Crack Resistance Of Asphalt Concrete And The Test Specimen Molding Method

With the development of national economy and the progress of science, high-RCCdams and high embankment dams have widely been built in the world. Asphalt concretehas been applied in both kinds of dams for its particular properties high flexibility, strongcrack-resistant and earthquake-resistant, and self-healing capability, and incrasinglyattracting the attenton of experts in the dam engineering field. Especially it has beenbeing used as waterproof elements in concrete gravity dam upstream faces andembankment dams. The cracking-resistant tests using asphalt concrete as imperviouselements on RCC dam upstream faces is less researched and there is no ready theory sofor. In the embankment dam asphalt concrete core Wall projects, it has been found thereare big behaviour differences between core field samples and laboratory prepared ones.So it is very valuable to study the differences.This research consists of two parts. The first part is the research of cracking-resistantof asphalt concrete. It is performed by the method of prefabricating crack in a concretespecimen, simulating the expanding progress of RCC dam surface crack, observed andrecorded the expanding degree of sand asphalt specimens Which was placed on thesurface of concrete specimens when the cracks are opening. By applying the theory offracture mechanics the crack-resistant capability of sand asphalt concrete is analysed andinvestigated. The content of the second part is the study of forming methods ofembankment dam asphalt concrete core wall specimens prepared in the laboratory. It ismainly analyzing the different methods of forming a specimen in the laboratory tocompare the Marshall standard laboratory compaction method widely used in the worldwith the modified Marshall compaction method which developed Mr.Wang weibiao.Firstly, perform the test in the laboratory, by designing the asphalt concrete mix withfixed proportion, making specimens with the two compaction methods with differentcompaction blows, see which one is closer to the engineering practical yielded specimensby Marshall and triaxial tests. On the base of the study, perform the triaxial test on threefiled core specimens and the specimens with the same mixture prepared by Mashallstandard compaction method and Modified Marshall compaction method respectivelyAccording to the test results, the behaviours of field core specimens, Marshallcompaction specimens and Modified Marshall compaction specimens are analysed andcompared. The test results has documented that Modified Marshall compaction method isthe better one in the engineering behaviour sense.