| Alkali activated cementitious material is a silicon aluminium inorganic cementitious materials, it is containing aluminosilicate minerals, building garbage and industrial waste, at room temperature or low temperature conditions, the prepared by alkali activator of a novel inorganic cementitious material. With fast hard early strength, strong corrosion resistance, high temperature resistance, high permeability resistance, etc.. Ffflorescence serious, greater brittleness of alkali activated materials still needs to be further improved, the nano materials can improve alkali activated materials for a variety of performance, in particular, can effectively improve the mechanical properties and effectively inhibit efflorescence of alkali activated materials.Large surface area, with high surface energy, can effectively reduce the porosity of the alkali activated materials, improve the density, and promote the hydration and hardening of the base material. The mechanical properties of the alkali activated materials can be improvedby nano materials, and has a significant inhibitory effect on the efflorescence. In this paper, we mainly study of Slag Based Alkali activated materials with steel slag, slag as the main raw material, with water glass as activator, nano alumina and nano silica as modified materials, using mechanical stirring and ultrasonic dispersion of dispersed, by injection molding method for the preparation of steel slag based alkali activated cementitious materials. Use nano materials on the improving of mechanical properties and efflorescence of alkali activated materials, the research of nanometer materials modified slag based alkali activated materials mechanism, specify the experiment scheme. Through press and pressure mercury, XRD, TG-DSC, SEM, hydration heat and titration experiments on the mechanical properties, porosity, hydration product, microstructure and efflorescence degree were analyzed. Through the experiment can be found the rules of nano material modify of alkali activated materials.Incorporation of nano silica, nanometer alumina and silica fume on alkali excitation material mechanical properties were improved, can be found in the same nano material of alkali excited improvement effect on the compressive strength of the material, with the decrease in diameter gradually increased. When the same kind of nano materials, the improvement effect of the mechanical agitation method on the strength of the nano material sample is lower than that of the ultrasonic dispersion. Using ultrasonic dispersion, the effect of the modified effect by nano silica is higher than that of the nano alumina and silicon oxide compound admixtures, complex doped nano material improvement effect is higher than that of the nano alumina, and the improvement effect of nano alumina is higher than that of silica fume. The increase rate of the early strength of nano silicon oxide reached 101.89%, and the late strength increase rate was only 37.89%, so the effect of nano materials on early strength was higher than that in the late stage.Study found that the greater the efflorescence of activator content more serious, when the water glass as 1.0 mode, sample efflorescence degree lowest when the modulus is increased or decreased, efflorescence degree were increases. When the content of NS1 and NS2 was 2%, the solution concentration of the sample was decreased by 13.66% and 32.57% compared with that of the blank sample. The smaller the diameter of nanoparticles inhibiting effect on efflorescence of the more obvious.The incorporation of nano materials can play a nucleation effect, micro particle filling effect and high active volcanic ash effect. Improve the hydration rate of specimen, specimen can effectively reduce the porosity and improve the content of hydration products in the specimen but does not affect the basic kinds of hydration products, can reduce the setting time, improve the sample strength and reduce the efflorescence degree of specimen. |
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