This study introduces the theory of asphalt aging with infrared adsorption spectrum. Qualitative and quantificational comparisons are carried out between Karamay asphalt ultraviolet radiation aging, after which asphalt turns from sol-type to gel-type and other aging types. The variance ratio of absorbance A at 1700 cm-1in infrared spectrum chart is consistent with the tendency of asphalt’s three general indexes, including penetration, ductility and softening point. The oxidation speed of ultraviolet radiation aging is 1.80~6.23 times that of thermal aging. In addition,the process of photo-oxidation, the order of carbonyl content in different asphalt samples, the influence of ultraviolet radiation on long term aging of asphalt and other useful information has been gained for better and further researches in this field.
Large diameter rock-socketed piles are usually used to support bridge with long-span or high piers. To research its mechanical properties in mountain area, field loading tests based on distributed fiber sensing technique were performed. The tests results indicate that shaft resistance came into play earlier than tip resistance and the upper load was borne mainly by shaft resistance. When the load-sharing ratio of tip resistance exceeded 10%, the enhancement phenomenon of shaft resistance occurred, which became more and more obvious with the increase of the ratio. The shaft resistance and tip resistance are not independent but interact of each other. The increase of tip resistance can promote the shaft resistance to play its role effectively. According to the field test results, the design method of rock-socketed piles was improved based on the enhancement phenomenon of shaft resistance. The calculation results indicate that the rock-socketed length of pile can be shorten effectively by this method which can obtain considerable economic benefits.
Abstract. Two heterocyclic-based energetic ionic salts were synthesized from 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (1), which was used as proton bases reacting with nitric or perchloric acid. They were characterized by elemental analysis, IR spectroscopy, and singlecrystal X-ray diffraction. In addition, their combustion heats were measured by oxygen bomb calorimetry and their heats of formation were predicted based on the combustion heats data. The non-isothermal ki-
The internal mechanical response of asphalt pavement structure is difficult to be obtained because of the limitations of theoretical calculation and present testing methods. In order to get practical information of instructure layers, this paper analyzed the cumulative and instantaneous strains of layers’ bottom of semi-rigid base asphalt pavement based on Accelerated Pavement Testing and Fiber Bragg Grating sensors, as well as got the spatial distribution and time-variation law of longitudinal, lateral and vertical strain responses under controlled loading condition. The research result shows that under the moving vehicle loads, there is an obvious alternative property of tension-compression as the strain response of the pavement structure, and different variation shapes of instantaneous stain are in different layers from top to down. Also the measured instantaneous three-direction strain of the bottom of each surface are higher than the calculated values with BISAR, while they anatomizes well in base. This paper can be regarded as useful and tentative research and application on future correlative study.
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