Conductive concrete and preparation method and application thereof

Abstract

The application discloses electrically conductive concrete and a preparation method and application thereof. The electrically conductive concrete comprises the following components: cement, gravel, sand, water reducing agent, dispersant, graphite powder, sodium alginate and composite fiber; the composite fiber comprises graphene oxide modified glass fiber and nanometer material modified polylactic acid fiber; the preparation method of the graphene oxide modified glass fiber comprises the following steps: soaking glass fiber in a graphene oxide dispersion solution for 5-12 min, and obtaining after drying; the preparation method of the nanometer material modified polylactic acid fiber comprises the following steps: soaking polylactic acid fiber in a solution containing nanometer magnesium oxide, nanometer aluminum oxide and graphene for 25-35 min, and obtaining after drying. Through the synergistic use of the components, the application effectively improves the cold resistance, electrical conductivity and mechanical strength of the concrete.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, and in particular to a conductive concrete, its preparation method, and its application. Background Technology

[0002] Frequent snow and ice events in frigid regions disrupt the daily lives of local residents. Concrete, one of the most widely used building materials today, boasts advantages such as high compressive strength, good durability, readily available raw materials, and convenient construction, making it extensively used in infrastructure projects such as buildings, bridges, roads, and airport runways. Conductive concrete active pavement heating technology, with its advantages of high efficiency, low maintenance costs, and virtually no environmental pollution, significantly improves the efficiency of snow and ice removal on roads.

[0003] However, conductive concrete pavement is mainly used in frigid regions where snow and ice events are frequent. During use, it will inevitably be affected by freeze-thaw cycles, resulting in problems such as poor freeze-thaw resistance and durability. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a conductive concrete.

[0005] The present invention also provides a method for preparing the above-mentioned conductive concrete.

[0006] The present invention also provides applications of the above-mentioned conductive concrete.

[0007] A conductive concrete according to a first aspect of the present invention comprises the following components: Cement, crushed stone, sand, water-reducing agent, dispersant, graphite powder, sodium alginate, and composite fibers; The composite fiber includes graphene oxide-modified glass fiber and nanomaterial-modified polylactic acid fiber; The preparation method of the graphene oxide modified glass fiber includes the following steps: immersing the glass fiber in a graphene oxide dispersion for 5-12 minutes, and then drying it to obtain the glass fiber. The preparation method of the nanomaterial-modified polylactic acid fiber includes the following steps: immersing polylactic acid fiber in a solution containing nano magnesium oxide, nano aluminum oxide, and graphene for 25-35 minutes, and then drying it to obtain the final product.

[0008] According to some embodiments of the present invention, the cement includes silicate cement.

[0009] According to some embodiments of the present invention, the strength grade of the silicate cement is not lower than P.O42.5.

[0010] The term “not less than” to “greater than or equal to” should be understood to include the number itself.

[0011] According to some embodiments of the present invention, the water-reducing agent includes a polycarboxylate water-reducing agent.

[0012] According to some embodiments of the present invention, in the composite fiber, the mass ratio of graphene oxide modified glass fiber to nanomaterial modified polylactic acid fiber is (1-4):(1-2).

[0013] According to some embodiments of the present invention, in the composite fiber, the mass ratio of graphene oxide modified glass fiber to nanomaterial modified polylactic acid fiber is (2-4):(1-2).

[0014] According to some embodiments of the present invention, the graphene oxide modified glass fiber is composed of long fibers, short fibers and medium fibers, wherein the mass ratio of long fibers, short fibers and medium fibers is 1:3:2.

[0015] According to some embodiments of the present invention, the short fibers are 5-10 mm long, the medium fibers are 10-15 mm long, and the long fibers are 15-20 mm long.

[0016] According to some embodiments of the present invention, the content of graphene oxide in the graphene oxide dispersion is 3-5 mg / mL.

[0017] According to some embodiments of the present invention, the preparation method of the nanomaterial modified polylactic acid fiber further includes a step of ultrasonicating the polylactic acid fiber immersed in a solution containing nano magnesium oxide, nano aluminum oxide and graphene.

[0018] According to some embodiments of the present invention, the power of the ultrasound is 350-370W.

[0019] According to some embodiments of the present invention, the mass ratio of the nano-magnesium oxide, nano-aluminum oxide, and graphene is (2-4):(3-5):(1-3).

[0020] According to some embodiments of the present invention, the polylactic acid fiber has a length of 5 mm to 7 mm.

[0021] According to some embodiments of the present invention, the polylactic acid fiber has a diameter of 35 μm-45 μm.

[0022] According to some embodiments of the present invention, the solvent used in the solution containing nano-magnesium oxide, nano-aluminum oxide, and graphene includes ethanol.

[0023] According to some embodiments of the present invention, the dispersant comprises hydroxypropyl methylcellulose.

[0024] According to some embodiments of the present invention, the conductive concrete comprises, by weight, the following: 80-120 parts cement, 140-160 parts crushed stone, 110-130 parts sand, 0.5-2 parts water-reducing agent, 0.1-1 part dispersant, 0.5-4 parts graphite powder, 0.1-1 part sodium alginate, and 2-6 parts composite fiber.

[0025] According to some embodiments of the present invention, the concrete comprises, by weight, the following components: 90-110 parts cement, 145-155 parts crushed stone, 110-120 parts sand, 0.8-1.2 parts water-reducing agent, 0.4-0.6 parts dispersant, 1-3 parts graphite powder, 0.3-0.6 parts sodium alginate, and 2-5 parts composite fiber.

[0026] According to some embodiments of the present invention, the conductive concrete further includes 40-50 parts water.

[0027] According to some embodiments of the present invention, the conductive concrete further includes 42-48 parts of water.

[0028] The method for preparing the above-described conductive concrete according to a second aspect embodiment of the present invention includes the following steps: mixing the components to obtain the concrete.

[0029] The application of the conductive concrete described above, or the concrete prepared by the above method, in the construction of traffic pavements according to the third aspect of the present invention.

[0030] According to some embodiments of the present invention, the road surface construction includes road surface construction in frigid regions.

[0031] According to some embodiments of the present invention, at least the following beneficial effects are achieved: This invention adds graphite powder, sodium alginate, and composite fibers to conductive concrete raw materials. The graphite powder can fill the gaps between the capillaries and fiber networks in the cement paste to form a continuous conductive path. Moreover, the formed conductive network remains stable at low temperatures. Sodium alginate molecular chains can bridge the fiber surface and the cement matrix. When microcracks appear in concrete during freeze-thaw cycles, moisture penetration activates sodium alginate, dynamically repairing the microcracks caused by the freeze-thaw cycle. Furthermore, sodium alginate can synergistically disperse conductive components such as graphite powder and nano-graphene as a dispersant, preventing their aggregation and ensuring uniform distribution of conductive fillers in the matrix, forming continuous electronic conduction pathways. Sodium alginate itself contains abundant carboxyl and hydroxyl groups; these functional groups partially ionize in the alkaline environment of cement pore fluid, releasing mobile Na+. + Ions form ion-conducting channels, which work synergistically with composite fibers and graphite powder for conductivity; Graphene oxide-modified glass fibers in composite fibers impart conductivity to the originally insulating glass fibers through graphene oxide modification, forming a rigid conductive skeleton. Nanomaterial-modified polylactic acid fibers can form a flexible skeleton, thus forming a "rigid and flexible" reinforcing network, which enhances the toughness of the material and the stability of the conductive network. At the same time, it can also resist compressive and tensile stress, improving compressive and flexural strength. Furthermore, graphene oxide-modified glass fibers can effectively increase the toughness and tensile strength of concrete, effectively inhibiting the formation of concrete cracks. Simultaneously, graphene oxide itself possesses excellent mechanical properties and a high specific surface area. After modification on the surface of glass fibers, it can form a uniformly dispersed lubricating layer, allowing for better dispersion and transmission of stress within the concrete, thereby reducing the generation and propagation of cracks. Additionally, the high conductivity of graphene oxide contributes to the uniform distribution of temperature within the concrete, reducing local temperature differences and further improving the concrete's resistance to temperature variations. Nanomaterial-modified polylactic acid fibers, through composite modification with nano-magnesium oxide, nano-alumina, and graphene, allow the active functional groups on the surface of the nanomaterials to form chemical bonds with cement hydration products. This can compact the fiber-matrix interface, densify the microstructure, and offset the cumulative damage caused by ice crystal expansion during freeze-thaw cycles. Therefore, this invention, through the synergistic use of its components, effectively improves the cold resistance, conductivity, and mechanical strength of concrete.

[0032] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0033] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0034] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0035] In the description of this invention, the use of terms such as first, second, third, etc., is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0036] In the description of this invention, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0037] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0038] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0039] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0040] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0041] Unless otherwise specified, "about" in this invention means that the allowable error is within ±5%.

[0042] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0043] In the embodiments of this application, unless otherwise specified, P.O42.5 ordinary Portland cement was purchased from Shuangfeng Conch Cement. Sand: Fineness modulus 2.5, apparent density 2.65 g / cm³ 3 Natural river sand; Crushed stone: 20mm in diameter, crushing index 15%, water absorption rate 5%, apparent density 2590kg / m³ 3 gravel; Polycarboxylate superplasticizer: TB-EfficienX polycarboxylate superplasticizer, purchased from Shenzhen Xinchuangcai Technology Co., Ltd.

[0044] The graphite powder is flake graphite with a particle size of 800 mesh and a graphite purity of 99%.

[0045] Example 1 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 2 parts graphite powder; 0.4 parts sodium alginate; Three parts of composite fiber.

[0046] The composite fiber includes graphene oxide-modified glass fiber and nanomaterial-modified polylactic acid fiber, with a mass ratio of 3:1.

[0047] The preparation method of graphene oxide modified glass fiber is as follows: (1) Weigh out graphene oxide and disperse it (using ultrasonic dispersion, ultrasonic for 30 min) in water. The mass-volume ratio of graphene oxide to water is 4 mg / mL to obtain graphene oxide dispersion.

[0048] (2) Glass fiber (composed of long fiber, short fiber and medium fiber, wherein the mass ratio of long fiber, short fiber and medium fiber is 1:3:2, the length of the short fiber is 5-10 mm, the length of the medium fiber is 10-15 mm and the length of the long fiber is 15-20 mm) is soaked in graphene oxide dispersion for 10 min and dried at 105 °C to obtain glass fiber modified with graphene oxide.

[0049] The preparation method of modified polylactic acid fiber (PLA) is as follows: Nano-magnesium oxide, nano-alumina, and graphene were dispersed in a 99.9% ethanol solution and ultrasonically dispersed (360w) for half an hour. For every 5g of nanomaterials, 1000ml of ethanol liquid was used to soak 5kg of polylactic acid fibers (approximately 6mm long and approximately 40μm in average diameter). The polylactic acid fibers were then immersed in the ethanol dispersion containing the nanomaterials and ultrasonically dispersed for half an hour before being removed and air-dried.

[0050] Among them, nano-magnesium oxide, nano-aluminum oxide, and graphene have a particle size of about 300-500nm, and the mass ratio of nano-magnesium oxide, nano-aluminum oxide, and graphene is 3:4:2.

[0051] This example also provides a method for preparing the above-mentioned conductive concrete, the steps of which are as follows: (1) Put cement, sand and gravel into a concrete mixer and dry mix for about 15 seconds to obtain the first mixture; (2) Add the weighed water-reducing agent and water (about 70% of the amount) to the mixer and mix with the first mixture for about 40 seconds until the concrete is fully fluidized. Then add the dispersant, graphite powder, sodium alginate and composite fiber. Rinse the container containing the water-reducing agent with the remaining water and pour the rinse water into the mixer. Mix again for 5 minutes to fully mix. Finally, mold and cure the mixed concrete according to the test standards of the corresponding performance to obtain the concrete sample.

[0052] Example 2 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 1 part graphite powder; 0.4 parts sodium alginate; Four parts of composite fiber.

[0053] The composite fiber includes graphene oxide-modified glass fiber and nanomaterial-modified polylactic acid fiber, with a mass ratio of 3:1.

[0054] The preparation method is the same as in Example 1.

[0055] Example 3 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 3 parts graphite powder; 0.5 parts sodium alginate; Two parts of composite fiber.

[0056] The composite fiber includes graphene oxide-modified glass fiber and nanomaterial-modified polylactic acid fiber, with a mass ratio of 3:2.

[0057] The preparation method is the same as in Example 1.

[0058] Example 4 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 0.4 parts sodium alginate; Three parts of composite fiber.

[0059] The composite fiber includes graphene oxide-modified glass fiber and nanomaterial-modified polylactic acid fiber, with a mass ratio of 3:1.

[0060] Comparative Example 1 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 2 parts graphite powder; 0.4 parts sodium alginate.

[0061] The preparation method is the same as in Example 1.

[0062] Comparative Example 2 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 2 parts graphite powder; 0.4 parts sodium alginate; Three parts of graphene oxide modified glass fiber.

[0063] The preparation method is the same as in Example 1.

[0064] Comparative Example 3 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 2 parts graphite powder; 0.4 parts sodium alginate; Three parts of nanomaterial-modified polylactic acid fiber.

[0065] The preparation method is the same as in Example 1.

[0066] Comparative Example 4 This example provides a conductive concrete, with the following raw material composition by weight: 100 parts of P.O42.5 ordinary Portland cement; 115 portions of sand; 150 portions of crushed stone; 45 parts water; 1 part polycarboxylate superplasticizer; 0.5 parts of hydroxypropyl methylcellulose; 2 parts graphite powder; Three parts of composite fiber.

[0067] The composite fiber includes graphene oxide-modified glass fiber and nanomaterial-modified polylactic acid fiber, with a mass ratio of 3:1.

[0068] Detection example Mechanical properties and resistivity tests were conducted on the conductive concrete samples from the examples and comparative examples. The compressive strength and flexural strength of the test blocks from the examples and comparative examples, cured for 28 days and subjected to 300 freeze-thaw cycles, were tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T 50081-2019). Three test blocks were used in each group, with dimensions of 40mm × 40mm × 160mm; all were cast. After standard curing, the mechanical properties and resistivity were tested. The resistance was measured using the DC power supply two-electrode method, which allowed for the determination of the resistance of the test specimen, and the resistivity was calculated.

[0069] Table 1

[0070] The results are shown in Table 1. It can be seen that, compared with the comparative example, the concrete prepared in Examples 1-4 still has good compressive strength and flexural strength in freeze-thaw cycles, and the resistivity of the concrete specimens prepared in Examples 1-3 at 28 days of age is significantly lower than that of the comparative example.

[0071] The embodiments of the present invention have been described in detail above with reference to the examples. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A conductive concrete, characterized in that, Includes the following components: Cement, crushed stone, sand, water-reducing agent, dispersant, graphite powder, sodium alginate, and composite fibers; The composite fiber includes graphene oxide-modified glass fiber and nanomaterial-modified polylactic acid fiber; The preparation method of the graphene oxide modified glass fiber includes the following steps: immersing the glass fiber in a graphene oxide dispersion for 5-12 minutes, and then drying it to obtain the glass fiber. The preparation method of the nanomaterial-modified polylactic acid fiber includes the following steps: immersing polylactic acid fiber in a solution containing nano magnesium oxide, nano aluminum oxide, and graphene for 25-35 minutes, and then drying it to obtain the final product.

2. The conductive concrete according to claim 1, characterized in that, The water-reducing agent includes a polycarboxylate water-reducing agent.

3. The conductive concrete according to claim 1, characterized in that, In the composite fiber, the mass ratio of graphene oxide modified glass fiber to nanomaterial modified polylactic acid fiber is (1-4):(1-2).

4. The conductive concrete according to claim 1, characterized in that, The graphene oxide modified glass fiber is composed of long fibers, short fibers and medium fibers, wherein the mass ratio of long fibers, short fibers and medium fibers is 1:3:

2. Preferably, the short fibers are 5-10 mm long, the medium fibers are 10-15 mm long, and the long fibers are 15-20 mm long.

5. The conductive concrete according to claim 1, characterized in that, The graphene oxide dispersion contains 3-5 mg / mL of graphene oxide.

6. The conductive concrete according to claim 1, characterized in that, The mass ratio of the nano-magnesium oxide, nano-aluminum oxide, and graphene is (2-4):(3-5):(1-3).

7. The conductive concrete according to claim 1, characterized in that, The conductive concrete comprises, by weight parts: 80-120 parts cement, 140-160 parts crushed stone, 110-130 parts sand, 0.5-2 parts water-reducing agent, 0.1-1 part dispersant, 0.5-4 parts graphite powder, 0.1-1 part sodium alginate, and 2-6 parts composite fiber.

8. The conductive concrete according to claim 7, characterized in that, The concrete comprises, by weight parts: 90-110 parts cement, 145-155 parts crushed stone, 110-120 parts sand, 0.8-1.2 parts water-reducing agent, 0.4-0.6 parts dispersant, 1-3 parts graphite powder, 0.3-0.6 parts sodium alginate, and 2-5 parts composite fiber.

9. The method for preparing conductive concrete according to any one of claims 1-8, characterized in that, Includes the following steps: The components are then mixed together to obtain the final product.

10. The application of the conductive concrete according to any one of claims 1-8 or the conductive concrete prepared by the preparation method according to claim 9 in the construction of traffic pavement.

Images