High-strength rubberized concrete and method for preparing the same

Abstract

The application discloses high-strength rubber concrete, comprising the following raw materials in parts by weight: cement 27-32 parts, blast furnace slag powder 11-13 parts, fly ash 6-9 parts, fine aggregate 70-80 parts, modified rubber particles 2-5 parts, coarse aggregate 94-101 parts, water reducing agent 0.4-0.5 parts, anti-freezing agent 0.08-0.25 parts, early strength agent 0.03-0.1 parts and water 15-16 parts. The raw materials for preparing the concrete are subjected to low-temperature treatment, and then are stirred and formed under low-temperature conditions, and then are subjected to standard curing, the thermal expansion coefficient of cement stone is less than that of the modified rubber particles, the volume expansion degree of the rubber particles is greater than that of the particle cement stone shell, the interface transition zone range is reduced, and in the later continuous hydration process, the internal stress caused by the uneven expansion makes the interface transition zone more compact in the hydration process, the compaction curing effect is achieved, and the interface transition zone strength is improved.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and in particular relates to a high-strength rubber concrete and its preparation method. Background Technology

[0002] Rubber concrete is a special type of concrete prepared by partially replacing fine aggregate in ordinary concrete with rubber particles. It has excellent vibration damping properties and has been used to some extent in railway sleepers and bearings. However, due to the hydrophobic properties of rubber, there is a noticeable interface transition zone between the rubber particles and cement paste, and the addition of rubber particles can lead to a decrease in concrete strength.

[0003] Based on the above, this paper proposes a method for preparing high-strength rubber concrete, which reduces the range of the interface transition zone and improves the strength of the interface transition zone, thereby increasing the strength of the rubber concrete. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. This invention treats the raw materials for concrete preparation at low temperature, mixes and molds them under low temperature conditions, and then performs standard curing. Since the thermal expansion coefficient of cement stone is less than that of rubber particles, the volume expansion of rubber particles is greater than that of the outer shell of cement stone particles, which reduces the range of the interface transition zone. Moreover, during the subsequent continuous hydration process, the internal stress generated by uneven expansion makes the interface transition zone more compact during hydration, achieving the effect of compaction curing and improving the strength of the interface transition zone.

[0005] To achieve the above-mentioned objectives, the technical solution provided by this invention patent is as follows:

[0006] A high-strength rubber concrete comprises the following raw materials in parts by weight: 27-32 parts cement, 11-13 parts blast furnace slag powder, 6-9 parts fly ash, 70-80 parts fine aggregate, 2-5 parts modified rubber granules, 94-101 parts coarse aggregate, 0.4-0.5 parts water-reducing agent, 0.08-0.25 parts antifreeze agent, 0.03-0.1 parts early-strength agent, and 15-16 parts water.

[0007] Furthermore, the method for preparing the modified rubber particles is as follows:

[0008] The first step is to prepare a modification solution, which is one of the following: a sodium hydroxide solution with a concentration of 1%-5%, a polyvinyl alcohol solution with a concentration of 1%-3%, and a silane coupling agent ethanol solution with a concentration of 1%-3%.

[0009] The second step is to completely immerse the rubber particles in the modification solution and stir for 1 hour. After stirring, place the rubber particles in the modification solution in an oven to dry or air dry to obtain modified rubber particles.

[0010] Furthermore, the cement is P·O52.5 ordinary Portland cement.

[0011] Furthermore, the specific surface area of ​​the blast furnace slag powder is ≥400m². 2 / kg, blast furnace slag powder 28d activity index ≥95%.

[0012] Furthermore, the fly ash has a 45μm sieve residue of ≤45% and a 28-day strength activity index of ≥70%.

[0013] Furthermore, the coarse aggregate has a particle size range of 5-25 mm, and the fine and coarse aggregates are in a dry state.

[0014] Furthermore, the modified rubber particles have a particle size range of 0.08-5 mm.

[0015] Furthermore, the water-reducing agent is a polycarboxylate-based or naphthalene-based agent, and the water reduction rate of the water-reducing agent is ≥14%.

[0016] Furthermore, the antifreeze is one or two of nitrite, nitrate, carbonate, sulfate, low alcohol and carboxylate.

[0017] Furthermore, the early strength agent is one or two of the following: inorganic salt early strength agent, organic early strength agent, crystalline early strength agent, and composite early strength agent.

[0018] A method for preparing high-strength rubber concrete, the method specifically includes the following steps:

[0019] S1. Weigh out the water-reducing agent, antifreeze, early strength agent and water in proportion and mix them evenly to prepare a mixed solution A. Store the mixed solution A at a temperature of -12℃ to 0℃.

[0020] S2. Weigh the solid materials according to the proportion and refrigerate them at -12℃ to 0℃. After refrigeration, pour them into a forced mixer for mixing. The mixing time is 1 minute. The solid materials include cement, blast furnace slag powder, fly ash, fine aggregate, modified rubber particles and coarse aggregate.

[0021] S3, add the mixed solution A into a forced mixer and stir for 2 minutes to make the mixed solution A and solid materials evenly mixed to obtain concrete C;

[0022] S4 involves placing the concrete C from S3 at a temperature of -12℃ to 0℃ for molding and curing for 3 days, followed by standard curing for 60 days to obtain high-strength rubber concrete.

[0023] Furthermore, the temperature of the solid material and the mixed solution A is maintained between -12°C and 0°C during the stirring in the forced mixer.

[0024] Furthermore, the standard curing specifically involves placing the formed concrete under conditions of a temperature of 20±2℃ and humidity >95% for curing.

[0025] Based on the above technical solution, the high-strength rubber concrete and its preparation method of this invention have achieved the following technical effects through practical application:

[0026] 1. The present invention discloses a method for preparing high-strength rubber concrete by subjecting the raw materials for concrete preparation to low-temperature treatment and mixing and molding under low-temperature conditions, followed by standard curing. Since the thermal expansion coefficient of cement stone is less than that of rubber particles, the volume expansion of rubber particles is greater than that of the outer shell of cement stone particles, thereby reducing the range of the interface transition zone. Moreover, during the subsequent continuous hydration process, the internal stress generated by uneven expansion makes the interface transition zone more compact during hydration, achieving the effect of compaction curing, improving the strength of the interface transition zone, improving the overall performance of concrete, and reducing the impact of modified rubber particles on the strength of concrete.

[0027] 2. The present invention provides a method for preparing high-strength rubber concrete by adding an early-strength agent to the concrete, thereby improving the strength of the concrete during the low-temperature forming period. Detailed Implementation

[0028] To make the objectives, technical solutions, and effects of this invention clearer, specific examples are provided below. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this invention.

[0029] When modifying rubber granules, multiple modification solutions can be selected to modify the rubber granules; when the modification solution is sodium hydroxide solution and polyvinyl alcohol solution, the rubber granules are soaked and stirred in sodium hydroxide solution and polyvinyl alcohol solution in sequence and then dried to obtain modified rubber granules;

[0030] When the modification solution is a sodium hydroxide solution and a silane coupling agent ethanol solution, the rubber particles are soaked and stirred in the sodium hydroxide solution and the silane coupling agent ethanol solution in sequence, and then dried to obtain modified rubber particles.

[0031] By using various modification solutions to modify the rubber particles, the adhesion between the rubber particles and cement paste was improved, and the impact of the modified rubber particles on the subsequent concrete strength was reduced.

[0032] Example 1

[0033] Three portions of rubber granules with a particle size range of 0.315-0.63 mm were soaked and stirred in a 3% sodium hydroxide solution for 1 hour, and then dried to obtain modified rubber granules.

[0034] Weigh the raw materials for low-temperature modified rubber high-strength concrete: according to the following mass parts, weigh out the following: 31 parts of P·O52.5 ordinary Portland cement, 12 parts of blast furnace slag powder, 8 parts of fly ash, 71 parts of fine aggregate, 3 parts of modified rubber granules, 99 parts of coarse aggregate, 0.5 parts of polycarboxylate superplasticizer, 0.1 parts of calcium nitrite, 0.03 parts of sodium formate, and 15 parts of water;

[0035] The mixture of polycarboxylate superplasticizer, sodium formate, water and sodium nitrite was stirred evenly and then refrigerated at -12°C until it reached a constant temperature.

[0036] The solid materials were refrigerated at -12℃ until constant temperature, and then poured into a forced mixer and mixed for 1 minute. The solid materials included P·O52.5 ordinary Portland cement, blast furnace slag powder, fly ash, fine aggregate, modified rubber particles and coarse aggregate.

[0037] Add the mixed solution to a forced mixer and stir for 2 minutes to mix it evenly with the solid material. Shape the mixture into a mold (molding size 100mm×100mm×100mm) and cure it at -12℃ for 3 days. Then cure it under standard curing conditions for 60 days to obtain high-strength rubber concrete.

[0038] The 60-day compressive strength of high-strength rubber concrete was measured to be 62.2 MPa.

[0039] Example 2

[0040] Three parts of rubber granules with a particle size range of 0.315-0.63 mm were soaked and stirred in a 3% silane coupling agent ethanol solution for 1 hour, and then dried to obtain modified rubber granules.

[0041] Weigh the raw materials for low-temperature modified rubber high-strength concrete: according to the following mass parts, weigh out the following: 31 parts of P·O52.5 ordinary Portland cement, 12 parts of blast furnace slag powder, 8 parts of fly ash, 71 parts of fine aggregate, 3 parts of modified rubber granules, 99 parts of coarse aggregate, 0.5 parts of polycarboxylate superplasticizer, 0.1 parts of ethylene glycol, 0.03 parts of sodium formate, and 15 parts of water;

[0042] The mixed solution of polycarboxylate superplasticizer, water, sodium formate and sodium nitrite was refrigerated at -4°C until it reached a constant temperature.

[0043] The solid materials were refrigerated at -4℃ until constant temperature, and then poured into a forced mixer and mixed for 1 minute. The solid materials included P·O52.5 ordinary Portland cement, blast furnace slag powder, fly ash, fine aggregate, modified rubber particles and coarse aggregate.

[0044] Add the mixed solution to a forced mixer and stir for 2 minutes to mix it evenly with the solid materials. Shape the mixture (shape size 100mm×100mm×100mm) and cure it at -4℃ for 3 days. Then cure it under standard curing conditions for 60 days to obtain high-strength rubber concrete.

[0045] The 60-day compressive strength of high-strength rubber concrete was measured to be 58.0 MPa.

[0046] Comparative Example 1

[0047] Weigh three parts of rubber granules with a diameter of 0.315-0.63 mm, soak and stir them in a 3% silane coupling agent ethanol solution for 1 hour, and then take them out and dry them to obtain modified rubber granules.

[0048] Weigh the concrete raw materials: According to the mass parts, weigh the following: 31 parts of P·O52.5 ordinary Portland cement, 12 parts of blast furnace slag powder, 8 parts of fly ash, 71 parts of fine aggregate, 3 parts of modified rubber granules, 99 parts of coarse aggregate, 0.5 parts of polycarboxylate superplasticizer, 0.1 parts of ethylene glycol, 0.03 parts of sodium formate, and 15 parts of water;

[0049] Polycarboxylate superplasticizer, water, sodium formate, and sodium nitrite are mixed and stirred evenly to form a mixed solution;

[0050] Pour the solid materials into a forced mixer and mix for 1 minute; the solid materials include P·O52.5 ordinary Portland cement, blast furnace slag powder, fly ash, fine aggregate, modified rubber granules and coarse aggregate;

[0051] Add the mixed solution to a forced mixer and stir for 2 minutes to mix it evenly with the solid material. Shape the mixture and cure it under standard curing conditions for 60 days.

[0052] The concrete's 60-day compressive strength was measured to be 50.1 MPa.

[0053] In summary, based on the compressive strength test results of the cured concrete in Examples 1, 2, and Comparative Example 1, it can be seen that, compared with the concrete molding under normal temperature conditions, the compressive strength of the concrete molded at low temperature in Examples 1 and 2 is significantly better than that of the concrete molded at normal temperature in Comparative Example 1.

[0054] In Example 1, the 60-day compressive strength was 24.2% higher than that in Comparative Example 1, and in Example 2, the 60-day compressive strength was 15.8% higher than that in Comparative Example 1.

[0055] This invention effectively reduces the impact of added rubber particles on concrete strength. The relatively obvious interface transition zone between rubber particles and cement paste in rubber concrete is the main reason for the decrease in strength. The concrete is formed and initially cured at low temperatures, then transferred to room temperature for subsequent continuous curing. This is because there is a difference in the thermal expansion coefficients of cement paste and rubber particles (cement paste has a coefficient of thermal expansion of (11-20)×10⁻⁶). -6 The rubber is (100-185)×10 -6 The rubber particles expand more than the outer shell of the cement granules, which reduces the size of the interface transition zone. Furthermore, during the subsequent continuous hydration process, the internal stress generated by the uneven expansion makes the interface transition zone more compact, achieving the effect of compaction and curing, and improving the strength of the interface transition zone.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for preparing high-strength rubber concrete, characterized in that, The method specifically includes the following steps: S1. Weigh out the water-reducing agent, antifreeze, early strength agent and water in proportion and mix them evenly to prepare a mixed solution A. Refrigerate the mixed solution A at a temperature of -12℃ to 0℃. S2. Weigh the solid materials according to the proportion and refrigerate them at -12℃ to 0℃. After refrigeration, pour them into a forced mixer for mixing. The mixing time is 1 minute. The solid materials include cement, blast furnace slag powder, fly ash, fine aggregate, modified rubber particles and coarse aggregate. The temperature of the solid material and mixed solution A is maintained between -12°C and 0°C during the mixing process in the forced mixer; The method for preparing the modified rubber particles is as follows: The first step is to prepare a modification solution, which is one of the following: a sodium hydroxide solution with a concentration of 1%-5%, a polyvinyl alcohol solution with a concentration of 1%-3%, and a silane coupling agent ethanol solution with a concentration of 1%-3%. The second step is to completely immerse the rubber particles in the modification solution and stir for 1 hour; after stirring, place the rubber particles in the modification solution in an oven to dry or air dry to obtain modified rubber particles. S3, add the mixed solution A into a forced mixer and stir for 2 minutes to make the mixed solution A and solid materials evenly mixed to obtain concrete C; S4 involves placing the concrete C from S3 at a temperature of -12℃ to 0℃ for molding and curing for 3 days, followed by standard curing for 60 days to obtain high-strength rubber concrete.

2. The method for preparing high-strength rubber concrete according to claim 1, characterized in that, The standard curing process specifically involves placing the formed concrete under conditions of a temperature of 20±2℃ and humidity >95% for curing.

3. The method for preparing high-strength rubber concrete according to claim 1, characterized in that, The high-strength rubber concrete comprises the following raw materials in parts by weight: 27-32 parts cement, 11-13 parts blast furnace slag powder, 6-9 parts fly ash, 70-80 parts fine aggregate, 2-5 parts modified rubber granules, 94-101 parts coarse aggregate, 0.4-0.5 parts water-reducing agent, 0.08-0.25 parts antifreeze agent, 0.03-0.1 parts early-strength agent, and 15-16 parts water.

4. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The cement is P·O52.5 ordinary Portland cement.

5. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The specific surface area of ​​the blast furnace slag powder is ≥400 m². 2 / kg, blast furnace slag powder 28d activity index ≥95%.

6. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The fly ash has a 45μm sieve residue of ≤45% and a 28-day strength activity index of ≥70%.

7. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The coarse aggregate has a particle size range of 5-25 mm, and the fine and coarse aggregates are in a dry state.

8. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The modified rubber particles have a particle size range of 0.08-5 mm.

9. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The water-reducing agent is a polycarboxylate-based or naphthalene-based agent, and the water reduction rate of the water-reducing agent is ≥14%.

10. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The antifreeze is one or two of the following: nitrite, nitrate, carbonate, sulfate, low alcohol, and carboxylate.

11. The method for preparing high-strength rubber concrete according to claim 3, characterized in that, The early strength agent is one or two of the following: inorganic salt early strength agent, organic early strength agent, crystalline early strength agent, and composite early strength agent.