A lightweight marine concrete cement, its method of preparation and use

Abstract

The present disclosure relates to the technical field of ocean engineering, and particularly relates to a light marine concrete cement, a preparation method and application thereof; the light marine concrete cement comprises the following components in parts by weight: 80-120 parts by weight of cement, 10-30 parts by weight of activated fly ash, 20-50 parts by weight of activated slag, 5-10 parts by weight of cellulose ether, 25-40 parts by weight of modified rubber particles, 2-10 parts by weight of reinforcing agent, 0.2-5 parts by weight of retarder and 10-30 parts by weight of inorganic gel material. The present disclosure provides a light marine concrete cement with light weight and corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of ocean engineering, in particular to a light marine concrete cement, a preparation method and application thereof. BACKGROUND

[0002] Marine structures (caisson, wave protection dyke, bridge pier, etc.) are long-term served in the environment of high chlorine, high humidity, freeze-thaw, sulfate and scouring, so there are multiple requirements for marine concrete, such as high strength, high durability and low density. The current technology mainly uses ordinary Portland cement, large amount of mineral admixtures (mineral powder, fly ash, silica fume) and ordinary water reducing agent system. In order to reduce the dead weight, some engineering uses lightweight aggregate such as ceramsite and pumice to replace ordinary sand and stone, but it will bring the disadvantage of strength reduction.

[0003] Therefore, there is an urgent need for a new type of light marine concrete cement to simultaneously meet the advantages of lightness and corrosion resistance. SUMMARY

[0004] The purpose of the present application is to provide a light marine concrete cement, a preparation method and application thereof to solve the problems in the related art.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] According to a first aspect of the embodiments of the present disclosure, a light marine concrete cement is provided, which comprises the following components by weight:

[0007] 80-120 parts by weight of cement, 10-30 parts by weight of activated fly ash, 20-50 parts by weight of activated mineral powder, 5-10 parts by weight of cellulose ether, 25-40 parts by weight of modified rubber particles, 2-10 parts by weight of reinforcing agent, 0.2-5 parts by weight of retarder and 10-30 parts by weight of inorganic gel material.

[0008] In one aspect of the embodiments of the present disclosure, the marine concrete cement comprises the following components by weight:

[0009] 90-100 parts by weight of cement, 15-20 parts by weight of fly ash, 35-40 parts by weight of activated mineral powder, 5-8 parts by weight of cellulose ether, 30-35 parts by weight of modified rubber particles, 3-8 parts by weight of reinforcing agent, 1-1.5 parts by weight of retarder and 20-25 parts by weight of inorganic gel material;

[0010] The cellulose ether is selected from hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, hydroxyethyl cellulose, methylcellulose or carboxymethyl cellulose.

[0011] The reinforcing agent is selected from carbon black, inorganic fiber, polymer fiber or metal fiber.

[0012] In an aspect of the embodiments of the present disclosure, the reinforcing agent is selected from carbon black, inorganic fiber, polymer fiber.

[0013] In an aspect of the embodiments of the present disclosure, the inorganic fiber is selected from basalt fiber, alkali-resistant glass fiber, carbon fiber or calcium carbonate whisker.

[0014] In an aspect of the embodiments of the present disclosure, the activated fly ash and activated slag are obtained by activating fly ash and slag respectively by an alkali activator aqueous solution; the alkali activator comprises sodium silicate, and further comprises at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium sulfate, sodium aluminate.

[0015] In an aspect of the embodiments of the present disclosure, the modified rubber particles are prepared by the following steps:

[0016] Step 1-a: providing rubber particles; performing a surface decontamination process on the rubber particles to obtain clean rubber particles;

[0017] Step 2-a: adding the clean rubber particles into a potassium permanganate aqueous solution, and adding glacial acetic acid dropwise to adjust the pH value of the solution to 2.0-2.5; heating to 55-65℃, and performing an oxidation reaction for 2-4h; during the reaction, supplementing glacial acetic acid every 10-30min to keep the pH value of the solution less than 2.5;

[0018] Step 3-a: after the reaction is completed, performing filtration, washing and drying to obtain the product of step 3-a;

[0019] Step 4-a: adding the product of step 3-a into a sodium bisulfite aqueous solution, and performing a sulfonation reaction at room temperature for 1-2h;

[0020] Step 5-a: after the reaction is completed, performing filtration, washing and drying to obtain the product of step 5-a;

[0021] Step 6-a: adding the product of step 5-a into a calcium chloride aqueous solution, and reacting at room temperature for 1.5-3h;

[0022] Step 7-a: after the reaction is completed, performing filtration, washing and drying to obtain the modified rubber particles.

[0023] In an aspect of the embodiments of the present disclosure, the inorganic gel material is a calcium-based bentonite gel material.

[0024] In an aspect of the embodiments of the present disclosure, the calcium-based bentonite gel material is prepared by the following steps:

[0025] Step 1-b: providing calcium bentonite; adding the calcium bentonite into water, heating to 55-65℃, stirring at a stirring rate of 300-500 r / min for 30-60 min to obtain a calcium bentonite slurry;

[0026] Step 2-b: providing xanthan gum; dissolving the xanthan gum in water, stirring at a stirring rate of 100-300 r / min for 5-15 min, and then standing for 3-6 h to complete swelling;

[0027] Step 3-b: providing lignocellulose and aluminum hydroxide; subjecting the lignocellulose and aluminum hydroxide to a ball milling process to obtain a mixture; adding the mixture into water, and subjecting to ultrasonic to obtain an aluminum hydroxide slurry;

[0028] Step 4-b: providing a polyacrylic acid aqueous solution and a polycarboxylic acid water reducer, mixing the two, and stirring at a stirring rate of 200-500 r / min for 1-3 min to obtain a polymer mixture;

[0029] Step 5-b: under mechanical stirring, adding the product obtained in step 1-b into the product obtained in step 2-b, heating to 50-60℃, and continuing to stir for 1-2 h; then sequentially adding the product obtained in step 3-b and the product obtained in step 4-b; continuing to stir for 20-50 min to obtain a slurry of step 5-b;

[0030] Step 6-b: pouring the slurry obtained in step 5-b into a mold, first placing in a 5℃ refrigerator for 2-5 h; and then placing at room temperature for 20-30 h; to obtain the calcium bentonite gel material.

[0031] In an aspect of the embodiments of the present disclosure, the reinforcing agent is selected from modified carbon black; the modified carbon black is prepared by the following steps:

[0032] Step 1-c: providing carbon black raw material, treating the carbon black raw material with nitric acid to obtain a product of step 1-c;

[0033] Step 2-c: subjecting the product obtained in step 1-c to a first surface grafting modification using chloromethyl oxirane to obtain surface grafted carbon black;

[0034] Step 3-c: subjecting the product obtained in step 2-c to a second surface grafting modification using polyethyleneimine to obtain the modified carbon black.

[0035] In an aspect of the embodiments of the present disclosure, the reinforcing agent is selected from ordinary carbon black.

[0036] In an aspect of the embodiments of the present disclosure, the reinforcing agent is selected from alkali-resistant glass fiber.

[0037] In one aspect of the embodiments of the present disclosure, the retarder is selected from a hydroxyl carboxylic acid salt retarder, a polyol retarder, a polyose retarder, a phosphate retarder, or a borate retarder.

[0038] In one aspect of the embodiments of the present disclosure, specifically, the retarder is selected from sorbitol, sodium gluconate, sodium citrate, sodium tartrate, sodium tripolyphosphate, sodium pyrophosphate, or sodium tetraborate.

[0039] According to a second aspect of the embodiments of the present disclosure, there is provided a method for preparing the aforementioned lightweight marine concrete cement, comprising the following steps:

[0040] Step 1: uniformly stirring cement, activated fly ash, activated slag, modified rubber particles, cellulose ether, reinforcing agent, inorganic gel material, and retarder to obtain a premix;

[0041] Step 2: adding water to the premix and uniformly stirring to obtain a concrete mixture;

[0042] Step 3: pouring the concrete mixture into a mold, curing, and demolding to obtain the lightweight marine concrete cement.

[0043] According to a third aspect of the embodiments of the present disclosure, there is provided an application of the aforementioned lightweight marine concrete cement in marine engineering.

[0044] Compared with the prior art, the present application has the beneficial effect of providing a lightweight marine concrete cement that is both lightweight and corrosion-resistant. DETAILED DESCRIPTION

[0045] The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present disclosure. Instead, they are merely examples of apparatuses and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0046] For the purposes of this application, the technical solutions and advantages of the present application will be more apparent, the technical solutions of the present application will be described in detail below with reference to the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, not all embodiments. The embodiments described herein are illustrative in nature and serve to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as limiting the present application.

[0047] The present disclosure will be further described below with reference to the embodiments. It should be understood that these embodiments are only used to illustrate the present disclosure and not to limit the scope of the present disclosure.

[0048] Embodiment One

[0049] comprising the following steps:

[0050] 1. Preparation of modified rubber particles:

[0051] The rubber particles (rubber particles used in the examples and comparative examples are all obtained by crushing waste tires and passing through a 20-mesh sieve) were immersed in a 2wt% NaOH solution for 30 min to remove surface oil and impurities, and then washed with water, drained, and dried to obtain clean rubber particles.

[0052] The clean rubber particles were added to a 5wt% aqueous potassium permanganate solution, and glacial acetic acid was added dropwise to adjust the pH of the solution to 2.1. The temperature was raised to 65°C, and the oxidation reaction was carried out for 2.5 h. During the reaction, glacial acetic acid was added every 20 min to maintain the pH of the solution less than 2.5.

[0053] After the reaction was completed, the rubber particles were filtered, washed with water, and dried, and then added to a 6.5wt% aqueous sodium bisulfite solution for sulfonation at room temperature for 1.5 h.

[0054] After the reaction was completed, the rubber particles were filtered, washed, and dried, and then added to a 10wt% aqueous calcium chloride solution for reaction at room temperature for 2.5 h. After the reaction was completed, the rubber particles were filtered, washed, and dried to obtain modified rubber particles.

[0055] 2. Preparation of calcium-based bentonite gel material:

[0056] 50 parts by weight of calcium-based bentonite (fineness 95-99 mesh, montmorillonite content about 60%) were weighed and added to 200 parts by weight of water. The temperature was raised to 60°C, and the mixture was stirred at a stirring rate of 350 r / min for 45 min to obtain a calcium-based bentonite slurry.

[0057] 4 parts by weight of xanthan gum were provided, and the xanthan gum was dissolved in 12 parts by weight of water. The mixture was stirred at a stirring rate of 200 r / min for 10 min, and then left to stand for 4 h to complete the swelling.

[0058] 3 parts by weight of lignocellulose and 10 parts by weight of aluminum hydroxide were provided. The lignocellulose and aluminum hydroxide were subjected to a ball milling process to obtain a mixture. The mixture was added to 50 parts by weight of water, and an aluminum hydroxide slurry was obtained after ultrasonic treatment at 40 kHz for 1 h. In the ball milling process, the lignocellulose and aluminum hydroxide were added to a ball milling tank, 10 mm zirconia balls were added as grinding balls, the ball-to-material ratio was 8:1, and an appropriate amount of ethanol was added. The mixture was ball milled at a stirring rate of 250 r / min for 3 h.

[0059] An aqueous solution of polyacrylic acid (25W molecular weight, 25% aqueous solution) and a polycarboxylic acid water reducer (SP-409) were mixed and stirred at a stirring rate of 500 r / min for 3 min to obtain a polymer mixture.

[0060] Under mechanical stirring (200 r / min), the calcium bentonite slurry was added into the xanthan gum solution, and the temperature was raised to 55°C, and the stirring was continued for 1.5 h; then the aluminum hydroxide slurry and the polymer mixture were added in turn; the stirring was continued for 45 min to obtain a slurry; the slurry was poured into a mold, and was first placed in a 5°C refrigerator for 4 h; then it was placed at room temperature for 24 h; thus a calcium bentonite gel material was obtained.

[0061] 3. Preparation of activated fly ash and activated slag:

[0062] An alkali activator was prepared by dissolving 3 parts by weight of sodium hydroxide, 7.2 parts by weight of sodium silicate and 4 parts by weight of sodium metaaluminate in 55 parts by weight of water.

[0063] The fly ash was provided, and was soaked in the alkali activator for 3 h, and then was filtered, washed and dried to obtain an activated fly ash.

[0064] The slag was provided, and was soaked in the alkali activator for 4.5 h, and then was filtered, washed and dried to obtain an activated slag.

[0065] 4. Preparation of lightweight marine concrete cement:

[0066] 95 parts by weight of cement (low-alkali ordinary portland cement), 18 parts by weight of the activated fly ash prepared above, 40 parts by weight of the activated slag prepared above, 32 parts by weight of the modified rubber particles prepared above, 5 parts by weight of cellulose ether (hydroxypropyl methylcellulose), 4 parts by weight of reinforcing agent (alkali-resistant glass fiber), 25 parts by weight of the calcium bentonite gel material prepared above and 1 part by weight of retarder sodium tetraborate were stirred uniformly to obtain a premix; 50 parts by weight of water was added to the premix, and was stirred uniformly to obtain a concrete mixture; the concrete mixture was poured into a mold, and was demolded after curing for 48 h to obtain the lightweight marine concrete cement of Example One.

[0067] Example Two

[0068] comprising the following steps:

[0069] 1. Preparation of calcium bentonite gel material:

[0070] 50 parts by weight of calcium bentonite (fineness 95-99 mesh, montmorillonite content about 60%) was weighed, and was added into 200 parts by weight of water, and the temperature was raised to 60°C, and was stirred at a stirring rate of 350 r / min for 45 min to obtain a calcium bentonite slurry;

[0071] Providing 4 parts by weight of xanthan gum; dissolving the xanthan gum in 12 parts by weight of water, stirring at a stirring rate of 200 r / min for 10 min, and then standing for 4 h to complete swelling;

[0072] Providing 3 parts by weight of lignocellulose and 10 parts by weight of aluminum hydroxide; subjecting the lignocellulose and the aluminum hydroxide to a ball milling process to obtain a mixture; adding the mixture to 50 parts by weight of water to obtain an aluminum hydroxide slurry after ultrasonic treatment at 40 kHz for 1 h; wherein the ball milling process is as follows: adding the lignocellulose and the aluminum hydroxide to a ball milling tank, adding 10 mm zirconium oxide balls as grinding balls, wherein the ball-to-material ratio is 8:1; and adding an appropriate amount of ethanol, and ball milling at 250 r / min for 3 h.

[0073] Providing a polyacrylic acid aqueous solution (25W molecular weight, 25% aqueous solution) and a polycarboxylic acid water reducer (SP-409), mixing the two and stirring at a stirring rate of 500 r / min for 3 min to obtain a polymer mixture;

[0074] Under mechanical stirring (200 r / min), adding the calcium-based bentonite slurry to the xanthan gum solution, heating to 55℃, and continuing to stir for 1.5 h; then sequentially adding the aluminum hydroxide slurry and the polymer mixture; continuing to stir for 45 min to obtain a slurry; pouring the slurry into a mold, first placing it in a 5℃ refrigerator for 4 h; then placing it at room temperature for 24 h; obtaining a calcium-based bentonite gel material.

[0075] 2. Preparing activated fly ash and activated slag:

[0076] Preparing an alkali activator; the alkali activator is obtained by dissolving 3 parts by weight of sodium hydroxide, 7.2 parts by weight of sodium silicate and 4 parts by weight of sodium metaaluminate in 55 parts by weight of water.

[0077] Providing fly ash, soaking the fly ash in the alkali activator for 3 h, and then filtering, washing and drying to obtain activated fly ash.

[0078] Providing slag, soaking the slag in the alkali activator for 4.5 h, and then filtering, washing and drying to obtain activated slag.

[0079] 3. Preparing light marine concrete cement:

[0080] 95 parts by weight of cement (low-alkali ordinary silicate cement), 18 parts by weight of the aforementioned activated fly ash, 40 parts by weight of the aforementioned activated mineral powder, 32 parts by weight of rubber granules (obtained by crushing waste tires and passing them through a 20-mesh sieve, without modification), 5 parts by weight of cellulose ether (hydroxypropyl methylcellulose), 4 parts by weight of reinforcing agent (alkali-resistant glass fiber), 25 parts by weight of the aforementioned calcium-based bentonite gel material, and 1 part by weight of retarder sodium tetraborate were mixed evenly to obtain a premix; 50 parts by weight of water were added to the premix and mixed evenly to obtain a concrete mix; the concrete mix was poured into a mold, cured for 48 hours, and then demolded to obtain the lightweight marine concrete cement of Example 2.

[0081] The main difference between Example 2 and Example 1 is that Example 2 did not modify the rubber particles.

[0082] Example 3

[0083] Includes the following steps:

[0084] 1. Preparation of modified rubber granules:

[0085] Rubber granules (the rubber granules used in the examples and comparative examples are all obtained by crushing waste tires and passing them through a 20-mesh sieve) are provided. The rubber granules are soaked in a 2wt% NaOH solution for 30 minutes to remove surface oil and impurities. After washing with water, draining and drying, clean rubber granules are obtained.

[0086] Clean rubber granules were added to a 5 wt% potassium permanganate aqueous solution, and glacial acetic acid was added dropwise to adjust the pH of the solution to 2.1. The temperature was raised to 65℃ to carry out the oxidation reaction for 2.5 h. During the reaction, glacial acetic acid was added every 20 min to keep the pH of the solution below 2.5.

[0087] After the reaction was completed, the rubber particles were filtered, washed with water and dried. Then, they were added to a 6.5 wt% sodium bisulfite aqueous solution and sulfonated at room temperature for 1.5 h.

[0088] After the reaction was completed, the rubber particles were filtered, washed and dried, and then added to a 10wt% calcium chloride aqueous solution and reacted at room temperature for 2.5 h. After the reaction was completed, the modified rubber particles were obtained by filtration, washing and drying.

[0089] 2. Preparation of calcium-based bentonite materials:

[0090] Take 50 parts by weight of calcium bentonite (fineness 95-99 mesh, montmorillonite content of about 60%), add calcium bentonite to 200 parts by weight of water, heat to 60℃, stir at a stirring rate of 350 r / min for 45 min, and obtain a calcium bentonite slurry;

[0091] Provide 3 parts by weight of lignocellulose and 10 parts by weight of aluminum hydroxide; the lignocellulose and aluminum hydroxide are subjected to a ball milling process to obtain a mixture; the mixture is added to 50 parts by weight of water to obtain an aluminum hydroxide slurry after ultrasonic treatment at 40 kHz for 1 h; wherein the ball milling process is: the lignocellulose and aluminum hydroxide are added to a ball milling tank, 10 mm zirconium oxide balls are added as grinding balls, wherein the ball-to-material ratio is 8:1; and an appropriate amount of ethanol is added, and ball milling is carried out at 250 r / min for 3 h.

[0092] Under mechanical stirring (200 r / min), the aluminum hydroxide slurry is added to the calcium bentonite slurry, heated to 55℃, and stirred for 1.5 h; a slurry is obtained; the slurry is poured into a mold and cured at room temperature for 24 h; a calcium bentonite material is obtained.

[0093] 3. Preparation of activated fly ash and activated slag:

[0094] An alkali activator is prepared; the alkali activator is obtained by dissolving 3 parts by weight of sodium hydroxide, 7.2 parts by weight of sodium silicate and 4 parts by weight of sodium metaaluminate in 55 parts by weight of water.

[0095] Provide fly ash, soak the fly ash in the alkali activator for 3 h, then filter, wash and dry to obtain activated fly ash.

[0096] Provide slag, soak the slag in the alkali activator for 4.5 h, then filter, wash and dry to obtain activated slag.

[0097] 4. Preparation of lightweight marine concrete cement:

[0098] Mix 95 parts by weight of cement (low-alkali ordinary portland cement), 18 parts by weight of the aforementioned prepared activated fly ash, 40 parts by weight of the aforementioned prepared activated slag, 32 parts by weight of the aforementioned prepared modified rubber particles, 5 parts by weight of cellulose ether (hydroxypropyl methylcellulose), 4 parts by weight of reinforcing agent (alkali-resistant glass fiber), 25 parts by weight of the aforementioned prepared calcium bentonite material, and 1 part by weight of retarder sodium tetraborate to obtain a premix; add 50 parts by weight of water to the premix and mix well to obtain a concrete mixture; pour the concrete mixture into a mold, and after curing for 48 h, demold to obtain the lightweight marine concrete cement of Example Three.

[0099] The main difference between Example Three and Example One is that Example Three does not use xanthan gum and polyacrylic acid aqueous solution to crosslink the calcium bentonite.

[0100] Comparative Example One

[0101] The method comprises the following steps:

[0102] 1. Preparation of calcium bentonite gel material:

[0103] 50 parts by weight of calcium bentonite (fineness 95-99 mesh, montmorillonite content of about 60%) was weighed, and the calcium bentonite was added to 200 parts by weight of water, heated to 60°C, stirred at a stirring rate of 350 r / min for 45 min, to obtain a calcium bentonite slurry;

[0104] 4 parts by weight of xanthan gum was provided; the xanthan gum was dissolved in 12 parts by weight of water, stirred at a stirring rate of 200 r / min for 10 min, and then left to stand for 4 h to complete the swelling;

[0105] 3 parts by weight of lignocellulose and 10 parts by weight of aluminum hydroxide were provided; the lignocellulose and aluminum hydroxide were subjected to a ball milling process to obtain a mixture; the mixture was added to 50 parts by weight of water, and an aluminum hydroxide slurry was obtained after ultrasonic treatment at 40 kHz for 1 h; wherein the ball milling process was as follows: the lignocellulose and aluminum hydroxide were added to a ball milling tank, 10 mm zirconia balls were added as grinding balls, wherein the ball-to-material ratio was 8:1; and an appropriate amount of ethanol was added, and ball milling was carried out at 250 r / min for 3 h.

[0106] An aqueous solution of polyacrylic acid (25W molecular weight, 25% aqueous solution) and a polycarboxylic acid water reducer (SP-409) were provided, mixed and stirred at a stirring rate of 500 r / min for 3 min to obtain a polymer mixture;

[0107] Under mechanical stirring (200 r / min), the calcium bentonite slurry was added to the xanthan gum solution, heated to 55°C, and continued to stir for 1.5 h; then the aluminum hydroxide slurry and the polymer mixture were added in turn; continue to stir for 45 min to obtain a slurry; pour the slurry into a mold, first place it in a 5°C refrigerator for 4 h; then place it in a room temperature curing for 24 h; to obtain a calcium bentonite gel material.

[0108] 2. Preparation of activated fly ash and activated slag:

[0109] An alkali activator was prepared; the alkali activator was obtained by dissolving 3 parts by weight of sodium hydroxide, 7.2 parts by weight of sodium silicate and 4 parts by weight of sodium metaaluminate in 55 parts by weight of water.

[0110] The fly ash was soaked in the alkali activator for 3 h, then filtered, washed and dried to obtain an activated fly ash.

[0111] Mineral powder is provided, and the mineral powder is soaked in an alkaline activator for 4.5 hours. Then, it is filtered, washed, and dried to obtain activated mineral powder.

[0112] 3. Preparation of cement for marine concrete:

[0113] 107 parts by weight of cement (low-alkali ordinary silicate cement), 28 parts by weight of the aforementioned activated fly ash, 50 parts by weight of the aforementioned activated mineral powder, 5 parts by weight of cellulose ether (hydroxypropyl methylcellulose), 4 parts by weight of reinforcing agent (alkali-resistant glass fiber), 25 parts by weight of the aforementioned calcium-based bentonite gel material, and 1 part by weight of retarder sodium tetraborate were mixed evenly to obtain a premix; 50 parts by weight of water were added to the premix and mixed evenly to obtain a concrete mix; the concrete mix was poured into a mold, cured for 48 hours, and then demolded to obtain the marine concrete cement of Comparative Example 1.

[0114] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain any rubber material.

[0115] Comparative Example 2

[0116] Includes the following steps:

[0117] 1. Preparation of modified rubber granules:

[0118] Rubber granules (the rubber granules used in the examples and comparative examples are all obtained by crushing waste tires and passing them through a 20-mesh sieve) are provided. The rubber granules are soaked in a 2wt% NaOH solution for 30 minutes to remove surface oil and impurities. After washing with water, draining and drying, clean rubber granules are obtained.

[0119] Clean rubber granules were added to a 5 wt% potassium permanganate aqueous solution, and glacial acetic acid was added dropwise to adjust the pH of the solution to 2.1. The temperature was raised to 65℃ to carry out the oxidation reaction for 2.5 h. During the reaction, glacial acetic acid was added every 20 min to keep the pH of the solution below 2.5.

[0120] After the reaction was completed, the rubber particles were filtered, washed with water and dried. Then, they were added to a 6.5 wt% sodium bisulfite aqueous solution and sulfonated at room temperature for 1.5 h.

[0121] After the reaction was completed, the rubber particles were filtered, washed and dried, and then added to a 10wt% calcium chloride aqueous solution and reacted at room temperature for 2.5 h. After the reaction was completed, the modified rubber particles were obtained by filtration, washing and drying.

[0122] 2. Preparation of activated fly ash and activated mineral powder:

[0123] The alkali activator is prepared by dissolving 3 parts by weight of sodium hydroxide, 7.2 parts by weight of sodium silicate and 4 parts by weight of sodium metaaluminate in 55 parts by weight of water.

[0124] The fly ash is provided and soaked in the alkali activator for 3 h, and then filtered, washed and dried to obtain the activated fly ash.

[0125] The mineral powder is provided and soaked in the alkali activator for 4.5 h, and then filtered, washed and dried to obtain the activated mineral powder.

[0126] 3. Preparation of light marine concrete cement:

[0127] 103 parts by weight of cement (low-alkali ordinary portland cement), 26 parts by weight of the activated fly ash prepared above, 49 parts by weight of the activated mineral powder prepared above, 32 parts by weight of the modified rubber particles prepared above, 5 parts by weight of cellulose ether (hydroxypropyl methylcellulose), 4 parts by weight of reinforcing agent (alkali-resistant glass fiber) and 1 part by weight of retarder sodium tetraborate are stirred uniformly to obtain a premix; 50 parts by weight of water is added to the premix and stirred uniformly to obtain a concrete mixture; the concrete mixture is poured into a mold, demolded after curing for 48 h to obtain the marine concrete cement of Comparative Example 2.

[0128] Corrosion resistance and mechanical strength test:

[0129] First, the density of the samples of the examples and the comparative examples is tested;

[0130] Then, according to the test method in GB / T38140-2019, 2 batches of samples of the examples and the comparative examples are placed in a 50℃ humid heat curing box containing a 50℃±1℃ water container for curing, and the curing is carried out for 7d from the time when the test body is placed in the container; then the surface moisture of the test piece is wiped dry, and then the test body is placed in a 40℃ drying oven for drying for 24h; after the drying is completed, the first batch of samples is tested for compressive strength;

[0131] The second batch of samples is placed in a test piece rack in a vacuum salt-saturation device, and a vacuum pump is started; the test piece is pumped for 4h under a negative pressure of 0.08MPa, and then a prepared simulated seawater erosion solution is added from the water inlet and pumped for another 2h under a negative pressure of 0.08MPa. Thereafter, the negative pressure of 0.08MPa is kept unchanged, and the test piece is allowed to stand in the simulated seawater erosion solution for 18h to reach a fully saturated state. The test piece is taken out of the vacuum salt-saturation device, and one cycle of dry-wet immersion test is completed; the above steps are repeated 14 times within 28 days, and then the compressive strength is tested, and the results are shown in Table 1.

[0132] Table 1

[0133]

[0134] It can be seen that, compared with the comparative example, the example has a lighter density; the first example has a more excellent corrosion resistance and can maintain the mechanical properties in the marine environment; this is because the rubber particles are oxidized by potassium permanganate to generate a large number of polar groups such as carboxyl, hydroxyl and carbonyl on the surface; then sulfonated by sodium bisulfite to convert the carbonyl group into hydroxyl sulfonate; these polar groups change the originally hydrophobic rubber surface into a highly hydrophilic interface, so that the prepared calcium bentonite gel can fully wet and penetrate into the rubber surface micropores, achieving the effect of preventing further corrosion of seawater on the cement matrix, greatly improving the corrosion resistance of the cement; and, after calcium deposition, a CaSO4·2H2O and CaCO3 microcrystalline shell layer is deposited in situ on the rubber surface, which not only improves the rubber surface elastic modulus, but also forms a rigid transition layer to prevent stress concentration and avoid interface cracking; in addition, the -COO - Ca 2+ and -SO3 - Ca 2+ groups on the rubber surface form ionic bridge bonds with Ca 2+ , Al 3+ in the cement, and the hydroxyl group forms hydrogen bonds with the silicate network, achieving chemical anchoring and enhancing the mechanical properties.

[0135] Other embodiments of the present disclosure will be readily apparent to those skilled in the art upon considering the description of the disclosure and the practices disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptive changes of the present disclosure that follow the general principles of the present disclosure and include common knowledge or conventional techniques in the art that are not disclosed by the present disclosure.

Claims

1. A lightweight marine concrete cement, characterized in that, The marine concrete cement comprises the following components in parts by weight: 80-120 parts by weight of cement, 10-30 parts by weight of activated fly ash, 20-50 parts by weight of activated mineral powder, 5-10 parts by weight of cellulose ether, 25-40 parts by weight of modified rubber granules, 2-10 parts by weight of reinforcing agent, 0.2-5 parts by weight of retarder and 10-30 parts by weight of inorganic gel material. The modified rubber particles are prepared through the following steps: Step 1-a: Provide rubber granules; perform a process to remove oil and impurities from the surface of the rubber granules to obtain clean rubber granules; Step 2-a: Add clean rubber granules to a potassium permanganate aqueous solution, and add glacial acetic acid dropwise to adjust the pH of the solution to 2.0-2.5; raise the temperature to 55℃-65℃ to carry out the oxidation reaction for 2-4 hours; during the reaction, add glacial acetic acid every 10-30 minutes to keep the pH of the solution below 2.

5. Step 3-a: After the reaction is complete, the product of step 3-a is obtained by filtration, washing and drying. Step 4-a: Add the product obtained in step 3-a to an aqueous solution of sodium bisulfite and carry out a sulfonation reaction at room temperature for 1-2 hours; Step 5-a: After the reaction is complete, the product of step 5-a is obtained by filtration, washing and drying. Step 6-a: Add the product obtained in step 5-a to an aqueous solution of calcium chloride and react at room temperature for 1.5-3 hours; Step 7-a: After the reaction is complete, the modified rubber particles are obtained by filtration, washing and drying. The inorganic gel material is a calcium-based bentonite gel material; The calcium-based bentonite gel material is prepared by the following steps: Step 1-b: Provide calcium-based bentonite; add the calcium-based bentonite to water, heat to 55℃-65℃, and stir at a stirring rate of 300-500r / min for 30-60min to obtain calcium-based bentonite slurry; Step 2-b: Provide xanthan gum; dissolve the xanthan gum in water, stir at a stirring rate of 100-300 r / min for 5-15 min, and then let it stand for 3-6 h to complete the swelling; Step 3-b: Provide lignocellulose and aluminum hydroxide; subject the lignocellulose and aluminum hydroxide to a ball milling process to obtain a mixture; add the mixture to water and sonicate to obtain an aluminum hydroxide slurry; Step 4-b: Provide an aqueous solution of polyacrylic acid and a polycarboxylate superplasticizer, mix the two and stir at a stirring rate of 200-500 r / min for 1-3 min to obtain a polymer mixture; Step 5-b: Under mechanical stirring, add the product obtained in step 1-b to the product obtained in step 2-b, heat to 50℃-60℃, and continue stirring for 1-2 hours; then add the products obtained in step 3-b and step 4-b in sequence; continue stirring for 20-50 minutes to obtain the slurry of step 5-b. Step 6-b: Pour the slurry obtained in step 5-b into a mold, place it in a 5°C refrigerator for 2-5 hours; then cure it at room temperature for 20-30 hours to obtain the calcium-based bentonite gel material.

2. The lightweight marine concrete cement according to claim 1, characterized in that, The marine concrete cement comprises the following components in parts by weight: 90-100 parts by weight of cement, 15-20 parts by weight of fly ash, 35-40 parts by weight of activated mineral powder, 5-8 parts by weight of cellulose ether, 30-35 parts by weight of modified rubber granules, 3-8 parts by weight of reinforcing agent, 1-1.5 parts by weight of retarder and 20-25 parts by weight of inorganic gel material. The cellulose ether is selected from hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, hydroxyethyl cellulose, methylcellulose or carboxymethyl cellulose; The reinforcing agent is selected from carbon black, inorganic fibers, polymer fibers, or metal fibers.

3. The lightweight marine concrete cement according to claim 1 or 2, characterized in that, The activated fly ash and activated mineral powder are obtained by activating fly ash and mineral powder respectively with an alkaline activator aqueous solution; The alkaline activator comprises sodium silicate, and also comprises at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium sulfate, and sodium aluminate.

4. The lightweight marine concrete cement according to claim 1 or 2, characterized in that, The reinforcing agent is selected from modified carbon black; the modified carbon black is prepared through the following steps: Step 1-c: Provide carbon black raw material, and treat the carbon black raw material with nitric acid to obtain the product of step 1-c; Step 2-c: The product obtained in step 1-c is subjected to the first surface grafting modification using chloromethyl ethylene oxide to obtain surface-grafted carbon black; Step 3-c: The product obtained in step 2-c is subjected to a second surface grafting modification using polyethyleneimine to obtain the modified carbon black.

5. A method for preparing the lightweight marine concrete cement according to any one of claims 1-4, characterized in that, The method includes the following steps: Step 1: Mix cement, activated fly ash, activated mineral powder, modified rubber particles, cellulose ether, reinforcing agent, inorganic gelling material and retarder evenly to obtain premix; Step 2: Add water to the premix and stir evenly to obtain concrete mix; Step 3: Pour the concrete mix into the mold, and after curing and demolding, obtain the lightweight marine concrete cement.

6. The application of lightweight marine concrete cement according to any one of claims 1-4 in marine engineering.

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