Applied Mechanics and Materials Vols. 744-746

Abstract: The cohesive zone model (CZM) is being increasingly used to simulate fracture and fragmentation processes in metallic, polymeric, and ceramic materials and their composites. The CZM regards fracture as a gradual phenomenon in which separation takes place across an extended crack tip. This paper introduces the concept of CZM, the constitutive relations of CZM, the influence of the shape of the interface law and up-to-date applications of CZM to bituminous mixtures and pavement structures. Furthermore, some current challenges and the future directions to the modeling of fracture in bituminous materials and pavements are briefly discussed.

Abstract: The Beijing-Tianjin-Tanggu expressway is the first highway which is built by using World Bank loan in china. With the influence of service life increasing and traffic growing, the diseases appear such as rut, crack and poor flatness, so the use performance of the highway obviously degrades. Pavement overhaul effectively reduces the appearing of pavement diseases and prolongs the service life of the road. This paper conducts a detailed research on the engineering management and construction quality control of the Beijing-Tianjin-Tanggu expressway overhaul which has strong reference significance on highway overhaul.

Abstract: In this paper, the constitutive model of the asphalt pavement permanent deformation is analyzed, which is based on the asphalt pavement permanent deformation. In order to reasonably predict the asphalt pavement permanent deformation, the domestic and foreign research results are thorough investigated. It shows that the nonlinear viscoelastic - elastoplastic constitutive model of Peng Miaojuan improves the defects of various models. This constitutive model comprehensively reflects the characteristics of permanent deformation of asphalt pavement.

Abstract: In the environment of noise pollution, the noise of pavement is one of the main sources of pollution. It has serious impact on the natural and social environment and interference with people's learning and work. The research shows that the tire or road noise will be a major part of the traffic noise when the car speed is greater than 30km/h and the truck speed is greater than 50km/h [1]. This paper analyzes the status quo of study of rubber asphalt overlay noise reduction and mechanism. Through effective traffic noise test method, we have analysis the noise reduction effect of rubber asphalt overlay. Results of the study shows that rubber asphalt overlay can well reduce road traffic noise and it has a good effect of improving the comfort of driving.

Abstract: In order to improve the accuracy and reliability of the defect recognition in rails, the new principle and methods of NDT should be explored, and the safety of railway operation and guiding the repair can be guaranteed. The study is aiming at comparing and analyzing the characteristics of destructive data signals with non-destructive ones. The damage and defect can be judged by the differences of the processed data in the frequency domain and energy spectrum. The location of the defect and damage can be obtained by the singularities of destructive signals using wavelet data processing method: continuous wavelet transform, Mallat algorithm and à Trous algorithm. Based on the above consequence, à Trous algorithm is found that its result is more similar to the real damage location, which proves that the method can be used in the real damage detection and provide us more precise defect location information for early warning.

Abstract: In this paper, advantages of the Sideway Force Coefficient Routine Investigation Machine (SCRIM) are analyzed for testing the Sideway Force Coefficient (SFC). Then influence factors are explored such as environmental conditions (test speed, test temperature, bumps degree) on the SFC test value. Furthermore some suggestion are put forward for SCRIM testing SFC value, and the safety precautions are emphasized on what drivers should pay more attention.

Abstract: This paper concerns the simulation of Mode I fracture with a local concrete damage model in explicit finite element code LSDYNA. A reliable modeling of fracture is essential in the analysis of tension-dominated problems, as well as the prediction of concrete damage due to cracking. A special focus of this paper is placed on an effective representation of the tensile localization in finite element modeling while generalized macro material properties are employed to modeling meso-scale problems. An investigation into the use of a typical damage plasticity concrete model within LSDYNA Explicit, based on the crack band theory, is described in detail. The main focus of the current paper is on the tensile softening branch.

Abstract: Analyzing the related literature at home and abroad, this paper summarized the results and shared them with reasearchers involved in the field on the recycled aggregate concrete (RAC). In this paper, the durability of RAC will be described from the following several aspects: absorption, chloride permeability, freezing and thawing resistance, carbonation, the sulfate corrosion resistance, drying shrinkage, creep and abrasion resistance. This paper expounded the present situation and progress in the study of the durability of recycled aggregate concrete.Then, some key technical problems needed to be studied were pointed out and many suggestions were put forward.

Abstract: This paper explains and demonstrates the aging performance and structure of bio-asphalt with analytical results from hot stage microscopy, infrared spectroscopic and nuclear magnetic resonance spectra. The experimental results showed that the aging of bio-asphalt is mainly caused by a large amount of coke substance generated during the process, and the addition of BHT can improve the aging resistance of bio-asphalt to some extent. Catalytic hydrogenation facilitate the removal of aldehyde, ketone and carbon-carbon double bond so as to strengthen the aging resistance of bio-asphalt, nuclear magnetic analysis further confirms the results from IR .

Abstract: The fatigue failure modes of reinforced concrete beams externally strengthened with basalt fiber reinforced polymer(BFRP) sheets was examined in an experimental and analytical study. One strengthened beam failed due to the debonding and fracture of U-wraps FRP sheet at the anchors,and the others failed the fatigue fracture of the longitudinal tensile reinforcements. Based on Code for Design of strengthening concrete structure, the fatigue failure of RC bending members strengthened with FRP was analysed,and the indicate that with reinforcement ratio of 0.612% and fatigue stress ratio of 0.3, only the fatigue fracture of steel bars occured rather than the crushing of concrete in the compression zone.