Study Of Copper Slag Alkali-Excited Cementitious Material To Solidify Soil

With the rapid development of my country’s economy,the investment in road transportation and other infrastructure has been increasing.At present,the traditional road performance research of solidified soil mainly focuses on cement solidified soil,two-ash solidified soil and so on.Traditional solidified soil has the disadvantages of poor water stability,poor early strength,high cost,etc.,and it will also cause harm to the environment during the mining and use of raw materials.Copper slag is a kind of industrial slag,and its large-scale stockpiling not only consumes land resources,but also harms the environment.In order to reduce the consumption of resources and environmental pollution,following the concept of"turning waste into treasure",the use of low-cost copper slag instead of part of the cement to solidify the soil can not only achieve the purpose of improving the strength of the soil,but also solve the problem of copper The slag storage and environmental pollution problems have also reduced costs and achieved economic and environmental double benefits.First,the basic mechanical properties of copper slag cementitious materials were studied through indoor tests.On this basis,unconfined compressive strength tests,consolidation compression tests and freeze-thaw cycle tests were carried out to determine the mechanical properties and frost resistance of solidified soils.Were studied.X-ray diffraction（XRD）and scanning electron microscopy（SEM）were used to analyze the phase components and microscopic morphology of the hydration products,and to explore the solidification mechanism of the cement copper slag solidified soil.The main research content and research results of this article are as follows:（1）Research on the basic mechanical properties of copper slag cementitious materialsNaOH as an alkali activator can activate the activity of copper slag and effectively promote the hydration reaction process.The strength of copper slag alkali-activated cementitious material increases first and then decreases with the increase of W/C and NaOH content.The setting time and compressive strength of copper slag cement composite cementitious materials are affected by the W/C and copper slag blending amount.The strength increases slightly with the copper slag blending amount,and increase first and then decrease with the increase of W/C.（2）Research on mechanical properties and frost resistance of cement-copper slag solidified soilCement copper slag can improve the compressive strength of solidified soil.Under the same condition of curing age and cement copper slag ratio,the unconfined compressive strength of solidified soil increases with the increase of additives.The compressibility of solidified soil gradually decreases with the increase of admixture content and curing age.When the admixture content is 8%and the cement copper slag ratio is 6:2,the soil body changes from highly compressible soil after seven days of curing.For low compressibility soil,admixtures can significantly improve the compressibility of the soil.The incorporation of admixtures can improve the frost resistance of solidified soil.After ten freeze-thaw cycles,the strength loss rate and quality loss The rates all meet the freeze resistance index of solidified soil.（3）Study on the solidification mechanism of cement copper slag solidified soilThrough XRD and SEM microscopic test techniques,the solidification mechanism of cement copper slag solidified soil was studied.The test results show that a series of hydration reactions will occur after the soil is mixed with cement copper slag,and cementitious substances such as C-S-H,C-A-H,AFt and Fe（OH）₂/Fe（OH）₃are formed.The cementitious substances are filled in In the gap between the soil particles,the soil particles are cemented with each other,so that the soil structure is more compact and the strength is improved,so as to achieve the purpose of solidifying the soil.