Applied Mechanics and Materials Vols. 97-98

Abstract: This paper demonstrates a type of SBS modified asphalt which added 8% TPS as the mixture for bridge pavement. Four types of asphalt mixtures were designed for composing four types of material forms. The fatigue characteristics of different types of combination of materials are studied by three-point fatigue tests of small beams. Equations of fatigue characteristics are obtained based on the experimental studies. Results show that antifatigue characteristics of SMA13+AC16 are better than others, while the sensitive degrees of fatigue life of four composite structures are generally the same to stress level.

Abstract: It is difficult to evaluate soft foundation treatment technology using the traditional mathematical approaches, because there are not only quantitative factors but also qualitative factors which affecting the evaluation result. To analyze the non-quantitative problems and make the complicated technology assessment simple, multi-level synthetic fuzzy evaluation is utilized and numerical examples of national defense highway construction show the model is appropriate.

Abstract: It is important to reduce asphalt mixture strong absorption characteristics to improve anti-rutting ability and reduce the urban heat island effect. This paper firstly studies the suction and exothermic regular pattern of existing three types, five kinds of asphalt pavement structure. It turns out that there are differences in suction and exothermic characteristics of different types of pavement structure. Suspension close-grained type structure has higher adiabatic heating; gap-type skeleton has faster speed of suction and exothermic; and dense skeleton has more total quantity of heat storage. Accordingly, test and analysis of cooling effect of Gap-type skeleton asphalt pavement has conducted by adopting smear reflective materials to reduce reflectance and surface adding insulation materials, The results show that reducing reflectivity is the best way which can reduce by 5 centigrade around. In addition , improving effectiveness has also been studied by adding light-colored stone partly replacing mineral aggregate, and substituting busing mullite for aggregate below2.36 mm is the best cooling way ,which can reduce by 3.3 centigrade.

Abstract: Filter layer is directly related to underground trench drainage, and the current design criterion for filter layer is relatively coarse, the classification of soil is not considered, filter layer thickness and the uniformity of filter material are not required, and so the current design criterion can not meet the needs of underground trench design of loess donga. Aimed at underground trench characteristic of loess donga, based on subgrade functional mode, this paper puts forward equivalent aggregate size , evenness control standards, the number of filter layers and thickness determination principle.

Abstract: Based on the fiber Bragg grating sensing technology, a FBG sensor is designed to monitor the dynamic response of asphalt concrete; the sensitivity coefficient of FBG sensor is 1.28pm/με. Through the static load test, the correlation between strain and wavelength variation is 0.1797µε/pm, after second packaged and embedded in SMA-13 asphalt concrete. The instantaneous impact on the road of high-speed vehicles is simulated by using drop hammer. The results are shown that the Sensor can satisfy the requirements of practical applications and succeed in monitoring the dynamic response of asphalt concrete. The monitored signal can reflect the viscoelastic-plastic deformation law of asphalt concrete. The sensor can be used to monitor the dynamic response of asphalt concrete.

Abstract: The dynamic response of saturated asphalt pavement subjected to moving vehicle load is studied. Based on the porous media theory, a three-dimensional finite element model is developed and the temporal and spatial distribution of three directional stresses and strains are calculated in saturated pavement and compared with those in dry condition. The results show obvious difference between saturated and dry asphalt pavement, especially in asphalt layer.

Abstract: The most important step of building a new airport is site selection. Before selecting the new airport site, Airport planners should study many factors and rank the various sites. In fact, airport site selection is a complex multi-objective optimization problem, which involves a variety of factors. Taking “the civil airport construction and management requirements” as a foundation, the paper has screened and expanded the influence factors of selecting the civil airport site and constructed site appraisal system, and put forward the DAGF model，which constructed Evaluation System by improved Delphi method, obtained weighted matrix by AHP, analyzed experts score by gray correlation and got evaluation findings by Fuzzy evaluating. Meanwhile the paper has compiled the procedure of the computation process with MATLAB. Finally the research results has been applied to the selecting site of the second Capital airport in practice and obtained the satisfactory result. Therefore the paper constructed the comprehensive evaluation model, which provides the effective method for selecting the civil airport site, and makes the site selection more scientific, more reasonable and simpler. It has the extremely important reference significance and the instructional function to select the optimal airport site.

Abstract: ABAQUS software is adopted. And the three-dimensional finite element models, respectively oblique and vertical reinforcements, are used for the calculation of the prestressed concrete pavement structure. The prestress is imposed on pavement by changing the temperature of reinforcements. Then through the analysis of mechanical behavior of the two kinds of prestressed reinforcement concrete pavements under the standard load. The results show that the oblique reinforcement pavement is flatter and the range of influnence is smaller. These data of the two kinds of pavements are provided for engineering design and construction.

Abstract: Based on the feasibility analysis of the chloride’s released capability, a certain proportion of the chloride was added into the ordinary asphalt mixture to form a new chloride-stored asphalt mixture. The mixing proportion was determined and its pavement and anti-icing performance were analyzed. The research indicates that: the stored chloride has good releasability. The new asphalt mixture not only has better high temperature stability and low temperature anti-bending capability than the ordinary one, but could also remove the road ice effectively.

Abstract: From the traveler’s view, this paper uses random utility theory of the disaggregate model to construct travelers transportation choice model, employ software STATA to calibrate parameter for getting utility function for prediction, and then employ the critical condition which make rail transit and regular transit coordinated to calculate reasonable rail transit station spacing. Finally, example is given, the results show that rail transit station spacing based on passenger travel choice, make rail transit and regular transit to achieve harmonization and complementarities, and improve overall operating efficiency of urban transit system.