Test Research On The Effect Of Anti-Permeability And Anti-Sulfate Erosion On High-Silicon Iron Ore Tailings Concrete

The thesis regards the high-silicon iron ore tailings as the object of research, the tailings is from QiDaShan iron ore factory of Liaoning Anshan. The main chemical compositions of the tailings is SiO2, and the main mineral components is quartz, the granularity is mainly distributed in about 120 microns.According to the basic theory of mechanochemical, the tailings was milled, it shows that the granularity of D50 has reached to about 9.4 microns. Through the microscopic test of XRD, the crystallinity of SiO2 has reduced significantly, and the ash is qualified. After the mechanochemical activation, take the high-silicon iron ore tailings as auxiliary cementitious material of concrete, compound concrete in proportions of 10%、20%、30%、 40%.By experimenting the concrete, analyzed the effect of anti-permeability and anti-sulfate erosion. Sets 10 groups impermeability test, including two series of adding water reducing agent or not adding water reducing agent, Each series has 5 groups, include one group that without admixture and four groups that take the tailings displaced the concrete of cement.Make 20 groups test specimen of anti-sulfate erosion, include ten groups in rinsing and ten groups in sulfate solution. The study result shows that the impervious performance of high-silicon iron ore tailings concrete is superior to normal concrete. The quantity proportions of cement that instead by tailings reached to 30%, and the concrete that mixed with water reducing agent increased to 40%. The anti-sulfate erosion of cement concrete that partly replacing by tailings is superior to normal concrete, the quantity proportions of cement that instead by tailings can reach to 40%.The hardened cement pastes and tailings-cement hardened pastes was analyzed by XRD method. The analysis shows that during the same period, the Ca(OH)2 diffraction strongest peak of tailings-cement hardened pastes group are always below the hardened cement pastes group. Based on the basic theory of activation of mechanochemical and cementitious material science, the secondary hydration reaction was happened in tailings-cement hardened pastes group.