Research On Performance And Application Of Alkali Activated Steel Slag/Slag Cementitious Material

With the incessant expansion of our country’s industrial scale,the accumulation of common industrial solid wastes such as steel slag and slag has been increasing year by year,which has brought huge challenges to the development of our country’s cities.How to effectively use these solid wastes for high-level applications has always been a common concern of the entire industry.To solve this problem,this article selects material A as part of the alkaline excitation agent to motivate steel slag and slag,adds the right amount of NaOH,and material B as an intensifier to prepare alkali-activated steel slag/slag cementing materials,and replace the traditional cementitious materials to be used in sprayed concrete.It provides theoretical support for new green cementitious materials to replace cement and prepare sprayed concrete for application in the field of foundation pit support engineering.The main research contents of this paper are as follows:(1)Research on the mechanical properties of alkali-activated steel slag/slag cementitious materials.design the mix ratio according to the composition and characteristics of various solid waste.Through orthogonal test,choose the mix ratio of hightest compressive strength and flexural strength.And select four representative sets of mortar specimens for microscopic tests such as electron microscope scanning and energy spectrum testing.The study found that the 3d and 28 d flexural strengths of the alkali-activated steel slag-slag cementitious material under the optimal ratio can meet the 32.5 strength grade of slag portland cement,and it has early strength.Features of high flexural resistance and through scanning electron microscopy,it was found that the 28 d hydration product has high structural density and the best activation effect.(2)Research on the durability of alkali-activated steel slag/slag cementitious materials.In this paper,the durability of alkali-activated cementitious materials is tested through the dry shrinkage performance,frost resistance performance,and sulfate corrosion resistance performance tests.The results show that the dry shrinkage ratio of the prepared alkali-activated steel slag-slag cementitious material is less than 32.5 grade slag.Portland cement,the volume stability is relatively good,and the freezing resistance and sulfate erosion resistance are stronger than 32.5 grade slag cement.(3)Research on engineering of alkali-activated steel slag/slag cementitious material.Based on the excellent performance of the formulated alkali-activated steel slag/slag cementitious material.Use alkali-activated cementitious materials to replace c Portland Cement,and use iron tailings to strip the waste rock into coarse and fine aggregates,which are formulated into solid waste shotcrete.Through compressive strength test,split tensile strength test,permeability test and sulfate freeze-thaw corrosion test,the performance of concrete are researched.Relying on the foundation pit support project of a certain city in Liaoning Province,the sprayed concrete prepared in the indoor test was used for on-site test spraying.The study found that: when the amount of cementing material per square concrete is 435 kg,the water consumption is 200 kg,the coarse aggregate is 882.5kg,the fine aggregate is 882.5kg,the sprayed concrete has the best compressive strength and splitting tensile strength,and it has good permeability and resistance.Sulfate freeze-thaw erosion performance.Andthe sprayed concrete prepared by the indoor test was sprayed on site,the results show that this kind of all-solid waste sprayed concrete can better meet the actual needs of the construction site in the engineering construction,and the construction effect is good.