A green high-performance concrete and its preparation method

Abstract

The present invention belongs to the technical field of concrete, and particularly relates to a green high-performance concrete and a preparation method thereof. A green high-performance concrete comprises 360-390 parts of total binder, 1650-1800 parts of aggregate, 120-140 parts of water, 7.0-7.8 parts of water reducer, and 4-6 parts of retarder; the total binder comprises the following components: 250-280 parts of cement, 52-60 parts of mineral powder, 10-15 parts of silica fume, and 35-40 parts of fly ash; the aggregate comprises the following components: 730-800 parts of sand and 930-1010 parts of stone; the preparation method of the retarder comprises the following steps: reacting polyether polyol, hexamethylene diisocyanate, and organic base 1 for 12-24 h to obtain a mixed system, adding lignin and organic base 2 into the mixed system, reacting for 18-48 h, and then obtaining the retarder through treatment. The present invention provides a new method for preparing a water reducer. The prepared water reducer and retarder are applied to concrete, which respectively improve the workability (slump, spread) of concrete, the compressive strength, and the maximum water pressure of impermeability. The synergistic effect is better.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete, and particularly relates to a green high-performance concrete and a preparation method thereof. Background Art

[0002] In recent years, high-performance concrete, as a relatively new concrete technology, has been developing rapidly and applied to many actual engineering projects. Due to its many excellent properties such as high durability, high workability, high strength, and high volume stability, high-performance concrete is considered to be the most comprehensive concrete in the world at present. It has been adopted in many important projects so far, especially in projects such as bridges, high-rise buildings, and seaport buildings. High-performance concrete has excellent properties that ordinary concrete cannot match. The research on high-performance concrete is one of the hottest topics in the field of civil engineering today. If high-performance concrete is considered in combination with environmental protection, ecological protection, and sustainable development, it becomes green high-performance concrete.

[0003] Green high-performance concrete refers to a new type of concrete material prepared by using recyclable materials, renewable energy, and low-carbon technologies, which has the advantages of high strength, good durability, and low carbon emissions. Among them, "green" means that this kind of concrete consumes less natural resources and has lower carbon emissions during the production and use processes, has less impact on the natural environment, and meets the requirements of sustainable development; "high-performance" means that this kind of concrete has high strength, durability, and other mechanical properties, can improve the safety of building structures, and extend the service life of buildings. During the preparation process of green high-performance concrete, construction personnel usually use a certain proportion of industrial waste residues such as fly ash, silica fume, and quartz powder to replace traditional cement clinker to improve the strength and durability of green high-performance concrete and meet strict engineering construction requirements.

[0004] The performance of concrete is deeply affected by the characteristics of aggregates. As the main component of concrete (accounting for more than 60%), aggregates not only bear loads and resist erosion, but also significantly affect the stability of concrete. It is found that the size of aggregates is directly related to key indexes such as the initial slump, slump retention ability, and slump loss of concrete. In addition, the soil pollution on the surface of aggregates will weaken the adhesion between aggregates and cement, form weak strength areas, reduce the overall strength, and damage the carbonation resistance and weather resistance of concrete. At the same time, the aggregation of soil may also cause local strength reduction, constituting a safety hazard.

[0005] In order to optimize the performance of concrete, water reducers, as an important additive, are widely used to improve the performance of fresh concrete and hardened concrete. Although water reducers are known for their small dosage and remarkable effects, their preparation process is complex and energy-consuming. Especially in the high-energy-consuming field of the building materials industry, energy conservation and emission reduction are particularly important.

[0006] During the hardening process, concrete faces the problem of uneven water evaporation. Slow and uneven water evaporation leads to the formation of a large number of fine pores, which has an adverse impact on the strength of concrete. In practical engineering such as road paving, the joint gaps caused by multiple parallel pavings and the microcracks generated during the hardening process of concrete will further weaken the strength and durability of concrete and affect its long-term use stability. In view of these problems, there is an urgent need to innovate and develop a green high-performance concrete to improve the quality and efficiency of concrete repair and promote the progress of the building materials field. Summary of the Invention

[0007] One of the objectives of the present invention is to provide a green high-performance concrete that can significantly improve the workability (slump, spread) of concrete, compressive strength, and maximum water pressure resistance to infiltration.

[0008] To achieve one of the objectives of the present invention, the technical solution adopted by the present invention is:

[0009] A green high-performance concrete, the green high-performance concrete includes 360 - 390 parts of total binder, 1650 - 1800 parts of aggregate, 120 - 140 parts of water, 7.0 - 7.8 parts of water reducer, 4 - 6 parts of retarder; the total binder includes the following components: 250 - 280 parts of cement, 52 - 60 parts of mineral powder, 10 - 15 parts of silica fume, 35 - 40 parts of fly ash; the aggregate includes the following components: 730 - 800 parts of sand, 930 - 1010 parts of stone; the preparation method of the retarder includes the following steps: reacting polyether polyol, hexamethylene diisocyanate, and organic base 1 for 12 - 24 h to obtain a mixed system, adding lignin and organic base 2 to the mixed system and reacting for 18 - 48 h, and then obtaining the retarder through treatment.

[0010] Further, the mass ratio of the polyether polyol, hexamethylene diisocyanate, and organic base 1 is 400:(150 - 165):(120 - 150); the lignin and organic base 2 are added to the mixed system in a mass ratio of 1:(0.5 - 0.7).

[0011] Further, the mass ratio of the organic base 1 and organic base 2 is 1:(1.2 - 1.4); the organic base 1 and organic base 2 are one of triethylamine and pyridine.

[0012] Further, the preparation method of the water reducer includes the following steps:

[0013] (1) Take terminal olefin polyether, 30% hydrogen peroxide, ferrous sulfate, and acrylic acid and place them in water to obtain liquid A; take acrylic acid and N-hydroxymethylacrylamide and place them in water to obtain liquid B; take methacryloyloxyethyl trimethyl ammonium chloride, vitamin C, and mercaptopropionic acid and place them in water to obtain liquid C; add the said liquid B and liquid C to liquid A respectively, and react at 35-50 °C for 60-90 min, and obtain intermediate 1 after treatment;

[0014] (2) React the said intermediate 1, cellulose, N,N,N',N'-tetramethylazodicarboxamide, and triphenylphosphine at 60-90 °C for 16-24 h, and obtain the water reducing agent after treatment.

[0015] Furthermore, the dosage ratio of terminal olefin polyether, 30% hydrogen peroxide, ferrous sulfate, and acrylic acid in liquid A is 180 g:(3.5-5) mL:(0.5-0.8) g:(3-5) g.

[0016] Furthermore, the mass ratio of acrylic acid and N-hydroxymethylacrylamide in liquid B is 1:(0.15-0.21).

[0017] Furthermore, the mass ratio of methacryloyloxyethyl trimethyl ammonium chloride, vitamin C, and mercaptopropionic acid in liquid C is 1:(0.12-0.17):(0.45-0.5).

[0018] Furthermore, the terminal olefin polyether is one of isoprenyl polyoxyethylene ether and 4-hydroxybutyl vinyl polyoxyethylene ether.

[0019] Furthermore, the green high-performance concrete includes 361-389 parts of total binder, 1670-1801 parts of aggregate, 130-140 parts of water, 7.2-7.8 parts of water reducing agent, and 4-6 parts of retarder; the total binder includes the following components: 260-280 parts of cement, 54-58 parts of mineral powder, 10-12 parts of silica fume, and 36-39 parts of fly ash; the aggregate includes the following components: 735-791 parts of sand and 935-1010 parts of stone.

[0020] Even further, the fineness modulus of the sand is 2.4-3.0, and the maximum particle size of the stone is preferably 25 mm

[0021] The second object of the present invention is to provide a preparation method of green high-performance concrete.

[0022] To achieve the second object of the present invention, the technical solution adopted by the present invention is:

[0023] Take the said total binder, aggregate, water, water reducing agent, and retarder, stir and mix them to obtain green high-performance concrete.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. Due to the uneven surface of lignin fiber, lignin fiber has a stronger binding force with cement or aggregate, thus reducing the cracking of concrete. Lignocellulose has a strong cross-linking and patching function. It is grafted with polyethylene glycol to prepare a retarder, which can lock moisture in it to keep water and retard setting, further increasing the binding force between lignin fiber and cement or aggregate, thus further reducing the cracking of concrete and improving the impermeability of cement. After silica fume is incorporated into concrete, on the one hand, under the alkaline activation in concrete, due to the secondary reaction between silica fume and Ca(OH)2 generated during the hydration process of cement, C-S-H gel and calcium silicate hydrate are generated, making the concrete more dense; when fly ash and slag are incorporated into concrete, the heat of hydration can be reduced by reducing the amount of cement used, thus reducing the possibility of concrete cracks. Incorporating fly ash increases the volume of the concrete paste, and a large amount of paste fills the pores between aggregates, wrapping and lubricating the aggregate particles, so that the concrete mixture has better cohesion and plasticity, and maintains the good dispersion property of cement.

[0026] 2. The surface of cellulose is rich in hydroxyl groups. The cellulose is grafted onto the polycarboxylate superplasticizer by esterification reaction with some carboxylic acids of the polycarboxylate superplasticizer. The present invention proposes a new method for superplasticizer preparation. The prepared superplasticizer and retarder are applied to concrete, respectively improving the workability (slump, spread) of concrete, the compressive strength and the maximum water pressure of impermeability. The synergistic effect is better. Specific Embodiments

[0027] The technical solution of the present invention will be further described below in conjunction with specific embodiments. However, those skilled in the art should understand that the following embodiments are only used to illustrate the present invention and should not be regarded as a limitation to the present invention. The specific conditions not specified in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, unless otherwise specified, are all conventional products obtained through commercial channels.

[0028] Example 1

[0029] A green high-performance concrete, the preparation method of which includes the following steps:

[0030] (1) Preparation of retarder

[0031] 400 g of polyethylene glycol 400, 165 g of hexamethylene diisocyanate, and 120 g of triethylamine are added to 1 L of N,N-dimethylformamide (DMF) and stirred for reaction for 24 h to obtain a mixed system. Then, 200 g of lignin and 100 g of pyridine are added to the mixed system and stirred for reaction for 48 h. After that, the reaction solution is filtered and dried to obtain the retarder.

[0032] (2) Preparation of retarder

[0033] Add 180 g of isoprenyl polyoxyethylene ether (TEPG-2400) to 200 mL of water. After dissolution, add 4 mL of 30% hydrogen peroxide, 0.5 g of ferrous sulfate and 5 g of acrylic acid to obtain Solution A; place 13 g of acrylic acid and 2 g of N-hydroxymethylacrylamide in 15 mL of deionized water to obtain Solution B; place 3 g of methylacryloyloxyethyltrimethylammonium chloride, 0.4 g of vitamin C and 1.5 g of mercaptopropionic acid in 40 mL of deionized water to obtain Solution C; simultaneously drop Solution C and Solution B into Solution A. After the dropping is completed, place the reaction solution at 40 °C for reaction for 75 min, and then add 30% sodium hydroxide aqueous solution to neutralize the reaction solution to pH = 5.55 to obtain Intermediate 1.

[0034] React 400 g of Intermediate 1, 20 g of cellulose, 12 N,N,N',N'-tetramethylazodicarboxamide and 22 g of triphenylphosphine in 500 mL of N,N-dimethylformamide (DMF) at 90 °C for 16 h. After filtration, prepare it into a 40% aqueous solution, which is the water reducing agent.

[0035] (3) Preparation of concrete

[0036] Weigh 260 parts of cement, 54 parts of mineral powder, 11 parts of silica fume, 36 parts of fly ash, 735 parts of sand, 935 parts of stone, 130 parts of water, 7.22 parts of water reducing agent and 4 parts of retarder according to the formula and stir for 3 min to obtain green high-performance concrete.

[0037] Example 2

[0038] A kind of green high-performance concrete, the preparation method thereof comprises the following steps:

[0039] (1) Preparation of retarder

[0040] Add 400 g of polypropylene glycol 400, 150 g of hexamethylene diisocyanate and 150 g of pyridine to 700 mL of N,N-dimethylamide (DMF), stir and react for 36 h to obtain a mixed system. Then add 180 g of lignin and 110 g of triethylamine to the mixed system, stir and react for 60 h, and then filter and dry the reaction solution to obtain the retarder.

[0041] (2) Preparation of retarder

[0042] Add 180 g of 4-hydroxybutyl vinyl polyoxyethylene ether (VPEG-2400) to 200 mL of water. After dissolution, add 5 mL of 30% hydrogen peroxide, 0.8 g of ferrous sulfate, and 4 g of acrylic acid to obtain Solution A; place 14 g of acrylic acid and 3 g of N-hydroxymethylacrylamide in 25 mL of deionized water to obtain Solution B; place 4 g of methacryloyloxyethyltrimethylammonium chloride, 0.5 g of vitamin C, and 1.8 g of mercaptopropionic acid in 50 mL of deionized water to obtain Solution C; synchronously add Solution C and Solution B dropwise to Solution A. After the addition is completed, place the reaction solution at 35 °C for reaction for 90 min, and then add 30% sodium hydroxide aqueous solution to neutralize the reaction solution to pH = 6 to obtain Intermediate 1.

[0043] React 400 g of solid Intermediate 1, 15 g of cellulose, 15 g of N,N,N',N'-tetramethylazodicarboxamide, and 25 g of triphenylphosphine in 700 mL of N,N-dimethylformamide (DMF) at 60 °C for 24 h. After filtration, prepare it into a 35% aqueous solution to obtain a water reducing agent.

[0044] (3) Prepare concrete

[0045] Weigh 270 parts of cement, 56 parts of mineral powder, 11 parts of silica fume, 38 parts of fly ash, 763 parts of sand, 971 parts of stone, 135 parts of water, 7.50 parts of water reducing agent, and 5 parts of retarder according to the formula and stir evenly to obtain green high-performance concrete.

[0046] Example 3

[0047] A green high-performance concrete, and its preparation method includes the following steps:

[0048] (1) Prepare a retarder

[0049] Add 400 g of polyethylene glycol 400, 160 g of hexamethylene diisocyanate, and 135 g of triethylamine to 800 mL of N,N-dimethylformamide (DMF), stir and react for 24 h to obtain a mixed system. Then add 150 g of lignin and 105 g of triethylamine to the mixed system, stir and react for 72 h, and then filter and dry the reaction solution to obtain a retarder.

[0050] (2) Prepare a retarder

[0051] Add 180 g of isoprenyl polyoxyethylene ether (TEPG-2400) to 200 mL of water. After dissolution, add 3.5 mL of 30% hydrogen peroxide, 0.7 g of ferrous sulfate, and 3 g of acrylic acid to obtain Solution A; place 15 g of acrylic acid and 2.5 g of N-hydroxymethylacrylamide in 20 mL of deionized water to obtain Solution B; place 3.5 g of methacryloyloxyethyltrimethylammonium chloride, 0.6 g of vitamin C, and 1.6 g of mercaptopropionic acid in 45 mL of deionized water to obtain Solution C; simultaneously add Solution C and Solution B dropwise to Solution A. After the addition is complete, place the reaction solution at 50 °C for reaction for 60 min, and then add 30% sodium hydroxide aqueous solution to neutralize the reaction solution to pH = 6.5 to obtain Intermediate 1.

[0052] React 400 g of solid Intermediate 1, 18 g of cellulose, 18 N,N,N',N'-tetramethyldiazodicarboxamide, and 27 g of triphenylphosphine in 500 mL of N,N-dimethylformamide (DMF) at 70 °C for 18 h. After filtration, prepare it into a 30% aqueous solution, which is the water reducing agent.

[0053] (3) Prepare concrete

[0054] Weigh 280 parts of cement, 58 parts of mineral powder, 12 parts of silica fume, 39 parts of fly ash, 791 parts of sand, 1010 parts of stone, 140 parts of water, 7.78 parts of water reducing agent, and 6 parts of retarder according to the formula and stir evenly to obtain green high-performance concrete.

[0055] Comparative Example 1

[0056] A kind of green concrete, different from Example 1 in that: Step (1) is omitted, and the retarder in Step (3) is replaced with an equal amount of lignin.

[0057] Comparative Example 2

[0058] A kind of green concrete, different from Example 1 in that: Step (2) is omitted, and the water reducing agent in Step (3) is replaced with an equal amount of Intermediate 1.

[0059] Comparative Example 3

[0060] A kind of green concrete, different from Example 1 in that: Steps (1) and (2) are omitted, the water reducing agent in Step (3) is replaced with an equal amount of Intermediate 1, the retarder in Step (3) is omitted, and an amount of cellulose equal to that of the water reducing agent and an amount of lignin equal to that of the retarder are added thereto.

[0061] Comparative Example 4

[0062] A kind of green concrete, different from Example 1 in that: Steps (1) and (2) are omitted, the water reducing agent in Step (3) is replaced with an equal amount of Intermediate 1, and the retarder in Step (3) is omitted.

[0063] Test Example

[0064] The samples prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests: specimens of concrete for each example and comparative example were prepared according to the test requirements. The size of the concrete compressive specimens was 100 mm×100 mm×100 mm, the size of the flexural specimens was 150 mm×150 mm×550 mm, the size of the impermeability specimens was 150 mm×φ175 mm×φ185 mm, and the size of the electric flux specimens was a cylinder with a diameter of (100±1) mm and a height of (50±2) mm. After each specimen was cured under standard conditions to the specified age, relevant tests were carried out. The slump of the concrete was tested according to GB50164-92 "Concrete Quality Control Standard" to evaluate the fluidity of the concrete. The compressive strength test was carried out according to "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" GB / T50081-2019. The impermeability test was carried out using an impermeability tester according to "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" GB / T50082-2009, and the anti-chloride ion penetration test was carried out by the electric flux method. The comparative test results of each example and comparative example are shown in Table 1.

[0065] Table 1

[0066]

[0067] As can be seen from Table 1, compared with Comparative Example 4 which only added Intermediate 1-polycarboxylate superplasticizer, the addition of superplasticizer and lignin in Comparative Example 1 improved the workability (slump, spread) of concrete, compressive strength and maximum water pressure of impermeability; the addition of Intermediate 1-polycarboxylate superplasticizer and retarder in Comparative Example 2 improved the workability (slump, spread) of concrete, compressive strength and maximum water pressure of impermeability; the addition of lignin, Intermediate 1-polycarboxylate superplasticizer and cellulose in Comparative Example 3 improved the compressive strength and maximum water pressure of impermeability, and reduced the workability (slump, spread); however, compared with Comparative Example 4, the electric flux (56 days) of the concrete in Examples 1-3 increased by 7-9 C. The workability (slump, spread), compressive strength and maximum water pressure of impermeability of Examples 1-3 were significantly better than those of Comparative Examples 1-4, which indicates that superplasticizer and retarder can not only individually improve the workability (slump, spread), compressive strength and maximum water pressure of impermeability of concrete, but also have a better synergistic effect.

[0068] The above are only the preferred embodiments of the present invention, not limited to the above examples. For those skilled in the art, various changes and modifications can be made under the principle of the present invention. Any modifications, improvements, etc. should be regarded as within the protection scope of the present invention.

Claims

1. A green high performance concrete, characterized in that: The green high-performance concrete comprises 360-390 parts of total adhesive, 1650-1801 parts of aggregate, 120-140 parts of water, 7.0-7.8 parts of water reducer, and 4-6 parts of retarder; the total adhesive comprises the following components: 250-280 parts of cement, 52-60 parts of mineral powder, 10-15 parts of silica fume, and 35-40 parts of fly ash; the aggregate comprises the following components: 730-800 parts of sand and 930-1010 parts of stone; the preparation method of the retarder comprises the following steps: reacting polyether polyol, hexamethylene diisocyanate, and organic base 1 for 12-24 hours to obtain a mixed system, adding lignin and organic base 2 to the mixed system for reaction for 18-48 hours, and then treating to obtain the retarder; The preparation method of the water reducing agent comprises the following steps: (1) Put terminal olefin polyether, 30% hydrogen peroxide, ferrous sulfate and acrylic acid in water to obtain liquid A; put acrylic acid and N-hydroxymethyl acrylamide in water to obtain liquid B; put methacryloyloxyethyl trimethyl ammonium chloride, vitamin C and mercaptopropionic acid in water to obtain liquid C; add the liquid B and liquid C to liquid A respectively, react at 35-50°C for 60-90 minutes, and then treat to obtain intermediate 1; (2) The intermediate 1, cellulose, N,N,N',N'-tetramethylazodicarbonamide and triphenylphosphine are reacted at 60-90° C. for 16-24 hours, and the water reducing agent is obtained after treatment.

2. The green high performance concrete according to claim 1, characterized in that: The mass ratio of the polyether polyol, hexamethylene diisocyanate and organic base 1 is 400: (150-165): (120-150); the lignin and organic base 2 are added to the mixed system at a mass ratio of 1: (0.5-0.7).

3. The green high performance concrete according to claim 1, characterized in that: The mass ratio of the organic base 1 to the organic base 2 is 1:(1.2-1.4); the organic base 1 and the organic base 2 are one of triethylamine and pyridine.

4. The green high performance concrete according to claim 1, characterized in that: The amount ratio of the terminal olefin polyether, 30% hydrogen peroxide, ferrous sulfate and acrylic acid in the liquid A is 180g: (3.5-5)mL: (0.5-0.8)g: (3-5)g.

5. The green high performance concrete according to claim 1, characterized in that: The mass ratio of acrylic acid to N-hydroxymethyl acrylamide in the liquid B is 1:(0.15-0.21).

6. The green high performance concrete according to claim 1, characterized in that: The mass ratio of methacryloyloxyethyl trimethylammonium chloride, vitamin C and mercaptopropionic acid in the C liquid is 1: (0.12-0.17): (0.45-0.5).

7. The green high performance concrete according to claim 1, characterized in that: The terminal olefin polyether is one of isoprene polyoxyethylene ether and 4-hydroxybutyl vinyl polyoxyethylene ether.

8. The green high performance concrete according to claim 1, characterized in that: The green high-performance concrete includes 361-389 parts of total adhesive, 1670-1801 parts of aggregate, 130-140 parts of water, 7.2-7.8 parts of water reducer, and 4-6 parts of retarder; the total adhesive includes the following components: 260-280 parts of cement, 54-58 parts of mineral powder, 10-12 parts of silica fume, and 36-39 parts of fly ash; the aggregate includes the following components: 735-791 parts of sand and 935-1010 parts of stone.

9. The method for preparing green high performance concrete according to claim 1, characterized in that: The following steps are involved: The total adhesive, aggregate, water, water reducing agent and retarder are mixed and stirred to obtain green high performance concrete.

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