| Concrete materials have many aspects of applications in engineering.However,the fine aggregate sand is in a shortage situation now.Lead-zinc tailing sand is lead-zinc mine production waste,generated by a large number of accumulation in the tailings.It is urgent to solve this realistic problem that the recycling of used sand.This article selects the lead-zinc tailing sand mixed with concrete,partly replace fine aggregate sand and preparation of concrete with lead zinc tailing sand.From multiple aspects systematically the static and dynamic splitting tensile performance of concrete have been researched.At the same time,using software ANSYS/LS-DYNA software for numerical simulation of dynamic splitting tensile test.The main contents and conclusions of this paper are as follows:(1)Going to prepare cube specimens,prism specimens and disk specimens,test and obtain the static mechanical strength of concrete with different mixing amount of the lead-zinc tailing sand.From the research statistics,it shows that the static mechanical strength of concrete increases first and then decreases when the dosage of lead-zinc tailing sand is large.By the proportion of lead-zinc tailing sand reaches 40%,the static mechanical strength of concrete reaches the maximum value and the related performance is fine.However,there is a certain difference in the mechanical strength of concrete at different ages at different mixing ratios.(2)A Split Hopkinson Pressure Bar device with a diameter of 100 mm was used to carry out dynamic splitting tensile tests on concrete disc specimens mixed with different lead-zinc tailing sand contents under different impact pressure.Take some measures to ensure the accuracy of the test.For the aim of acquiring the waveform of strain,dynamic data acquisition system is in the use.The “three-wave method” is used to process and calculate the waveform data,and the stress,strain and strain rate of concrete mixed with lead-zinc tailing sand are obtained.(3)These have been processed and analyzed that the stress and strain data of lead-zinc tailing sand concrete.The trend of stress-strain curve,dynamic amplification factor(DIF),the effect of mixing amount on dynamic splitting tensile strength and the failure state of splitting surface were compared with that of ordinary concrete.The research results indicated that the trend of stress-strain curve of lead-zinc tailing sand concrete with different dosage is steeper in the ascending section,while it shows the differences in the descending section.The dynamic splitting tensile strength and DIF value are all keep pace with the strain rate,showing an obvious strain rate correlation.However,in the aspects of the dynamic splitting tensile strength and DIF value of concrete,the increase ranges of which with different lead and zinc tailing dosages are different.The concrete specimen splits into two pieces.When the strain rate reaches a higher strain rate,the specimen splits into multiple blocks and the crack width of the specimen gradually increases,finally forming a large penetrating crack on the splitting surface.(4)Planning to use ANSYS/LS-DYNA and LS-Prepost software for the aim of building the finite element model of dynamic splitting tensile test.The MAT BRITTLE DAMAGE model was used to simulate the dynamic splitting tensile test of concrete with lead-zinc tailing sand.And with the change of impact velocities,these are acquired that the splitting failure patterns and the stress-strain curves.Compared with the actual dynamic splitting tensile test,we found that there is very little variation in the stress-strain curves between numerical simulation and dynamic splitting test,and the parameters of the MAT BRITTLE DAMAGE constitutive model selected are reasonable and in line with the actual dynamic test conditions.The failure pattern of concrete splitting surfaces obtained by numerical simulation are similar to the actual dynamic tests,which well reproduces the failure state of concrete specimen in dynamic splitting tensile test. |
PDF Full Text Request