Research on the Cementitious Properties and Fiber Reinforced Effect of Full Tailings Solid Waste-Based Filling Materials
In response to the problem of insufficient strength of the filling body caused by the high content of ultrafine particles in the full tailings of a gold mine,alkali-activated cementitious materials were prepared from mining solid waste,and different lengths of polypropylene fibers(3-18 mm)were added as reinforcing agents to study their effects on the flow properties and compressive strength of the filling material.SEM was used to reveal the material's cementitious properties and fiber reinforced effect from the microstructure.The results are concluded as follows.Firstly,the surface of ultrafine particles in the full tailings is prone to forming a water film,which leads to a decrease in cohesion and is the main reason for the low strength of the filling body.Secondly,as the fiber length increases,the slump,fluidity,and consistency of the filling slurry all decrease,but the bleeding rate decreases firstly and then increases.Thirdly,the compressive strength of the filling body increases firstly and then decreases with the increase of fiber length.When the fiber length is 12 mm,the compressive strength at 3 d and 28 d reaches the maximum values of 3.12 MPa and 8.05 MPa,which are 254.55％and 41.48％higher than the specimens without fiber added at the same curing age,respectively.Fourthly,fibers play a bridging and anchoring role in the matrix,effectively resisting and transmitting external loads,thereby increasing the compressive strength of the filling body.However,if the fibers are too long,they can easily cause clusters and entanglements,forming weak surfaces,leading to a reduction in strength.
Full tailingsPolypropylene fiberCemented fillingAlkali-activatedCompressive strength
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