For most precious metal mines, cemented tailings backfill slurry (CTBS) with different cement-sand

ratio and solid concentration are transported into the gobs to keep the stability of the stope and mitigate

environmental pollution by mine tailing. However, transporting several kinds of CTBS through the same

pipeline will increase the risk of pipe plugging. Therefore, the joint impacts of cement-sand ratio and

solid concentration on the rheological characteristics of CTBS need a more in-depth study. Based on the

experiments of physical and mechanical parameters of fresh slurry, the loss of pumping pressure while

transporting CTBS with different cement-sand ratio, flux and solid mass concentration were measured

using pumping looping pipe experiments to investigate the joint impacts of cement-sand ratio and solid

concentration on the rheological characteristics of CTBS. Meanwhile, the effect of different stopped pumping

time on blockage accident was revealed and discussed by the restarting pumping experiments. Furthermore,

Fluent software was applied to calculate the pressure loss and velocity distribution in the pipeline to further

analysis experimental results. The overall trends of the simulation results were good agreement with the

experiment results. Then, the numerical model of the pipeline in the Sanshandao gold mine was conducted

to simulate the characteristics of CTBS pipeline transportation. The results show that the pumping pressure

of the delivery pump can meet the transportation requirements when there is no blockage accident. This

can provide a theoretical method for the parameters optimizing in the pipeline transportation system.

The rheological property of asphalt is an important factor affecting the pavement performance of asphalt binder, and the fundamental reason for the change of asphalt rheological property is the strong evolution of asphalt material meso structure. However, the internal mechanism of rejuvenated asphalt mastic system is complex and its rules are difficult to grasp. Aiming to study the relationship between meso mechanical parameters and rheological parameters of rejuvenated asphalt mastic, the meso structure model of rejuvenated asphalt mastic was established and improved based on the discrete element method. Moreover, the meso parameters of the model were obtained by the objective function method, and then the influences of various factorswere studied to construct the mathematical constitutive model of rheological parameter modulus and meso mechanical parameters. Combing with the reliability of the improved Burgers model was verified based on the rheological test results of rejuvenated asphalt mastic. In addition, the virtual test of dynamic shear rheological dynamic frequency scanning was carried out on the asphalt mastic sample by particle flow software. By adjusting the mesomechanical parameters, the simulation results (complex shear modulus and phase angle)were consistent with the test results. This study clarified the relationship between mesomechanics and macro performance, and this model could be used to obtain the complex shear modulus of rejuvenated asphalt mastic under different types, filler-asphalt ratio and external force environments by adjusting particle flow, wall boundary and other conditions, which can greatly save the workload for the later research and provide a theoretical basis for production experiments.