Low-shrinkage high-durability self-compacting concrete as well as preparation method and application thereof

Abstract

The invention provides low-shrinkage high-durability self-compacting concrete as well as a preparation method and application thereof. The concrete is prepared by mixing 3-9 parts of Portland cement, 10-22 parts of fine aggregate, 13-34 parts of coarse aggregate and a mixture of an environment-friendly material, urea, a calcium source and water, the environment-friendly material is a plant source, and the concentration of the environment-friendly material is 4-10 g / l. The low-shrinkage high-durability self-compacting concrete is good in water permeability, long / short-term strength, durability, fatigue resistance and stripping resistance, meanwhile, natural resources are saved, and the concrete is environmentally friendly and low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to a low-shrinkage and high-durability self-compacting concrete, a preparation method thereof and an application thereof. Background Art

[0002] Concrete generally refers to an engineering composite material composed of cementitious materials and aggregates bonded together as a whole. It is commonly used in house construction and road construction. Generally, cement is used as the cementitious material and sand and gravel are used as aggregates.

[0003] With the continuous improvement of urbanization, the requirements for the performance of concrete materials are getting higher and higher. On the one hand, for example, traditional concrete pavements lack the ability to breathe and penetrate rainwater, resulting in the inability of rainwater to penetrate into the ground, forming a large amount of water on the road surface and affecting the replenishment of urban groundwater, causing damage to the ecological environment. On the other hand, due to various factors such as the intrusion of various harmful substances and environmental changes, traditional concrete pavements are prone to deterioration over time, and various deteriorating substances (such as raw sewage, seawater, acid rain, etc.) enter from the environment. They will cause various defects, such as steel corrosion, crack formation, peeling, etc. In addition, repeated changes in the external environment, such as various weathering effects, will also make concrete materials fragile and not durable over time. On the other hand, some high-strength concretes have large self-shrinkage and are prone to cracking.

[0004] In the prior art, the improvement and maintenance of material durability, water permeability, and self-shrinkage are not ideal, and are often achieved by adding minerals and chemicals, which not only consumes natural resources but is also not environmentally friendly. Therefore, how to develop an environmentally friendly and resource-saving concrete material that also has excellent durability, water permeability, and self-shrinkage is a problem that needs to be solved. Summary of the invention

[0005] The present invention aims to overcome the above-mentioned defects in the prior art and provide a low shrinkage and high durability self-compacting concrete, a preparation method and its application. By adding plant sources, the self-compacting properties of concrete materials can be improved. Shrinkage, water permeability, long / short term Strength, durability, fatigue resistance and spalling resistance, which helps to improve The construction quality is minimized from the influence of external climate and environment; at the same time, the use of plant sources can save natural resources, be environmentally friendly and low-cost.

[0006] The present invention provides the following technical solutions to solve the above problems.

[0007] In a first aspect, the present invention provides a low-shrinkage and high-durability self-compacting concrete, which is prepared by mixing a mixture including 3-9 parts of silicate cement, 10-22 parts of fine aggregate, 13-34 parts of coarse aggregate, environmentally friendly materials, urea, a calcium source and water, wherein the environmentally friendly materials are of plant origin and the concentration thereof is 4-10 g / l.

[0008] In some embodiments, the silicate cement is 3-8 parts, for example, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, and 8 parts.

[0009] In some embodiments, the fine aggregate is 10-21 parts, for example, 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 14 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 20.5 parts, and 21 parts.

[0010] In some embodiments, the coarse aggregate is 14-33 parts, for example, 14 parts, 14.56 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, and 33 parts.

[0011] In some embodiments, the particle size of the coarse aggregate is 10 mm-20 mm.

[0012] In the present invention, the aggregate may come from river sand.

[0013] In some embodiments, the plant source is selected from peas, watermelon seeds, pumpkin seeds and sword beans, preferably selected from peas, watermelon seeds and pumpkin seeds, and most preferably peas.

[0014] In some embodiments, the calcium source may be a calcium source conventionally used in the art, preferably selected from calcium hydroxide, calcium oxide and calcium chloride, such as calcium hydroxide.

[0015] In some embodiments, the concentration of the plant source is 5-9.5 g / l, such as 5 g / l, 6 g / l, 7 g / l, 8 g / l, 9 g / l, 9.5 g / l.

[0016] In some embodiments, the concentration of urea is 4-12 g / l, preferably 5-11 g / l, for example 5 g / l, 6 g / l, 7 g / l, 8 g / l, 9 g / l, 10 g / l, 11 g / l.

[0017] In some embodiments, the concentration of the calcium source is 5-13 g / l, preferably 5.5-12.5 g / l. Such as 5.5g / l, 5.55g / l, 6g / l, 7g / l, 8g / l, 9g / l, 10g / l, 11g / l, 12g / l, 12.5g / l.

[0018] In the present invention, the concentration refers to the concentration in water.

[0019] In the present invention, urea, calcium source and plant source act, and their decomposition products contribute to the improvement and maintenance of the self-shrinkage, durability, fatigue resistance, spalling resistance and water permeability of the final concrete material.

[0020] In some embodiments, the low shrinkage and high durability self-compacting concrete further comprises any additives that do not affect the above effects.

[0021] In some embodiments, the additive includes a water reducer; the water reducer here includes but is not limited to lignin sulfonate water reducer, naphthalene sulfonate water reducer, melamine water reducer, polycarboxylic acid high performance water reducer or aminosulfonate high efficiency water reducer.

[0022] In the present invention, the water reducing agent refers to a substance that can reduce the unit water consumption, improve the fluidity of the mixture, and improve workability.

[0023] In some embodiments, the amount of the water reducing agent is 0.3-1 part, for example, 0.3 part, 0.33 part, 0.4 part, 0.5 part, 0.6 part, 0.75, 0.8 part, 0.9 part, and 1 part.

[0024] In some embodiments, the additive includes inorganic chopped fibers.

[0025] In some embodiments, the inorganic chopped fibers are used in an amount of 1-11% by weight of the total weight of the material (excluding water); for example, 1%, 3%, 6%, 9% or 11%.

[0026] In some embodiments, the additive includes a defoaming agent.

[0027] In some embodiments, the additive includes a bulking agent.

[0028] In some embodiments, the additive includes a retarder.

[0029] In a second aspect, the present invention provides a method for preparing the low shrinkage and high durability self-compacting concrete as described above, comprising the following steps:

[0030] Preparation Part A: Grind the plant source into powder for later use;

[0031] Prepare Part B: Mix 3-9 parts of Portland cement, 10-22 parts of fine aggregate and 13-34 parts of coarse aggregate until uniform;

[0032] Obtaining the low-shrinkage and high-durability self-compacting concrete: mixing the mixture in Part B with the powder, urea, calcium source and water in Part A, and stirring to obtain the low-shrinkage and high-durability self-compacting concrete.

[0033] In some embodiments, during the preparation of the Part B, the fine aggregate and the coarse aggregate may be preheated to remove some impurities.

[0034] In some embodiments, the preheating temperature may be a conventional temperature in the art, preferably, the preheating temperature is 80-150°C.

[0035] In some embodiments, during the preparation of the part B, the water reducing agent is further added and mixed evenly.

[0036] In some embodiments, during the preparation of the B part, the inorganic chopped fibers are further added and mixed uniformly.

[0037] In some embodiments, the stirring time is 15 to 120 minutes.

[0038] In some embodiments, in the step of obtaining the low shrinkage and high durability self-compacting concrete, water may be added to the mixture in Part B first, and then the powder, urea and calcium source in Part A may be added after waiting for 5-10 minutes.

[0039] In a third aspect, the present invention provides an application of the low shrinkage and high durability self-compacting concrete as described above in the field of construction.

[0040] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0041] The reagents and raw materials used in the present invention are commercially available.

[0042] The positive and progressive effects of the present invention are:

[0043] In the present invention, firstly, the application of plant sources reduces the excessive use of natural resources, thus saving resources and reducing environmental pollution.

[0044] Secondly, by adopting a specific concentration of plant sources, the low shrinkage and high durability self-compacting concrete in the present invention has better uniformity and stability, which is beneficial to ensuring the construction quality. Optionally combined with other raw materials such as water reducers, inorganic short fibers, defoamers, expansion agents, retarders, etc., the comprehensive properties of the obtained low shrinkage and high durability self-compacting concrete can be improved, including mechanical properties such as compressive strength, flexural strength, durability, fatigue resistance, spalling resistance and water permeability.

[0045] Furthermore, the low shrinkage and high durability self-compacting concrete of the present invention has excellent adaptability and can be constructed and maintained for a long time in a variety of climates and environments without being restricted by temperature, humidity, etc., which makes it have a wide range of application prospects, especially in areas with large seasonal changes. These characteristics make the low shrinkage and high durability self-compacting concrete of the present invention Shrinkage-resistant self-compacting concrete in road repair and new construction It has high practical value and Market potential. DETAILED DESCRIPTION

[0046] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0047] In the following examples and comparative examples, 1 part corresponds to 100 kg.

[0048] Example 1: A low shrinkage and high durability self-compacting concrete is prepared by the following steps:

[0049] A. Take watermelon seeds and grind them into fine powder for later use;

[0050] B. Take 3.5 parts of Portland cement, 10.5 parts of fine aggregate and 14.56 parts of coarse aggregate and stir these components thoroughly to mix them evenly.

[0051] C. 1m 3 About 5 minutes after water was added to the mixture in B, the ground watermelon seed powder, urea and calcium hydroxide were added to obtain a final concrete mixture, wherein the concentration of watermelon seed powder was 5 g / l, the concentration of urea was 5 g / l, and the concentration of calcium hydroxide was 5.55 g / l.

[0052] Example 2: A low shrinkage and high durability self-compacting concrete is prepared by the following steps:

[0053] A. Take watermelon seeds and grind them into fine powder for later use;

[0054] B. Take 8 parts of Portland cement, 21 parts of fine aggregate and 32.2 parts of coarse aggregate and stir these components thoroughly to mix them evenly.

[0055] C. 2m 3 About 5 minutes after water was added to the mixture in B, ground watermelon seed powder, urea and calcium hydroxide were added to obtain a final concrete mixture, wherein the concentration of watermelon seed powder was 9.5 g / l, the concentration of urea was 11 g / l, and the concentration of calcium hydroxide was 12 g / l.

[0056] Example 3: A low shrinkage and high durability self-compacting concrete is prepared by the following steps:

[0057] A. Grind pumpkin seeds into fine powder and set aside;

[0058] B. Take 3.5 parts of Portland cement, 10.5 parts of fine aggregate and 14.56 parts of coarse aggregate and stir these components thoroughly to mix them evenly.

[0059] C. 1m 3About 5 minutes after water was added to the mixture in B, ground pumpkin seed powder, urea, and calcium hydroxide were added to obtain the final concrete mix, wherein the concentration of pumpkin seed powder was 5 g / l. The concentration of urea is 5g / l and the concentration of calcium hydroxide is The concentration is 5.55g / l.

[0060] Example 4: A low shrinkage and high durability self-compacting concrete is prepared by the following steps:

[0061] A. Grind pumpkin seeds into fine powder and set aside;

[0062] B. Take 8 parts of Portland cement, 21 parts of fine aggregate and 32.2 parts of coarse aggregate and stir these components thoroughly to mix them evenly.

[0063] C. 2m 3 About 5 minutes after the water was added to the mixture in B, the ground pumpkin seed powder, urea and calcium hydroxide were added to obtain the final concrete mixture, wherein the concentration of pumpkin seed powder was 9.5 g / l, the concentration of urea was 11 g / l, and the concentration of calcium hydroxide was 12 g / l.

[0064] Example 5: A low shrinkage and high durability self-compacting concrete is prepared by the following steps:

[0065] A. Take peas and grind them into fine powder, set aside;

[0066] B. Take 3.5 parts of Portland cement, 10.5 parts of fine aggregate, 14.56 parts of coarse aggregate and 1 part of water reducing agent, and stir these components thoroughly to mix them evenly.

[0067] C. 1m 3 About 5 minutes after the water was added to the mixture in B, the ground pea flour, urea and calcium hydroxide were added to obtain a final concrete mix, wherein the concentration of pea flour was 5 g / l, the concentration of urea was 5 g / l, and the concentration of calcium hydroxide was 5.55 g / l.

[0068] Example 6: A low shrinkage and high durability self-compacting concrete is prepared by the following steps:

[0069] A. Take peas and grind them into fine powder, set aside;

[0070] B. Take 8 parts of Portland cement, 21 parts of fine aggregate and 32.2 parts of coarse aggregate and stir these components thoroughly to mix them evenly.

[0071] C. 2m 3 About 5 minutes after the water was added to the mixture in B, the ground pea flour, urea and calcium hydroxide were added to obtain a final concrete mix, wherein the concentration of pea flour was 9.5 g / l, the concentration of urea was 11 g / l and the concentration of calcium hydroxide was 12 g / l.

[0072] Comparative Example 1: A low shrinkage and high durability self-compacting concrete, which is prepared by the following steps:

[0073] Take 3.5 parts of Portland cement, 10.5 parts of fine aggregate, and 14.56 parts of coarse aggregate, stir these components thoroughly to mix them evenly, and add 1m of water. 3 to obtain the final concrete mix.

[0074] Comparative Example 2: A low shrinkage and high durability self-compacting concrete, which is prepared by the following steps:

[0075] Take 3.5 parts of Portland cement, 10.5 parts of fine aggregate, and 14.56 parts of coarse aggregate, and stir these components thoroughly to mix them evenly.

[0076] 1m 3 About 5 minutes after water was added to the above mixture, urea and calcium hydroxide were added to obtain a final concrete mix, wherein the concentration of urea was 5 g / l and the concentration of calcium hydroxide was 5.55 g / l.

[0077] Compressive strength test and flexural strength test: The above concrete mixture was cured to prepare a 150×150×150mm specimen, and 3 specimens were taken for each example or comparative example. The compressive strength was tested after 30 days and 60 days in a natural environment according to IS 516,1959, and the average value was taken. The above concrete mixture was cured to prepare a 100×100×500mm specimen, and 3 specimens were taken for each example or comparative example. The flexural strength was tested after 30 days and 60 days in a natural environment according to IS 516,1959, and the average value was taken. The above concrete mixture was cured to prepare a 150×150×150mm specimen, and 3 specimens were taken for each example or comparative example. The water absorption was tested after 30 days according to ASTM-C1202, 2012, and the average value was taken. The above concrete mixture was cured to prepare a 100 mm × 100 mm × 515 mm sample, which was sealed with a plastic wrap, and the length shrinkage value of the concrete after casting was tested using a CABR-NES non-contact shrinkage deformation instrument at (20±2)°C. The test results are listed in Table 1 below.

[0078] Table 1

[0079]

[0080]

[0081] As can be seen from the above table, compared with comparative examples 1-2, embodiments 1-6 of the present invention using plant sources all have better compressive strength, flexural strength, water absorption and autogenous shrinkage after being placed for 30 days or 60 days, among which the embodiment using pea source has the best effect.

Claims

1. A low shrinkage and high durability self-compacting concrete, characterized in that: The invention is prepared by mixing a mixture including 3-9 parts of silicate cement, 10-22 parts of fine aggregate, 13-34 parts of coarse aggregate, environmentally friendly material, urea, a calcium source and water, wherein the environmentally friendly material is of plant origin and has a concentration of 4-10 g / l.

2. The low shrinkage and high durability self-compacting concrete according to claim 1, characterized in that: The plant source is selected from peas, watermelon seeds, pumpkin seeds and sword beans.

3. The low shrinkage and high durability self-compacting concrete according to claim 1, characterized in that: The concentration of the plant source is 5-9.5 g / l.

4. The low shrinkage and high durability self-compacting concrete according to claim 1, characterized in that: The coarse aggregate is 14-33 parts; and / or The fine aggregate is 10-21 parts; and / or The silicate cement is 3-8 parts; and / or The low shrinkage and high durability self-compacting concrete may further include any additives that do not affect the above effects.

5. The low shrinkage and high durability self-compacting concrete according to claim 1, characterized in that: The calcium source is selected from calcium hydroxide, calcium oxide and calcium chloride; and / or The concentration of the urea is 4-12 g / l; and / or The concentration of the calcium source is 5-13 g / l.

6. The low shrinkage and high durability self-compacting concrete according to claim 1, characterized in that: The low shrinkage and high durability self-compacting concrete may further include any additives that do not affect the above effects.

7. The low shrinkage and high durability self-compacting concrete according to claim 6, characterized in that: The additive is selected from water reducing agent, inorganic short fiber, defoaming agent, expansion agent and retarder.

8. A method for preparing a low shrinkage and high durability self-compacting concrete according to any one of claims 1 to 7, characterized in that: The steps include: Preparation Part A: Grind the plant source into powder for later use; Prepare Part B: Mix 3-9 parts of Portland cement, 10-22 parts of fine aggregate and 13-34 parts of coarse aggregate until uniform; Obtaining the low-shrinkage and high-durability self-compacting concrete: mixing the mixture in Part B with the powder, urea, calcium source and water in Part A, and stirring to obtain the low-shrinkage and high-durability self-compacting concrete.

9. The preparation method according to claim 8, characterized in that: In the preparation of the B part, the fine aggregate and the coarse aggregate are preheated to remove some impurities, preferably, the preheating temperature is 80-150° C.; and / or In the preparation of the B part, the water reducing agent is further added and mixed evenly; and / or In the preparation of the B part, the inorganic chopped fibers are further added and mixed uniformly; and / or The stirring time is 15 to 120 minutes; and / or In the step of obtaining the low shrinkage and high durability self-compacting concrete, water is first added to the mixture in part B, and then the powder, urea and calcium source in part A are added after 5-10 minutes.

10. Use of the low shrinkage and high durability self-compacting concrete according to any one of claims 1 to 7 in the field of construction.

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