A bio-based hybrid polymeric water-repellent cementitious material and a method of making the same

Abstract

The application discloses a kind of bio-based hybrid polymerization water-repellent cementitious materials and preparation method thereof, belong to building material technical field, solve the problem that traditional cement-based cementitious material is easy to scatter in water, pollute environment and low later strength when used for underwater construction, the water-repellent cementitious material is composed of the following mass parts of raw materials: 100 parts of fast hardening cement, 25-50 parts of stone powder, 25-50 parts of fly ash, 10-15 parts of silica powder, 25-35 parts of metakaolin, 0-10 parts of nano clay, 1-2 parts of water reducing agent, 0.5-5 parts of starch, 30-60 parts of water, 5-10 parts of organic monomer, 0.05-0.3 parts of initiation system and 0.005-0.05 parts of crosslinking agent.The water-repellent cementitious material prepared by the application has good dispersion resistance and water repellency underwater, maintains the integrity of components to facilitate the full hydration reaction, and has higher mechanical compressive strength.

Description

[Technical Field]

[0001] This invention belongs to the field of building materials technology, specifically relating to a bio-based hybrid polymer water-repellent cementitious material and its preparation method. [Background Technology]

[0002] Cement-based cementitious materials have extremely wide applications in civil engineering and are the most widely used building materials. However, during underwater construction, traditional cement-based cementitious material mixtures are easily eroded by water, resulting in problems such as aggregate segregation and cement loss, which compromises concrete quality and can easily pollute the aquatic environment. To improve construction quality and reduce pollution, various methods of water isolation and dewatering treatment must be adopted, which greatly increases the difficulty and cost of construction. With the continuous development and increase of underwater engineering, higher requirements are placed on the selection of cementitious materials and construction processes used in underwater construction to ensure construction quality and reduce costs. Cementitious materials must possess properties such as non-segregation underwater and low water seepage.

[0003] Chinese invention patent CN106747146A discloses an underwater anti-dispersion cement-based grouting material, which uses UWB-II and cellulose ether-based anti-dispersion agents. The prepared cement-based grouting material has low cement loss and good anti-dispersion and fluidity after being injected into water. However, it has disadvantages such as large dosage of anti-dispersion agent and high cost, which limits its application in practical engineering.

[0004] Chinese invention patent CN101607807A discloses a polyurethane cement composite material that combines the advantages of both polyurethane slurry and cement slurry. The resulting composite material overcomes the disadvantage of easy loss under the action of flowing water. However, it has the disadvantage of low compressive strength after consolidation, making it difficult to meet the mechanical strength design requirements.

[0005] Therefore, there is an urgent need to develop a cement-based binder that can effectively resist water flow and has high strength after hardening in water. This is of great significance for the construction of underwater structures, the extension of service life, and the promotion of environmental protection. [Summary of the Invention]

[0006] In order to overcome the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a bio-based hybrid polymer water-repellent cementitious material and its preparation method, which can effectively resist water flow and has high strength after solidification and hardening in water.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A bio-based hybrid polymer water-repellent cementitious material, wherein the water-repellent cementitious material comprises, by weight, the following components: 100 parts rapid-hardening cement, 30-60 parts water, 25-50 parts stone powder, 25-50 parts fly ash, 10-15 parts silica fume, 25-35 parts metakaolin, 0-10 parts nano-clay, 1-2 parts water-reducing agent, 0.5-5 parts starch, 5-10 parts organic monomer, 0.05-0.3 parts initiation system, and 0.005-0.05 parts crosslinking agent.

[0009] Preferably, the stone powder has a particle size of 10-50 μm, the fly ash has a specific surface area of ​​300-600 m² / kg, the silica powder has a particle size of 5-30 μm, and the metakaolin has a specific surface area of ​​500 m² / kg; the stone powder, fly ash, silica powder, and metakaolin are compounded to obtain aggregate.

[0010] Preferably, the nano-clay is nano-montmorillonite with a particle size of 10-50 nm; and / or, the starch is any one or any combination of two or more of corn starch, sweet potato starch, and glutinous rice starch.

[0011] Preferably, the organic monomer is a compound of acrylamide and acrylate, and the mass ratio of acrylamide to acrylate is 0.3-0.5.

[0012] Preferably, the acrylate is any one or any combination of two or more of potassium acrylate, sodium acrylate, calcium acrylate, and magnesium acrylate.

[0013] Preferably, the initiation system is a compound of an initiator and a co-initiator, and the mass ratio of the initiator to the co-initiator is 0.8-1.2.

[0014] Preferably, the initiator is a water-soluble oxidant, and is any one or a combination of two of hydrogen peroxide and persulfate; the persulfate is any one or a combination of more than two of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0015] Preferably, the co-initiator is a water-soluble reducing agent, and is any one or a combination of two of ferrous sulfate and sulfite, wherein the sulfite is any one or a combination of two or more of sodium sulfite, sodium bisulfite, potassium sulfite and potassium bisulfite.

[0016] Preferably, the crosslinking agent is any one or any combination of two or more of divinylbenzene, hydroxyethyl methacrylate, and N-hydroxymethylacrylamide.

[0017] On the other hand, a method for preparing a bio-based hybrid polymer water-repellent cementitious material is also provided, comprising the following steps:

[0018] (1) Dissolve starch in water and hydrolyze the starch to obtain a starch solution;

[0019] (2) Dissolve the organic monomer in water, add the initiator and co-initiator to the organic monomer solution, stir at a speed of 120-150 rpm for 1 min, add the crosslinking agent to the organic monomer solution, stir at a speed of 150-180 rpm for 2 min, so that the initiator, co-initiator and crosslinking agent are fully dissolved, and a mixed solution is obtained for later use.

[0020] (3) Weigh out cement, aggregate, nano clay and water-reducing agent according to the mass fraction, pour them into a dry powder mixer and mix for 3 minutes to obtain mixed powder for later use;

[0021] (4) Pour the starch solution obtained in step (1) and the mixed solution obtained in step (2) into the mixed powder obtained in step (3), stir slowly for 1 minute, and then stir quickly for 2 minutes to obtain the bio-based hybrid polymer water-repellent gelling material.

[0022] The technical solution adopted in this invention has the following beneficial effects:

[0023] Bio-based hybrid polymerization technology is adopted. Bio-based hybrid polymerization forms a binder matrix rich in organic groups through the hydrolysis of starch. Combined with the polymerization reaction of organic matter, the hydration reaction of cement, and the physical bonding effect of mineral admixtures, a highly cohesive colloid is formed, which can resist water erosion.

[0024] In addition, due to the improving effect of organic matter on the cement matrix, the cured cementitious material has higher mechanical strength. This cementitious material can be further combined with fine aggregate and coarse aggregate to form various forms of building materials such as mortar, grouting material and concrete, thus broadening the application scenarios. It has great potential application value in reducing the difficulty and cost of underwater structure construction, improving construction quality and reducing environmental pollution.

[0025] The bio-based hybrid polymeric water-repellent cementitious material prepared by this invention exhibits excellent anti-dispersion and water-repellent properties underwater, maintaining the integrity of its components and thus facilitating the full hydration reaction, resulting in higher mechanical compressive strength. This solves the problems of traditional cement-based cementitious materials easily dispersing in water, polluting the environment, and exhibiting low later-stage strength when used in underwater construction, thereby improving the safety and reliability of underwater structures.

[0026] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. [Attached Image Description]

[0027] The invention will be further described below with reference to the accompanying drawings:

[0028] Figure 1 This is a schematic diagram illustrating the principle of bio-based hybrid polymerization of the present invention.

Detailed Implementation Methods

[0029] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0030] like Figure 1 As shown, the applicant discovered that ammonium acrylate and acrylate organic monomers undergo a polymerization reaction under the action of an initiating system to generate polymers. These polymers can effectively adsorb cement and other admixture particles, enhancing the cohesive force between particles and preventing them from being dispersed by the water flow after injection. This ensures that the various components of the cementitious material maintain their integrity and constant proportions after injection, which is beneficial for the subsequent hydration reaction and strength increase of the cementitious material. Simultaneously, because the polymerization reaction of the organic monomers occurs synchronously with the cement hydration reaction, the compatibility between the organic polymer network within the cementitious material matrix and the cement hydration products is improved. The polymers and cement hydration products interpenetrate and penetrate each other, forming an organic-inorganic community, which contributes to the strength improvement of the cementitious material.

[0031] In addition, starch hydrolysis forms a binder with active hydroxyl and carboxyl groups, which can increase the cohesiveness of cement paste and increase the anti-dispersion properties of cement particles.

[0032] The applicant also discovered that by rationally blending the polymerization reaction of organic matter, the hydration reaction of cement, the hydrolysis reaction of starch, and the comprehensive physical properties of mineral admixtures, an organic-inorganic hybrid polymer is formed, preventing the dispersion of particles underwater.

[0033] In view of the problems existing in the prior art and in conjunction with a series of discoveries by the applicant, the first aspect of the present invention provides a bio-based hybrid polymer water-repellent cementitious material.

[0034] The raw materials for preparing this bio-based hybrid polymeric water-repellent cementitious material include, by weight:

[0035] Rapid-hardening silicate cement 100 copies stone powder 25-50 servings fly ash 25-50 servings silicon powder 10-15 servings metakaolin 25-35 servings Nano clay 0-10 copies Water reducing agent 1-2 portions starch 0.5-5 portions water 30-60 servings organic monomers 5-10 servings Triggering system 0.05-0.3 parts Crosslinking agent 0.005-0.05 portions

[0036] The above technical solution involves compounding stone powder, fly ash, silica fume, and metakaolin to produce aggregate.

[0037] As a preferred technical solution, the stone powder has a particle size of 10-50 μm and the fly ash has a specific surface area of ​​300-600 m². 2 / kg, silica powder particle size 5-30μm, metakaolin specific surface area 500m² 2 / kg.

[0038] As a preferred technical solution, the bio-based hybrid polymer water-repellent cementitious material comprises the following components by weight: 100 parts rapid-hardening silicate cement, 25 parts stone powder, 50 parts fly ash, 15 parts silica fume, 25 parts metakaolin, 4 parts nano clay, 1.5 parts water-reducing agent, 2 parts starch, 40 parts water, 8 parts acrylate, 0.2 parts initiator, and 0.05 parts crosslinking agent.

[0039] As a preferred technical solution, the starch is glutinous rice starch. Of course, it can also be any one of corn starch, sweet potato starch, or a combination of any two of these starches.

[0040] As a preferred technical solution, the particle size of the nano-clay is 20-50nm.

[0041] As a preferred technical solution, the organic monomer is an acrylate, and more preferably a combination of acrylate and acrylamide.

[0042] As a preferred technical solution, the initiation system is a combination of an initiator and a co-initiator.

[0043] As a preferred technical solution, the initiator is at least one of hydrogen peroxide and persulfate.

[0044] As a preferred technical solution, the co-initiator is at least one of ferrous sulfate and sulfite.

[0045] As a preferred technical solution, the crosslinking agent is at least one of divinylbenzene, hydroxyethyl methacrylate, and N-hydroxymethylacrylamide.

[0046] A second aspect of this invention provides a method for preparing a bio-based hybrid polymeric water-repellent cementitious material, comprising the following steps:

[0047] Step 1: Dissolve starch in water, stir at 400 rpm for 1 minute, and let stand for 30-60 minutes to allow the starch to hydrolyze and obtain a starch solution.

[0048] Step 2: Dissolve the organic monomer in water, add the initiator and co-initiator to the organic monomer solution, stir at 120-150 rpm for 1 min, add the crosslinking agent to the organic monomer solution, stir at 150-180 rpm for 2 min to fully dissolve the initiator, co-initiator and crosslinking agent, and obtain a mixed solution for later use.

[0049] Alternatively, the required water can be divided into four portions at 70% / 10% / 10% / 10%, and the organic monomer, initiator, co-initiator and crosslinking agent can be dissolved in the four portions of water respectively. Stir each portion at 150 rpm for 1 min and set aside.

[0050] Step 3: Weigh out the cement, aggregate, nano clay and water-reducing agent according to the formula, pour them into a dry powder mixer and mix for 3 minutes to obtain a mixed powder for later use.

[0051] Step 4: Pour the starch mixture, organic mixture, or four solutions of a single solute into the mixed powder obtained in Step 2, stir slowly for 1 minute, and then stir rapidly for 2 minutes to obtain a bio-based hybrid polymer water-repellent gelling material.

[0052] The embodiments of the present invention are described in detail below. The embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0053] Example 1

[0054] In this embodiment, the raw material components, by mass, include:

[0055] Rapid-hardening silicate cement 100 copies stone powder 50 copies fly ash 25 copies silicon powder 10 copies metakaolin 20 copies Nano clay 6 copies Water reducing agent 1.5 copies starch 1 copy water 40 copies organic monomers 6 copies Initiator 0.1 copies Co-initiator 0.1 copies Crosslinking agent 0.02 copies

[0056] Preparation process:

[0057] Step 1: Dissolve starch in water, stir at 400 rpm for 1 minute, and let stand for 30-60 minutes to allow the starch to hydrolyze.

[0058] Step 2: Dissolve the organic monomer in water, add the initiator and co-initiator to the organic monomer solution, stir at 120-150 rpm for 1 min, add the crosslinking agent to the organic monomer solution, stir at 150-180 rpm for 2 min to fully dissolve the initiator, co-initiator and crosslinking agent, and obtain a mixed solution for later use.

[0059] Step 3: Weigh out the cement, various aggregates, nano clay, and water-reducing agent according to the formula, pour them into a dry powder mixer and mix for 3 minutes to obtain a mixed powder for later use.

[0060] Step 4: Pour the mixed solution into the mixed powder obtained in Step 3, stir slowly for 1 minute, and then stir rapidly for 2 minutes to obtain the bio-based hybrid polymer water-repellent cementitious material.

[0061] Example 2

[0062] In this embodiment, the raw material components, by mass, include:

[0063] Rapid-hardening silicate cement 100 copies stone powder 25 copies fly ash 50 copies silicon powder 15 copies metakaolin 25 copies Nano clay 4 copies Water reducing agent 2 copies starch 0.5 copies water 40 copies organic monomers 8 copies Initiator 0.15 copies Co-initiator 0.15 copies Crosslinking agent 0.03 copies

[0064] Preparation process:

[0065] Step 1: Dissolve starch in water, stir at 400 rpm for 1 minute, and let stand for 30-60 minutes to allow the starch to hydrolyze.

[0066] Step 2, more preferably, divide the required water into four portions according to 70% / 10% / 10% / 10%, dissolve the organic monomer, initiator, co-initiator and crosslinking agent in the four portions of water respectively, and stir each portion at a speed of 150 rpm for 1 min, and set aside.

[0067] Step 3: Weigh out the cement, various aggregates, water-reducing agent and starch according to the formula, pour them into a dry powder mixer and mix for 3 minutes to obtain a mixed powder for later use;

[0068] Step 4: Pour the starch mixture and four portions of single solute solution into the mixed powder obtained in Step 2, stir slowly for 1 minute, and then stir rapidly for 2 minutes to obtain the bio-based hybrid polymer water-repellent gelling material.

[0069] Example 3

[0070] In this embodiment, the raw material components, by mass, include:

[0071]

[0072]

[0073] Preparation process:

[0074] Step 1: Dissolve starch in water, stir at 400 rpm for 1 minute, and let stand for 30-60 minutes to allow the starch to hydrolyze.

[0075] Step 2: Dissolve the organic monomer in water, add the initiator and co-initiator to the organic monomer solution, stir at 120-150 rpm for 1 min, add the crosslinking agent to the organic monomer solution, stir at 150-180 rpm for 2 min to fully dissolve the initiator, co-initiator and crosslinking agent, and obtain a mixed solution for later use.

[0076] Step 3: Weigh out the cement, various aggregates, nano clay, water-reducing agent and starch according to the formula, pour them into a dry powder mixer and mix for 3 minutes to obtain a mixed powder for later use.

[0077] Step 4: Pour the starch mixture and organic mixture into the mixed powder obtained in Step 3, stir slowly for 1 minute, and then stir rapidly for 2 minutes to obtain the bio-based hybrid polymer water-repellent gelling material.

[0078] Implementation results:

[0079] A small amount of gelling material was measured using a cylindrical container with a diameter of 25 mm and a height of 25 mm and injected into 30 ml of water. The results of the water rise height and strength for each group are shown in Table 1.

[0080] The comparison between the control example of pure grouting material and Examples 1 and 2 shows that:

[0081] The addition of organic monomers can enhance the cohesiveness of the slurry and prevent excessive dissolution of components in water, thereby achieving...

[0082] Good water-repellent effect;

[0083] The surrounding water environment is less affected, the turbidity is low, and it can recover its clarity in a shorter time.

[0084] By avoiding excessive water intrusion, the water-repellent cementitious material prepared by this invention can better maintain the integrity of the slurry shape and components, thereby exhibiting higher strength.

[0085] Table 1:

[0086]

[0087] In summary, the embodiments of this invention utilize the hydrolysis of starch in biological organisms into colloids containing organic groups. Simultaneously, the organic monomers undergo polymerization reactions after mixing to generate organic macromolecules, enhancing the cohesive force between particles in the cementitious material mixture and preventing the dispersion and segregation of each component. The water-repellent cementitious material exhibits good underwater anti-dispersion properties, enabling effective water-repellent construction. Furthermore, due to the improving effect of organic matter on the cement matrix, the cured cementitious material possesses higher mechanical strength. This cementitious material can be further combined with fine and coarse aggregates to form various forms of building materials such as mortar, grouting materials, and concrete, broadening its application scenarios. It has significant potential application value in reducing the difficulty and cost of underwater structure construction, improving construction quality, and reducing environmental pollution.

[0088] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Those skilled in the art should understand that the invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the invention will be included within the scope of the claims.

Claims

1. A bio-based hybrid polymeric water-repellent cementitious material, characterized in that, The raw materials of the water-repellent cementitious material include the following components by weight: 100 parts rapid-hardening cement, 30-60 parts water, 25-50 parts stone powder, 25-50 parts fly ash, 10-15 parts silica fume, 25-35 parts metakaolin, 0-10 parts nano-clay, 1-2 parts water-reducing agent, 0.5-5 parts starch, 5-10 parts organic monomer, 0.05-0.3 parts initiating system, and 0.005-0.05 parts crosslinking agent, wherein the mass of nano-clay is not 0, and the organic monomer is a compound of acrylamide and acrylate, and the mass ratio of acrylamide to acrylate is 0.3-0.5; The preparation method of the above-mentioned bio-based hybrid polymer water-repellent cementitious material includes the following steps: (1) Dissolve starch in water and hydrolyze the starch to obtain a starch solution; (2) Dissolve the organic monomer in water, add the initiator and co-initiator to the organic monomer solution, stir at a rate of 120-150 rpm for 1 min, add the crosslinking agent to the organic monomer solution, stir at a rate of 150-180 rpm for 2 min, so that the initiator, co-initiator and crosslinking agent are fully dissolved, and a mixed solution is obtained for later use; (3) Weigh out cement, aggregate, nano clay and water-reducing agent according to the mass parts, pour them into a dry powder mixer and stir for 3 minutes to obtain mixed powder for later use; (4) Pour the starch solution obtained in step (1) and the mixed solution obtained in step (2) into the mixed powder obtained in step (3), stir slowly for 1 minute, and then stir quickly for 2 minutes to obtain the bio-based hybrid polymer water-repellent gelling material.

2. The bio-based hybrid polymeric water-repellent cementitious material according to claim 1, characterized in that, The stone powder has a particle size of 10-50 μm, and the fly ash has a specific surface area of ​​300-600 m². 2 / kg, the particle size of the silica powder is 5-30μm, and the specific surface area of ​​the metakaolin is 500m². 2 / kg; aggregates are prepared by compounding stone powder, fly ash, silica fume and metakaolin.

3. The bio-based hybrid polymeric water-repellent cementitious material according to claim 1, characterized in that, The nano-clay is nano-montmorillonite with a particle size of 10-50 nm; and / or, the starch is any one or any combination of two or more of corn starch, sweet potato starch, and glutinous rice starch.

4. The bio-based hybrid polymeric water-repellent cementitious material according to claim 1, characterized in that, The acrylate is any one or any combination of two or more of potassium acrylate, sodium acrylate, calcium acrylate, and magnesium acrylate.

5. The bio-based hybrid polymeric water-repellent cementitious material according to claim 1, characterized in that, The initiation system is a compound of an initiator and a co-initiator, and the mass ratio of the initiator to the co-initiator is 0.8-1.

2.

6. The bio-based hybrid polymeric water-repellent cementitious material according to claim 5, characterized in that, The initiator is a water-soluble oxidant, and is any one or a combination of two of hydrogen peroxide and persulfate; the persulfate is any one or a combination of more than two of ammonium persulfate, potassium persulfate, and sodium persulfate.

7. The bio-based hybrid polymeric water-repellent cementitious material according to claim 5, characterized in that, The co-initiator is a water-soluble reducing agent, and is any one or a combination of two of ferrous sulfate and sulfites. The sulfite is any one or a combination of two or more of sodium sulfite, sodium bisulfite, potassium sulfite, and potassium bisulfite.

8. The bio-based hybrid polymeric water-repellent cementitious material according to claim 1, characterized in that, The crosslinking agent is any one or any combination of two or more of divinylbenzene, hydroxyethyl methacrylate, and N-hydroxymethylacrylamide.

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