Test Technology Study on Mesoscopic Shear Strength of Mineral Aggregate Contact Surface

AbstractQuantitative test technology on the mesoscopic strength of the mineral aggregate contact surface of bituminous-stabilized macadam was studied, which include the shear adhesion strength τa between aggregates and bitumen, the cohesion strength τc of bitumen binder itself, and the total shear strength τt of mineral aggregate contact surface. The HC-40 hydraulic force measurement device and the self-designed test die were used to apply shear load on the contact surface of the mineral aggregate to determine the shear failure load in different kinds of bitumen, thickness of oil film, and temperatures. On the basis of the relationship between the shear adhesion strength τa, the cohesion strength τc, shear adhesion failure area Sa, shear cohesion failure area Sc, the total area of mineral aggregate contact surface St and the shear failure load F, then the shear adhesion strength τa and the total shear strength τt can be calculated by using the property of shear cohesion strength τc of bitumen binder. The results show that the shear cohesion strength τc of bitumen binder has obvious correlation with bitumen quality and experimental temperature while the shear adhesion strength τa between aggregates and bitumen obviously relates to bitumen quality, experimental temperature, and oil film thickness. Confirming the shear strength characteristics of the contact surface is important in the study of the crack and raveling resistance abilities of the mixture.