Early-strength and toughening type backfill material and construction method thereof
By using early strength and toughening backfill materials, including hot silicate cement, graphene oxide and triethanolamine, combined with the construction method of cofferdam isolation and spraying permanent condensate, the problems of cement shedding and insufficient durability repair of concrete defects in the runner passage of water conservancy engineering construction have been solved, and higher impact wear and cavitation performance have been achieved.
Patent Information
- Application Number
- CN202510054755.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2025-05-30
AI Technical Summary
When repairing concrete defects in water conservancy construction runners, the existing technology is prone to falling off and breaking of mud, and failing to effectively reinforce the slightly eroded surface, resulting in the expansion of defects and increasing maintenance costs.
Provides an early strength and toughening backfill material, including water, hot silicate cement, sand and graphene oxide, doped with triethanolamine as early strength agent, isolate the repair area through the cofferdam, clean up the damaged parts, and repair it after spraying permanent condensate.
This backfill material can significantly shorten the time to reach the design strength, enhance the bonding effect with old concrete, improve toughness and impact wear and cavitation resistance, and extend the service life of the repaired parts.
Smart Images
Figure CN120058303A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of cofferdam construction, and particularly relates to an early-strength and toughness-increasing backfill material and a construction method thereof. Background Art
[0002] The durability of concrete is generally defined as its resistance to atmospheric erosion, chemical erosion, physical wear or any deterioration process. Concrete with good durability can maintain its original shape, quality and function during long-term service. The flow channel is one of the important buildings in water conservancy projects. However, since the flow channel is directly exposed to the high-speed water flow environment, it is prone to damage such as abrasion, cavitation and erosion during operation. The main defect types include: holes, seepage cracks, seepage points, pitted surfaces, breakages, etc. The main reasons are the poor local pouring quality of the flow channel concrete and the erosion of the flow channel by high-speed water flow. Therefore, it is very necessary to carry out inspection and repair of the flow channel, which is of great significance to the long-term safe operation of the hydropower station.
[0003] At present, epoxy fine aggregate concrete, epoxy mortar, pre-shrunk mortar and other materials are mainly used to repair the defects of the flow channel concrete. However, due to many factors such as the maintenance period, environment, and the differences in elasticity and deformation at the bonding interface between the repair backfill material and the old concrete, phenomena such as the shedding and breakage of the mortar are likely to occur after repair. At the same time, in view of the continuous deterioration of the performance of the flow channel concrete during the operation period, the existing mild erosion surface has not been strengthened and repaired, which may cause the defects to expand, further resulting in large-area breakage and shedding, increasing the maintenance cost. Therefore, it is urgent to repair the abrasion and cavitation damage parts on the surface of the flow channel of water conservancy project buildings, improve the durability of water conservancy project buildings, and enable the hydropower project to operate in a long-term, safe and reliable manner. Summary of the Invention
[0004] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this part, the abstract and the title. However, such simplifications or omissions shall not be used to limit the scope of the present invention.
[0005] In view of the above and / or problems existing in the prior art, the present invention is proposed.
[0006] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide an early-strength and toughness-increasing backfill material.
[0007] To solve the above technical problems, the present invention provides the following technical solutions:
[0008] The raw material components of the backfill material include, by weight, 264 - 281 parts of water, 528 - 564 parts of cement, and 1458 - 1465 parts of sand;
[0009] Among them, the cement is heat Portland cement.
[0010] As a preferred embodiment of the early-strength and toughened backfill material of the present invention, wherein: the backfill material further includes graphene oxide.
[0011] As a preferred embodiment of the early-strength and toughened backfill material of the present invention, wherein: the doping amount of the graphene oxide compared to the mass of the cement is 0.13 - 0.17 wt%.
[0012] As a preferred embodiment of the early-strength and toughened backfill material of the present invention, wherein: the backfill material further includes an early-strength agent, and the early-strength agent is triethanolamine.
[0013] As a preferred embodiment of the early-strength and toughened backfill material of the present invention, wherein: the doping amount of the triethanolamine compared to the mass of the cement is 0.8 - 1.2 wt%.
[0014] As a preferred embodiment of the early-strength and toughened backfill material of the present invention, wherein: the sand is composed of river sand and machine-made sand.
[0015] As a preferred embodiment of the early-strength and toughened backfill material of the present invention, wherein: the particle size of the sand is 0 - 5 mm.
[0016] Another object of the present invention is to overcome the deficiencies in the prior art and provide a construction method for an early-strength and toughened backfill material.
[0017] To solve the above technical problems, the present invention provides the following technical solutions:
[0018] Demarcate the repair area, isolate the repair area with a cofferdam, after draining the accumulated water, clean the part of the runner eroded and damaged with a steel brush to obtain a fresh concrete surface;
[0019] Spray the fresh concrete surface with a liquid permanent sealer, repair it with the backfill material, and then spray the liquid permanent sealer again after the backfill material hardens, thus completing the construction of the early-strength and toughened backfill material.
[0020] As a preferred embodiment of the construction method of the early-strength and toughened backfill material of the present invention, wherein: the eroded and damaged part is the loose and fragile part.
[0021] As a preferred embodiment of the construction method of the early-strength and toughened backfill material of the present invention, wherein: the number of times of spraying the liquid permanent sealer again after the backfill material hardens is 3 - 4 times.
[0022] A further object of the present invention is to overcome the deficiencies in the prior art and provide an application of a construction method of an early-strength and toughened backfill material in the anti-abrasion of a flow channel.
[0023] Beneficial effects of the present invention:
[0024] (1) For the early-strength and toughened backfill material provided by the present invention, 1 wt% of the early-strength agent triethanolamine is added, which can most effectively shorten the time for the backfill material to reach the designed strength and enhance the bonding effect between the backfill material and the old concrete. 0.15 wt% of the nanomaterial graphene oxide is added, which can effectively improve the toughness of the backfill material and further enhance the bonding strength between the backfill material and the old concrete.
[0025] (2) The construction method provided by the present invention can effectively improve the anti-abrasion and cavitation resistance of the repaired part by cleaning the damaged part, repairing it with the early-strength and toughened backfill material, and finally spraying the DPS liquid three times. Description of the drawings
[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:
[0027] Figure 1 It is the compressive strength diagram of the backfill materials prepared in Example 1 of the present invention and Comparative Examples 1-4;
[0028] Figure 2 It is the volume loss rate diagram of the backfill materials prepared in Example 1 of the present invention and Comparative Example 5;
[0029] Figure 3 It is the scanning electron microscope diagram of the DPS surface used in Example 2 of the present invention;
[0030] Figure 4 It is the scanning electron microscope diagram of the concrete surface in the repaired area used in Example 2 of the present invention;
[0031] Figure 5 It is the scanning electron microscope diagram of the concrete surface after spraying DPS in the repaired area in Example 2 of the present invention;
[0032] Figure 6 It is the anti-abrasion performance diagram of the flow channel after the repair in Example 2 of the present invention and Comparative Example 6. Detailed implementation manners
[0033] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following describes the specific embodiments of the present invention in detail in conjunction with the embodiments of the specification.
[0034] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.
[0035] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.
[0036] The low-heat Portland cement used in the present invention is P·LH42.5, with a density of 3.24 g / cm 3 , a consistency of 26.4%, an initial setting time of 178 min, a final setting time of 232 min, a 7-day compressive strength of 26.5 MPa, a 28-day compressive strength of 48.5 MPa, a 7-day flexural strength of 5.5 MPa, and a 28-day flexural strength of 8.2 MPa.
[0037] The chemical components of the low-heat Portland cement used in the present invention include 23.10% SiO 2 , 3.78% Al 2 O 3 , 4.59% Fe 2 O 3 , 59.44% CaO, 4.15% MgO, 1.74% SO 3 , an alkali content of 0.38%, and a loss on ignition of 1.12%.
[0038] The sand used in the present invention has a mud content of 0.9%, a mud lump content of 0.3%, a saturated surface dry apparent density of 2595 kg / m 3 , a saturated surface dry bulk density of 1447 kg / m 3 , a porosity of 42.5%, and a moisture content of 0.135%.
[0039] The raw materials used in the present invention are all commercially available without special instructions.
[0040] The test method for the volume loss rate in the present invention is as follows: The repaired part is flushed with water at a fixed flow rate of 30 m / s, an angle of 90°, and a sand content of 2.5%. The volume loss rate is measured with a 3D scanner at 30 min, 60 min, 90 min, and 120 min respectively.
[0041] Example 1
[0042] This example provides an early-strength and toughness-enhancing backfill material. By weight, this backfill material comprises the following components: 264.9 parts of water, 563.7 parts of low-heat portland cement, and 1459.6 parts of sand, and is doped with 0.15 wt% of graphene oxide and 1 wt% of triethanolamine based on the mass of the cement. Among them, the sand is composed of 40 wt% river sand with a particle size below 5 mm and 60 wt% machine-made sand.
[0043] Comparative Example 1
[0044] The difference between this comparative example and Example 1 is that the doping amount of the early-strength agent triethanolamine (based on the cement) is adjusted to 0 wt%, 2 wt%, 3 wt%, and 4 wt% respectively, and the remaining components are the same as those in Example 1, obtaining backfill materials with different triethanolamine doping amounts in this comparative example.
[0045] Comparative Example 2
[0046] The difference between this comparative example and Example 1 is that NaCl with triethanolamine adjusted to 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt% (doping amount based on the cement) is used as the early-strength agent, and the remaining components are the same as those in Example 1, obtaining backfill materials with different NaCl doping amounts in this comparative example.
[0047] Comparative Example 3
[0048] The difference between this comparative example and Example 1 is that Na with triethanolamine adjusted to 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt% 2 SO 4 (doping amount based on the cement) is used as the early-strength agent, and the remaining components are the same as those in Example 1, obtaining backfill materials with different Na 2 SO 4 doping amounts in this comparative example.
[0049] Comparative Example 4
[0050] The difference between this comparative example and Example 1 is that Ca(NO 3 ) 2 with triethanolamine adjusted to 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt% (doping amount based on the cement) is used as the early-strength agent, and the remaining components are the same as those in Example 1, obtaining backfill materials with different Ca(NO 3 ) 2 doping amounts in this comparative example.
[0051] For the backfill materials of Example 1 and Comparative Examples 1 to 4, pour them into a mold of 100mm×100mm×100mm and cure for 28 days, then conduct the compressive strength test. The results are as Figure 1 shown, where (a) the early strength agent in the backfill material is NaCl, (b) the early strength agent in the backfill material is Na 2 SO 4 , (c) the early strength agent in the backfill material is Ca(NO 3 ), (d) the early strength agent in the backfill material is triethanolamine. 2
[0052] According to Figure 1 the influence of different types and different doping amounts of early strength agents on the compressive strength of the backfill material, it can be seen that when the early strength agent is triethanolamine, the compressive strength of the backfill material after 28 days of curing is the highest, reaching more than 45 MPa. And when the addition amount of triethanolamine is 1 wt%, the compressive strength increases faster.
[0053] Comparative Example 5
[0054] The difference between this comparative example and Example 1 is that the doping amounts of graphene oxide (compared with cement) are adjusted to 0 wt%, 0.05 wt%, 0.1 wt%, 0.2 wt%, and 0.25 wt% respectively, and the other components are the same as those in Example 1, obtaining backfill materials with different doping amounts of graphene oxide in this comparative example.
[0055] Conduct the volume loss rate test on the backfill materials prepared in Example 1 and Comparative Example 5. The results are as Figure 2 shown.
[0056] From Figure 2 the analysis, it can be known that incorporating graphene oxide into mortar can improve the toughness of the backfill material, but the degree of improvement in its toughness does not increase with the increase of the doping amount of graphene oxide. The optimal doping amount of graphene oxide is 0.15 wt%.
[0057] Example 2
[0058] This example provides a construction method for an early strength and toughness - enhanced backfill material, specifically as follows:
[0059] Pretreatment: Demarcate the repair area, isolate the repair area with a cofferdam. After draining the accumulated water, use a steel brush to clean the loose and fragile parts of the eroded and damaged part to obtain a fresh concrete surface;
[0060] Construction repair: First spray a layer of Densified Pore Structure Concrete (DPS) on the fresh concrete surface, then use the backfill material in Example 1 to repair the above - mentioned area. After the backfill material hardens, spray DPS 3 times, and the construction of the early strength and toughness - enhanced backfill material is completed.
[0061] Surface morphology analysis was carried out on the DPS, repaired area concrete, and concrete sprayed with DPS used in Example 2, and the results are as Figures 3 - 5 shown. Among them, Figure 3 is the scanning electron microscope image of DPS. (a) is the scanning electron microscope image of DPS, and (b) is the scanning electron microscope image of DPS with the EDS analysis point magnified. Figure 4 is the scanning electron microscope image of the concrete surface, Figure 5 is the scanning electron microscope image of the concrete surface sprayed with DPS.
[0062] Comparing Figures 3 - 5 it can be seen that the distribution of crystal substances and structural characteristics on the concrete surface can be clearly observed. A large number of calcium hydroxide crystals are scattered, a small amount of calcium silicate accumulates in it, and there are also many pores and cracks. On the surface of the concrete sprayed with DPS, in addition to calcium hydroxide crystals, many newly formed calcium silicates are observed to adhere to the surface. These calcium silicates have various shapes, some are granular, some are agglomerated, and some are layered. Generally speaking, the content of calcium silicate in the concrete sprayed with DPS increases, and some pores and cracks are filled with the newly formed calcium silicate.
[0063] Comparative Example 6
[0064] The difference between this comparative example and Example 2 is that the number of times of DPS spraying is adjusted to 0 times and 6 times respectively, and the rest of the construction steps are the same as those in Example 2, and the construction of the early-strength and toughened backfill material in this comparative example is completed.
[0065] The anti-abrasion and erosion resistance performance of the flow channel after repair in Example 2 and Comparative Example 6 was tested, and the results are as Figure 6 shown, where (a) is the volume of the erosion pit, (b) is the area of the erosion pit, and (c) is the average depth of the erosion pit.
[0066] From Figure 6 it can be seen that the overall effect of DPS increases rapidly with the increase of the spraying times and then increases slowly. When DPS is sprayed 3 times, the volume, area, and average depth of the erosion pit change greatly. When the number of DPS spraying times is greater than 3 times, the change of the erosion pit morphology becomes smaller. Therefore, spraying DPS 3 times after the backfill material hardens has the best repair effect on the flow channel.
[0067] In summary, the present invention optimizes triethanolamine as the best early-strength agent and the best dosage of 1wt%, and doping an appropriate amount of graphene oxide improves the mechanical properties of the backfill material.
[0068] In addition, a construction method for the early-strength and toughened backfill material is also provided, which effectively improves the anti-abrasion and cavitation erosion resistance of the repaired part by cleaning the damaged part of the flow channel, repairing it with the backfill material, and spraying the liquid permanent setting agent.
[0069] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.
Claims
1. An early-strengthening and toughening backfill material, characterized in that: The backfill material raw materials include, by weight, 264-281 parts of water, 528-564 parts of low-heat silicate cement, 1458-1465 parts of sand, and, Compared with low-heat silicate cement, the graphene oxide doping amount is 0.13-0.17wt%, and compared with low-heat silicate cement, the triethanolamine doping amount is 0.8-1.2wt%.
2. The early-strength and toughening backfill material according to claim 1, characterized in that: The doping amount of the graphene oxide relative to the low-heat silicate cement is 0.15 wt %.
3. The early-strength and toughening backfill material according to claim 1, characterized in that: The doping amount of the triethanolamine relative to the low heat Portland cement is 1 wt %.
4. The early-strength and toughening backfill material according to claim 1, characterized in that: The sand consists of river sand and machine-made sand.
5. The early-strength and toughened backfill material according to claim 4, characterized in that: The particle size of the sand is 0 to 5 mm.
6. The early-strength and toughened backfill material according to claim 4, characterized in that: The content of the river sand relative to the sand is 40 wt %, and the content of the machine-made sand relative to the sand is 60 wt %.
7. The early-strength and toughened backfill material according to claim 1, characterized in that: It has the following characteristics: after the backfill material is poured into a 100mm×100mm×100mm mold and cured for 28 days, the compressive strength is 45 to 50 MPa.
8. A construction method for early-strengthening and toughening backfill material, characterized in that: include, Define the repair area, isolate it with a cofferdam, drain the accumulated water, and use a steel brush to clean the damaged parts of the flow channel to obtain a fresh concrete surface; Spray the fresh concrete surface with perpetual setting liquid, repair it with backfill material, and then spray it with perpetual setting liquid again after the backfill material hardens, thus completing the construction of early strength and toughening backfill material.
9. The construction method of the early-strength and toughening backfill material according to claim 8, characterized in that: After the backfill material is hardened, the permanent setting liquid is sprayed 3 to 4 times.
10. Application of the construction method of the early-strengthening and toughening backfill material as claimed in any one of claims 8 to 9 in the anti-wear of flow channels.