Expriments Research On The Performance Of Asphalt Concrete Using Stone Chips Instead Of Sand

With its good performance and low investment, flexible pavement has been used in countrywide grade highway more than 80%. Among the aggregates of common asphalt mixture, the content of fine aggregate involving mainly natural sand, stone chips and artificial sand is about 50%. In which, the cost of artificial sand is too high. For the natural sand, as important construction material, its resource is reducing constantly. Whereas, a large number of stone chips produced during the process of building broken stone are utilized rarely. The stability of the asphalt concrete can be improved through the interlock between the stone chips and coarse aggregate forming rubs obstruction in asphalt concrete. Because of some reasons, the content of stone chips among the fine aggregate in high grade pavement is not more than that of sand which is recommended in the specification for construction of highway asphalt pavement.Feasibility using large proportion stone chips instead of sand will be investigated in this thesis. Based on indoor test, the performance of the asphalt concrete of Model AC-161 dense-graded aggregate usually used in road pavement is studied, in which, three types of proportion of stone chips instead of sand at 50%, 75%, 90% were used. Analyzed parameters are optimum asphalt content, the voids, Marshall stability, dynamic stability, residual stability, low temperature splitting tensile strength and low temperature stiffness modulus etc.The results of test showed that pavement performance of the asphalt concrete using large proportion stone chips instead of sand is good, and the above necessary parameters meet the requiement of the specification. By contrast and analysis, the all-around performance of asphalt concrete using 75% stone chips instead of sand is more suitable, and 75% is a more perfect proportion.