Study On Expansion Characteristics Of Steel Slag Particles And Properties Of Its Mixtures

With the rapid development of iron and steel industry at home and abroad,the accumulation of iron and steel slag accumulates year by year.However,the comprehensive utilization of steel slag is quite different at home and abroad.The residual value of steel slag has been well developed abroad.Some countries even use100% of steel slag.However,the utilization rate of steel slag in China is still relatively low.The main problems are foundation pit backfilling,roadbed use,cement and concrete mixture admixtures,etc.The comprehensive utilization of steel slag can not be changed slowly.For the waste of land resources,environmental problems,ecological damage and other conditions.In view of this situation,this paper observes and understands the utilization of steel slag base road,analyses the factors and changes of poor volume stability of steel slag,determines the law of water expansion of steel slag cylinder specimen,analyses the shape characteristics and physical parameters of steel slag particles in the process of water expansion,and tests the unconfined compressive strength of cement stabilized steel slag inorganic binder for 7d and 28 d,and adopts the numbers.Character image speckle technique was used to record the bending and tensile strength of beam specimens at 7d and 28 d and the displacement and deformation curves at the same rate to study the mechanism of steel slag expansion.The results show that the expansibility of steel slag is an important factor affecting the volume stability of road steel slag.The chemical composition of free calcium oxide and magnesium oxide can form 0.98%~1.14% expansion.The steel slag treated by immersion water can effectively reduce the expansion rate,but the strength of the corresponding mixture will be reduced and the integrity will be worse.The length-width ratio and the width ratio of steel slag particles before and after immersion are analyzed and calculated.Flatness,practical sphericity,sphericity,roundness and regularity are six parameters indicators.It is found that the shape parameters of particles have significant changes,and the particles also exhibit expansion and disintegration.The unconfined compressive strength and flexural-tensile strength of 7 days are less than 28 days as a whole,the maximum destructive force of 7 days is 110.1-131.7 kN,the strength value is 6.2-7.5 MPa,and the maximum destructive force of 28 days is153.6.The strength of cement-stabilized slag-macadam mixture is 8.7-10.4 MPa,the failure value of 7 days is near 10 kN,and the limit value of 28 days is about 14 kN.The strength of cement-stabilized slag-macadam mixture for 7 days and 28 days reaches the maximum when the replacement ratio of macadam-steel slag to volume is 60:40.