Anti-erosion auxiliary gel material and preparation method and application thereof

Abstract

The application discloses an anti-erosion auxiliary gel material and a preparation method and application thereof. The preparation method of the anti-erosion auxiliary gel material comprises the following steps: 1) mixing regenerated red brick powder with a particle size of 3-10 microns, waste concrete regenerated micro powder with a particle size of less than 10 microns and water to perform a pre-hydration reaction, and then separating a solid product to obtain pre-hydration regenerated powder; 2) calcining the pre-hydration regenerated powder, and then rapidly cooling to room temperature and performing grinding to obtain active regenerated powder; and 3) uniformly mixing the regenerated red brick powder with a particle size of less than 3 microns and the active regenerated powder to obtain the anti-erosion auxiliary gel material. The anti-erosion auxiliary gel material can be added in a large amount in concrete, can effectively improve the anti-Cl ‑ erosion performance of the concrete, does not affect the mechanical properties of the concrete, and is suitable for large-scale industrialized production and application.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an anti-erosion auxiliary gel material, its preparation method, and its application. Background Technology

[0002] With the rapid development of marine engineering, higher requirements have been placed on the corrosion resistance of concrete. The corrosive medium Cl in the marine environment... - Although it has a relatively small impact on the microstructure of concrete, it easily diffuses within the concrete and can reduce the OH content on the surface of the reinforcing steel. - The concentration of certain substances leads to acidification in the contact area between the concrete and the passivation film, inducing steel corrosion. This results in extreme expansion stress at the steel-concrete interface, ultimately causing the concrete to expand and crack from the inside until it completely detaches, making effective repair difficult. Therefore, improving the concrete's resistance to Cl- is crucial. - Corrosion resistance is key to extending the lifespan of marine structures.

[0003] Currently, the main methods to improve the Cl-resistance of concrete are surface protection and concrete structure optimization. - Corrosion resistance. Surface protection methods suffer from the problem of surface protective coatings being prone to wear and peeling, while optimizing the microstructure of concrete can directly improve Cl. - The difficulty of erosion makes this method more promising for application. Research has found that Cl... - The erosion rate in concrete depends primarily on the density of the hardened paste microstructure and the effect of hydration products such as Friedel salts on Cl. - The chemical curing behavior of the slurry can be improved by using auxiliary cementitious materials with pozzolanic activity to fill the pores, thereby increasing the density of the hardened slurry and hindering the formation of Cl-. - The diffusion of Cl, and the hydration of auxiliary cementitious materials can also generate Cl - Minerals with adsorption capacity. However, existing auxiliary cementitious materials based on fly ash, slag, recycled red brick powder, etc., can improve the resistance of concrete to Cl to some extent. - It exhibits good corrosion resistance, but requires a relatively high dosage to achieve good Cl-resistance. - The erosion effect also leads to a significant decrease in the early strength of concrete, making it difficult to meet the requirements of practical applications.

[0004] Therefore, it is necessary to develop a method that can effectively improve the Cl resistance of concrete. - The development of auxiliary gel materials that have good corrosion resistance without affecting the mechanical properties of concrete is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-erosion auxiliary gel material, its preparation method, and its application.

[0006] The technical solution adopted in this invention is:

[0007] A method for preparing an anti-erosion auxiliary gel material includes the following steps:

[0008] 1) Mix recycled red brick powder with a particle size of 3μm to 10μm, recycled waste concrete powder with a particle size of ≤10μm and water to carry out a pre-hydration reaction, and then separate the solid product to obtain pre-hydrated recycled powder.

[0009] 2) The prehydrated regenerated powder is calcined, then rapidly cooled to room temperature and ground to obtain active regenerated powder;

[0010] 3) Mix recycled red brick powder with a particle size <3μm and active recycled powder to obtain an anti-erosion auxiliary gel material.

[0011] Preferably, the mass ratio of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete micro powder with a particle size of ≤10μm in step 1) is 1:1.5 to 2.

[0012] Preferably, the amount of water used in step 1) is 0.8 to 1.2 times the total weight of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete micro powder with a particle size of ≤10μm.

[0013] Preferably, in step 1), the mass fraction of SiO2 in the recycled red brick powder with a particle size of 3μm to 10μm is 55% to 65%, and the mass fraction of Al2O3 is 15% to 25%.

[0014] Preferably, the recycled red brick powder with a particle size of 3μm to 10μm in step 1) is made by crushing and grinding sintered clay bricks with a sintering temperature of 800℃ to 1000℃.

[0015] Preferably, in step 1), the mass fraction of SiO2 in the waste concrete recycled micro powder with a particle size ≤10μm is 20%–30%, the mass fraction of CaO is 20%–25%, the mass fraction of Al2O3 is 5%–8%, and the mass fraction of quartz sand is ≤40%.

[0016] Preferably, the waste concrete recycled micro powder with a particle size ≤10μm in step 1) is made from waste concrete through crushing and grinding.

[0017] Preferably, the prehydration reaction in step 1) is carried out at a temperature of 50℃ to 80℃ for a reaction time of 48h to 72h.

[0018] Preferably, the prehydration reaction in step 1) is carried out under intermittent stirring, with stirring for 3 to 7 minutes every 50 to 70 minutes.

[0019] Preferably, the calcination in step 2) is carried out at a temperature of 600℃~800℃ for a time of 0.5h~1h.

[0020] Preferably, in step 3), the mass ratio of recycled red brick powder with a particle size <3μm to active recycled powder is 1:3.5 to 4.5.

[0021] Preferably, in step 3), the mass fraction of SiO2 in the recycled red brick powder with a particle size <3μm is 55%–65%, and the mass fraction of Al2O3 is 15%–25%.

[0022] Preferably, the recycled red brick powder with a particle size of <3μm in step 3) is made by crushing and grinding sintered clay bricks with a sintering temperature of 800℃~1000℃.

[0023] An anti-erosion auxiliary gel material is prepared by the above-described method.

[0024] A type of concrete comprising the aforementioned erosion-resistant auxiliary gel material.

[0025] The principle of this invention: The pozzolanic reaction of recycled red brick powder with a particle size of 3μm to 10μm in cement paste typically occurs after 90 days, and the amount of reaction products is small, with poor adhesion to other hydration products. Direct addition to concrete leads to a significant decrease in the early strength of the concrete. This invention addresses the difference in the impact of recycled red brick powder with a particle size of 3μm to 10μm and recycled red brick powder with a particle size <3μm on the hydration process and microstructure of the paste by treating them differently. Recycled red brick powder with a particle size of 3μm to 10μm has low hydration activity, which affects the workability and mechanical properties of the cement paste. Therefore, it is mixed with recycled waste concrete micropowder with a particle size ≤10μm for prehydration and high-temperature activation to produce active recycled powder (recycled waste concrete micropowder with a particle size ≤10μm contains both CSH gel and Ca(OH)2, while recycled red brick powder with a particle size of 3μm to 10μm contains CSH gel and Ca(OH)2). Recycled red brick powder with a particle size of 10 μm can react with CSH gel and Ca(OH)2 to form CASH gel, which then coats the surface of the recycled red brick powder particles, altering their surface properties. After heat treatment, it can form minerals mainly composed of β-C2S, improving the interfacial adhesion between the recycled red brick powder particles and hydration products, and optimizing the adhesion between the recycled red brick powder particles and hydration products in cement paste. Meanwhile, recycled red brick powder with a particle size <3 μm can exert nucleation and filling effects in the paste, refining pores and increasing Cl... - The migration path makes concrete resistant to Cl. - Its erosion capacity is enhanced, and it has a large specific surface area and high volcanic ash activity. Its participation in the slurry hydration reaction can generate substances with Cl... -The hydration products of the curing process make recycled red brick powder with a particle size <3μm suitable for direct use. The resulting auxiliary gel material can be added in large quantities to concrete, effectively improving its resistance to chloride ions. - It has good corrosion resistance and does not affect the mechanical properties of concrete.

[0026] The beneficial effects of this invention are: the anti-corrosion auxiliary gel material of this invention can be added in large quantities to concrete, which can effectively improve the concrete's resistance to chloride ions. - It exhibits excellent corrosion resistance without affecting the mechanical properties of concrete, making it suitable for large-scale industrial production applications.

[0027] Specifically:

[0028] 1) This invention utilizes recycled waste concrete micro powder with a particle size ≤10μm to prehydrate and activate recycled red brick powder with a particle size of 3μm to 10μm at high temperature, thereby changing the surface properties of the recycled red brick powder with a particle size of 3μm to 10μm and optimizing the bonding between the recycled red brick powder with a particle size of 3μm to 10μm and the hydration products in the cement paste.

[0029] 2) The erosion-resistant auxiliary gel material of this invention increases the dosage of recycled red brick powder in concrete products, fully utilizes the pozzolanic activity of recycled red brick powder, and enhances the curing properties of Cl in the hydration products. - The quantity of products of this capability has effectively improved the erosion resistance of concrete.

[0030] 3) By controlling the particle size and surface activity, this invention ensures the mechanical properties of concrete while increasing the amount of recycled red brick powder, making the resulting erosion-resistant auxiliary gel material meet existing standards and has high practical application value. Attached Figure Description

[0031] Figure 1 The images show the XRD patterns of the recycled red brick powder and prehydrated recycled powder with particle sizes of 3μm to 10μm in Example 1.

[0032] Figure 2 This is a SEM image of the prehydrated regenerated powder from Example 1. Detailed Implementation

[0033] The present invention will be further explained and described below with reference to specific embodiments.

[0034] Example 1:

[0035] An anti-erosion auxiliary gel material is prepared by the following method:

[0036] 1) Recycled red brick powder with a particle size of 3μm to 10μm (made from sintered clay bricks with a sintering temperature of 800℃ to 1000℃ through crushing and grinding, with a mass fraction of SiO2 of 55% to 65% and a mass fraction of Al2O3 of 15% to 25%), recycled waste concrete micro powder with a particle size of ≤10μm (made from waste concrete through crushing and grinding, with a mass fraction of SiO2 of 20% to 30%, a mass fraction of CaO of 20% to 25%, a mass fraction of Al2O3 of 5% to 8%, and a mass fraction of quartz sand of ≤40%) and water are mixed at a mass ratio of 1:1.5:2.5 and reacted at a constant temperature of 70℃ for 72h. During the reaction, the mixture is stirred for 5min every 1h. The solid matter is filtered to obtain pre-hydrated recycled powder.

[0037] 2) The pre-hydrated regenerated powder was calcined at 800℃ for 0.5h, then rapidly cooled to room temperature and ground until there was no obvious agglomeration, thus obtaining active regenerated powder;

[0038] 3) Mix recycled red brick powder with a particle size <3μm (made from sintered clay bricks with a sintering temperature of 800℃~1000℃ through crushing and grinding, with a mass fraction of SiO2 of 55%~65% and a mass fraction of Al2O3 of 15%~25%) and active recycled powder at a mass ratio of 1:4 to obtain an anti-erosion auxiliary gel material.

[0039] The X-ray diffraction (XRD) patterns of recycled red brick powder and prehydrated recycled powder with particle sizes of 3μm to 10μm in this embodiment are shown below. Figure 1 As shown.

[0040] Depend on Figure 1 It can be seen that when recycled red brick powder with a particle size of 3μm to 10μm is pre-hydrated together with recycled waste concrete powder, hydration products such as ettringite and calcium hydroxide are generated in the pre-hydrated recycled powder.

[0041] The scanning electron microscope (SEM) image of the prehydrated regenerated powder in this embodiment is shown below. Figure 2 As shown.

[0042] Depend on Figure 2 It can be seen that the hydration products such as C-(A)-SH gel generated during the prehydration process can form a coating layer on the particle surface, which helps to improve the surface activity of the particles in the future.

[0043] Example 2:

[0044] An anti-erosion auxiliary gel material is identical to Example 1 except that the pre-hydration reaction temperature in step 1) is adjusted from "70℃" to "50℃" during preparation.

[0045] Example 3:

[0046] An anti-erosion auxiliary gel material is identical to Example 1 except that the pre-hydration reaction temperature in step 1) is adjusted from "70℃" to "60℃" during preparation.

[0047] Example 4:

[0048] An anti-erosion auxiliary gel material is identical to Example 1 except that the pre-hydration reaction temperature in step 1) is adjusted from "70℃" to "80℃" during preparation.

[0049] Example 5:

[0050] An anti-erosion auxiliary gel material is identical to Example 1 except that the calcination temperature in step 2) is adjusted from "800℃" to "600℃" during preparation.

[0051] Example 6:

[0052] An anti-erosion auxiliary gel material is identical to Example 1 except that the calcination temperature in step 2) is adjusted from "800℃" to "700℃" during preparation.

[0053] Example 7:

[0054] An anti-erosion auxiliary gel material is identical to Example 1 except that the mass ratio of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete micro powder with a particle size of ≤10μm is adjusted from "1:1.5" to "1:1.75" in step 1).

[0055] Example 8:

[0056] An anti-erosion auxiliary gel material is identical to Example 1 except that the mass ratio of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete micro powder with a particle size of ≤10μm is adjusted from "1:1.5" to "1:2" in step 1).

[0057] Comparative Example 1:

[0058] An auxiliary gel material, the preparation method of which is as follows:

[0059] The auxiliary gel material is obtained by mixing recycled red brick powder (same as in Example 1) with a particle size <3μm and prehydrated recycled powder (same as in Example 1) at a mass ratio of 1:4.

[0060] Comparative Example 2:

[0061] An auxiliary gel material, the preparation method of which is as follows:

[0062] 1) Mix recycled red brick powder with a particle size of 3μm to 10μm (same as in Example 1), recycled waste concrete micro powder with a particle size of ≤10μm (same as in Example 1) and water at a mass ratio of 1:1.5:2.5, react at room temperature for 72 hours, stirring for 5 minutes every 1 hour during the reaction, filter to obtain pre-hydrated recycled powder;

[0063] 2) The pre-hydrated regenerated powder was calcined at 800℃ for 0.5h, then rapidly cooled to room temperature and ground until there was no obvious agglomeration, thus obtaining active regenerated powder;

[0064] 3) Mix recycled red brick powder (same as in Example 1) with particle size <3μm and active recycled powder at a mass ratio of 1:4 to obtain the auxiliary gel material.

[0065] Performance testing:

[0066] Concrete samples were prepared by adding the anti-erosion auxiliary gel materials of Examples 1-8 and Comparative Examples 1-2 to cement-based materials. The specific preparation process is as follows: The concrete sample mix proportion was designed according to "JGJ 55-2011 Code for Mix Proportion Design of Ordinary Concrete" (231 parts by mass of silicate cement, 99 parts by mass of auxiliary cementitious materials, 35 parts by mass of polycarboxylate superplasticizer, 1020 parts by mass of coarse aggregate, 830 parts by mass of fine aggregate, and 160 parts by mass of water; the coarse aggregate was crushed stone with a bulk density of 1610 kg / m³). 3 The crushing value is 5.0%; the fine aggregate is Class II river sand with a fineness modulus of 3.0 and a density of 1.52 kg / m³. 3 According to the mix proportion, the raw materials were weighed and added to the mixer in the following order: coarse aggregate, silicate cement, auxiliary cementitious materials, polycarboxylate superplasticizer, fine aggregate, and water. The mixture was stirred for at least 2 minutes until the raw materials were completely and evenly mixed. Then, concrete samples were prepared for performance testing. The test results are shown in the table below:

[0067] Table 1 Performance test results of concrete samples

[0068]

[0069] Note:

[0070] Compressive strength: Tested in accordance with "GB / T 50081-2019 Standard for Test Methods of Physical and Mechanical Properties of Concrete".

[0071] Cl - Diffusion coefficient: The test was conducted in accordance with the "T0579-2020 Test Method for Chloride Ion Penetration Resistance of Cement Concrete (RCM Method)" in "JTG 3420-2020 Test Procedures for Cement and Cement Concrete in Highway Engineering".

[0072] Example: C30 concrete prepared using silicate cement.

[0073] As shown in Table 1:

[0074] 1) Compared with the concrete sample made from the erosion-resistant auxiliary gel material of Example 1 (a mixture of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete powder with a particle size of ≤10μm, followed by prehydration and high-temperature calcination), the concrete sample made from the auxiliary gel material of Comparative Example 1 (a mixture of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete powder with a particle size of ≤10μm, followed by only prehydration treatment and no high-temperature calcination treatment), the concrete sample made from the auxiliary gel material of Comparative Example 2 (a mixture of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete powder with a particle size of ≤10μm, followed by room temperature prehydration treatment), and the reference example, Cl - The diffusion coefficient was reduced by 20% to 30%, the 3d compressive strength was comparable to the reference example, and the 150d compressive strength was increased by about 6 MPa compared to the reference example.

[0075] 2) With temperature changes during prehydration, the concrete samples made from the erosion-resistant auxiliary gel materials of Examples 2-4 showed a decrease in 3-day compressive strength of 2-4 MPa compared to the concrete sample made from the erosion-resistant auxiliary gel material of Example 1, but the change in later compressive strength was smaller; compared to the reference example, the concrete samples made from the erosion-resistant auxiliary gel materials of Examples 2-4 showed a decrease in 3-day compressive strength of 2-4. - The diffusion coefficient decreased by 10% to 20%, but increased by 4% to 15% compared with the concrete sample made of the anti-erosion auxiliary gel material in Example 1. This indicates that increasing the prehydration temperature will promote the hydration reaction. Within a certain range, increasing the prehydration temperature can obtain auxiliary gel materials with better performance.

[0076] 3) As the temperature decreases during calcination, the concrete samples made from the erosion-resistant auxiliary gel materials in Examples 5-6 show less change in early compressive strength and a decrease in later compressive strength compared to the reference example. This indicates that the decrease in calcination temperature reduces the amount of CSH gel converted to β-C2S, thereby affecting the surface activity of the auxiliary gel material.

[0077] 4) Concrete samples made with the erosion-resistant auxiliary gel material of Examples 7-8 (using a relatively smaller amount of recycled red brick powder with a particle size of 3μm-10μm) showed an increase in compressive strength of 1MPa-3MPa compared to concrete samples made with the erosion-resistant auxiliary gel material of Example 1, but Cl - The increased diffusion coefficient indicates that recycled red brick powder with a particle size of 3μm to 10μm can improve the erosion resistance of concrete, but its contribution to compressive strength is relatively low.

[0078] 5) In Comparative Example 1, no high-temperature calcined pre-hydrated recycled powder was used in the preparation of the auxiliary cementitious material. The compressive strength of the resulting concrete sample decreased significantly. - The diffusion coefficient is similar to that of the reference example;

[0079] 6) In Comparative Example 2, the auxiliary cementitious material was not pre-hydrated in a high-temperature environment during preparation, resulting in a reduced amount of hydration products. Consequently, the compressive strength of the concrete sample prepared was lower than that of the concrete samples prepared with the auxiliary gel materials in Examples 1-8, and Cl - The diffusion coefficient is similar to that of the reference example;

[0080] In summary, the erosion-resistant auxiliary cementitious material prepared based on recycled red brick powder in this invention can effectively improve the surface activity of recycled red brick powder and enhance the resistance of concrete to chloride ions. - It enhances the erosion resistance and ensures the mechanical properties of concrete at all ages, enabling the application of large amounts of recycled red brick powder in concrete preparation.

[0081] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an anti-erosion auxiliary gel material, characterized in that, Includes the following steps: 1) Mix recycled red brick powder with a particle size of 3μm to 10μm, recycled waste concrete powder with a particle size of ≤10μm and water to carry out a pre-hydration reaction, and then separate the solid product to obtain pre-hydrated recycled powder. 2) The prehydrated regenerated powder is calcined, then rapidly cooled to room temperature and ground to obtain active regenerated powder; 3) Mix recycled red brick powder with a particle size <3μm and active recycled powder to obtain an anti-erosion auxiliary gel material; In step 1), the mass ratio of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete micro powder with a particle size of ≤10μm is 1:1.5 to 2. Step 1) The prehydration reaction is carried out at a temperature of 50℃~80℃ for a reaction time of 48h~72h; In step 3), the mass ratio of recycled red brick powder with a particle size <3μm to active recycled powder is 1:3.5 to 4.

5.

2. The preparation method according to claim 1, characterized in that: Step 1) The amount of water used is 0.8 to 1.2 times the total weight of recycled red brick powder with a particle size of 3μm to 10μm and recycled waste concrete micro powder with a particle size of ≤10μm.

3. The preparation method according to claim 1, characterized in that: In step 1), the recycled red brick powder with a particle size of 3μm to 10μm contains 55% to 65% SiO2 and 15% to 25% Al2O3 by mass. In step 1), the recycled waste concrete micropowder with a particle size ≤10μm contains 20% to 30% SiO2, 20% to 25% CaO, 5% to 8% Al2O3, and ≤40% quartz sand by mass.

4. The preparation method according to claim 1, characterized in that: Step 2) The calcination is carried out at a temperature of 600℃~800℃ for a time of 0.5h~1h.

5. The preparation method according to claim 1, characterized in that: Step 3) The recycled red brick powder with a particle size <3μm has a SiO2 mass fraction of 55% to 65% and an Al2O3 mass fraction of 15% to 25%.

6. An anti-erosion auxiliary gel material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 5.

7. A type of concrete, characterized in that, It includes the erosion-resistant auxiliary gel material as described in claim 6.

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