An admixture for a cement-based sensing material, its preparation method, and a cement-based sensing material

Abstract

The present invention discloses an admixture for cement-based sensing materials, its preparation method, and a cement-based sensing material. The admixture comprises the following components by mass percentage: 80% - 90% of tobacco leaf extract and 10% - 20% of R-B dry powder; the R-B dry powder is rutin powder and / or baicalin powder. The preparation method is as follows: adding the R-B dry powder into the tobacco leaf extract and adjusting the pH to alkaline, placing it in an ultrasonic constant temperature water bath, ultrasonicating, standing still, and filtering to obtain the product. The above-mentioned admixture for cement-based sensing materials is applied to cement-based sensing materials. The admixture of the present invention has a simple preparation process, low cost, can make full use of waste and inferior tobacco leaves, is green and environmentally friendly, has a good retarding effect, and can extend the setting time as needed.

Description

Technical Field

[0001] The present invention relates to an admixture for cement materials, its preparation method and cement-based materials, and particularly to an admixture for cement-based sensing materials, its preparation method and cement-based sensing materials. Background Art

[0002] Concrete is a hydraulic structure material widely used in water conservancy and hydropower projects. Due to many defects such as capillary pores, microcracks, and interfacial transition zones existing in the concrete itself, it is easily eroded by harmful ions in the air and environmental water, resulting in a decrease in strength and durability, and ultimately leading to a decline in service life and structural damage. The erosion ions penetrate into the interior of the concrete and react chemically with the hydration products of cement to form new products, causing diseases such as expansion and cracking, resulting in the destruction of the concrete; this destruction process occurs continuously from the concrete surface to the interior along with the diffusion of erosion ions in the concrete, and at the same time, it is accompanied by continuous changes in the microscopic structures such as the pore structure, microcracks, and interfacial transition zones in the concrete, thereby leading to changes in the electrochemical characteristic parameters of the concrete.

[0003] During the erosion process of hydraulic concrete, it is difficult to meet the requirements only by visual inspection for the degree of damage, the destruction process, and the remaining life caused by the erosion. The existing technologies cannot realize the real-time online monitoring and data acquisition of the degree of erosion damage and the destruction process of hydraulic concrete. Studying the monitoring sensing materials and methods for erosion in hydraulic concrete, and real-time monitoring and mastering the changes in the electrochemical characteristic parameters and microscopic structures during the erosion process of hydraulic concrete, are of great significance for mastering the performance change laws of hydraulic concrete under the action of environmental medium erosion, scientifically evaluating the degree of erosion damage of hydraulic concrete, and predicting the service life of hydraulic structures, and thus ensuring the safe use of hydraulic concrete structures.

[0004] Retarders can effectively control the setting time of cement-based sensing materials, so that there is better compatibility between the cement-based sensing materials and concrete, ensuring the stability of the cement-based sensing materials, and can be used more accurately, efficiently, and durably to detect the changes in various electrochemical characteristic parameters in the concrete, and then evaluate the degree of damage of the concrete. However, the existing retarders still need to be further improved in controlling the gel time of cement-based sensing materials. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide an admixture for cement-based sensing materials that can inhibit the cement hydration process and delay the setting time;

[0006] The second object of the present invention is to provide a preparation method for the above-mentioned admixture for cement-based sensing materials;

[0007] The third object of the present invention is to provide a cement-based sensing material containing the above-mentioned admixture of the cement-based sensing material.

[0008] Technical solution: The admixture of the cement-based sensing material described in the present invention comprises the following components by mass percentage: 80%-90% of tobacco leaf extract and 10%-20% of R-B dry powder, and the R-B dry powder is rutin powder and / or baicalin powder.

[0009] Among them, the R-B dry powder includes rutin powder and baicalin powder; the mass of the rutin powder and the mass of the baicalin powder respectively account for 40%-60% of the total mass of the R-B dry powder. The purity of the rutin powder is >95%, and the chemical formula is C 27 H 30 O 16 , with a molecular weight of 610.52; the purity of the baicalin powder is >95%, and the chemical formula is C 21 H 18 O 11 , with a molecular weight of 446.36.

[0010] For the above-mentioned admixture of the cement-based sensing material, the tobacco leaf extract is prepared by the following method:

[0011] (1) After drying waste and inferior tobacco leaves in an oven, they are ground and sieved to obtain powder;

[0012] (2) The powder is added to distilled water and boiled, and then naturally cooled. This step is repeated to obtain a boiling solution;

[0013] (3) The boiling solution is filtered and heated and concentrated to obtain a tobacco leaf extract.

[0014] Among them, in step (2), the material-liquid ratio of the powder to distilled water is 0.01-0.02 g / mL; when boiling, the heating rate is maintained at 6-7 °C / min, and the temperature is raised from room temperature to 80-90 °C, and boiled for 40-60 min, and then naturally cooled to room temperature to ensure that the active ingredients in the waste and inferior tobacco leaves can be extracted. This step is repeated to obtain a boiling solution; preferably, it is repeated 3 times;

[0015] Among them, in step (3), the heating and concentration are carried out until the volume ratio of the boiling solution to the extract is (4-5):1 to ensure that the concentration of the active ingredients in the extract reaches a certain requirement.

[0016] For the preparation method of the above-mentioned admixture of the cement-based sensing material, 10%-20% of R-B dry powder is added to 80%-90% of the tobacco leaf extract, and the pH is adjusted to alkaline, and then ultrasonic treatment is carried out, followed by standing and filtering to obtain the admixture of the cement-based sensing material.

[0017] Among them, the R-B dry powder includes rutin powder and baicalin powder. After the rutin powder and baicalin powder are mixed, they are added to the tobacco leaf extract.

[0018] Among them, 10%-20% of the R-B dry powder is added to 80%-90% of the tobacco leaf extract and the pH is adjusted to alkaline, then it is placed in an ultrasonic constant temperature water bath and ultrasonicated at room temperature for 15-30 min, and left standing for 30-60 min, and then filtered to obtain the admixture of the cement-based sensing material.

[0019] The cement-based sensing material of the present invention includes the admixture of the cement-based sensing material as described above.

[0020] Among them, the admixture of the cement-based sensing material is mixed with water and then incorporated into the cement-based sensing material, and the dosage is 1%-2% of the cement dosage to ensure that the admixture has a relatively good retarding effect.

[0021] Among them, it also includes a cement matrix, graphene dispersed in the cement matrix, and nano-conductive carbon black; the water-cement ratio of the cement matrix is (0.2-0.6):1; the dosage of graphene is 0.5%-2.0% of the cement dosage; the dosage of the nano-conductive carbon black is 0.2%-1.0% of the cement dosage.

[0022] Principle of the invention: A large number of natural components in the tobacco leaf extract, such as tobacco polyphenols and tobacco polysaccharides, contain polyhydroxy groups in their macromolecular structures. These polyhydroxy groups can form hydrogen bonds with O on the surface of the cement hydration products, making it easier to form a network structure on the surface of the cement particles and delaying the cement hydration reaction. Rutin and baicalin, as small molecular structures, can be embedded in the network structure on the surface of the cement particles, increasing the active hydroxyl groups in the admixture molecules and making the network structure more dense, giving full play to its retarding effect. In addition, these hydroxyl groups can also associate with water molecules through hydrogen bonds, forming a stable water film on the surface of the cement particles, thereby further inhibiting the hydration process of the cement and delaying the setting time. 2- to form hydrogen bonds, making it easier to form a network structure on the surface of the cement particles, delaying the cement hydration reaction. Rutin and baicalin, as small molecular structures, can be embedded in the network structure on the surface of the cement particles, increasing the active hydroxyl groups in the admixture molecules and making the network structure more dense, giving full play to its retarding effect. In addition, these hydroxyl groups can also associate with water molecules through hydrogen bonds, forming a stable water film on the surface of the cement particles, thereby further inhibiting the hydration process of the cement and delaying the setting time.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following remarkable effects: (1) The present invention makes full use of waste and inferior tobacco leaves and has extremely high social value and ecological value. A large number of natural components in tobacco leaves, such as tobacco polyphenols and tobacco polysaccharides, contain a large number of active functional groups hydroxyl groups, which produce a synergistic effect with the hydroxyl groups in rutin and baicalin, increasing the active hydroxyl groups in the admixture molecules. The hydroxyl groups can react with O on the surface of the cement hydration products. 2-Hydrogen bonds are formed. At the same time, the hydroxyl groups can associate with water molecules through hydrogen bonds, forming a stable water film on the surface of cement particles, thereby inhibiting the hydration process of cement and delaying the setting time. (2) The preparation process of the admixture of the present invention is simple and low in cost. It can make full use of waste and inferior tobacco leaves, is green and environmentally friendly, and has a good retarding effect, and can extend the setting time as needed. Detailed implementation mode

[0024] The present invention will be further described in detail below.

[0025] Example 1

[0026] The admixture includes 90% tobacco leaf extract and 10% R-B dry powder by mass ratio. Among them, the R-B dry powder includes 50% rutin powder and 50% baicalin powder by mass ratio. The preparation method of the admixture includes: First, prepare the tobacco leaf extract. After drying the waste and inferior tobacco leaves in an oven, grind and sieve them to obtain powder; add the powder to distilled water and boil it. The material-liquid ratio of the powder to distilled water is 0.01 g / mL; when boiling, keep the heating rate at 7 °C / min, heat from room temperature to 90 °C, boil for 60 min, and cool naturally to room temperature. Repeat this step 3 times to obtain the boiling solution; filter the boiling solution and heat and concentrate it until the volume ratio of the boiling solution to the extract is 4:1 to obtain the tobacco leaf extract. Then add 10% R-B dry powder by mass ratio to 90% tobacco leaf extract and adjust the pH to alkaline. Place it in an ultrasonic constant temperature water bath and ultrasonicate for 30 min at room temperature. After standing for 60 min, filter to obtain it.

[0027] Add this admixture to the cement-based sensing material at an admixture amount of 1.0% relative to the cement dosage. The water-cement ratio is 0.5, the graphene admixture amount is 1% of the cement dosage, and the nano-conductive carbon black admixture amount is 0.5% of the cement dosage. Stir with a mixer at a rate of 100 - 250 r / min to make standard sample 1 for testing the initial setting and final setting times.

[0028] Example 2

[0029] The admixture includes tobacco leaf extract and R-B dry powder with a mass ratio of 85% and 15% respectively. Among them, the R-B dry powder includes rutin powder and baicalin powder with a mass ratio of 40% and 60% respectively. The preparation method of the admixture includes: First, prepare the tobacco leaf extract. After drying the waste tobacco leaves in an oven, grind and sieve them to obtain powder; add the powder to distilled water and boil. The material-liquid ratio of the powder to distilled water is 0.01 g / mL; when boiling, maintain the heating rate at 7 °C / min, heat from room temperature to 90 °C, boil for 60 min, cool naturally to room temperature, and repeat this step 3 times to obtain the boiling solution; filter the boiling solution and heat and concentrate it until the volume ratio of the boiling solution to the extract is 4:1 to obtain the tobacco leaf extract. Then add 10% of the R-B dry powder by mass to 90% of the tobacco leaf extract and adjust the pH to alkaline. Place it in an ultrasonic constant temperature water bath and ultrasonicate for 30 min at room temperature. After standing for 60 min, filter to obtain it.

[0030] Add the admixture to the cement-based sensing material at a dosage of 1.0% relative to the mass of cement. The water-cement ratio is 0.5, the graphene dosage is 1% of the cement dosage, and the nano-conductive carbon black dosage is 0.5% of the cement dosage. Stir with a mixer at a rate of 100 - 250 r / min to prepare Standard Sample 2 for testing the initial setting time and final setting time.

[0031] Example 3

[0032] The admixture includes tobacco leaf extract and R-B dry powder with a mass ratio of 85% and 15% respectively. Among them, the R-B dry powder includes rutin powder and baicalin powder with a mass ratio of 60% and 40% respectively. The preparation method of the admixture includes: First, prepare the tobacco leaf extract. After drying the waste tobacco leaves in an oven, grind and sieve them to obtain powder; add the powder to distilled water and boil. The material-liquid ratio of the powder to distilled water is 0.01 g / mL; when boiling, maintain the heating rate at 7 °C / min, heat from room temperature to 90 °C, boil for 60 min, cool naturally to room temperature, and repeat this step 3 times to obtain the boiling solution; filter the boiling solution and heat and concentrate it until the volume ratio of the boiling solution to the extract is 4:1 to obtain the tobacco leaf extract. Then add 20% of the R-B dry powder by mass to 80% of the tobacco leaf extract and adjust the pH to alkaline. Place it in an ultrasonic constant temperature water bath and ultrasonicate for 30 min at room temperature. After standing for 60 min, filter to obtain it.

[0033] Add the admixture to the cement-based sensing material at a dosage of 1.0% relative to the mass of cement. The water-cement ratio is 0.5, the graphene dosage is 1% of the cement dosage, and the nano-conductive carbon black dosage is 0.5% of the cement dosage. Stir with a mixer at a rate of 100 - 250 r / min to prepare Standard Sample 3 for testing the initial setting time and final setting time.

[0034] Example 4

[0035] The admixture includes tobacco leaf extract and 10% of R-B dry powder in a mass ratio of 90%. Among them, the R-B dry powder includes rutin powder and baicalin powder in a mass ratio of 50%. The preparation method of the admixture includes: First, prepare the tobacco leaf extract. After drying the waste tobacco leaves in an oven, grind and sieve them to obtain powder; add the powder to distilled water and boil it. The material-liquid ratio of the powder to distilled water is 0.01 g / mL; when boiling, maintain the heating rate at 7 °C / min, heat up from room temperature to 90 °C, boil for 60 min, and cool naturally to room temperature. Repeat this step 3 times to obtain the boiling solution; filter the boiling solution and heat-concentrate it until the volume ratio of the boiling solution to the extract is 4:1 to obtain the tobacco leaf extract. Then add 10% of R-B dry powder in mass ratio to 90% of the tobacco leaf extract and adjust the pH to alkaline. Place it in an ultrasonic constant temperature water bath and ultrasonicate for 30 min at room temperature. After standing for 60 min, filter to obtain it.

[0036] Add this admixture to the cement-based sensing material at an admixture content of 2% relative to the mass of cement, with a water-cement ratio of 0.5, a graphene admixture content of 1% of the cement dosage, and a nano-conductive carbon black admixture content of 0.5% of the cement dosage. Stir with a mixer at a rate of 100 - 250 r / min to prepare standard sample 4 for testing the initial setting time and final setting time.

[0037] Example 5

[0038] The admixture includes tobacco leaf extract and 10% of R-B dry powder in a mass ratio of 90%. Among them, the R-B dry powder is rutin powder. The preparation method of the admixture includes: First, prepare the tobacco leaf extract. After drying the waste tobacco leaves in an oven, grind and sieve them to obtain powder; add the powder to distilled water and boil it. The material-liquid ratio of the powder to distilled water is 0.01 g / mL; when boiling, maintain the heating rate at 7 °C / min, heat up from room temperature to 90 °C, boil for 60 min, and cool naturally to room temperature. Repeat this step 3 times to obtain the boiling solution; filter the boiling solution and heat-concentrate it until the volume ratio of the boiling solution to the extract is 4:1 to obtain the tobacco leaf extract. Then add 10% of R-B dry powder in mass ratio to 90% of the tobacco leaf extract and adjust the pH to alkaline. Place it in an ultrasonic constant temperature water bath and ultrasonicate for 30 min at room temperature. After standing for 60 min, filter to obtain it.

[0039] Add this admixture to the cement-based sensing material at an admixture content of 2% relative to the mass of cement, with a water-cement ratio of 0.5, a graphene admixture content of 1% of the cement dosage, and a nano-conductive carbon black admixture content of 0.5% of the cement dosage. Stir with a mixer at a rate of 100 - 250 r / min to prepare standard sample 5 for testing the initial setting time and final setting time.

[0040] Example 6

[0041] The admixture includes tobacco leaf extract and R-B dry powder with a mass ratio of 90% and 10% respectively. Among them, the R-B dry powder is baicalin powder. The preparation method of the admixture includes: First, prepare the tobacco leaf extract. After drying the waste tobacco leaves in an oven, grind and sieve them to obtain powder; add the powder to distilled water and boil it. The material-liquid ratio of the powder to distilled water is 0.01 g / mL; when boiling, maintain the heating rate at 7 °C / min, heat from room temperature to 90 °C, boil for 60 min, and cool naturally to room temperature. Repeat this step 3 times to obtain the boiling solution; filter the boiling solution and heat and concentrate it until the volume ratio of the boiling solution to the extract is 4:1 to obtain the tobacco leaf extract. Then add 10% of the R-B dry powder by mass to 90% of the tobacco leaf extract and adjust the pH to alkaline. Place it in an ultrasonic constant temperature water bath and ultrasonicate for 30 min at room temperature. After standing for 60 min, filter to obtain it.

[0042] Add the admixture to the cement-based sensing material at an admixture amount of 2% relative to the mass of cement. The water-cement ratio is 0.5, the graphene admixture amount is 1% of the cement dosage, and the nano-conductive carbon black admixture amount is 0.5% of the cement dosage. Stir with a mixer at a rate of 100 - 250 r / min to prepare Standard Sample 6 for testing the initial setting time and final setting time.

[0043] Example 7

[0044] The admixture includes tobacco leaf extract and R-B dry powder with a mass ratio of 80% and 20% respectively. Among them, the R-B dry powder includes rutin powder and baicalin powder with a mass ratio of 40% and 60% respectively. The preparation method of the admixture includes: First, prepare the tobacco leaf extract. After drying the waste tobacco leaves in an oven, grind and sieve them to obtain powder; add the powder to distilled water and boil it. The material-liquid ratio of the powder to distilled water is 0.01 g / mL; when boiling, maintain the heating rate at 7 °C / min, heat from room temperature to 90 °C, boil for 60 min, and cool naturally to room temperature. Repeat this step 3 times to obtain the boiling solution; filter the boiling solution and heat and concentrate it until the volume ratio of the boiling solution to the extract is 4:1 to obtain the tobacco leaf extract. Then add 10% of the R-B dry powder by mass to 90% of the tobacco leaf extract and adjust the pH to alkaline. Place it in an ultrasonic constant temperature water bath and ultrasonicate for 30 min at room temperature. After standing for 60 min, filter to obtain it.

[0045] The admixture was added to the cement-based sensing material at a dosage of 1% relative to the mass of cement. The water-cement ratio was 0.5, the graphene dosage was 1% of the cement dosage, and the nano-conductive carbon black dosage was 0.5% of the cement dosage. It was stirred with a mixer at a rate of 100 - 250 r / min to prepare standard sample 7 for testing the initial setting time and final setting time.

[0046] Example 8

[0047] The admixture included 90% of tobacco leaf extract and 10% of R-B dry powder by mass ratio. Among them, the R-B dry powder included 50% of rutin powder and 50% of baicalin powder by mass ratio. The preparation method of the admixture included: First, prepare the tobacco leaf extract. After drying the waste tobacco leaves in an oven, they were ground and sieved to obtain powder; the powder was added to distilled water for boiling, and the material-liquid ratio of the powder to distilled water was 0.02 g / mL; during boiling, the heating rate was maintained at 6 °C / min, heated from room temperature to 80 °C, boiled for 40 min, and naturally cooled to room temperature. This step was repeated 3 times to obtain the boiling solution; the boiling solution was filtered and heated and concentrated until the volume ratio of the boiling solution to the extract was 5:1 to obtain the tobacco leaf extract. Then, 10% of the R-B dry powder by mass ratio was added to 90% of the tobacco leaf extract and the pH was adjusted to alkaline. It was placed in an ultrasonic constant temperature water bath and ultrasonicated at room temperature for 30 min. After standing for 60 min, it was filtered to obtain the product.

[0048] The admixture was added to the cement-based sensing material at a dosage of 2% relative to the mass of cement. The water-cement ratio was 0.2, the graphene dosage was 0.5% of the cement dosage, and the nano-conductive carbon black dosage was 0.2% of the cement dosage. It was stirred with a mixer at a rate of 100 - 250 r / min to prepare standard sample 8 for testing the initial setting time and final setting time.

[0049] Example 9

[0050] The admixture comprises tobacco leaf extract and R-B dry powder with a mass ratio of 90% and 10% respectively. Among them, the R-B dry powder comprises rutin powder and baicalin powder with a mass ratio of 50% and 50% respectively. The preparation method of the admixture includes: first, preparing the tobacco leaf extract. After drying the waste and inferior tobacco leaves in an oven, they are ground and sieved to obtain powder; adding the powder into distilled water for boiling, and the material-liquid ratio of the powder to distilled water is 0.02 g / mL; during boiling, maintaining the heating rate at 6 °C / min, heating from room temperature to 80 °C, boiling for 40 min, and naturally cooling to room temperature, repeating this step 3 times to obtain the boiling solution; filtering the boiling solution and heating and concentrating it until the volume ratio of the boiling solution to the extract is 5:1 to obtain the tobacco leaf extract. Then, adding 10% of the R-B dry powder by mass to 90% of the tobacco leaf extract and adjusting the pH to alkaline, placing it in an ultrasonic constant temperature water bath, ultrasonically treating it at room temperature for 30 min, standing for 60 min, and then filtering to obtain the product.

[0051] The admixture is added to the cement-based sensing material at an amount of 2% relative to the mass of cement, with a water-cement ratio of 0.6, a graphene content of 2% of the cement dosage, and a nano-conductive carbon black content of 1% of the cement dosage, and stirred with a mixer at a rate of 100 - 250 r / min to prepare standard sample 9 for testing the initial setting time and final setting time.

[0052] Comparative Example 1

[0053] Based on Example 1, the difference from Example 1 is that no admixture is added to the cement-based sensing material, and a standard sample is prepared for testing the initial setting time and final setting time.

[0054] Comparative Example 2

[0055] Based on Example 1, the difference from Example 1 is that the admixture added to the cement-based sensing material is molasses retarder (commercial admixture).

[0056] Comparative Example 3

[0057] Based on Example 1, the difference from Example 1 is that no tobacco leaf extract is added.

[0058] Comparative Example 4

[0059] Based on Example 1, the difference from Example 1 is that no R-B dry powder is added.

[0060] Comparative Example 5

[0061] Based on Example 1, the difference from Example 1 is that the degree of heating and concentration is 2:1.

[0062] Comparative Example 6

[0063] Based on Example 1, different from Example 1, the heating rate is 15 °C / min.

[0064] Comparative Example 7

[0065] Based on Example 1, different from Example 1, the temperature is raised to 70 °C.

[0066] Comparative Example 8

[0067] Based on Example 1, different from Example 1, the boiling time is 20 min.

[0068] In the present invention, the initial setting time and final setting time are tested according to GB / T 1346-2011 "Test Methods for Water Requirement for Normal Consistency, Setting Time and Soundness of Cement".

[0069] Test the influence of Examples 1-7 on the setting time of the cement sample, as shown in Table 1.

[0070] Table 1 Influence of Examples 1-7 and Comparative Examples 1-7 on the setting time of the cement sample.

[0071] Serial number Initial setting time Final setting time Serial number Initial setting time Final setting time Example 1 267 317 Comparative example 1 181 233 Example 2 274 332 Comparative example 2 250 303 Example 3 278 327 Comparative example 3 229 288 Example 4 297 352 Comparative example 4 254 300 Example 5 291 344 Comparative example 5 243 304 Example 6 289 341 Comparative example 6 255 312 Example 7 286 345 Comparative example 7 233 298 Example 8 282 339 Comparative example 8 232 300 Example 9 280 335

[0072] The test data show that compared with the sample without admixture, the initial setting time and final setting time of the sample with admixture are both increased. Among them, for the admixture with a mass ratio of 90% tobacco leaf extract and 10% R-B dry powder, and when the dosage is 2.0%, the initial setting time and final setting time increase the most, increasing by 64.1% and 51.1% respectively. It can be seen from Examples 1, 4 and Examples 2, 7 that as the dosage of the admixture and the proportion of R-B dry powder in the admixture increase, the setting time of the sample is longer.

[0073] It can be seen from Examples 2 and 3 that when the rutin addition amount in the R-B dry powder is larger than the baicalin addition amount, the initial setting time and final setting time are longer; it can be seen from Examples 4, 5 and 6 that when rutin powder and baicalin powder are added simultaneously in the R-B dry powder, the retarding effect is better.

[0074] As can be seen from Comparative Example 2, compared with the commercial retarder, the admixture of the present invention has a better retardation effect. As can be seen from Comparative Examples 5, 6, 7, and 8, with the decrease in the degree of heating and concentration, the increase in the heating rate, the decrease in the heating temperature, and the shortening of the boiling time, the initial setting time and the final setting time of the admixture both decrease. This is because the concentration of the tobacco leaf extract is diluted and the extraction degree of the tobacco leaf extract is insufficient, resulting in a certain retardation efficiency, but the retardation efficiency is greatly reduced. In addition, as can be seen from Comparative Example 3, the admixture without the addition of the tobacco leaf extract hardly shows a retardation effect. As can be seen from Example 1 and Comparative Example 4, without adding the R-B dry powder, the retardation efficiency of the admixture is significantly reduced; as can be seen from Example 1 and Comparative Examples 3 and 4, when the tobacco leaf extract and the R-B dry powder are added simultaneously, a synergistic effect can be exerted. The active ingredient in the tobacco leaf extract provides an embedding site for the R-B dry powder. Under the combined action of the two, the hydration process of cement is further inhibited, and the retardation effect of the admixture is improved.

[0075] Thus, it can be seen that the admixture prepared by the present invention has a good retardation effect on the cement-based sensing material and significantly prolongs the setting time.

Claims

1. An admixture for cement-based sensing materials, characterized in that, It comprises the following components by mass percentage: 80%-90% of tobacco leaf extract and 10%-20% of R-B dry powder; the R-B dry powder is rutin powder and / or baicalin powder; The tobacco leaf extract is prepared by the following method: (1) After drying waste tobacco leaves in an oven, grind and sieve them to obtain powder; (2) Add the powder to distilled water and boil, then cool naturally, and repeat this step to obtain a boiling solution; the material-liquid ratio of the powder to distilled water is 0.01-0.02 g / mL; the heating rate is 6-7 °C / min, heat up to 80-90 °C, and the boiling time is 40-60 min; (3) Filter and heat-concentrate the boiling solution to obtain the tobacco leaf extract; the heating is concentrated until the volume ratio of the boiling solution to the extract is (4-5):

1.

2. The admixture for cement-based sensing materials according to claim 1, characterized in that, The R-B dry powder includes rutin powder and baicalin powder; the mass of the rutin powder and the mass of the baicalin powder respectively account for 40%-60% of the total mass of the R-B dry powder.

3. A preparation method of the admixture for cement-based sensing materials according to claim 1, characterized in that, Add 10%-20% of the R-B dry powder by mass percentage to 80%-90% of the tobacco leaf extract and adjust the pH to alkaline, then perform ultrasonic treatment, let it stand, and filter to obtain the admixture of the cement-based sensing material.

4. A cement-based sensing material, characterized in that, It includes the admixture of the cement-based sensing material described in claim 1.

5. The cement-based sensing material according to claim 4, characterized in that, The admixture of the cement-based sensing material is mixed with water and then incorporated into the cement-based sensing material, and the dosage is 1%-2% of the cement dosage.

6. The cement-based sensing material according to claim 4, characterized in that, It also includes a cement matrix, graphene dispersed in the cement matrix, and nano-conductive carbon black; the water-cement ratio of the cement matrix is (0.2-0.6):1; the graphene dosage is 0.5-2.0% of the cement dosage; the nano-conductive carbon black dosage is 0.2-1.0% of the cement dosage.