Study on the Stability of Chemically Modified Steel Slag Powder and Its Slurry Properties
In order to improve the stability and mechanical properties of steel slag powder,the modification test of raw steel slag was carried out.The changes in mineral composition of steel slag powder before and after modification,as well as the hydration activity,strength development and stability of modified steel slag powder composite cement were studied by characterization methods such as X-ray,Fourier transform infrared spectros-copy and hydration calorimetry.The results showed that some CaCO3,Ca(OH)2 and calcium ferrite reacted with H2SO4 to form CaSO4.The exothermic hydration and calcium-silica ratio of alkali-activated steel slag were low,and the crystallization of Ca(OH)2 was reduced,which affected the strength development.Water vapor accelerated the hydration reaction of f-CaO,which significantly improved the late strength of the composite slurry.The mod-ified steel slag powder promoted the hydration reaction of the original steel slag slurry and the active minerals.The 48 h heat of hydration of the steel slag slurry modified with weak acid,weak base,strong acid,strong base,mineral powder and water vapor was enhanced by 2.50%,-72.62%,81.67%,42.99%and 110.63%,respectively,as compared to that of the original steel slag.The alcoholic amine promoted the formation of AFt and AFm and in-duced the structure to be densified,but the mill aid modification had limited stabilization improvement of the slurry.
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