To evaluate the anti-fatigue performance of asphalt pavement affected by temperature and solve the problem of an inaccurate estimation of fatigue damage by adopting a single fixed temperature, the impact of different surface temperatures and their combinations on the fatigue damage to asphalt pavement is analyzed based on Miner law of accumulative fatigue damage, taking the temperature field prediction model for asphalt pavement developed by Dresden University of Technology in Germany for example. According to a considerable amount of measured surface temperature data, different surface temperature combinations and representative values in temperature intervals are determined and the change regularity of fatigue damage in asphalt pavement is studied. The analysis result shows that (1) the fatigue damage estimated by adopting surface temperature combinations is more accurate than that estimated by adopting a single fixed temperature; (2) when the number of temperature intervals forming a temperature combination is considerably large, the estimated fatigue damage in asphalt pavement is more accurate, whereas when the number of temperature intervals is considerably less, the fatigue damage caused by the representative values of the temperature intervals varies; and (3) the fatigue damage caused by a high temperature (or upper limit) for the representative value of the temperature intervals is larger than that caused by a low temperature (lower limit).

The mix of warm and hot recycled asphalt mixtures were determined after reclaimed asphalt mixture (RAP) analysis and mix design. With similar aggregate gradation, the RAP content in warm recycled asphalt mixture increased to 45%, guaranteeing good performance of the warm recycled mixture. Thus, the 30% RAP restriction in asphalt mixture was surpassed. The fatigue performance of the warm recycled asphalt mixture, its hot counterpart, and hot mix asphalt (HMA) was tested using the four-point bending test. The testing result indicates that, although the fatigue performance of warm recycled asphalt mixture is not as good as that of HMA, it is superior to that of the hot recycled asphalt mixture, especially at high strain levels. The fatigue life of warm recycled asphalt mixture is 1.5 times that of the hot recycled asphalt mixture.

A cement mortar mixer that can test torque is designed to realize online observation of working performance of the cement mortar and to predict cement mortar slump. The influence of different rotating speeds and mixing timeson cement mortar quality is analyzed using factors of slump and torque. The best stirring speed is determined to be 180 r/min and the best mixing time 60-180 s. The relation between cement mortar slump and torque at different shear rates is studied, and different power functionsfor different shear rates are found. At a given shear rate, i.e., a rotation speed of 180 r/min, the relation between slump and torque is set up, which could provide a test method and theoretical basis for cement mortar online quality control and slump forecast.

In order to analyze the stress varieties in cement pavement slabs caused by load with the existence of base cracks, the influences of moduli, crack locations and quantities of semi-rigid base and lean concrete base, thickness of cement concrete slab and size of load and other factors on the load stress of cement concrete pavement slab were analyzed through experimental simulation methods. The analysis result indicates that:(1) The road surface deflection increases with the number of base cracks increasing; (2) The tensile stress at the bottom of concrete slab decreases with the increase of base modulus and slab thickness, the increase in slab thickness more substantially minimizes stress than does the increase in base modulus; (3) The stress of concrete slab increases sharply with the presence of base cracks, and the slab bottom tensile stress increases with the number of base cracks increasing; (4) The load increase is an important factor causing load stress increase; so overload must be strictly controlled.

Current theories on the thawing compression of frozen soil exhibit a number of inadequacies because of the failure to consider the effect of moisture. Considering the effect of temperature coupled with moisture and stress and introducing a field variable of void ratio e, the model of thaw compression deformation of ice-rich frozen soil was established. By comparing its simulated results with the experimental results, it can be seen that theoretical model accurately reflects the deformation process of ice-rich frozen soil. The test and the calculation results both indicate that the thawing compression deformation of ice-rich frozen soil results from the combined action of several factors such as temperature, moisture, and stress. The deformation of ice-rich frozen soil is mainly attributed to the thawing-compression-drainage (TCD) process, in which the deformation process is basically completed. The deformation in the TCD process accounts for most of the total deformation of frozen soil. Moreover, the deformation tends toward stability in this process. The thawing settlement property of frozen soil determines its deformation law, which is the mechanism of the thawing compression deformation of ice-rich frozen soil.

Wind is the main factor that affects soil erosion and the severity of wind-sand disasters. Therefore, it is of critical importance to analyze the influence of remodeling topography units on the near-surface wind conditions when studying wind erosion in the road domain and its control methods. The impact of different remodeling topography units on the near-surface wind conditions during road construction is studied by field observations of the railway from Jining to Erenhot. Results indicate that, even after affected by the different terrain units, the near-surface wind profiles are still in accordance with logarithm law or piecewise logarithm law. However, the effective elevation in the logarithm formula is no longer the surface absolute elevation. In addition, the horizontal wind velocity field changes as the terrain changes. In case of windward slope, the wind velocity increases gradually from the bottom to the top, and the increment rate has a linear relationship with the length of the slope. On the other hand, to leeward slope, the wind velocity decreases dramatically just below the top of the slope at first, and then reduces slowly till the bottom.

To evaluate the influence of concrete creep effect on spatial stress in concrete, the formulas for recursive calculation of equivalent nodal loads of concrete creep of PC composite unit under multi-axial stress was considered. The formulas are extended to general cases, and then an FEM program for calculating concrete creep is developed. A typical continuous PC bridge is illustrated to analyze the regular pattern of structural creep behavior. The differences in creep calculation modes using different codes and variation characteristic of main girder deflection are found. The service stage characteristics of a PC box girder are evaluated to determine the redistribution of longitudinal normal stress at the top, bottom, and principal stress at the web. Finally, recommendations for the reasonable arrangement of prestressed tendons are provided.

For the compression-shear failure of a reinforced concrete bridge beam with diagonal reinforcement, the calculation of ultimate shear capacity is proposed based on the modified compression field theory (MCFT). Shear force is shared by the shear compression zone of concrete, stirrups, and diagonal reinforcements intersecting with diagonal cracks. The shear capacities of concrete in the tensile and compression areas are calculated. The new balance equation between the average stress and the internal force of cracked concrete is established, and the effects of diagonal reinforcement on the stress of diagonal cracks are considered. This procedure considers the constitutive relation conditions of materials and the deformation compatibility of concrete. The theoretical shear capacity predicted by MCFT is validated by the test results of two reinforced concrete beams, providing a reference for calculating the capacity of reinforced concrete beam.

In order to study the aerodynamic interference effects of single and multiple blunt bodies on the rectangular, reverse right angle, reverse inner convex arc, and reverse outer convex arc sections of serial bluff bodies, the finite volume method and the SIMPIE algorithm, the uniform viscous incompressible flow around blunt bodies at a subcritical Reynolds number was simulated by computational fluid dynamics (CFD) technology. The aerodynamic coefficient was analyzed, and the aerodynamic coefficients under various conditions (e.g. different wind angles of attack, chamfer dimensions, and cylinder spacing) were calculated. Results show that the drag and lift, as well as the torque coefficients, of each section of a single blunt decrease in accordance with the sequence of wind flow around the rectangular, reverse right angle, reverse inner convex arc, and reverse outer convex arc sections at different wind angles of attack. The drag and lift, as well as the torque coefficient, of the reverse right angle, reverse inter convex arc, and reverse outer convex arc sections successively decrease with increasing chamfer dimensions. The downstream blunt body produces more significant changes than does the upstream blunt body in terms of variation trend and value because of the aerodynamic interference effect.

On the basis of a non-associated flow rule and the upper bound theorem for limit analysis, the expression of surrounding rock pressure on shallow tunnels was derived by constructing a simple failure pattern. Strength reduction technique was applied to study the stability of shallow tunnels under certain levels of surrounding rock pressure; this analysis was based on the internal consumption and external energy conservation principle. The optimized upper bound solutions of surrounding rock pressure and the safety factor for shallow tunnels were obtained by nonlinear optimization methods. Results show that the dilatancy of geomaterials and the lateral pressure coefficient of surrounding rock significantly affect the surrounding rock pressure and stability of shallow tunnels. Furthermore, the lateral pressure coefficient is an important factor in relation to the stability of such tunnels.

This study used FLAC to simulate the excavation of unsymmetrical loaded tunnels with various transversal gradients, surrounding rock grades, and thicknesses of side covering soil by considering all factors that affect these unsymmetrical loaded tunnels. The deformation behavior and displacements of key points were analyzed. The effects of unsymmetrical loading are negligible when the thickness of the side covering soil exceeds 21 m, and pre-reinforcement is needed prior to excavation when the thickness of the side covering soil is less than 15 m. These data were used in simulating tunnel pre-reinforcement in different conditions. Results indicate that in the condition of surrounding rocks V, a main problem is insufficient counter pressure in the shallow buried side when the thickness of the side covering soil is less than 7 m. By contrast, overpressure in the deep buried side needs to be addressed when the thickness of the side covering soil is more than 7 m. These findings were verified in actual practice. The conclusions of this study can be used as references to design and construct similar engineering projects.

Studies on active transit signal priority (active TSP) focus primarily on the advantages and parameters of priority strategies within a given cycle time, which is not necessarily the optimal cycle. With consideration for the restrictions resulting from arterial coordination, the effect of three active TSP strategies on vehicle delays at a key intersection on an arterial road was discussed. Using an actual case, the effect of possible real volume variations on optimal cycles under active TSP strategies was analyzed. Results show that under special flow conditions, additional benefits exist when the cycle time is increased from the value generated by the TRRL approach. The extent of increase can rise with the ratio of priority phase flow to nonpriority phase flow. Cycle time can be dynamically established in accordance with the flow conditions in actual operations. The findings also show that the efficacy of red truncation is better than that of green extension.

There are many 0 km/h speed stop point records in the floating car data (FCD), which has some spatial relations with the vehicle queue length in front of intersection. A new method for computing vehicle queue length in front of intersection based on FCD of stop points was described. First, the data on normal queue points are calculated from stops by map matching based on the geographic location of the stops, the continuous relationship between the queue points and movement points and the relative location to the intersections on a road link. Second, the relative positional relationship of FCD at intersections is calculated on the basis of the data on normal stops and by two-step statistics. Vehicle queue length at intersections is then calculated on the basis of the stopping distances of floating cars and the distribution density at intersections. An example is presented to demonstrate how the algorithm functions.

The chaos control of freeway mainline was studied by using variable speed limits and fuzzy-neural networks (FNNs) based on subtractive clustering. Based on the uncertainty and nonlinearity of a traffic system, the establishment of a knowledge base of a mainline chaos controller for freeway was proposed by using data mining technology. The chaos control principle of mainline variable speed limits in freeway was briefly introduced. The Takagi-Sugeno FNNs chaos controller was designed, where traffic density, upstream traffic volume, and maximal Lyapunov exponent were selected as the input variables, whereas mainline speed upper limit was selected as the output variable of the controller. Subtractive clustering was used to determine the controller structure, including the extraction of fuzzy rules and generation of initial parameters. The radius of the clustering centers was optimized using the genetic algorithm, and the parameters of the fuzzy controller were optimized using FNN. The simulation result indicated that order motion on freeway can be realized by using the mainline intelligent chaos controller designed based on the proposed method to suppress traffic jam and to enhance traffic volume.

In order to improve the fuel economy and reduce the emissions of hybrid vehicles, according to the power flow distribution and energy use in hybrid vehicles, the strategy of the minimization of instantaneous equivalent fuel consumption was put forward. Based on analyzing the relationship between power transmission and energy flow in a series hydraulic hybrid, and taking the virtual equivalent fuel consumption of an energy storage element accumulator as a criterion, the model of the minimization of transient equivalent fuel consumption in hydraulic hybrid vehicles was established. Energy management for such vehicles is also discussed. The parameters of a bus are taken as examples in simulating the fuel economy of hydraulic hybrid vehicles. In the simulation, the developed strategy is applied to the initial periods of the urban driving and highway driving cycles. Results show that (1) the proposed strategy achieves a 30% improvement rate for the fuel economy of hydraulic hybrid vehicles, and that (2) minimizing instantaneous equivalent fuel consumption presents remarkable advantages in improving energy conservation in vehicles.

To predict the performance of three-dimensional (3D) finite-length noise barriers, a simplified method is presented to calculate the acoustic pressure of noise barriers by a theoretical approach. Based on noise diffraction theory and acoustic calculations of two-dimensional barriers, the proposed method considers diffraction around 3D barriers. This method can calculate the acoustic pressure of a one-sided noise barrier and parallel noise barriers. Comparisons are made by the fast multipole boundary element method using Virtual. Lab software. The simulation results show that the acoustic pressure and curve tendency are in very good agreement in the frequency range from 20 to 2 000 Hz. When calculating the acoustic pressure of a one-sided barrier, the absolute error is 1.95 dB and the relative error is 2.98%. When calculating the acoustic pressure of parallel barriers, the absolute error is 2.43 dB and the relative error is 3.75 %. These results prove the accuracy of the simplified method. Compared with other complicated methods, the simplified method does not require integrals and is easier to perform and more useful. This method can be used to study and design 3D finite-length noise barriers.