沥青混合料配合比设计中级配曲线选取的探讨

Discussion on Selecting of the Grading curve in the mix proportion design of asphalt mixture

通过选择推荐的级配范围的上、中、下限三种级配,对其进行马歇尔试验、空隙率、等混合料性能试验,分析级配选择对沥青混合料各项性能的影响。结果表明:级配从上限到下限空隙率、间隙率、渗水系数、稳定度、动稳定度增大;毛体积密度、残余稳定度减小;沥青混合料级配上限虽然密实,但矿料间隙率不符合技术要求;下限空隙率偏大、渗水不符合要求一般不能采用;中限的各项指标均符合要求;

By selecting the upper limit, the middle limit and lower limit of grading recommended in JTG 1740 - 2004, the Marshall stabili- ty, VV, VMA, dynamic stability, water seepage coefficient and the residual stability tests were carried out, and then gradation selection effect on the properties of the asphalt mixture was analyzed. The results show that ： with the grading increasing from upper to lower, the VV, VMA, water seepage coefficient, Marshall stability and dynamic stability increase, while the bulk specific gravity of bituminous mixtures and the residual stability reduce. Although the grading upper limit is dense, the percent voids in mineral aggregate in bituminous dont con- form to the requirements. The percent air voids in bituminous mixtures is larger and the water seepage coefficient dont conform to the re- quirements, SO the lower grading limit cant be used. The middle grading limit can be used, because every index meets the requirements.