Application Of Unaged Steel Slag In Cement Stabilized Crushed Stone Base Course

Although steel slag is a by-product of the steelmaking process,the degree of utilization of steel slag in China is very low,resulting in the accumulation of large amounts of waste steel slag and occupation of land resources.The properties of steel slag are similar to those of ordinary crushed stone and have been studied to apply it to road bases.Since the steel slag has a certain degree of swell ability,the steel slag that is naturally aged to a stable one is generally used in the research.This paper attempts to apply the new steel slag within 2 weeks of age to the cement stabilized macadam base,which is of great significance for improving the utilization rate of steel slag,saving highway construction cost,and saving land resources and protecting the environment.This article first tested the expansivity of the new steel slag within 2 weeks of age which produced from Yuanli steel plant in Quzhou city and its water swell rate was found not meet the specification requirements.After testing,it was found that 0.5% of the silica ash content can effectively inhibit the expansion of the slag to reduce the immersion water swelling rate by 91%.requirements.And 0.5% silica fume can make the immersion water swelling rate meet the specification requirementsIn the study of raw materials,aggregate image measurement system(AIMS)was used to measure and analyze the particle shape and surface characteristics of steel slag and gravel.Under the premise of uniform grading,cement,and silica ash content,0%,25%,50%,and 75% new steel slag was added to the cement stabilized macadam,and the mechanical properties,performance,durability,compaction performance of the test specimens with different slag contents were tested respectively.The study found that the angularity and surface texture of the steel slag was more abundant than that of the gravel.The steel slag was larger than that of the gravel and was closer to the sphere.The acceleration value of the cement stabilized steel slag gravel with different steel slag content under the same compaction work was tested by using a rapid test device for cement stabilized macadam compaction degree.It was found that the greater the amount of steel slag,the worse the compaction performance of the cement stabilized steel slag gravel base layer。The addition of a 0.5% dose of silica fume to the new steel slag within 2 weeks of age guarantees that its expansion meets the requirements,and that the new steel slag after the addition of silica fume can be applied to the road base to replace part of the gravel.Considering the trend of the mechanical properties and durability of cement stabilized steel slag gravel,and the trend of compaction performance changing with the steel slag content,when more steel slags are utilized as much as possible,this study believes that the reasonable reference content of new steel slag should not exceed 50%,and the specific application needs to be combined with the actual needs of the mixture ratio test.