阅读说明：本技术 一种混凝土外加剂的制备方法 (preparation method of concrete admixture ) 是由 刘西 盛侃 于 2019-09-20 设计创作，主要内容包括：本发明实施例公开了一种混凝土外加剂的制备方法,包括步骤一、称取二氧化硅,将二氧化硅粉碎后备用；步骤二、将三聚氰胺放入装有去离子水的容器中,搅拌升温,使三聚氰胺完全溶解,然后保持温度不变,在常压下加入烧碱溶液并调节pH值,反应结束后制得三聚氰胺和三聚氰酸的混合水溶液；步骤三、向步骤二制备的三聚氰胺和三聚氰酸的混合水溶液中加入水性聚氨酯,搅拌升温后,进行恒温反应,制得聚氨酯组合树脂水溶胶；步骤四、将聚氨酯组合树脂水溶胶与步骤一粉碎后的二氧化硅混合,搅拌均匀后精磨,制得所述的混凝土外加剂。本发明通过高温提纯和研磨,得到粒度小于1μm的二氧化硅粉料,火山灰水化活性更高,对促进混凝土早强起到积极作用。(the embodiment of the invention discloses a preparation method of a concrete admixture, which comprises the following steps of weighing silicon dioxide, and crushing the silicon dioxide for later use; step two, putting melamine into a container filled with deionized water, stirring and heating to completely dissolve the melamine, then keeping the temperature unchanged, adding a caustic soda solution under normal pressure, adjusting the pH value, and obtaining a mixed aqueous solution of the melamine and cyanuric acid after the reaction is finished; step three, adding waterborne polyurethane into the mixed aqueous solution of melamine and cyanuric acid prepared in the step two, stirring and heating, and then carrying out constant-temperature reaction to prepare polyurethane combined resin hydrosol; and step four, mixing the polyurethane combined resin hydrosol with the silicon dioxide crushed in the step one, uniformly stirring and finely grinding to obtain the concrete admixture. According to the invention, through high-temperature purification and grinding, the silicon dioxide powder with the granularity of less than 1 mu m is obtained, the volcanic ash hydration activity is higher, and the method plays a positive role in promoting the early strength of concrete.)

1. The preparation method of the concrete admixture is characterized by comprising the following steps:

Step one, weighing silicon dioxide, and crushing the silicon dioxide for later use;

Step two, putting melamine into a container filled with deionized water, stirring and heating to completely dissolve the melamine, then keeping the temperature unchanged, adding a caustic soda solution under normal pressure, adjusting the pH value, and obtaining a mixed aqueous solution of the melamine and cyanuric acid after the reaction is finished;

Step three, adding waterborne polyurethane into the mixed aqueous solution of melamine and cyanuric acid prepared in the step two, stirring and heating, and then carrying out constant-temperature reaction to prepare polyurethane combined resin hydrosol;

And step four, mixing the polyurethane combined resin hydrosol with the silicon dioxide crushed in the step one, uniformly stirring and finely grinding to obtain the concrete admixture.

2. The method for producing a concrete admixture according to claim 1, characterized in that: the preparation method of the silicon dioxide comprises the steps of placing the silicon ash into an environment with the temperature of 1000-1100 ℃ for roasting, and then removing impurities.

3. The method for producing a concrete admixture according to claim 2, characterized in that: the purity of the silica fume is more than 95%.

4. The method for producing a concrete admixture according to claim 1, characterized in that: the particle size of the crushed silicon dioxide is less than 1 mu m.

5. The method for producing a concrete admixture according to claim 1, characterized in that: and the molar ratio of the melamine to the deionized water in the second step is 1: 20.

6. the method for producing a concrete admixture according to claim 1, characterized in that: and in the second step, the temperature is increased to 70 ℃ by stirring.

7. The method for producing a concrete admixture according to claim 1, characterized in that: the concentration of the caustic soda solution is 30% by mass, and the pH value is adjusted to 11-13.

8. the method for producing a concrete admixture according to claim 1, characterized in that: in the third step, the mass percentage concentration of the waterborne polyurethane is 30%, and the molar ratio of the melamine to the waterborne polyurethane is 1: 3.

9. The method for producing a concrete admixture according to claim 1, characterized in that: and step three, stirring and heating to 150 ℃, and carrying out constant-temperature reaction under the reaction pressure of 0.4-0.6 Mpa.

10. The method for producing a concrete admixture according to claim 1, characterized in that: the mol ratio of the polyurethane combined resin hydrosol to the silicon dioxide is 1: 0.5-1.

Technical Field

the embodiment of the invention relates to the technical field of building material processing, in particular to a preparation method of a concrete admixture.

Background

The concrete is an artificial stone material which is prepared by mixing a cementing material, an aggregate and water according to a proper proportion, and then blending, molding and hardening the mixture. The concrete admixture (material) is added before or during the mixing of the concrete to improve the performance of the fresh concrete or the hardened concrete. Therefore, according to the characteristics of the concrete in the processes of mixing, conveying and hardening, the rheological property, the durability and other properties need to be improved by adding additional materials, and finally the mechanical requirements of the hardened concrete are met.

At present, the effect of concrete admixture is poor due to the influence of physicochemical properties of various materials, process requirements and the like, and the normal use of the concrete admixture is seriously influenced.

Disclosure of Invention

therefore, the embodiment of the invention provides a preparation method of a concrete admixture, which aims to solve the problem of poor effect of the concrete admixture in the prior art.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

According to a first aspect of embodiments of the present invention, there is provided a method for preparing a concrete admixture, comprising the steps of:

step one, weighing silicon dioxide, and crushing the silicon dioxide for later use;

Step two, putting melamine into a container filled with deionized water, stirring and heating to completely dissolve the melamine, then keeping the temperature unchanged, adding a caustic soda solution under normal pressure, adjusting the pH value, and obtaining a mixed aqueous solution of the melamine and cyanuric acid after the reaction is finished;

Step three, adding waterborne polyurethane into the mixed aqueous solution of melamine and cyanuric acid prepared in the step two, stirring and heating, and then carrying out constant-temperature reaction to prepare polyurethane combined resin hydrosol;

And step four, mixing the polyurethane combined resin hydrosol with the silicon dioxide crushed in the step one, uniformly stirring and finely grinding to obtain the concrete admixture.

Further, the preparation method of the silicon dioxide comprises the steps of placing the silicon ash into an environment with the temperature of 1000-1100 ℃ for roasting, and then removing impurities.

Further, the purity of the silica fume is more than 95%.

Furthermore, the particle size of the crushed silicon dioxide is less than 1 μm.

further, the molar ratio of the melamine to the deionized water in the second step is 1: 20.

Further, in the second step, the temperature was raised to 70 ℃ by stirring.

Further, in the second step, the concentration of the caustic soda solution is 30% by mass, and the pH value is adjusted to 11-13.

further, in the third step, the mass percentage concentration of the waterborne polyurethane is 30%, and the molar ratio of the melamine to the waterborne polyurethane is 1: 3.

Further, in the third step, the temperature is raised to 150 ℃ by stirring, and the constant temperature reaction is carried out, wherein the pressure is 0.4-0.6 Mpa.

Furthermore, the molar ratio of the polyurethane combined resin hydrosol to the silicon dioxide is 1: 0.5-1.

The embodiment of the invention has the following advantages: the embodiment of the invention provides a preparation method of a concrete admixture, which is characterized in that silicon dioxide powder with the granularity of less than 1 mu m is obtained through high-temperature purification and grinding, the volcanic ash hydration activity is higher, and the preparation method plays a positive role in promoting the early strength of concrete. In addition, the polyurethane combined resin hydrosol with the water reducing function is uniformly mixed with the active silicon dioxide powder with the granularity less than 1 mu m, so that the specific surface adsorption is overcome to a certain degree, the addition of the active silicon dioxide is greatly improved, and the coagulation accelerating and early strength performance of the concrete additional material is more excellent.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

FIG. 1 is a particle size distribution diagram of Portland cement provided in application example 1 of the present invention;

FIG. 2 is one of the electron micrographs of Portland cement provided in application example 1 of the present invention;

FIG. 3 is a second photograph of a portland cement provided in application example 1 according to the present invention under an electron microscope;

FIG. 4 is one of the electron micrographs of the concrete admixture, which is provided in application example 1, of the present invention;

FIG. 5 is a second drawing of an electron microscope of the concrete admixture according to application example 1 of the present invention;

FIG. 6 is a specific surface area of a concrete admixture according to application example 1 of the present invention;

FIG. 7 shows the influence of the concrete admixture provided in application example 1 of the present invention on the tapping strength of aerated concrete.

FIG. 8 is a flow chart showing a process for producing a concrete admixture, which is provided in example 1 of the present invention.

Detailed Description

the present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.