Applied Mechanics and Materials Vols. 97-98

Abstract: Experimental results showed that low heat accumulation asphalt mixture had a marked effect on the reduction of surface temperatures. However changes in temperature over the test methods were not thoroughly studied. In the process of test, LJ infrared powder is used to prepare for making the content of 6% asphalt mixture specimen. Several temperature data of infrared powder specimen were compared with the data of ordinary specimen. Each number was compared and analyzed. At last, concrete temperature variation discipline of the temperature field was found.

Abstract: Turnout, where a train changes its running track, is one of the crucial technologies in China’s high-speed railway construction, turnout is always the important and difficult to maintenance. In order to keep the high technology of turnout and reduce the maintenance work, we based on the experience of accumulated from the design, manufacture and laid technology of high speed turnout, and the scientific maintenance method of high speed turnout was explored. Maintenance of high speed turnout should be in accordance with its high performance requirements and take appropriate measures of maintenance to ensure the high speed turnout working safely.

Abstract: According to traffic operation characteristics and lane changing maneuvers, combining with the export notice signs and considering the worst driving conditions, the gap acceptance theory and kinematics are employed to establish the length of lane change operation between interchanges with probability theory. To operating speed as the premise, the necessary length that drivers change to the inside lane from the nearside lane is analyzed in terms of waiting for the gap acceptance, and the necessary length that drivers change to the nearside lane from the inside lane is also analyzed in terms of running for the gap acceptance, then calculation model of minimum net distance between interchanges on eight-lane expressway is constructed. The recommended value is then put forward.

Abstract: This paper aims to explore the reasonability of an evaluation method on high temperature performance of asphalt mixture through a series of experiements. The first step of these experiements is to formulate specimens of different high-temperature performances by Gyratory Testing Machine which simulates the on-road pavement to the most extent , and then adopt triaxial dynamic compression test to compare and analyze high-temperature performances of these specimens. By introducing concepts and indicators such as validity, reliability, discrimination, this paper evaluates comprehensively the discrimination results of various compression test parameters on high-temperature performance of asphalt mixture. It concludes that the evaluation effect of compression stiffness modulus is best, followed by the slope of logarithmic creep curve and accumulated strain area, and the evaluation effect of final compression strain is comparatively poor. That provides an objective evaluation method on high temperature performances of asphalt mixtures.

Abstract: In order to study the effects on the performance of continuously reinforced concrete pavement (CRCP) of some factors, eleven CRCP test sections were designed and constructed in Yanwei Expressway in China. The factors considered included concrete material, base configuration, epoxy coated of steel, transverse steel orientation, the depth of longitudinal reinforcement and the active cracks spacing. Concrete properties tests, early age cracking monitor and falling weight deflectometer tests were all carried out in these test sections. Furthermore, the field investigations to several other CRC pavements having been open for years in China were carried out also and cluster cracking and punchout distress were considered as the performance criteria of CRCP. Finally, the effects on CRCP performance of some factors were discussed. Results show that, the CRCP performance when the separating layer between the concrete slab and cement treated base is asphalt concrete is better than that when the separating layer is paraffin, and the thicker the asphalt mixture separating layer the better the CRCP performance; the modification of transverse steel skew angle can improve the CRCP performance; the concrete material, transverse steel skew and base have more effects on cluster cracking than the separating layer between concrete slab and base does; and the active cracks at the spacing of 1 to 5 m can prevent the occurrence of natural cracks between them.

Abstract: Viewing so many overload vehicles, this paper analyzes the stress distribution of asphalt pavement structure under heavy traffic theoretically, according to the main asphalt pavement structure form in our country. By using elastic layer theory and BISAR3.0 program, analyzed the mechanical response variation of semi-rigid base asphalt pavement under different axle loads. The results showed that the mechanical response and the stress indexes of pavement structure under heavy traffic changed significantly. Therefore, in asphalt pavement design, the impact of heavy traffic should be fully considered and we must take measures to control the overload situation.

Abstract: The drop distance, times of dynamic compaction and other parameters are studied by on-site testing in order to analyse quantitatively the impact on effective reinforcement depth and radius of the red sandstone rubble soil. Large amounts of on-site test data shows that compactness standard is 93%, strong encryption range is 1.0～4.0m, the effective impact depth is 4～6m and the effective impact radius is 2.5～3.5m. At the same time, through comparison and verification the on-site testing data and numerical analysis, the relationship between times of dynamic compacting and sandstones subside is . Further more, it is revealed that dynamic compaction can restrain effectively the deformation of high fill embankment of the red sandstone rubble soil.

Abstract: As a quick, accurate and efficient inspecting equipment, the Portable Falling Weight Deflectometer (PFWD) is widely used in subgrade modulus evaluation in the foreign countries. However, most analysis methods used in the modulus back calculation of PFWD is based on the classical Boussinesq solution or empirical formulas, which could hardly reflect the resilient of subgrade accurately. In this paper, the elastic half-space theory is introduced into the analysis of modulus back calculation, and with the integral transform and the numerical analysis, this paper provides an approximate method to evaluate the elastic modulus of subgrade.

Abstract: The water damage resistance performance of micro-surfacing is studied by means of gradation and clay content; It can be found that the cleaness of powder lot in the mineral aggregates plays an important role on water damage resistance ability of micro-surfacing; The MB test is proved to be more convenient for evaluating the cleaness and clay content in aggregates than the SE test, and the MBV for micro-surfacing is given so as to make sure the favorable water resistance ability of the mixture.

Abstract: Highway, especially expressway plays a very important role in economic development of today. To deal with the traffic load, the surface of expressway should have the nature of strength, load-bearing ability, skid-resistance, free of penetration and duration. AC is one of the high type pavements. With the rapid development of highway, most of the AC pavement will be destroyed by heavy traffic loads, and should be maintained with millions of waste materials produced. Plant-mixed hot-regenerated AC is to recycle these waste materials, and apply part of them as one of the ingredients of the new AC of the new pavement. Method of mix design of the Plant-mixed hot-regenerated AC is discussed is this article. The method was applied in the maintenance of the Chang-Ying expressway and has obtained relatively obvious economic effect and social effect.