Study On Mechanical Properties Of Cement Stabilized Steel Slag Base

China is a large country with iron and steel production capacity,and Handan,Hebei Province is also an important steel production capacity area.The output of steel slag as an industrial by-product of steelmaking is about 1/10 of that of crude steel.Compared with the full utilization of steel slag in Europe,the United States,Japan and other developed countries,the current utilization rate of steel slag in China is only 30%,and most of the rest have not been properly dealt with,but the occupation of cultivated land affects the environment.On the other hand,with the vigorous development of infrastructure construction in our country,the mining of stone is more and more,resulting in the depletion of resources and the destruction of the environment.Compared with ordinary stone,steel slag used as road material has many advantages,such as rough surface,hard,wear resistance and so on,but it also has the disadvantage of easy expansion with water.The purpose of this paper is to study the application of steel slag as aggregate in semi-rigid base,so as to further improve the use of steel slag in China,reduce the demand for stone,the impact of the environment.The research contents and results of this paper are as follows:1.Study on Microstructure and chemical composition of steel slag and its expansibility.In this paper,by means of microscopic electron microscope test,X-ray diffraction and X-ray fluorescence spectrum analysis,the alkalinity is calculated theoretically,and the dilatancy is determined by immersion expansion test.The test results show that the steel slag used in this test is mainly oxides of calcium,iron and silicon,accounting for about 80%of its composition.The micro-electron microscope shows that the surface of steel slag is rough and has obvious pore structure,and the alkalinity of steel slag is about 3,which belongs to medium and low alkalinity steel slag.The immersion expansion test of steel slag shows that its expansion rate is about 1.2%,which is less than 2% required by the code.2.Study on the mix ratio design,mechanical properties test and strength mechanism of steel slag base.According to the gradation distribution of steel slag and gravel,the mixture ratio is designed and the specimen is formed,and the mechanical tests of the specimens are carried out.and the statistical analysis results show that the addition of steel slag can improve the compressive strength,splitting strength and other mechanical properties of the semi-rigid base,and the 7d strength of the specimen obtained by vibration compaction is basically above 7MPa,and the average strength of 90 d can reach 10 MPa,modulus of resilience in 2000-2500 MPa,splitting strength in 0.72-1.56 MPa and flexural tensile strength in 1.03-1.9MPa.The morphology,material composition and element distribution of the hydration products are captured by electron microscope and energy spectrum experiments.3.The temperature shrinkage,drying shrinkage and fatigue properties of the composites are studied on the basis of excellent mechanical properties.The results show that the addition of steel slag can reduce the dry shrinkage coefficient of semi-rigid base and increase the temperature shrinkage coefficient.On the premise of ensuring excellent gradation,the addition of steel slag increase the fatigue performance of the base,and the fatigue equations with 95% and 50% guarantee rate are obtained.The research results of this paper are of great theoretical and practical significance for saving resources and protecting the environment and reducing Semi-rigid base diseases to improve the quality of road engineering in China.