A method for modifying waste rubber particles and its application in mortar

Abstract

This invention discloses a method for modifying waste rubber particles and its application in mortar. The invention comprises the following raw materials in parts by weight: 200-400 parts cement, 100-200 parts water, 800-900 parts sand, 2-8 parts waste rubber particles, 15-30 parts modifier, 8-10 parts sodium hydroxide, 8-10 parts anhydrous ethanol, and 5-10 parts potassium ferrate. This invention uses poly-3-methoxytyramine solution as the modifier. The principle of poly-3-methoxytyramine modification is not only to increase the polarity and oxygen-containing groups of rubber, but more importantly, to introduce more organic functional groups, promoting the bonding between rubber and cementitious materials. Adding the modified rubber to mortar can improve the compressive strength and flexural strength of the mortar. The modification method proposed in this invention can increase the compressive strength of rubber mortar by 35.1% and the flexural strength by 18.1%.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a method for modifying waste rubber particles and its application in mortar. Background Technology

[0002] Waste rubber is difficult to degrade under natural conditions, not only occupying land, polluting the environment, damaging plant growth, and posing safety hazards, but also causing enormous resource waste. Therefore, further expanding the application scope of waste rubber and increasing its utilization efficiency are urgent issues that need to be addressed, and have significant social and economic implications for alleviating resource shortages and improving environmental pollution. Based on material properties, using some solid waste materials as building materials can greatly alleviate the problem of solid waste accumulation, achieving waste utilization.

[0003] For example, the Chinese patent "A Concrete Prepared Using Modified Waste Rubber Powder" (CN 101880147A) describes a process where the waste rubber is modified using a surface treatment prepared by mixing a traditional NaOH solution with anhydrous ethanol, followed by a modification process using γ-(methacryloyloxy)propyltrimethoxysilane, sodium dodecyl sulfate, and silica sol. This modification allows the waste rubber to provide higher strength to the mortar. However, for the treatment of waste rubber, the organic modifier in this patent requires mixing two uncommon organic reagents, adding an extra step to the waste rubber treatment process, increasing costs, and posing a significant burden on both environmental protection and practicality. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for modifying waste rubber particles and exploring its application in mortar. This invention uses 3-methoxytyramine solution as a modifier. The principle of 3-methoxytyramine modification is not only to increase the polarity and oxygen-containing groups of rubber, but more importantly, to introduce more organic functional groups, promoting the bonding between rubber and cementitious materials. Adding the modified rubber to mortar can improve the compressive strength and flexural strength of the mortar.

[0005] The present invention provides a method for modifying waste rubber particles, comprising the following steps:

[0006] S1. Soak the rubber granules in the surface treatment agent, wash them, take them out, put them in potassium ferrate solution, stir, filter, wash and dry them.

[0007] S2. Add the rubber particles treated in S1 to the modification solution, stir, and adjust the pH value of the mixed solution to the preset value. After standing for a period of time, filter and wash to obtain modified rubber particles; wherein, the modification solution is a 3-methoxytyramine solution.

[0008] Furthermore, in S1, the surface treatment agent is a mixture of NaOH solution and anhydrous ethanol, and the ratio of NaOH solution to anhydrous ethanol is 1:0.8 by mass.

[0009] Further, in S1, the amount of rubber particles is 2-8 parts by mass, the amount of surface treatment agent is 8 parts, the amount of potassium ferrate solution is 10 parts, and the pH value of the potassium ferrate solution is 2 and the concentration is 5%.

[0010] Furthermore, in S1, the surface treatment agent is immersed for 55-65 minutes, and the washing is performed with deionized water.

[0011] Furthermore, in S1, after adding potassium ferrate solution, the stirring time is 2.5-3.5 hours and the temperature is 70-80℃. After stirring, the rubber particles are filtered, washed with deionized water until the washing solution is close to neutral, and then dried.

[0012] Furthermore, in S2, the concentration of the 3-methoxytyramine solution is 0.2%.

[0013] Furthermore, in S2, the pH of the mixed solution is 8-9, and the static reaction is carried out by placing the mixed solution in a dark place for 24 hours.

[0014] Modified rubber particles obtained according to the above-mentioned method for modifying waste rubber particles.

[0015] Based on the above-mentioned application of modified rubber particles in the preparation of mortar slurry.

[0016] A mortar mix comprising the following components:

[0017] By weight, the composition is: 200-400 parts cement, 100-200 parts water, 800-900 parts sand, and 2-8 parts modified rubber granules.

[0018] This invention utilizes potassium ferrate and poly-3-methoxytyramine for modification. Building upon traditional oxidative modification, it introduces water-absorbing groups such as hydroxyl groups, providing a more predictable rubber-cement bonding method at the structural level. This further solves the problems of non-wetting and difficult bonding of rubber as aggregate with the matrix. Simultaneously, the addition of modified rubber to the mortar enhances its acid resistance and oxidation resistance, further reducing the inevitable decline in mechanical properties. This makes it suitable for various engineering designs and construction projects facing long-term environmental erosion threats.

[0019] The present invention has the following beneficial effects:

[0020] 1. By modifying with 3-methoxytyramine, hydrophilic and organic groups are introduced, which solves the problem of insufficient viscosity of rubber particles in mortar and can be used as a reinforcing filler for mortar.

[0021] 2,3-Methoxytyramine modification enhances the polarity of rubber molecules, reduces their swelling degree, and prevents mortar from cracking due to excessive expansion during use.

[0022] 3. After modification with 3-methoxytyramine, the flexural strength and compressive strength of the modified rubber were significantly improved, with the compressive strength increasing by 35.1% and the flexural strength increasing by 18.1%.

[0023] 4. Modified rubber with the introduction of hydrophilic groups has a significant improvement in adhesion to cementitious matrices.

[0024] 5. The preparation process of this invention is simple. The modified rubber mortar produced by the method of this invention can achieve a compressive strength of 33.7 MPa and a flexural strength of 6.2 MPa after 7 days of curing; and a compressive strength of 41.9 MPa and a flexural strength of 10.4 MPa after 28 days of curing.

[0025] 6. The main raw material used in this invention is industrial solid waste, which greatly reduces the pollution caused by industrial solid waste discharge and alleviates the land occupation caused by the large-scale stockpiling of industrial solid waste. At the same time, this invention also greatly reduces the cost of mortar production and reduces resource consumption. Attached Figure Description

[0026] Figure 1 This is a flow chart illustrating the preparation process of the modified rubber particles and mortar of the present invention. Detailed Implementation

[0027] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0028] like Figure 1 As shown, the present invention provides a method for modifying waste rubber particles, comprising the following steps:

[0029] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0030] S2: Surface pretreatment of waste rubber particles: Add 2-8 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for 55-65 minutes, then take it out and wash it with deionized water.

[0031] S3: Add the rubber particles obtained in step S2 to 10 parts of potassium ferrate solution, wherein the potassium ferrate solution has a pH of 2 and a concentration of 5%. Stir continuously at 70-80℃ for 2.5-3.5 hours.

[0032] S4: Filter the rubber particles and wash with deionized water until the washing solution is nearly neutral, then dry.

[0033] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the mixed solution to 8-9 while stirring.

[0034] S6: Place the mixed solution in a dark place and allow it to react for 24 hours.

[0035] S7: Filter and wash the rubber particles to obtain modified rubber particles.

[0036] In this invention, waste rubber is typically obtained from waste tires and other waste materials. It usually contains a significant amount of zinc stearate, a residue present in tire rubber. This residue greatly affects the bonding between the waste rubber and cement slurry. Poor adhesion of the rubber drastically reduces the mechanical properties of the mortar. Soaking in sodium hydroxide can effectively remove the zinc stearate layer from the surface of the waste rubber, making the surface rougher and initially improving the bonding between the rubber and cement slurry. However, the contact angle between the waste rubber and cement slurry is still greater than 90 degrees. Therefore, various methods are explored to modify the surface of the rubber, including introducing organic polar groups and hydrophilic groups to promote the formation of strong chemical bonds between the rubber and the mortar. This invention uses potassium ferrate for the first step of rubber oxidation, followed by modification with 3-methoxytyramine. Ultimately, small particles dominated by amino hydroxyl groups are formed on the rubber surface, greatly improving the hydrophilicity of the rubber and producing high-performance modified rubber particles.

[0037] like Figure 1 As shown, the present invention also provides a method for preparing mortar using modified rubber particles as aggregate, comprising the following steps:

[0038] S1. Raw materials for the preparation: by weight, 300 parts cement, 150 parts water, 880 parts sand, and 2-8 parts modified rubber granules;

[0039] S2. After mixing the above-mentioned raw materials, mortar slurry is obtained.

[0040] The mortar is hardened, and then the hardened mortar is cured to the specified age.

[0041] The introduction of modified rubber increases the compressive strength of the mortar and enhances its toughness. Under the modification method of this invention, the modified rubber mortar has achieved a strength close to that of normal aggregate mortar.

[0042] Example 1:

[0043] A mortar material according to this embodiment is composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 880 parts sand, and 2 parts modified rubber particles.

[0044] A method for preparing mortar using modified rubber particles includes the following steps:

[0045] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0046] S2: Surface pretreatment of waste rubber particles: By weight, add 2 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0047] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0048] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0049] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the solution to 8.5 while stirring;

[0050] S6: Place the solution in a dark place and allow it to react completely for 24 hours;

[0051] S7: Filter and wash the rubber particles to obtain modified rubber particles;

[0052] S8: According to the raw material mass parts, weigh 300 parts of cement, 150 parts of water, 880 parts of sand, and 2 parts of modified rubber particles. Mix the modified rubber particles with the other raw materials and stir evenly with a mixer to obtain mortar slurry.

[0053] S9: Harden the mortar, and then cure the hardened mortar to the specified age to determine the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0054] The modified rubber mortar prepared in Example 1 of this invention was subjected to curing for 28 days and compressive strength tests after curing. The test results are shown in Table 1. It can be concluded that the compressive strength of the modified rubber mortar after curing for 7 days is 33.7 MPa and the flexural strength is 5.7 MPa. After curing for 28 days, the compressive strength is 41.9 MPa and the flexural strength is 9.8 MPa.

[0055] Example 2:

[0056] A mortar material according to this embodiment is composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 860 parts sand, and 4 parts modified rubber particles.

[0057] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0058] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0059] S2: Surface pretreatment of waste rubber particles: By weight, add 4 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0060] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0061] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0062] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the solution to 8.5 while stirring;

[0063] S6: Place the solution in a dark place and allow it to react completely for 24 hours;

[0064] S7: Filter and wash the rubber particles to obtain modified rubber particles;

[0065] S8: Weigh out 300 parts of cement, 150 parts of water, 860 parts of sand, and 4 parts of modified rubber granules according to the mass of raw materials. Mix the modified rubber granules with the other raw materials and stir evenly with a mixer to obtain mortar.

[0066] S9: Harden the mortar, and then cure the hardened mortar to the specified age to determine the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0067] The modified rubber mortar prepared in Example 2 of this invention was cured for 28 days and its compressive strength was tested. The test results are shown in Table 1. It can be concluded that the compressive strength of the modified rubber mortar after 7 days of curing is 29.7 MPa and the flexural strength is 5.9 MPa. After 28 days of curing, the compressive strength is 37.9 MPa and the flexural strength is 10.1 MPa.

[0068] Example 3:

[0069] This embodiment of a mortar slurry is composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 840 parts sand, and 6 parts modified rubber particles.

[0070] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0071] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0072] S2: Surface pretreatment of waste rubber particles: By weight, add 6 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0073] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0074] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0075] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the solution to 8.5 while stirring;

[0076] S6: Place the solution in a dark place and allow it to react completely for 24 hours;

[0077] S7: Filter and wash the rubber particles to obtain modified rubber particles;

[0078] S8: Weigh out 300 parts of cement, 150 parts of water, 840 parts of sand, and 6 parts of modified rubber granules according to the mass of raw materials. Mix the modified rubber granules with the other raw materials and stir evenly with a mixer to obtain mortar.

[0079] S9: Harden the mortar, and then cure the hardened mortar to the specified age to determine the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0080] The modified rubber mortar prepared in Example 3 of this invention was subjected to curing for 28 days and compressive strength tests after curing. The test results are shown in Table 1. It can be concluded that the compressive strength of the modified rubber mortar after curing for 7 days is 24.6 MPa and the flexural strength is 6.2 MPa. After curing for 28 days, the compressive strength is 28.4 MPa and the flexural strength is 10.4 MPa.

[0081] Example 4:

[0082] A mortar material according to this embodiment is composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 820 parts sand, and 8 parts modified rubber particles.

[0083] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0084] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0085] S2: Surface pretreatment of waste rubber particles: By weight, add 8 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0086] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0087] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0088] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the solution to 8.5 while stirring;

[0089] S6: Place the solution in a dark place and allow it to react completely for 24 hours;

[0090] S7: Filter and wash the rubber particles to obtain modified rubber particles;

[0091] S8: Weigh out 300 parts of cement, 150 parts of water, 820 parts of sand, and 8 parts of modified rubber granules according to the mass of raw materials. Mix the modified rubber granules with the other raw materials and stir evenly with a mixer to obtain mortar.

[0092] S9: Harden the mortar, and then cure the hardened mortar to the specified age to determine the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0093] The modified rubber mortar prepared in Example 4 of this invention was subjected to a 28-day curing test and a compressive strength test after curing. The test results are shown in Table 1. It can be concluded that the compressive strength of the modified rubber mortar after 7 days of curing is 18.7 MPa and the flexural strength is 5.8 MPa. After 28 days of curing, the compressive strength is 22.9 MPa and the flexural strength is 9.9 MPa.

[0094] Example 5:

[0095] A mortar material according to this embodiment is composed of the following raw materials in parts by weight: 360 parts cement, 120 parts water, 880 parts sand, and 2 parts modified rubber particles.

[0096] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0097] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0098] S2: Surface pretreatment of waste rubber particles: By weight, add 2 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0099] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0100] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0101] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the solution to 8.5 while stirring;

[0102] S6: Place the solution in a dark place and allow it to react completely for 24 hours;

[0103] S7: Filter and wash the rubber particles to obtain modified rubber particles;

[0104] S8: According to the mass fraction of raw materials, weigh out 360 parts of cement, 120 parts of water, 880 parts of sand, and 2 parts of modified rubber granules. Mix the modified rubber granules with the other raw materials and stir evenly with a mixer to obtain mortar slurry.

[0105] S9: Harden the mortar, and then cure the hardened mortar to the specified age to determine the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0106] The modified rubber mortar prepared in Example 5 of this invention was subjected to curing for 28 days and compressive strength tests after curing. The test results are shown in Table 1. It can be concluded that the compressive strength of the modified rubber mortar after curing for 7 days is 28.4 MPa and the flexural strength is 5.3 MPa. After curing for 28 days, the compressive strength is 36.5 MPa and the flexural strength is 7.8 MPa.

[0107] Example 6:

[0108] A mortar material according to this embodiment is composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 880 parts sand, and 2 parts modified rubber particles.

[0109] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0110] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0111] S2: Surface pretreatment of waste rubber particles: By weight, add 2 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0112] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0113] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0114] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the solution to 8 while stirring;

[0115] S6: Place the solution in a dark place and allow it to react completely for 24 hours;

[0116] S7: Filter and wash the rubber particles to obtain modified rubber particles;

[0117] S8: According to the raw material mass parts, weigh 300 parts of cement, 150 parts of water, 880 parts of sand, and 2 parts of modified rubber particles. Mix the modified rubber particles with the other raw materials and stir evenly with a mixer to obtain mortar slurry.

[0118] S9: Harden the mortar, and then cure the hardened mortar to the specified age to determine the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0119] The modified rubber mortar prepared in Example 6 of this invention was subjected to a 28-day curing test and a compressive strength test after curing. The test results are shown in Table 1. It can be concluded that the compressive strength of the modified rubber mortar after 7 days of curing is 31.5 MPa and the flexural strength is 5.3 MPa. After 28 days of curing, the compressive strength is 39.2 MPa and the flexural strength is 9.2 MPa.

[0120] Example 7:

[0121] A mortar material according to this embodiment is composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 880 parts sand, and 2 parts modified rubber particles.

[0122] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0123] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0124] S2: Surface pretreatment of waste rubber particles: By weight, add 2 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0125] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0126] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0127] S5: Add the obtained rubber particles to a 0.2% 3-methoxytyramine solution, and adjust the pH of the solution to 9 while stirring;

[0128] S6: Place the solution in a dark place and allow it to react completely for 24 hours;

[0129] S7: Filter and wash the rubber particles to obtain modified rubber particles;

[0130] S8: According to the raw material mass parts, weigh 300 parts of cement, 150 parts of water, 880 parts of sand, and 2 parts of modified rubber particles. Mix the modified rubber particles with the other raw materials and stir evenly with a mixer to obtain mortar slurry.

[0131] S9: Harden the mortar, and then cure the hardened mortar to the specified age to determine the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0132] The modified rubber mortar prepared in Example 7 of this invention was subjected to a 28-day curing test and a compressive strength test after curing. The test results are shown in Table 1. It can be concluded that the compressive strength of the modified rubber mortar after 7 days of curing is 32.1 MPa and the flexural strength is 5.4 MPa. After 28 days of curing, the compressive strength is 39.4 MPa and the flexural strength is 9.4 MPa.

[0133] Comparative Example 1:

[0134] This comparative example of a mortar mix is ​​composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 880 parts sand, and 2 parts modified rubber granules.

[0135] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0136] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0137] S2: Surface pretreatment of waste rubber particles: Add 2 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0138] S3: Add the rubber particles obtained in step S2 to 10 parts of a 5% potassium ferrate solution (the pH of the potassium ferrate solution is adjusted to 2 with sulfuric acid) and stir continuously at 75°C for 3 hours.

[0139] S4: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0140] S5: Place the solution in a dark place and allow it to react for 24 hours.

[0141] S6: Filter and wash the rubber particles to obtain modified rubber particles;

[0142] S7: According to the mass fraction of raw materials, weigh out 300 parts of cement, 150 parts of water, 880 parts of sand, and 2 parts of modified rubber granules. Mix the modified rubber granules with the other raw materials and stir evenly with a mixer to obtain mortar slurry.

[0143] S8: Harden the mortar, then cure the hardened mortar to the specified age and measure the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0144] The modified rubber mortar prepared in Comparative Example 1 of this invention was cured for 28 days and its compressive strength was tested. The test results are shown in Table 2. It can be concluded that the compressive strength of the modified rubber mortar after 7 days of curing is 28.7 MPa and the flexural strength is 5.5 MPa. After 28 days of curing, the compressive strength is 36.9 MPa and the flexural strength is 9.5 MPa.

[0145] Comparative Example 2:

[0146] This comparative example of a mortar mix is ​​composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 880 parts sand, and 2 parts modified rubber granules.

[0147] A method for preparing mortar using modified rubber particles as aggregate includes the following steps:

[0148] S1: Preparation of surface treatment agent: Weigh NaOH solution and anhydrous ethanol in a mass ratio of 1:0.8, add them to an ultrasonic cleaner and stir evenly;

[0149] S2: Surface pretreatment of waste rubber particles: Add 2 parts of waste rubber particles to 8 parts of the surface treatment agent obtained in step S1, clean and soak in an ultrasonic cleaner for about 60 minutes, then take it out and wash it with deionized water.

[0150] S3: Filter the rubber particles and wash with deionized water until the solution is nearly neutral, then dry.

[0151] S4: Place the solution in a dark place and allow it to react for 24 hours.

[0152] S5: Filter and wash the rubber particles to obtain modified rubber particles;

[0153] S6: According to the raw material mass parts, weigh 300 parts of cement, 150 parts of water, 880 parts of sand, and 2 parts of modified rubber particles. Mix the modified rubber particles with the other raw materials and stir evenly with a mixer to obtain mortar slurry.

[0154] S7: Harden the mortar, then cure the hardened mortar to a specified age and measure its compressive strength after 7 days, 28 days, and 28 days of curing.

[0155] The modified rubber mortar prepared in Comparative Example 2 of this invention was cured for 28 days and its compressive strength was tested. The test results are shown in Table 2. It can be concluded that the compressive strength of the modified rubber mortar after 7 days of curing is 26.7 MPa and the flexural strength is 5.3 MPa. After 28 days of curing, the compressive strength is 34.5 MPa and the flexural strength is 9.1 MPa.

[0156] Comparative Example 3:

[0157] This comparative example of a mortar is composed of the following raw materials in parts by weight: 300 parts cement, 150 parts water, 880 parts sand, and 2 parts waste rubber granules.

[0158] The modified rubber mortar preparation method described above in this embodiment includes the following steps:

[0159] S1: Weigh out 300 parts of cement, 150 parts of water, 880 parts of sand, and 2 parts of waste rubber granules according to the mass of raw materials. Mix the waste rubber granules with the other raw materials and stir evenly with a mixer to obtain mortar.

[0160] S2: Harden the mortar, then cure the hardened mortar to a specified age and measure the compressive strength after 7 days of curing, 28 days of curing, and after curing.

[0161] The modified rubber mortar prepared in Comparative Example 3 of this invention was cured for 28 days and its compressive strength was tested. The test results are shown in Table 2. It can be concluded that the compressive strength of the modified rubber mortar after 7 days of curing is 19.8 MPa and the flexural strength is 4.8 MPa. After 28 days of curing, the compressive strength is 31.0 MPa and the flexural strength is 8.3 MPa.

[0162] Table 1. Test results of compressive / flexural strength of the modified rubber mortars prepared in Examples 1-5.

[0163]

[0164] Table 2. Test results of compressive / flexural strength of the modified rubber mortars prepared in Examples 1, 3, Comparative Examples 1, 2, and 3.

[0165]

[0166]

[0167] Table 3. Test results of compressive / flexural strength of the modified rubber mortars prepared in Examples 1, 6, and 7.

[0168]

[0169] Compared to Example 1, Comparative Example 1 did not involve modification with poly3-methoxytyramine, but was only modified with NaOH and KMnO4; Comparative Example 2, compared to Example 1, only underwent NaOH treatment; Comparative Example 3 did not undergo any modification treatment.

[0170] As can be observed from Tables 1 and 2, Example 1 exhibits the best compressive strength performance, with a 35.1% increase in compressive strength and an 18.1% increase in flexural strength compared to the unmodified Comparative Example 3. Example 3 shows the best flexural strength, which is 6.1% higher than that of Example 1.

[0171] Table 3 shows that the modified solution is more effective at pH 8.5 than at pH 8 or 9. pH has a certain influence on the modification effect of poly-3-methoxytyramine, and the modification effect is best at pH 8.5.

[0172] The performance test results for Comparative Examples 1, 2, and 3 are shown in Table 2. The performance test data in Table 2 demonstrate that the modification with poly-3-methoxytyramine significantly improves the compressive and flexural strength of the modified rubber mortar, thereby enhancing the usability of the mortar system produced by this invention.

[0173] For any points not covered above, existing technologies shall apply.

[0174] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for modifying waste rubber granules, characterized in that, Includes the following steps: S1. Soak the waste rubber granules in a surface treatment agent, wash them, take them out, put them in a potassium ferrate solution, stir, filter, wash, and dry them. S2. Add the waste rubber particles treated in S1 to the modification solution, stir, and adjust the pH value of the mixed solution to the preset value. After standing for a period of time, filter and wash to obtain modified rubber particles; wherein, the modification solution is a 3-methoxytyramine solution.

2. The method for modifying waste rubber particles according to claim 1, characterized in that, In S1, the surface treatment agent is a mixture of NaOH solution and anhydrous ethanol, and the ratio of NaOH solution to anhydrous ethanol is 1:0.8 by mass.

3. The method for modifying waste rubber particles according to claim 1, characterized in that, In S1, by mass parts, the amount of waste rubber particles is 2-8 parts, the amount of surface treatment agent is 8 parts, the amount of potassium ferrate solution is 10 parts, and the pH value of the potassium ferrate solution is 2 and the concentration is 5%.

4. The method for modifying waste rubber particles according to claim 1, characterized in that, In S1, the surface treatment agent is immersed for 55-65 minutes, and the washing after immersion is done with deionized water.

5. The method for modifying waste rubber particles according to claim 1, characterized in that, In S1, after adding potassium ferrate solution, the stirring time is 2.5-3.5 hours and the temperature is 70℃-80℃. After stirring, the waste rubber particles are filtered, washed with deionized water until the washing solution is close to neutral, and then dried.

6. The method for modifying waste rubber particles according to claim 1, characterized in that, In S2, the concentration of the 3-methoxytyramine solution is 0.2%.

7. The method for modifying waste rubber particles according to claim 1, characterized in that, In S2, the pH of the mixed solution is 8-9, and the static reaction is carried out by placing the mixed solution in a dark place for 24 hours.

8. Modified rubber particles obtained by the waste rubber particle modification method according to any one of claims 1-7.

9. The application of the modified rubber particles according to claim 8 in the preparation of mortar slurry.

10. A mortar grout, characterized in that, Includes the following components: The composition, by weight, is 200-400 parts cement, 100-200 parts water, 800-900 parts sand, and 2-8 parts of the modified rubber particles obtained as described in claim 8.

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