为了从细观角度深入分析沥青混凝土的断裂机理,根据概率理论,建立了集料质量级配与二维数量级配的关系,并通过计算机随机投放技术生成了具有2种不同沥青膜厚度的沥青混合料二维数字试件;利用离散元方法,模拟了沥青混合料小梁试件的断裂过程,分析了沥青砂浆抗拉强度、砂浆与集料黏结强度和沥青膜厚度对沥青混合料断裂过程的影响.结果表明:对于沥青膜较厚的沥青混合料而言,起裂阶段和扩展阶段的裂纹主要出现在沥青砂浆中,沥青砂浆的抗拉强度是影响混合料断裂的主要因素;当沥青膜较薄时,起裂和扩展阶段的裂纹在沥青砂浆内部和砂浆与集料界面中都有发现,砂浆抗拉强度决定着混合料的破坏应力和应变,砂浆与集料的黏结强度决定着混合料裂纹扩展的速率.%In order to investigate fracture failure mechanism of asphalt mixture from micro-structure, probability rnmethod has been used to present a theoretical formula which develops to convert the aggregate weight gradation rninto the two-dimension (2D) quantity gradation. Two 2D digital specimens with different thicknesses of asphalt rnfilms are generated based on particle generation algorithm. Based on the discrete element method, the fracture rnprocess of asphalt mixture beam has been simulated and the effect of asphalt film thickness, cohesive strength of rnasphalt mastics and adhesive strength between asphalt mastic and aggregate on the fracture failure of asphalt mix rnture has been also investigated. The results show that the cracking has the tendency to occur in asphalt mastics rnfor asphalt mixture with thick asphalt films and the cohesive strength of asphalt mastics has a great influence on rnfracture failure of this type mixture. For asphalt mixture with thin films, the early cracking often appears in as rnphalt mastics and propagation of cracking occurs at the interface between aggregates and mastics. Fracture initia rntion is dominated by the cohesive strength of asphalt mastics and propagation of cracking is controlled by adhesive rnstrength between asphalt mastic and aggregate for mixture with thin films.
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