Preparation process of improved recycled concrete aggregate marine cement-based material

Abstract

The application relates to the technical field of marine cement preparation, and particularly discloses a preparation process of a modified recycled concrete aggregate marine cement-based material, which comprises the following steps: (1) mixing recycled concrete aggregate with a sodium silicate aqueous solution and then performing hydrothermal reaction; after the completion of the hydrothermal reaction, the aggregate is separated, dried and then I-grade pretreated aggregate is obtained; (2) mixing the I-grade pretreated aggregate with paraffin, heating the mixture to melt the paraffin, stirring the mixture, cooling the mixture to room temperature under stirring, and then placing the obtained II-grade pretreated aggregate in a stirrer to perform mechanical stirring, so that modified recycled concrete aggregate is obtained; and (3) mixing the modified recycled concrete aggregate with cement and the like. Through the modification of the recycled concrete aggregate, the impermeability of the prepared cement-based material is effectively improved, the erosion caused by seawater is reduced, and the adverse influence of the recycled concrete aggregate on the mechanical properties of the cement-based material is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of marine cement preparation, and particularly relates to a preparation process of improved recycled concrete aggregate marine cement-based material. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general background of the application and does not necessarily constitute an admission by the patent applicant or the patent owner that this information forms part of the prior art already known in this field prior to the application of the present application.

[0003] A large amount of concrete waste will be generated in the process of demolishing concrete buildings. The concrete waste is processed into granular recycled concrete aggregate after crushing, screening, washing and other processes, thereby not only solving the problem of concrete waste treatment, but also realizing resource utilization. Marine cement-based material is mainly a special building material used in seawater erosion environment, such as the construction of seaport wharf, sea embankment, cross-sea bridge pier, island, submarine tunnel and drilling platform. The structure of marine cement-based material construction is immersed in seawater for a long time, which faces serious corrosion problem, and the deterioration of the strength and durability of the structure is significant.

[0004] With the continuous exploitation of sand and stone resources as natural aggregate, the resources are increasingly reduced, and the price is rapidly rising. By using recycled concrete aggregate to replace natural aggregate, the above problems can be effectively alleviated. However, due to the high porosity and high water absorption of recycled concrete aggregate, combined with the micro-cracks caused by the crushing process, the mechanical property indexes of recycled concrete aggregate are difficult to reach the level of natural aggregate, which is not conducive to the application of recycled concrete aggregate. For example, marine cement-based material needs to have better resistance to seawater penetration caused by erosion than ordinary cement-based material, which makes it difficult to directly use recycled concrete aggregate to replace natural aggregate to prepare marine cement-based material. SUMMARY

[0005] In view of the above problems, the present application provides a preparation process of improved recycled concrete aggregate marine cement-based material, which improves the impermeability of the prepared cement-based material by improving the recycled concrete aggregate, helps to reduce the erosion caused by seawater, and reduces the adverse effects of recycled concrete aggregate on the mechanical properties of cement-based material. Specifically, the technical scheme of the present application is as follows.

[0006] A preparation process of improved recycled concrete aggregate marine cement-based material, comprising the following steps:

[0007] (1) The recycled concrete aggregate is mixed with sodium silicate aqueous solution and then stirred uniformly, and then subjected to hydrothermal reaction. After completion, the aggregate is separated, dried to obtain I-grade pretreated aggregate, and reserved.

[0008] (2) The first grade pretreated aggregate is mixed with paraffin wax, heated to the melting point of paraffin wax and stirred, then cooled to room temperature under stirring, and the obtained second grade pretreated aggregate is placed in a stirring machine, and the aggregate particles are stripped by mutual friction to peel the surface layer of the aggregate. After completion, screening is performed to obtain improved recycled concrete aggregate and a permeability inhibitor powder, which are ready for use.

[0009] (3) The permeability inhibitor powder is mixed with polyaluminum sulfate powder, pulverized, and then mixed with a silane coupling agent-anhydrous ethanol mixture, dried, and a modified permeability inhibitor is obtained, which is ready for use.

[0010] (4) The following raw materials are taken: cementitious components, river sand, the improved recycled concrete aggregate and the modified permeability inhibitor, silica fume, and water reducing agent. The above raw materials are mixed, water is added, and mixed again to obtain the marine cement-based material.

[0011] Further, in step (1), the particle size of the recycled concrete aggregate is 5-15 mm.

[0012] Further, in step (1), the ratio of the recycled concrete aggregate to the sodium silicate aqueous solution is 1 g: 20-30 mL. Optionally, the concentration of the sodium silicate aqueous solution is 4.5-7 wt.%.

[0013] Further, in step (1), the temperature of the hydrothermal reaction is 60-80°C, and the time is 6-7.5 hours.

[0014] Further, in step (1), the temperature of the drying is 90-120°C, and the time is 1-1.5 hours.

[0015] Further, in step (2), the ratio of the first grade pretreated aggregate to paraffin wax is 1.0 part by weight: 0.3-0.4 parts by weight.

[0016] Further, in step (2), the stirring time is 15-30 min.

[0017] Further, in step (2), the mechanical stirring time is 2-3.5 hours, and the stirring rate is 180-250 rpm.

[0018] Further, in step (3), the fineness of the powder obtained after pulverization is not less than 200 mesh.

[0019] Further, in step (3), the ratio of the permeability inhibitor powder, polyaluminum sulfate powder, and the mixture is 1 g: 0.08-0.13 g: 0.1-0.2 mL. Optionally, the concentration of the silane coupling agent in the mixture is 0.35-0.6 wt.%.

[0020] Further, in step (3), the silane coupling agent comprises at least one of KH550, KH560, KH570, A171, etc.

[0021] Further, in step (3), the drying temperature is 50-60℃, and the time is 10-20 min.

[0022] Further, in step (4), the proportions of the components in the raw material are as follows: cementitious component 30-44 parts by weight, river sand 40-55 parts by weight, modified recycled concrete aggregate 70-96 parts by weight, modified impermeability agent 3-5 parts by weight, silica fume 4-8 parts by weight, and water reducing agent 0.52-0.85 parts by weight.

[0023] Further, in step (4), the proportion of mixing water to cement is 0.38-0.43 parts by weight: 1.0 part by weight.

[0024] Further, in step (4), the particle size of the river sand is 0.1-0.25 mm.

[0025] Further, in step (4), the water reducing agent comprises at least one of polycarboxylic acid water reducing agent, nai water reducing agent, and lignin sulfonate water reducing agent.

[0026] Compared with the prior art, the technical scheme of the present application has at least the following beneficial effects:

[0027] The present application firstly adopts sodium silicate solution to perform hydrothermal reaction treatment on the recycled concrete aggregate, converts calcium hydroxide, a cement hydration product, into hydrated calcium silicate, and then mixes the hydrated calcium silicate with paraffin wax and heats the mixture to make the paraffin wax melt and penetrate into the pores of the aggregate, thereby effectively reducing the water absorption of the aggregate. Further, the present application strips the surface layer of the recycled concrete aggregate subjected to the above treatment through mutual friction, so that the obtained improved recycled concrete aggregate not only has a new surface, but also has exposed hydrated calcium silicate and a large number of exposed areas not covered by paraffin wax. Therefore, when preparing a cement-based material, not only can the problem of insufficient bonding force between the aggregate and the matrix be overcome, but the exposed hydrated calcium silicate can also promote cement hydration, form more hydration gel products at the interface between the aggregate and the matrix, further increase the interfacial bonding force, and reduce the adverse effects of the recycled concrete aggregate on the mechanical properties of the cement-based material. At the same time, the unreacted sodium silicate in the improved recycled concrete aggregate can also promote the gel activity of the silica fume when it enters the cement-based material, so that the unreacted sodium silicate further reacts with calcium hydroxide, a hydration product of the cement gel component, to produce a gel product, thereby promoting the mechanical strength of the cement-based material. In addition, the powder stripped from the surface of the aggregate is treated with polyaluminum sulfate and silane coupling agent to obtain a modified impermeability agent, so that the polynuclear hydroxyl complex formed by the polyaluminum sulfate embedded in the impermeability agent particles increases the bonding force between the impermeability agent particles and the matrix, prevents the impermeability agent powder from floating up, and facilitates the more uniform distribution of the impermeability agent powder in the cement material matrix to improve the impermeability of the cement material. Not only does the present application solve the problem of affecting the bonding between the aggregate and the matrix, but also the cement-based material prepared from the recycled concrete aggregate has better impermeability and is more suitable for use in marine engineering. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which form a part of the present description, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. Embodiments of the present application will be described and explained with additional specificity and detail with the drawings in which:

[0029] Figure 1 Figure of the improved recycled concrete aggregate sample prepared for the following Examples 1-3, Examples 5-7.

[0030] Figure 2 Figure of the modified impermeability agent sample prepared for the following Examples 1-3, Example 6, Example 7.

[0031] Figure 3 Figure of the compressive strength (left) and contact angle (right) test for the following Example 1.

[0032] Figure 4 Figure of the compressive strength (left) and contact angle (right) test for the following Example 2.

[0033] Figure 5Test chart for compressive strength (left) and contact angle (right) of the following Example 3.

[0034] Figure 6 Test chart for compressive strength (left) and contact angle (right) of the following Example 4.

[0035] Figure 7 Test chart for compressive strength (left) and contact angle (right) of the following Example 5.

[0036] Figure 8 Test chart for compressive strength (left) and contact angle (right) of the following Example 6.

[0037] Figure 9 Test chart for compressive strength (left) and contact angle (right) of the following Example 7. DETAILED DESCRIPTION

[0038] The application will be further described in conjunction with specific examples. It should be understood that these examples are used to illustrate the application but not to limit the scope of the application. The experimental methods in the following examples, if not otherwise specified, are usually carried out according to the conventional conditions or according to the conditions suggested by the manufacturers.

[0039] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as those commonly understood by one of ordinary skill in the art. The reagents or materials used in the present application can be purchased through conventional routes. Unless otherwise specified, the reagents or materials used in the present application are used according to the conventional methods in the art or according to the product instructions. In addition, any method and material similar or equivalent to those described can be applied in the present application. The technical solutions of the present application will be further described in conjunction with specific examples.

[0040] Example 1: A preparation process of a modified recycled concrete aggregate marine cement-based material, comprising the following steps:

[0041] (1) The recycled concrete aggregate with a particle size distribution between 5-15 mm is mixed with a 6% sodium silicate aqueous solution at a ratio of 1 g:20 mL, then stirred uniformly, and heated to 70°C for hydrothermal reaction for 6.5 hours. After completion, the aggregate is filtered out, dried at 100°C for 70 min, and I-grade pretreated aggregate is obtained for standby use.

[0042] (2) The I-grade pretreated aggregate is mixed with 200-mesh paraffin powder at a ratio of 1 part by weight:0.35 parts by weight, then heated to 90°C under stirring to melt the paraffin powder into a liquid state, and then continue stirring for 20 min. After completion, stop heating, and stir to cool to room temperature, then place the obtained II-grade pretreated aggregate in a blender for continuous mechanical stirring for 2.5 hours at a stirring rate of 220 revolutions / min. After completion, sieve to obtain a modified recycled concrete aggregate (such as Figure 1 (As shown) and anti-permeability powder, for later use.

[0043] (3) The antipermeability agent powder and polyaluminum sulfate powder are mixed at a ratio of 1g:0.1g and then ground. The mixture is then passed through a 250-mesh sieve. The resulting powder is mixed with a silane coupling agent-anhydrous ethanol mixture at a ratio of 1g:0.15mL, wherein the concentration of the silane coupling agent (KH550) in the mixture is 0.4wt.%. After stirring for 10min, the mixture is dried at 60℃ for 15min to obtain a modified antipermeability agent (such as...). Figure 2 (As shown), for later use.

[0044] (4) Take the following raw materials in the following proportions: 38 parts by weight of 42.5 ordinary Portland cement, 51 parts by weight of river sand (particle size distribution between 0.1 and 0.25 mm), 85 parts by weight of the modified recycled concrete aggregate of this embodiment, 4.2 parts by weight of the modified impermeable agent of this embodiment, 6.4 parts by weight of silica fume, and 0.7 parts by weight of polycarboxylate superplasticizer. Add the above raw materials to a mixer and stir for 3 minutes, then add 15.2 parts by weight of mixing water and stir for 2 minutes to obtain marine cement-based material.

[0045] Performance Testing: 1. The 28-day compressive strength of the marine cement-based material prepared in this embodiment was tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 3 (As shown in the middle left figure). 2. The marine cement-based material prepared in this embodiment is poured into a mold, hardened, demolded, and cured under standard conditions for 28 days. Then, the contact angle of the specimen is tested (e.g., ...). Figure 3 (As shown in the middle right figure). The test results of the above performance indicators are shown in the table below. Higher compressive strength indicates better mechanical properties of the material, and a larger contact angle indicates better hydrophobicity and stronger impermeability.

[0046]

[0047] Example 2: A preparation process for an improved recycled concrete aggregate marine cement-based material, comprising the following steps:

[0048] (1) Recycled concrete aggregate with a particle size distribution between 5 and 15 mm was mixed with a 7% sodium silicate aqueous solution at a ratio of 1 g: 25 mL and stirred evenly. Then, the mixture was heated to 60 °C for hydrothermal reaction for 7.5 hours. After the reaction was completed, the aggregate was filtered out and dried at 120 °C for 1 hour to obtain Grade I pretreated aggregate for later use.

[0049] (2) The first grade pretreated aggregate is mixed with 200 mesh paraffin powder at a ratio of 1 part by weight: 0.3 parts by weight, then heated to 90°C under stirring to melt the paraffin powder into liquid state, then continue stirring for 15 min. After completion, stop heating, and cool to room temperature under stirring, then put the obtained second grade pretreated aggregate into a blender for continuous mechanical stirring for 2 hours at a stirring rate of 250 revolutions / min. After completion, sieve to obtain modified recycled concrete aggregate (as shown in Figure 1 ) and a water repellent powder, ready for use.

[0050] (3) The water repellent powder is mixed with polyaluminum sulfate powder at a ratio of 1 g: 0.08 g, then ground, then sieved through a 200 mesh sieve, then the obtained powder is mixed with a silane coupling agent-absolute ethanol mixture at a ratio of 1 g: 0.1 mL, the concentration of silane coupling agent (KH560) in the mixture is 0.6 wt.%. After stirring for 10 min, dry at 50°C for 20 min to obtain a modified water repellent (as shown in Figure 2 ), ready for use.

[0051] (4) Take the following proportions of raw materials: 30 parts by weight of 42.5 ordinary portland cement, 40 parts by weight of river sand (particle size distribution between 0.1-0.25 mm), 70 parts by weight of the modified recycled concrete aggregate of the present embodiment, 3 parts by weight of the modified water repellent of the present embodiment, 4 parts by weight of silica fume, and 0.52 parts by weight of polycarboxylic acid water reducer. Add the above raw materials to a blender and stir for 3 min, then add 11.4 parts by weight of mixing water and stir for 2 min to obtain a marine cement-based material.

[0052] Performance test: The 28d compressive strength and contact angle (as shown in Figure 4 , left and right graphs, respectively) of the marine cement-based material prepared in the present embodiment were tested using the same method as in Example 1 above, and the test results are shown in the following table:

[0053]

[0054] Example 3: A preparation process of a modified recycled concrete aggregate marine cement-based material, comprising the following steps:

[0055] (1) The recycled concrete aggregate with particle size distribution between 5-15 mm is mixed with a 4.5% by mass sodium silicate aqueous solution at a ratio of 1 g: 30 mL, then stirred uniformly, then heated to 80°C for hydrothermal reaction for 6 hours. After completion, filter out the aggregate, then dry at 90°C for 1.5 hours to obtain a first grade pretreated aggregate, ready for use.

[0056] (2) The Grade I pretreated aggregate and 100-mesh paraffin powder are mixed at a ratio of 1 part by weight: 0.4 parts by weight. The mixture is then heated to 90°C under stirring and kept at this temperature until the paraffin powder melts into a liquid state. Stirring continues for 30 minutes. After this, heating is stopped, and the mixture is stirred and cooled to room temperature. The resulting Grade II pretreated aggregate is then placed in a mixer and continuously mechanically stirred for 3.5 hours at a stirring rate of 180 rpm. After this, the mixture is sieved to obtain modified recycled concrete aggregate (e.g., ...). Figure 1 (As shown) and anti-permeability powder, for later use.

[0057] (3) The antipermeability agent powder and polyaluminum sulfate powder are mixed at a ratio of 1g:0.13g and then ground. The mixture is then passed through a 200-mesh sieve. The resulting powder is then mixed with a silane coupling agent-anhydrous ethanol mixture at a ratio of 1g:0.2mL, wherein the concentration of the silane coupling agent (KH560) in the mixture is 0.35wt.%. After stirring for 10min, the mixture is dried at 60℃ for 10min to obtain a modified antipermeability agent (such as...). Figure 2 (As shown), for later use.

[0058] (4) Take the following raw materials in the following proportions: 44 parts by weight of 42.5 ordinary Portland cement, 55 parts by weight of river sand (particle size distribution between 0.1 and 0.25 mm), 96 parts by weight of the modified recycled concrete aggregate of this embodiment, 5 parts by weight of the modified impermeable agent of this embodiment, 8 parts by weight of silica fume, and 0.85 parts by weight of sodium lignosulfonate water-reducing agent. Add the above raw materials to a mixer and stir for 3 minutes, then add 18.92 parts by weight of mixing water and stir for 2 minutes to obtain marine cement-based materials.

[0059] Performance testing: The 28-day compressive strength and contact angle of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 5 (As shown in the left and right images), the test results are shown in the table below:

[0060]

[0061] Example 4: A preparation process for a recycled concrete aggregate marine cement-based material, comprising the following steps:

[0062] Take the following raw materials in the following proportions: 38 parts by weight of 42.5 ordinary Portland cement, 51 parts by weight of river sand (particle size distribution between 0.1 and 0.25 mm), 85 parts by weight of recycled concrete aggregate from step (1) of Example 1 above, 4.2 parts by weight of modified impermeable agent from Example 1 above, 6.4 parts by weight of silica fume, and 0.7 parts by weight of polycarboxylate superplasticizer. Add the above raw materials to a mixer and stir for 3 minutes, then add 15.2 parts by weight of mixing water and stir for 2 minutes to obtain marine cement-based material.

[0063] Performance test: the 28d compressive strength and contact angle of the marine cement-based material prepared in this example were tested by the same method as in Example 1 (as shown in the left and right graphs of Figure 6 Table 1, respectively), and the test results are shown in the following table:

[0064]

[0065] Example 5: A preparation process of a modified recycled concrete aggregate marine cement-based material, comprising the following steps:

[0066] (1) Mix the recycled concrete aggregate with a particle size distribution between 5-15 mm and a 7% mass fraction of sodium silicate aqueous solution at a ratio of 1 g: 25 mL, then stir uniformly, and then heat to 60°C for hydrothermal reaction for 7.5 hours. After completion, filter out the aggregate, dry it at 120°C for 1 hour, and obtain the I-grade pretreated aggregate, which is ready for use.

[0067] (2) Mix the I-grade pretreated aggregate with 200-mesh paraffin powder at a ratio of 1 part by weight: 0.3 parts by weight, then heat to 90°C under stirring to melt the paraffin powder into a liquid state, and then continue stirring for 15 min. After completion, stop heating and stir to cool to room temperature, and obtain the modified recycled concrete aggregate (as shown in Figure 1 ).

[0068] (3) Take the following proportions of raw materials: 30 parts by weight of 42.5 ordinary Portland cement, 40 parts by weight of river sand (particle size distribution between 0.1-0.25 mm), 70 parts by weight of the modified recycled concrete aggregate of this example, 4 parts by weight of silica fume, and 0.52 parts by weight of polycarboxylic acid water reducer. Add the above raw materials to the mixer and stir for 3 min, then add 11.4 parts by weight of mixing water and stir for 2 min, and obtain the marine cement-based material.

[0069] Performance test: the 28d compressive strength and contact angle of the marine cement-based material prepared in this example were tested by the same method as in Example 1 (as shown in the left and right graphs of Figure 7 Table 1, respectively), and the test results are shown in the following table:

[0070]

[0071] Example 6: A preparation process of a modified recycled concrete aggregate marine cement-based material, comprising the following steps:

[0072] (1) Recycled concrete aggregate with particle size distribution between 5-15 mm and 200 mesh paraffin powder are mixed according to the ratio of 1 part by weight: 0.35 parts by weight, then heated to 90°C under stirring to make the paraffin powder melt into liquid state, then continue stirring for 20 min. After completion, stop heating, and cool to room temperature under stirring, then put the obtained II grade pretreated aggregate into a blender for continuous mechanical stirring for 2.5 hours, with stirring rate of 220 rpm. After completion, sieve to obtain modified recycled concrete aggregate (as shown in Figure 1 ) and anti-permeation agent powder, ready for use.

[0073] (2) The anti-permeation agent powder is mixed with polyaluminum sulfate powder according to the ratio of 1 g: 0.08 g, then ground, then sieved through a 200 mesh sieve, then the obtained powder is mixed with a silane coupling agent-absolute ethanol mixture according to the ratio of 1 g: 0.1 mL, the concentration of silane coupling agent (KH560) in the mixture is 0.6 wt.%. After stirring for 10 min, dry at 50°C for 20 min to obtain modified anti-permeation agent (as shown in Figure 2 ), ready for use.

[0074] (3) Take the following proportions of raw materials: 38 parts by weight of 42.5 ordinary Portland cement, 51 parts by weight of river sand (particle size distribution between 0.1-0.25 mm), 85 parts by weight of modified recycled concrete aggregate of the present embodiment, 4.2 parts by weight of modified anti-permeation agent of the present embodiment, 6.4 parts by weight of silica fume, and 0.7 parts by weight of polycarboxylic acid water reducer. Add the above raw materials to a blender and stir for 3 min, then add 15.2 parts by weight of mixing water and stir for 2 min to obtain a marine cement-based material.

[0075] Performance test: the 28d compressive strength and contact angle (as shown in Figure 8 left and right images, respectively) of the marine cement-based material prepared in the present embodiment were tested using the same method as in Example 1 above, and the test results are shown in the following table:

[0076]

[0077] Example 7: A preparation process of a modified recycled concrete aggregate marine cement-based material, comprising the following steps:

[0078] (1) Mix recycled concrete aggregate with particle size distribution between 5-15 mm and 4.5% sodium silicate aqueous solution according to the ratio of 1 g: 30 mL, then stir uniformly, then heat to 80°C for hydrothermal reaction for 6 hours. After completion, filter out the aggregate, then dry at 90°C for 1.5 hours to obtain I grade pretreated aggregate, ready for use.

[0079] (2) The Grade I pretreated aggregate and 100-mesh paraffin powder are mixed at a ratio of 1 part by weight: 0.4 parts by weight. The mixture is then heated to 90°C under stirring and kept at this temperature until the paraffin powder melts into a liquid state. Stirring continues for 30 minutes. After this, heating is stopped, and the mixture is stirred and cooled to room temperature. The resulting Grade II pretreated aggregate is then placed in a mixer and continuously mechanically stirred for 3.5 hours at a stirring rate of 180 rpm. After this, the mixture is sieved to obtain modified recycled concrete aggregate (e.g., ...). Figure 1 (As shown) and anti-permeability powder, for later use.

[0080] (3) The impermeable agent powder is ground and then passed through a 200-mesh sieve to obtain a modified impermeable agent (such as...). Figure 2 (As shown), for later use.

[0081] (4) Take the following raw materials in the following proportions: 44 parts by weight of 42.5 ordinary Portland cement, 55 parts by weight of river sand (particle size distribution between 0.1 and 0.25 mm), 96 parts by weight of the modified recycled concrete aggregate of this embodiment, 5 parts by weight of the modified impermeable agent of this embodiment, 8 parts by weight of silica fume, and 0.85 parts by weight of sodium lignosulfonate water-reducing agent. Add the above raw materials to a mixer and stir for 3 minutes, then add 18.92 parts by weight of mixing water and stir for 2 minutes to obtain marine cement-based materials.

[0082] Performance testing: The 28-day compressive strength and contact angle of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (as shown in Figure 1). Figure 9 (As shown in the left and right images), the test results are shown in the table below:

[0083]

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation process for an improved recycled concrete aggregate marine cement-based material, characterized in that, Includes the following steps: (1) Mix recycled concrete aggregate with sodium silicate aqueous solution at a ratio of 1g:20~30mL and stir evenly. Then, perform hydrothermal reaction at 60~80℃ for 6~7.5 hours. After completion, separate the aggregate, dry it to obtain Grade I pretreated aggregate for later use. (2) The Grade I pretreated aggregate and paraffin wax are mixed in a ratio of 1.0 parts by weight: 0.3~0.4 parts by weight, heated until the paraffin wax melts and stirred. After the mixture is stirred, it is cooled to room temperature. The resulting Grade II pretreated aggregate is then placed in a mixer and mechanically stirred to peel off the surface of the aggregate particles through mutual friction. After the mixture is stirred, it is sieved to obtain the modified recycled concrete aggregate and the impermeable agent powder for later use. The mechanical stirring time is 2~3.5 hours and the stirring speed is 180~250 rpm. (3) The antipermeability agent powder and polyaluminum sulfate powder are mixed and ground, then a silane coupling agent-anhydrous ethanol mixture is added, mixed evenly, and dried to obtain the modified antipermeability agent for later use; the ratio of the antipermeability agent powder, polyaluminum sulfate powder, and mixture is 1g:0.08~0.13g:0.1~0.2mL; the concentration of silane coupling agent in the mixture is 0.35~0.6wt.%; (4) Take the following proportions of raw materials: 30-44 parts by weight of cementitious component, 40-55 parts by weight of river sand, 70-96 parts by weight of modified recycled concrete aggregate, 3-5 parts by weight of modified impermeable agent, 4-8 parts by weight of silica fume, and 0.52-0.85 parts by weight of water-reducing agent; mix the above raw materials evenly and then add mixing water and mix again to obtain the marine cement-based material.

2. The preparation process of the improved recycled concrete aggregate marine cement-based material according to claim 1, characterized in that, In step (1), the drying temperature is 90~120℃ and the time is 1~1.5 hours.

3. The preparation process of the improved recycled concrete aggregate marine cement-based material according to claim 1, characterized in that, In step (1), the concentration of the sodium silicate aqueous solution is 4.5~7 wt.%; in step (1), the particle size of the recycled concrete aggregate is 5~15 mm.

4. The preparation process of the improved recycled concrete aggregate marine cement-based material according to claim 1, characterized in that, In step (2), the stirring time is 15~30 min.

5. The preparation process of the improved recycled concrete aggregate marine cement-based material according to claim 1, characterized in that, In step (3), the fineness of the powder obtained after grinding is not less than 200 mesh.

6. The preparation process of the improved recycled concrete aggregate marine cement-based material according to claim 1, characterized in that, In step (3), the silane coupling agent includes at least one of KH550, KH560, KH570, and A171.

7. The preparation process of the improved recycled concrete aggregate marine cement-based material according to claim 1, characterized in that, In step (3), the drying temperature is 50~60℃ and the time is 10~20min.

8. The preparation process of the improved recycled concrete aggregate marine cement-based material according to any one of claims 1-7, characterized in that, In step (4), the ratio of mixing water to cement is 0.38~0.43 parts by weight: 1.0 parts by weight.

9. The preparation process of the improved recycled concrete aggregate marine cement-based material according to any one of claims 1-7, characterized in that, In step (4), the particle size of the river sand is 0.1~0.25mm.

10. The preparation process of the improved recycled concrete aggregate marine cementitious material according to any one of claims 1-7, characterized in that, In step (4), the water-reducing agent includes at least one of polycarboxylate water-reducing agent, naphthalene water-reducing agent, and lignin sulfonate water-reducing agent.

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