Advanced Engineering Forum Vol. 5

Abstract: Structural health monitoring of concrete infrastructures has attracted enormous attention due to the brittle nature of concrete. In this research, we report the carbon fibre/silicon rubber composite sensors and their excellent monitoring in concrete’s compression. It is shown that the electric resistance change synchronously with the mechanical deformation of concrete during the compression process. With the increase of carbon fibre fraction, the sensitivity decreases and the numerical equations to predict the structural change are also obtained. The experimental results reported here highlight the potential application of CF/silicon composites as an effective, real-time structural monitoring sensor with low-cost and long life.

Abstract: Abstract. Poisson’s ratio is one of the important parameters that can be used to reflect the deformation characteristics of solid materials. To further understand the mechanical behaviors of materials and improve the accuracy of the finite element simulation results, the Poisson’s ratio must be defined accurately. In this paper, DIC technology is employed to investigate the Poisson’s ratios of asphalt mixtures under the different gradation and different compaction conditions. It is found that the Poisson’s ratios of different asphalt mixture are quite different and the number of compaction had a greater influence on Poisson’s ratio. It also showed that Poisson’s ratio of asphalt mixture was not a constant under the 25°C temperature condition, but varied with load. The experiment data suggested that the curve of the load - Poisson’s ratio could be divided into three sections through the observation of the graph and it also could be used to investigate the properties of asphalt mixtures deformation resistance. General-purpose finite element software is used to simulate the different contact pressure and Poisson’s ratio under dynamic loading condition, in order to find the response of asphalt pavement structure based on the relationship between load and Poisson’s ratio. It was found that the relationship of load - Poisson’s ratio significantly affected the response of asphalt pavement. It meant that the relationship of load - Poisson’s ratio should be considered when designing the asphalt pavement to improve the asphalt pavement service life.

Abstract: The extreme climate in Tianshan area has a significant impact on the freeze-thaw resistance of concrete control structure for debris flow. This paper describes a fiber reinforced concrete designed for Tianshan area. The impact factors on the freeze-thaw resistance of concrete are analyzed. The optimal composition for concrete control structure is discussed. And the engineering economic of such material is compared with that of Portland cement concrete. Research results shows fiber reinforced concrete can greatly improve the freeze-thaw resistance of concrete, and significantly extend its life with a great of practical value.

Abstract: Cement asphalt mortar (CA) is mainly applied in track system of high-speed railways for vibration attenuation. The impact on dynamics performance of CA with the admixture of rubber powder was studied. The beam specimen made of CA was manufactured for analyzing its vibration frequency and damping characteristics by free attenuation vibration tests. Results showed that there was no big change for fundamental frequency after admixture of rubber powder. However, high order frequency and structural damping increased with the increase of admixture amount. Damping ratio of CA was increased by admixing rubber powder, which can be better for energy absorption and vibration attenuation.

Abstract: Aiming at detection of strength of shallow asphalt pavement under ice frozen, this thesis has developed the Penetrating Strength Detector of Shallow Pavement through finite element numerical simulation, whose theory is based on evaluating strength of asphalt pavement by penetrating depth of the penetrator impacting into asphalt pavement.

Abstract: In order to study influence of different factors on interlayer shear strength of fiber seal, an orthogonal experiment about four factors, respectively, test temperature, fiber content, asphalt content and gravel coverage, and three levels are developed with bevel shear test. The influence rules are evaluated by range analysis method. The result demonstrated that fiber content is the most correlative influencing factor. Thus provides a basis for the selection of material and performance of the fiber seal.

Abstract: Nanomaterials (nano powdered rubber VP401, VP501 and sepiolite and CaCo3 composites) were selected to improve the high-temperature and low-temperature performance of asphalt binder. Nanomaterial modified asphalt was prepared using the high shear machine. Laboratory experiments of asphalt binder and asphalt mixture were conducted to evaluate the properties of modified asphalt binder, including the penetration, ductility, softening point, viscosity, and etc. Also, asphalt mixture tests were carried out, such as the cleavage strength test, resilient modulus test, rutting test, water stability test and etc. Based on the test results, asphalt binder modified by 1% nano powdered rubber VP401 has better performance resistance to low temperature crack and rutting, compared to other nanomaterial modified asphalt binder.

Abstract: As pavement bear the comprehensive effect of environment factors at the same time, its internal temperature field distribute complicatedly and difficult to be predicted. Due to the internal temperature field of pavement is the key of pavement performance and service durability, this paper improved the layout scheme of the temperature field, based on the previous test scheme of factual temperature field. Using the factual temperature field data of asphalt pavement, this paper studied on the temperature distribution characteristic of each layer, summed the temperature filed distribution rule of asphalt pavement and put forward the control points of pavement design low temperature.This paper verified the universality of low design temperature in SHRP (Strategic Highway Research Program) and pointed out some problems like the low temperature design temperature (Tmin) had quite large safe factor.

Abstract: The mesh reinforcement technique of polymer mortar wire rope is a new reinforcement technique used more in the domestic fittest reinforcement project recent years. Recently, there is no unified technical standards, the detailed practice is not same in practical work. There are big differences among the reinforcement effects. The key issue of wire rope is whether add prestressed or not. If add, how much should be prestressed The difference of the actual practice and reinforcement effect reflects the understanding gap polymer mortar wire rope of mesh reinforcement technique action principle of the designer. A correct understanding of polymer mortar wire rope of mesh reinforcement technique the mechanism and the objective analysis strengthening effect and actively explore research in engineering application problems have a practical significance to promote the healthy development of the structure strengthening technology.

Abstract: The corrosion of steel dowels in concrete pavement can compromise the load transfer capability of joints and lead to premature damage. To solve this problem, the non-corrosive glass fibre reinforced polymers (GFRP) bar has been used as dowels in concrete pavement instead of the steel dowels.This thesis demonstrates the Load Transfer Characteristics of a GFRP dowels with the help of a 3D finite-element model, and various evaluation method and index are studied as well, including: (1)efficiency of load transfer , (2)coefficient of shear transfer , (3) distribution ratio of shear transfer. An accelerated test is applied to examine the long-term performance of the GFRP dowel bars by using self-designed equipment.This study shows that GFRP dowels is a feasible alternative to steel dowels which can entirely meet the needs of road performance, and the research results will be useful in the design and application of GFRP dowels in jointed concrete pavements.