Laboratory Study Of Triaxial Test On Graded Broken Stone

It is well known that flexible base can eliminating the reflecting crack and shrinkingcrack efficiently. As a typical kind of materials for flexible base, though the graded brokenstone has the advantage of drainage and economical property, this kind of asphalt pavementstill can not be adopted widely, which is just because of its low resilient modulus andunsymmetrical permanent deformation. That is why the flexible pavement developed soslowly in our country. The major purpose of this paper is to study the influence of grain-sizedistribution, molding method and different content of fly-ash on strength character,deformation, long-term performance of graded broken stone, which can provide some supportfor extension of flexible pavement.In the static triaxial test, the influence of molding method, grain-size distribution,compaction degree and content of fly-ash on static strength has been studied, which indicatesthat adopting vibrating molding method can improve the shear strength of graded brokenstone. And it is clear that the flexible base will not be wrecked in standard load. Specimens ofskeleton structure are prior to those of suspended-dense structure. The static strength can beimproved if certain fly-ash be added into specimen.In the study of dynamic triaxial test, it is obviously that the resilient modulus andinvariant of stress are power related. According to the range of invariant of stress in practicalproject, the range of resilient modulus can be obtained, which indicates that resilient modulusof specimens of vibrating molding method is higher than that of manual beating method ones,specimens of skeleton structure are prior to those of suspended-dense structure, resilientmodulus can be improved if certain fly-ash be added into specimen. For the permanentdeformation of graded materials, the same conclusions can be drawn as the resilient modulustest.Finally, through the longtime test in which about 10,000 loading cycles are carried out,the rules of deformation and resilient modulus are studied. As the development of loadingtimes, the permanent deformation of specimens can be separated into three styles: stable style,broken style and critical style. In the stable style, the deformation hardly augments eventually.But in the broken style the specimens burst into broken as well as they are loaded so that thedeformation increases rapidly. The critical style is just intervenient the stable style and thebroken style. Generally speaking the resilient modulus increases and the tendency of augmentis slower and slower as the development of loading times except the loading is too heavy. It is concurrent with the conclusion from measuring the resilient modulus of test road when it isconstructing and finished in one year that the resilient modulus of fexible base and semi-frigidbase increases in one year.