Research On Mechanical Properties Of Asphaltic Concrete Core Material

Because the asphalt concrete impervious core has advantages such as good performance of seepage and good adaptability with the uneven settlement of earth-rock dam, the embankent dam with asphaltic concrete core is used more and more widely. Compared to its used in engineering widely, the study of the basic mechanical properties of asphalt concrete core material is less, affecting the promotion and development of asphalt concrete in the embankent dam.In this paper, through the static triaxial shear test and the dynamic triaxial test,research the strength, deformation and dynamic characteristics of asphalt concrete core material and obtained some rule of mechanical properties of the asphalt concrete core material.The main research results as follows:(1) Study the influences of test temperature, shear rate on the results of static triaxial shear test of asphalt concrete core material.The temperature is lower, the strength of asphalt concrete is higher, softening and dilatancy are more obvious; At low temperature conditions, the shear rate is small, the strength of asphalt concrete is lowerand volumetric dilatancy is smaller, under normal temperature conditions, the shear rate has not affect on stress-strain curve, but the shear rate is smaller, the dilatancy of sample is less. The influence of confining pressure loading time on the stress-strain curve of asphalt concrete core material is small, but shear dilatancy is more obvious when the confining pressure loading time is longer, in triaxial shear test for asphalt concrete core material,shear test must begin after confining pressure volume deformation stability.(2) Study the strength property of asphalt concrete core material. the strength of asphalt concrete core material is nonlinear obvious, the nonlinear strength formula φ=φ0-△φ1g(σ3/pa) can describe the strength characteristics of asphalt concrete core material.(3) Study the dynamic deformation property of asphalt concrete core material. The backbone curve of dynamic triaxial test of asphalt concrete core material showed a good linear relationship. The backbone curve can be describe by the straight line which through the origin, and its elastic modulus are the slope of the line. The relationship of elastic modulus and mean sustained stress of asphalt concrete core material can be describe by Janbu formula under the same temperature and stress ratio.(4) Study the influences of test temperature and stress ratio on the results of static triaxial shear test of asphalt concrete core material. When the temperature is higher, the dynamic modulus of asphalt concrete core material is small, and the the damping ratio is bigger. When the stress ratio is bigger, the dynamic modulus is larger, and the damping ratio is smaller.(5) Study the dynamic strength of asphalt concrete core material under the dynamic load. the dynamic strength of asphalt concrete core material is very high, in the analysis of dynamic stability of embankent dam with asphaltic concrete core,the dynamic stability of rockfill material is more important.