Application Research Of Steel Slag Solidified Or Stabilized Soil

Steel slag is a solid waste discharged in the process of smelting steel.It has significant economic and social benefits when used as a road engineering material.Steel slag has the excellent characteristics of high cementitious activity,hard texture,low crushing value,high density and good wear resistance,but it has the issue of poor stability.Soil is a large amount of road engineering materials,which has good plasticity,but high porosity and poor water stability.For the level of roadbed and road base,according to the technical requirements of roadbed filling materials and road base materials,combined with the characteristics of steel slag and soil.This paper put forward the design principles of steel slag solidified soil and cement-steel slag stabilized soil materials,and studied the composition design and road performance of steel slag solidified soil roadbed filling materials and cement-steel slag stabilized soil road base materials.Microscopic testing methods were used to reveal the action mechanism of steel slag on soil.The physical and chemical modification effects of steel slag on soil were analyzed by decoupling.In addition,relying on the entity demonstration project,the construction key technology,engineering application effect,economic and social benefits of steel slag solidified soil roadbed filling material and cement-steel slag stabilized soil road base material were studied.By analyzing the technical requirements of roadbed filling materials and road base materials,and according to the characteristics of steel slag and soil.The structural models of steel slag solidified soil for roadbed filling materials and cement-steel slag stabilized soil for road base materials were constructed,and the issue to be solved were clarified.Therefore,the experimental design methods of steel slag solidified soil and cement-steel slag stabilized soil materials were put forward.For the roadbed filling materials,the effects of steel slag type,content and particle size on California bearing ratio(CBR),water absorption and expansion rate of steel slag solidified soil materials were discussed.The action mechanism of steel slag on soil was revealed by means of XRD(X-ray diffraction),FTIR(Fourier transform infrared spectroscopy)and SEM-EDS(scanning electron microscope-energy dispersive spectrometer).In addition,the physical and chemical modification effects of steel slag on soil were decoupled and analyzed by comparing the differences between the effects of steel slag and iron tailings mechanized sand solidified soil.The results showed that the CBR value,water absorption and expansion rate of solidified soil change due to the differences of physical and chemical properties of steel slag.The CBR value of solidified soil increases significantly with the increase of steel slag content and the decrease of steel slag particle size.While the water absorption and expansion rate of solidified soil decrease significantly with the increase of steel slag content and the decrease of steel slag particle size.The microscopic test results showed that the hydration reaction and ion exchange reaction occur after the steel slag is mixed into the soil.The decoupling analysis showed that the chemical modification effect of steel slag is dominant.The physical and chemical modification effect increases with the decrease of steel slag size.The physical modification effect does not change with the increase of age,but the chemical modification effect increases with the increase of age.For the road base material,the effects of steel slag content and cement dose on the unconfined compressive strength and splitting strength of cement-steel slag stabilized soil material were discussed.And the effects of steel slag content on the volume stability and durability of cement-steel slag stabilized soil material were studied.The results showed that the mechanical properties of cement-steel slag stabilized soil material are significantly improved with the increase of steel slag content and cement dose.Its drying-shrinkage resistance performance is significantly improved with the increase of steel slag content.While its water stability and frost resistance are firstly improved and then decreased with the increase of steel slag content.Relying on the entity demonstration project,the key construction technology,engineering application effect,economic and social benefits of steel slag solidified soil roadbed filling material and cement-steel slag stabilized soil road base material were studied.The results indicated that steel slag solidified soil and cement-steel slag stabilized soil are constructed according to the field mixing method,the engineering application effect are excellent,and have remarkable economic and social benefits.