on asphalt mixture, the results show that dynamic stability is rapidly declined with the decrease of wheel speed. The loading time has vital influence on the high temperature stability of asphalt mixture. Increasing load time is equivalent to raising the experimental temperature, and using the temperature conditions in specification to verify the high temperature stability of asphalt mixture for uphill sections with long and large longitudinal slope is unreasonable.

To investigate the moisture equilibrium of expansive soil embankments, a series of stress-dependent soil-water characteristic curve (SWCC) tests, one-year field monitoring on a trial covered expansive soil embankment, and numerical simulations of the process of moisture equilibrium of a covered expansive soil embankment under atmospheric effects over a period of ten years are conducted. The results show that (1)The effect of the stress state on the equilibrium moisture of expansive soil is clearly in the suction range of 0-3 MPa;(2)In the first year of service, the moisture content of the core of an expansive soil embankment increases gradually, the extent of moisture content fluctuation increases with increasing proximity to the slope side, and the differential settlement of the embankment is observed; (3)The moisture content of the core reaches a steady state, i.e., the moisture equilibrium state, on the sixth year of service; (4)The optimum moisture content of an expansive soil compacted in accordance with wet heavy compaction standard is close to the equilibrium moisture content, and it is better to use this standard to control field compaction of an expansive soil embankment in moist and hot areas in southern China.

This study presents a test method to evaluate the durability of the anti-skid performance of asphalt concrete. In this work, the influence of mixture gradation, asphalt-aggregate ratio, and temperature on the texture depth is discussed for the asphalt mixture that is commonly used forth in overlays. This mixture has a nominal maximum particle size of 9.5 mm. The durability test method is used to realize the deterioration of texture depth at different wheel load times, light intensities, and water-aging damages. Experimental results show that the test method can effectively evaluate the difference in texture depths between different gradations. Texture depth is found to increase with increasing coarse aggregate content but decrease with increasing asphalt-aggregate ratio and testing temperature. Meanwhile, the residual ratio of texture depth varies with changing laws and under different aging conditions and wheel load times.

Taking Edong Yangtze River Bridge as the research subject, the influence of error of unstressed cable length on the geometric shape and internal force of super-span hybrid girder cable-stayed bridge during completion is studied on the basis of the geometry control method with full consideration of the structural nonlinear geometrical effect. Moreover, the mechanical behaviors of the center and side spans of the bridge and their control strategies are discussed. The analysis shows that structural differences between the center and side spans exerted an influence on the geometric shape and internal force. The influence of unstressed cable length error on the geometric shape in the center span of the completed bridge is greater than that of the side span, whereas the impact on internal force in the side span is greater than that in the center span. The mechanical behavior is relatively independent between span types. In addition, the percentage change of the girder stress reaches the maximum level in the steel/concrete composite segment, in which the mechanical behavior is highly complicated. Therefore, its design and construction require close attention. Moreover, the difference in stiffness between the center and side spans has a remarkable impact on cable force redistribution in the completion stage, and the changes in cable force differ between the span types.

Application of nonlinear behavior laws is relatively complicated and difficult to master because of the unique configurations of special-shaped arch bridges. In this study, a self-compiled program is used to analyze the nonlinear behavior laws of five special-shaped arch bridges with distinct characteristics. Essentially, the beam-column effect is determined to be the most influential factor for arch-beam composite butterfly-shaped arch bridges, the large displacement effect has the greatest influence for flying swallow-type tied arch bridges, and the cable sag effect is the main factor for arch-tower cable-stayed bridges. For thrust crescent-shaped arch bridges, however, the influence of all nonlinear factors is rather little and can be neglected. In addition, the cable sag effect of inclined cables is more noticeable than that of vertical cables, and all nonlinear factors significantly influence the cable forces. Therefore, the cable sag effect should be considered, and the tension of inclined cables must be calculated by nonlinear methods. Moreover, because the deck slabs and crossbeams only carry load sand are not subject to force as a part of the entire structure, the nonlinear influence on their inner forces is negligible.Therefore, linear methods are appropriate; however, the large displacement effect should be considered when the displacement is calculated.

Equi-amplitude fatigue loading experiments on five reinforced concrete T-beams were conducted to observe the fatigue damage development. Three stages of fatigue damage were seen in the experiments. The damage rapidly developed early and late periods of the experiment but was relatively stable in between. The beam failed because of the brittle failure of the steel bars. The number of cracks, and the width and height also follow three stages: rapid development, stable development, and failure. The growth of almost all of the cracks stopped at the time of beam failure, except one or two main cracks that continued to grow. The deflection of the test beam and strain of the steel bars and concrete increased rapidly early in the fatigue cycles, with increasing fatigue cycles, whereas they were relatively stable in the middle stage but increased rapidly near the failure point. Finally, the S-N curve of the reinforced concrete T-beam was obtained.

By establishing a finite element (FE) model of reinforced concrete (RC) columns strengthened with steel wire mesh, the mechanical properties under low-cyclic loading are analyzed, and the correctness of the FE model is verified. Hysteretic curves, skeleton curves, strain curves, and changes in stiffness and ductility of the strengthened RC columns under various strengthening conditions are calculated in this study by using the FE model to examine the effects of axial compression ratio, longitudinal reinforcement ratio, concrete strength, steel wire quantity, and eccentric compression on the seismic behavior of the strengthened columns. The results show that an increase in axial compression ratio results in an improvement in the ultimate bearing capacity of the strengthened columns by 9%-17% and a reduction in ductility by 9%-15%. In addition, increases in the stirrup ratio, longitudinal reinforcement ratio, concrete strength, and steel wire quantity result in improvement in ultimate bearing capacity, and ductility of the strengthened columns can be improved by 2%-28%. Moreover, an increase in vertical pressure results in rapid development of eccentric, stirrup, and steel wire strains in the strengthened columns, which causes reductions in ultimate bearing capacity in the columns by 2%-13%, energy consumption by 35%, and additional reductions in stiffness and ductility.

A numerical method is proposed to study load and the environment couple effect during the service of a concrete bridge. By studying the corrosion process of reinforcement bars, the strain of the bars is decomposed into two parts, elastic strain and corrosion strain, and their ratio is defined as the corrosion factor. The time-dependent constitution of corrosion of the steel bar is obtained by introducing a nominal elastic module. According to the virtual work principle, the finite element formulation of the reinforcement concrete element is derived, and the computation sequence determined using the time history method is illustrated. The nonlinear finite element program is realized by the Fortran program to numerically solve the problem, which is verified by testing a model of three reinforced concrete beams. The results show that both stiffness matrix and the additional nodal load of the reinforcement concrete element should be considered in the couple effect analysis. The proposed method can be used to predict long-term mechanical properties of concrete bridges.

To study the effect of shear lag on a composite girder with steel truss webs, a three-dimensional finite element (FE) model, using the ANSYS FE software, and a corresponding FE model of composite girder with corrugated steel webs is established to perform a comparative analysis. The shear lag effect and distribution of shear lag coefficients along the cross section of the composite girder with steel truss webs are investigated under concentrated and uniform loads. The results show that (1) under concentrated and uniform loads, the shear lag effect is evident on the top and bottom plates of the composite girder with steel truss webs; (2) for the composite girder with steel truss webs, the shear lag effect is more pronounced under concentrated loads than under uniform loads; (3) under the same load, the normal stresses of the top and bottom plates of the composite girder with steel truss webs are less than those of composite girder with corrugated steel webs; and (4) the shear lag coefficient distributions of the top and bottom plates along the cross section are almost similar for the two types of composite girders.

Based on the LS-DYNA program, a vehicle's wheel is simulated by linear elastic material rubber and steel, and internal pressure in all tires is defined. Rotation of vehicle wheel 3D models is simulated through appropriate rotation and cylinder-shape constraints. The dynamic characteristics of the vehicle suspension system are simulated by using spring damper elements combined with dynamic characteristics of the vehicle suspension system. The theoretical quality distribution is well matched with practical systems by adjusting unit size and distribution. A fine finite vehicle element model is established to research the vibration response of vehicle-bridge coupling dynamic response based on a 3-axle heavy vehicle. Comparison of simulated and measured values of vehicle axle load applying natural frequency FEM is performed to verify the validity of the model. Taking a simply supported beam bridge as an example, LS-DYNA finite element software and MATLAB are used to simulate and analyze the mass-spring-damping vibration system, and the bridge vibration response subjected to vehicle load at constant speed is researched comparatively. The results show the feasibility of using a LS-DYNA fine model to analyze vehicle-bridge coupling vibration, but the computational workload is very high for this model.

For scientific and reasonable decision making regarding the through scheme of arterial highways in city areas, the grey correlation is commonly used to measure the closeness between an alternative scheme and an ideal scheme. In this paper, a grey lattice order decision-making method is proposed, and using the proposed method, the through schemes of arterial highway G204 in Yancheng City are compared. The analysis indicates that from the aspects of economic and environmental impacts, the through model that bypasses the city is the best through scheme despite an increase in detour distance of the vehicles using the route. The application results show that the grey lattice order method combines the advantages of the grey correlation and lattice order methods to better reflect the relative relationships of the pros and cons between alternatives.

The typical U.S. Bureau of Public Roads (BPR) volume-delay function is modified to construct the more suitable model to China's road traffic situation. Factors influencing road traffic impedance, such as the number of lanes,speed limit, intersection density, bus stop density, saturation and congestion are considered. On the basis of actual data collected from different main roads in Dalian city, traffic impedance functions for different road types (expressway, trunk road, secondary trunk road and slip road) are calculated using SPSS software. The results analysis of the traditional and improved BPR volume-delay functions is compared to certify the useful improved BPR volume-delay function.To apply road traffic impedance to the traditional four-step model,we calculate the daily conversion coefficients. These reflect the relationship between hourly traffic impedance and daily impedance function and suggest the suitable usage of daily conversion coefficients in further research.

To cope with the capacity limitations of enterprise's own transport fleet for container transport and the increasing competitive pressure, considering the operating costs and the demand uncertainty, an outsourcing decision-making problem for truck fleet with quantity discounts for continuous working shifts is presented. From the perspective of competition and social-effects analysis, we suggest an extended vehicle routing problem with time windows (VRPTW) vehicle scheduling model. The model minimizes costs and provides an evaluation system with minimal mileage and carbon emissions. By adjusting quantity-discount rules and task time windows, our model can be used to provide outsourcing solutions for different combinations of continuous working shifts. We also discuss the influence of other parameter settings on the decision schemes. Finally, we verify both the model and the algorithm using a simulation experiment. The experimental results show that using quantity discounts for fleet outsourcing decisions for different combinations of continuous working shifts improves both vehicle utilization and social benefits. We also highlight new research opportunities based on these results.

This study aims to satisfy the energy management contract (EMC) work schedule of the Ministry of Transport (MOT). The paper first defines EMC together with its connotations to clarify its specific demands for the market environment, economic policy, law, and technology policy. Using New Structural Economics theory, this study investigates specific actions that would enable the MOT to popularize EMCs. EMC development goes hand in hand with the development of a market-oriented economy; therefore, proposing commercial behavior in the transport market becomes a priority. Industry management should therefore guide private enterprises' EMC development in the light of its general trends. In terms of advancing the legal environment, we suggest implementation of a policy of "not-banned that in" and a diversified interest settlement mechanism to resolve interest disputes. In technical policy, we suggest drawing up "energy-saving projects verification and test guide for the transportation industry" and "energy-saving effects: Guidance for the transportation industry" to establish technological standards.