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为了提高沥青混合料的路用性能,利用颗粒流软件PFC~(2D)构建了沥青混合料单轴贯入数值试验方法,阐述了沥青混合料单轴贯入数值试验中试验条件的模拟方法和模型参数的取值,结合实体工程中AC-20室内单轴贯入试验评价了其可靠性。选取不同的原材料得到3组模型参数,基于单轴贯入数值试验研究了模型参数取值、粗集料级配、细集料级配和粗细集料比例对沥青混合料抗剪强度的影响规律。最后,通过室内单轴贯入试验确定了关键筛孔最佳通过率范围,提出了以抗剪强度最大为原则的AC-20矿料级配,并验证了其路用性能。结果表明:单轴贯入强度模拟曲线与室内实测曲线基本吻合;单轴贯入数值试验模型参数的取值对最大抗剪强度时集料的比例不产生影响;五档粗集料19~26.5mm,16~19mm,3.2~16mm,9.5~13.2mm,4.75~9.5mm的比例为3∶12∶5∶10∶10,细集料级配取I=0.75时所对应的级配,粗细集料比为60∶40时,沥青混合料抗剪强度最大;建议AC-20沥青混合料矿料级配9.5mm,4.75mm,2.36mm及0.075mm筛孔通过率分别为50%~60%、34%~44%、31%~37%和3%~7%;与规范推荐级配中值相比,优化级配AC-20混合料的抗剪强度、动稳定度分别提高了25%、27%。
In order to improve the road performance of asphalt mixture, a numerical experiment method of asphalt mixture uniaxial penetration was established by using particle flow software PFC ~ (2D), and the simulation method of test conditions in numerical experiment of asphalt mixture uniaxial penetration was described. Model parameters, combined with solid engineering AC-20 indoor uniaxial penetration test to evaluate its reliability. Three groups of model parameters were selected from different raw materials, and the influence of model parameters, coarse aggregate gradation, fine aggregate gradation and the ratio of coarse aggregate to fine aggregate on the shear strength of asphalt mixture . Finally, the optimal pass rate range of critical sieve was determined by indoor uniaxial penetration test. The gradation of AC-20 ore aggregate with the maximum shear strength was proposed and its road performance was verified. The results show that the simulation curves of uniaxial penetration strength are in good agreement with the measured ones in the laboratory. The values of parameters of uniaxial penetration numerical model have no influence on the proportion of aggregates with maximum shear strength. mm, 16 ~ 19mm, 3.2 ~ 16mm, 9.5 ~ 13.2mm, 4.75 ~ 9.5mm ratio of 3:12:5:10:10, fine aggregate level with I = 0.75 when the corresponding gradation, thickness set The asphalt mixture has the highest shearing strength when the material ratio is 60:40. It is suggested that the passing rates of grade 9.5mm, 4.75mm, 2.36mm and 0.075mm of AC-20 asphalt mixture are 50% -60% 34% -44%, 31% -37% and 3% -7%. Compared with the standard recommended grade, the shear strength and dynamic stability of the optimized grade AC-20 mixture increased by 25% 27%.