Experimental Study On Mechanical Properties Of Iron Mine Tailings Self-compacting Concrete

Iron mine tailings self-compacting concrete is a new type of self-compacting concreteon the basis of the ordinary self-compacting concrete, mixed with a certain amount of theiron-tailings sand to replace the natural sand as fine aggregate. This paper systematicallystudies the influence of the different replacement of Iron-tailings sand on the workabilityand basic mechanical properties of iron mine tailings self-compacting concrete. Thefollowing aspects were carried out in this paper:（1） The workability of iron mine tailings self-compacting concrete was studied has sixkinds of iron-tailings sand replacement rate, when water binder ratio,mineral admixturecontent, admixture content and coarse aggregate content were fixed, and with a common setof self-compacting concrete comparative analysis. The dynamic stability was studiedthrough the slump-flow test, T₅₀₀ flow-time test, L-Box test U-Box test, J-Ring test andV-funnel test. And the static stability was studied through the settlement column test andsieve segregation resistance test. To get a reasonable dosage of iron-tailings sand. Theexperimental results show that when the dosage of iron-tailings sand was40%,50%and60%, the iron mine tailings self-compacting concrete has better dynamic stability and staticstability. When the dosage was20%, the mixture’s flowability was too large, and the indexis on the high side, beyond the standard requirements of the index upper limit. When thedosage was40%, the mixture have the similar workability with the ordinaryself-compacting concrete.（2） The basic mechanical properties of iron mine tailings self-compacting concrete wasstudied has five kinds of iron-tailings sand replacement rate, through the cube compressivestrength test, split tensile strength test, flexural strength test, axial compressive strength testand elastic modulus. The experimental results show that when the dosage was40%, Thebasic mechanical properties index is better.（3）The relativity of the basic mechanical properties index was analysed include therelationship between cube compressive strength and apparent density, cube compressivestrength and elastic modulus, split tensile strength and cube compressive strength, axialcompressive strength and cube compressive strength. The analysis results show that theapparent density is increasing with the increase of cube compressive strength. The fittingresults between axial compressive strength and cube compressive strength show that SCC-1and ISCC-2have the axial compression ratio of high strength concrete. Used in calculating the elastic modulus of ordinary self-compacting concrete and other self-compactingconcrete, the calculation formula is not applicable to Iron mine tailings self-compactingconcrete.