Asphalt aging mechanism and recycling mechanism are studied in the paper, based on four components tests for aging asphalt and recycling asphalt, by comparing and analyzing the D-value between testing data and theory calculated data. Results show that asphalt four components changes regularly for aging asphalt, which some saturates and aromatics are changed into some asphaltenes and colloid. And the recycling mechanism is not regular for the same asphalt, which the mix result of asphalt four components depends on many factors, such as degree of aging, quantity of old asphalt, components and quantity of recycling agent. The study results can provide important theoretical basis for sustainable use and development of regeneration asphalt.
Waste ceramic tiles are broken into sandy gravel to configure reclaimed sand instead of part of normal sand. Bending strength tests and compressive strength tests of mortar samples were carried out under different substitution rate of ceramic tile wastes sand in different curing time, which the ratio of cement and the consistency of mixture were fixed. The results indicate that strength grade of masonry mortar recycled by ceramic tile wastes under different substitution rates can be improved 1 or 2 grades, and the strength linearly increases as the curing time increases under the same substitution rate, and the growth rates of bending strength and compressive strength are inconsistent.
The finite element analysis model was built as the real scale for mortar arch framework slope protection, and the displacement and strain at different points were collected by vertical loading pressure. So the mechanical mechanism can be studied, and the analysis was done between calculation results and testing results of solid miniature model. The studying results show that the point on the arch foot is the worst stress place for each arch, and the total displacement increase nonlinear as the distance from the slope top increases, and the bump phenomenon exists in the bottom of slope, the points are likely to be broken.
In this study, plant-mix hot reclaiming asphalt mixture can be used to surface and sub surface taking DAC-13I and DAC-20I asphalt mixture with five different RAP contents as 0%, 10%, 20%, 30%, 40%. The fatigue, rutting, water damage and cracking tests in laboratory have been taken to evaluate the road performance, and flexure, rutting, asphalt content tests have been taken on the trial sections to evaluate the practice road performance. The result of tests shows that plant-mix hot reclaiming asphalt mixture should be good service performance as new asphalt mixture when the RAP content is appropriate.
In this paper, rolling thin film oven is used to heat No.70 road asphalt to simulate asphalt aging. Six aging time tests of 0min, 40min, 85min, 180min, 240min and 300min were carried and the relationship of asphalt performance indexes before and after aging was got as well as four components. The analysis results indicate that: as the aging time increases, change processes of all performance indexes followed curve of index and the correlation coefficient reached significant level. Changing regularity of asphalt four components are also got: the contents of saturate and aromatic both decrease with the aging time increasing, while asphaltene content and resin content increased and the increasing speed of resin is faster. Key words: No.70 road asphalt; four components; performance index; aging.
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