阅读说明：本技术 一种利用纳米二氧化硅改性的再生骨料及其制备方法和应用 (Recycled aggregate modified by nano-silica and preparation method and application thereof ) 是由 李培龙 于 2020-07-03 设计创作，主要内容包括：本发明属于新型建筑材料技术领域,公开一种利用纳米二氧化硅改性的再生骨料及其制备方法和应用。该方法是将纳米二氧化硅加入中搅拌,配置成纳米二氧化硅溶液；然后将再生骨料浸泡在盐酸溶液中,除去表面残余砂浆,滤干后,自然风干,得到预处理的再生骨料；再将预处理的再生骨料放入纳米二氧化硅溶液中静止,取出自然风干,制得纳米二氧化硅改性的再生骨料。本发明改性的再生骨料更具有更好的力学性能和耐久性能。纳米二氧化硅能更好地分散在再生骨料中,聚团少,经浸泡的纳米二氧化硅能填充再生骨料内部微观孔隙,提高再生骨料的抗压性能,耐久性能,降低空隙率,有效提升了再生骨料的利用率。(The invention belongs to the technical field of novel building materials, and discloses a recycled aggregate modified by nano-silica, and a preparation method and application thereof. Adding nano silicon dioxide into the solution, and stirring the mixture to prepare nano silicon dioxide solution; then soaking the recycled aggregate in a hydrochloric acid solution, removing residual mortar on the surface, filtering, drying, and naturally drying to obtain a pretreated recycled aggregate; and then placing the pretreated recycled aggregate into a nano silicon dioxide solution for standing, taking out and naturally drying to prepare the nano silicon dioxide modified recycled aggregate. The modified recycled aggregate has better mechanical property and durability. The nano silicon dioxide can be better dispersed in the recycled aggregate, the agglomeration is less, the soaked nano silicon dioxide can fill the microscopic pores in the recycled aggregate, the compression resistance and the durability of the recycled aggregate are improved, the porosity is reduced, and the utilization rate of the recycled aggregate is effectively improved.)

1. A method for utilizing nano-silica modified recycled aggregate is characterized by comprising the following specific steps:

s1, adding nano silicon dioxide into the mixture and stirring the mixture to prepare a nano silicon dioxide solution;

s2, soaking the recycled aggregate in a hydrochloric acid solution, removing residual mortar on the surface, filtering, and naturally drying to obtain a pretreated recycled aggregate;

and S3, placing the pretreated recycled aggregate into the nano silicon dioxide solution obtained in the step S1, standing, taking out, and naturally drying to obtain the nano silicon dioxide modified recycled aggregate.

2. The method for recycling aggregate modified with nanosilica as claimed in claim 1, wherein the stirring speed in step S1 is 200-300 rpm.

3. The method for recycling aggregate modified by using nano-silica as claimed in claim 1, wherein the nano-silica in step S1 is hydrophobic nano-silica having a particle size of 10 to 20nm, and the nano-silica solution has a concentration of 2 to 3 wt.%.

4. The method for recycling the aggregate modified by using nano-silica as claimed in claim 1, wherein the recycled aggregate in step S2 is a primary recycled coarse aggregate, and the recycled aggregate has a particle size of 5 to 20 mm.

5. The method for recycling aggregate modified by nanosilicon dioxide as claimed in claim 1, wherein the concentration of the hydrochloric acid solution in step S2 is 2-3%, and the soaking time is 3-5 min.

6. The method for recycling aggregate modified by nano-silica according to claim 1, wherein the mass ratio of the hydrochloric acid solution to the recycled aggregate in step S2 is (1-2): 1.

7. the method for recycling aggregate modified by using nano-silica as claimed in claim 1, wherein the standing time in the step S3 is 12-24 hours.

8. The method for recycling aggregate modified by nanosilica according to claim 1, wherein the mass ratio of the nanosilica solution to the pretreated recycled aggregate in step S3 is (1-2): 1.

9. a nanosilica-modified recycled aggregate, characterised in that the modified recycled aggregate is made by the method of any of claims 1 to 8.

10. Use of the nanosilica-modified recycled aggregate of claim 9 in the field of the preparation of concrete.

Technical Field

The invention belongs to the technical field of novel building materials, and particularly relates to a recycled aggregate modified by utilizing nano silicon dioxide, and a preparation method and application thereof.

Background

The technology of using the nano silicon dioxide modified material is widely researched in all engineering circles, and the recycled aggregate is low in strength, large in porosity and coated with a layer of cement slurry on the surface, so that the recycled aggregate is prevented from being widely applied to engineering. The nano silicon dioxide is used for improving the material property of the recycled aggregate, and the material property of the recycled aggregate can be effectively improved. After the nano-silica solution is soaked, the nano-silica particles can fill microscopic pores in the recycled aggregate, and meanwhile, the bonding surface of the recycled aggregate and the new cement mortar is improved, and the compression resistance of the recycled aggregate is improved.

Disclosure of Invention

In order to solve the disadvantages and shortcomings of the prior art, the present invention aims to provide a method for modifying recycled aggregate by using nano silica. According to the method, the recycled aggregate is soaked in the nano silicon dioxide solution, so that the material performance of the recycled aggregate is improved.

The invention also aims to provide the modified recycled aggregate prepared by the method.

The invention further aims to provide application of the modified recycled aggregate.

The purpose of the invention is realized by the following technical scheme:

a method for utilizing nano-silica modified recycled aggregate comprises the following specific steps:

s1, adding nano silicon dioxide into the mixture and stirring the mixture to prepare a nano silicon dioxide solution;

s2, soaking the recycled aggregate in a hydrochloric acid solution, removing residual mortar on the surface, filtering, and naturally drying to obtain a pretreated recycled aggregate;

and S3, placing the pretreated recycled aggregate into the nano silicon dioxide solution obtained in the step S1, standing, taking out, and naturally drying to obtain the nano silicon dioxide modified recycled aggregate.

Preferably, the stirring speed in the step S1 is 200-300 r/min.

Preferably, in the step S1, the nano-silica hydrophobic nano-silica has a particle size of 10-20 nm, and the concentration of the nano-silica solution is 2-3 wt.%.

Preferably, the recycled aggregate in the step S2 is a primary recycled coarse aggregate, and the recycled aggregate has a particle size of 5-20 mm.

Preferably, the concentration of the hydrochloric acid solution in the step S2 is 2-3%, and the soaking time is 3-5 min.

Preferably, the mass ratio of the hydrochloric acid solution to the recycled aggregate in the step S2 is (1-2): 1.

preferably, the resting time in the step S3 is 12-24 h.

Preferably, the mass ratio of the nano-silica solution to the pretreated recycled aggregate in the step S3 is (1-2): 1.

the nano-silica modified recycled aggregate is prepared by the method.

The application of the nano silicon dioxide modified recycled aggregate in the field of concrete preparation.

Compared with the prior art, the invention has the following beneficial effects:

1. the recycled aggregate modified by the method has better mechanical property and durability than the common recycled aggregate.

2. The preparation method provided by the invention has the advantages of simple operation and strong practicability, and the selected oxidized hydrophobic nano-silica is uniformly dispersed in the recycled aggregate, so that the effect is better than that of a common nano-silica solution.

3. The recycled concrete can meet the application of special occasions of special projects, and the application range of the recycled concrete is widened.

Detailed Description

The following examples are presented to further illustrate the present invention and should not be construed as limiting the invention. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

The recycled aggregate adopted in the embodiment of the invention is a continuous graded recycled aggregate, and the particle size is 5-20 mm; the nano silicon dioxide is oxidized hydrophobic nano silicon dioxide with the particle size of 10-20 nm.