Applied Mechanics and Materials Vols. 97-98

Abstract: This paper do the experiments of trabecular bending test and trabecular bending creep test on AC-16C asphalt mixture of adding two kinds of mineral fibers and non fiber within the temperature of 10°C,5°C and 20°C, analysis the influence of adding mineral fiber to the asphalt mixture on the low temperature crack performance.

Abstract: Shackle model is used to study highway investment decision under uncertainty. In Shackle model, the uncertainty associated with possible outcomes for project benefit analysis is measured by degree of surprise, and a priority index for performance evaluation of each possible outcome and degree of surprise pair is proposed, thus, the standardized focus gain value and focus loss value from the expected outcome can be established. The standardized focus gain-over-loss ratios corresponding to multiple performance measures are synthesized into an overall ratio as the overall benefits, and then the proposed problem can be built as a multi-choice multi-dimensional knapsack problem which could be solved.

Abstract: In this paper, the stopping sight distance of passenger car based on the operating speed was regarded as guideposts, and its corresponding radius of horizontal curve and vertical curve was got according to the calculated results, and available for reference and application in the alignment design and safety evaluation for freeway.

Abstract: Visual information is the basis of highway traffic safety, which is important for a driver to take right actions in driving. From the driving theory and the driver’s sight characteristics, the concept of available sight distance is put forward. According to extend and apply the theory of the spatial intervisibility between two spots, the math model of calculating and analyzing the spatial available sight distance is built up, which is solved by use of parameter equations and space conversion. On the basis of this model, the safety evaluation model and the evaluation procedures are given. At last, the effectiveness of the model is tested in practical engineering applications, and it can provide the basis for highway geometric design and safety evaluation.

Abstract: Through the coupling analysis of temperature and displacement fields in freeze-thaw process of soil by ABAQUS software, a numerical simulation method of the two fields coupling in freeze-thaw process of soil is put forward. In computation, the temperature field is analyzed firstly, and then the physico-mechanical parameters are defined as functions of temperature field. The geometric model and boundary conditions of numerical simulation are identical with these in laboratorial tests. By comparing the computation results of soil freeze-thaw process with its laboratorial test results, it was found that on the curve of soil freeze-thaw process obtained from laboratorial tests there is a short frost-swelling phenomenon at the initial stage of freeze-thaw process, and then is continuous thaw condition, but on the numerical computation curve, the reflect of soil frost swelling stage isn’t obvious. With the exception of this the numerical computation result and laboratorial test result are more identical. The frost-swelling quantum is very small, so the main expression of overall deformation of soil is thaw-settlement deformation. Therefore the frost swelling phenomenon doesn’t influence the end quantum of settlement. For this reason, the computing method introduced in this paper can be used to conduct numerical simulation of the thaw-settlement of frozen soil and to a certain extent guide the designs of subgrade and pavement in permafrost zones.

Abstract: Using the uniform design method to design test of multi-compound mineral admixture and the secondary regression model to analysis the test results, we can obtain the optimum formulation of compound mineral admixture with steel slag powder, slag powder and fly ash. The results show that the uniform design method can significantly reduce the number of test and obtain the optimal formulation.

Abstract: An emerging machine learning technique, the support vector machine (SVM), based on statistical learning theory is very good at analyzing small samples and non-linear regression problem. The particle swarm optimize (PSO) can avoid the man-made blindness and enhance the efficiency and capability in forecasting. In this paper, SVM is applied to establish a model for asphalt pavement performance evaluation, optimized by PSO algorithm. In road engineering, PCI, SSI, SRI and IRI were selected as the asphalt pavement performance evaluation indexes, but it is difficult to get pavement condition index. This paper describes the relationships among the four indicators, and SSI, SRI and IRI were used for establishing the prediction model to forecast PCI based on PSO-SVM. The results show that the method is simple and effective for evaluation of asphalt pavement performance.

Abstract: While a vehicle running on the road, the vibration of vehicle and road are coupled and interacted. The vehicle in this paper is simplified into a two DOF vibration system and the road is dispersed as a multi-layer FEM system. Then considering the road and vehicle as a whole system, and each of them is a subsystem, we created the coupled dynamic analysis of vertical vehicle-road system and derived the dynamic equilibrium equation of vehicle-road system. We deduced the dynamic equilibrium equation of vehicle-road system by regarding the pavement roughness as a stimulate function, which is want to do some pioneering study in a coupled view about the interaction of vehicle and road.

Abstract: Although the addition of hydrated lime to mineral aggregates at asphalt production plants has become mandatory for use in all asphalt concrete mixtures, the consequences of such additives at asphalt binder- mineral aggregate contact in the hot bin have shown a great effect on the consistency properties of the resulting asphalt mastics as compared to that of a neat asphalt binder. Considering that many highway agencies in developing countries still use asphalt binders consistency properties to verify material specifications for acceptance and construction practices control to build sustainable highways, it is eminent that asphalt mastic other than neat asphalt binder should provide pertinent information for consistency characterization of the neat asphalt binder in question. Fundamental consistency properties of asphalt binder containing hydrated lime to a conventional No. 70 asphalt binder (Penetration Grade) designed to meet the JTG F40-2004 specification of China were investigated. Hydrated lime was dry mixed with neat asphalt binder at hydrated lime to binder ratio’s ranging from 0.0 to 1.5 in ratio increments of 0.3% by weight of asphalt. Analyses of test results show that asphalt mastic consistency properties are well-defined linear functions of hydrated lime content. Penetration and ductility shows a linear reduction at increased hydrated lime content estimated at 14 (0.1mm) and 15cm per 0.1% of hydrated lime increment respectively while softening point and apparent viscosity increases at the rate of 6oC and 0.1 centipoises per 0.1% of hydrated lime increment respectively.

Abstract: With uniaxle penetration test method and Triaxial Shear method test, the shear strengths for asphalt mixture were analyzed. It turns out that the result of triaxial shear test is a little conservative than that of uniaxle penetration test. Then reasonable structure factor for shear strength should be considered by uniaxle penetration test. Uniaxle penetration tests at different temperatures revealed there were a linear correlation between shear strength and temperature.The asphalt was not the main fator of shear strength at high temperature.