Preparation method and application of modified silica fume material

Abstract

The invention relates to a preparation method of a modified silica fume material, which belongs to the technical field of building materials, and comprises the following steps: adding silica fume into absolute ethyl alcohol, and uniformly dispersing to obtain silica fume dispersion liquid; and adding a silane coupling agent into deionized water, adding the prepared silane coupling agent hydrolysate into the silica fume dispersion liquid, placing in a water bath at 60-80 DEG C, magnetically stirring, filtering after completion, cleaning filter residues with deionized water, and finally performing vacuum drying and grinding to obtain the modified silica fume material. The silane coupling agent is adopted to modify the silica fume, amino silane reacts with silicon hydroxyl on the silica fume, the Zeta potential on the surface of the silica fume changes, negative charges are changed into positive charges, the steric hindrance among silica fume particles is increased, the number of large particles of the modified silica fume is reduced, and particle size distribution is more concentrated; and after the modified silica fume is doped into the fly ash cement, the fluidity of fly ash cement neat paste is improved, the dispersity of the modified silica fume is improved, and the early strength of the fly ash cement is improved.

Description

Technical field [0001] The present invention relates to a method of preparing modified silica ash material, belonging to the technical field of building materials. Background technique [0002] Fly ash cement refers to cement mixed from a fly ash and ordinary silicate cement. Due to the containing fly ash, it is low, and its hydration is low, the dry shrinkage is small, and the late intensity is high. However, its pre-strength has fallen sharply. The same is a volcanic ash, and the activity of the silicon ash is high, and the development of silica gray is blended into the drum cement, which has a certain help in the development of its previous strength. [0003] Silica ash, also known as silica powder, is a derivative produced when the industrial production of silicon metal is usually silicone ash. 2 The content is higher than 80%. With an appropriate amount of silicone ash instead of cement, silica ash will occur in the cement slurry, the micro-collective effect, the initial in ...

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Problems solved by technology

The process of the silica fume dispersion method is complicated, and it is prone to secondary agglomeration when it is mixed into the cement slurry with high alkalinity, which will reduce the compactness of the cement matrix; the Chinese invention patent application with the application number CN201510975172.5, published The silica fume dispersion modification method is through a certain concentration of Ca(OH) 2 The solution pre-treats the surface of silica fume to change the negative charge of the surface to positive charge, so as to achieve better dispersion effect. The method is to mix silica fume with Ca(OH) 2 In solution, by mixing with Ca(OH) 2 The reaction is used to modify the surface charge of silica fume. During the reaction process, silica fume will be consumed to a certain extent, which is not conducive to the subsequent improvement of the performance of the cement matrix, and has certain limitations.

There are also researchers who use mechanical ball milling and ultrasonic dispersion to disperse silica fume, but the final use effect in cement-based materials is not good.

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