Method for preventing cracking of concrete pavement and method for repairing concrete pavement
Spraying an impregnating agent with sodium silicate, potassium silicate, and lithium silicate onto concrete pavement forms CSH gel, preventing and healing cracks, addressing the inefficiencies of existing repair methods.
Patent Information
- Application Number
- JP2024111532
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-11
- Publication Date
- 2026-01-23
AI Technical Summary
Existing methods for repairing concrete pavement cracks require traffic restrictions and are time and cost-intensive, and there is a need for a method to prevent cracks from occurring and allow them to heal themselves.
Spraying an impregnating agent containing sodium silicate, potassium silicate, lithium silicate, and water with a dry solids concentration of 25 to 30% onto the concrete pavement to penetrate and react with calcium hydroxide, forming CSH gel for crack prevention and self-healing.
The method effectively prevents cracks and allows them to heal over time by forming CSH gel, providing long-term crack sealing and prevention.
Smart Images
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a method for preventing cracks in concrete pavement and a method for repairing concrete pavement. [Background technology]
[0002] Concrete pavement is stronger, more durable, and has a longer lifespan than asphalt pavement, so it is widely used in areas where maintenance and repair are difficult, such as inside tunnels and parking lots for large vehicles.
[0003] As mentioned above, concrete pavements are highly durable and have a long lifespan, and although the repair cycle is long, cracks can occur over time, making repairs necessary. A major method for repairing cracks in concrete pavements is the sealing method, which involves filling a filler (see Non-Patent Document 1). Non-Patent Document 1 describes a concrete pavement repair method that involves setting a perimeter area around the joints in the concrete pavement, filling the set area with a filler whose main component is polyurethane resin, and spreading it evenly. [Prior art documents] [Non-patent literature]
[0004] [Non-Patent Document 1] Pavement Committee, Pavement Design and Construction Subcommittee, "Pavement Maintenance and Repair Guidebook 2013," Japan Road Association, November 2013, pp. 100-102 Summary of the Invention [Problem to be solved by the invention]
[0005] However, the problems with the above sealing method include the need for traffic restrictions if it is used on an existing road, and the time and cost required to manually inject filler into the cracks.
[0006] The present invention has been made in consideration of the above-mentioned conventional problems, and its object is to provide a method for preventing cracks in concrete pavement that can prevent cracks from occurring in the concrete pavement and, even if cracks do occur, allow the cracks to heal themselves. Another object of the present invention is to provide a method for repairing concrete pavement that seals cracks in the concrete pavement while preventing future cracks. [Means for solving the problem]
[0007] One aspect of the present invention that solves the above problem is as follows. (1) A method for preventing cracking of concrete pavement, comprising spraying onto the concrete pavement an impregnating agent containing at least one of sodium silicate and potassium silicate, lithium silicate, and water, and having a dry solids concentration of 25 to 30% by mass.
[0008] (2) The method for preventing cracks in a concrete pavement according to (1) above, wherein the mass ratio of lithium silicate to at least one of sodium silicate and potassium silicate is 10:1 to 15:1.
[0009] (3) A method for preventing cracks in concrete pavement according to (1) or (2) above, wherein the impregnating agent further contains colloidal silica.
[0010] (4) A method for repairing a concrete pavement, comprising spraying onto the concrete pavement an impregnating agent containing at least one of sodium silicate and potassium silicate, lithium silicate, and water, and having a dry solids concentration of 25 to 30% by mass.
[0011] (5) The method for repairing a concrete pavement according to (4) above, wherein the mass ratio of lithium silicate to at least one of sodium silicate and potassium silicate is 10:1 to 15:1.
[0012] (6) A method for repairing a concrete pavement according to (4) or (5) above, wherein the impregnating agent further contains colloidal silica. [Effects of the Invention]
[0013] According to the present invention, it is possible to provide a method for preventing cracks in concrete pavement, which not only prevents cracks in concrete pavement but also enables the cracks, if any, to heal themselves. Furthermore, the present invention can provide a method for repairing concrete pavement that can seal cracks in the concrete pavement while preventing future cracks. [Brief explanation of the drawings]
[0014] [Figure 1] 1A and 1B are photographs of the surface of the concrete specimen of Example 1 taken using a microscope, (a) immediately after spraying the impregnating agent, (b) one week after spraying, and (c) four weeks after spraying. [Figure 2] 1A and 1B are photographs of the surface of the concrete specimen of Example 2 taken using a microscope, (a) immediately after spraying the impregnating agent, (b) one week after spraying, and (c) four weeks after spraying. [Figure 3] 1A and 1B are photographs of the surface of the concrete specimen of Comparative Example 1 taken using a microscope, (a) immediately after spraying the impregnating agent, (b) one week after spraying, and (c) four weeks after spraying. [Figure 4] 1A and 1B are photographs of the surface of the concrete specimen of Comparative Example 2 taken using a microscope, (a) immediately after spraying the impregnating agent, (b) one week after spraying, and (c) four weeks after spraying. DETAILED DESCRIPTION OF THE INVENTION
[0015] <How to prevent cracks in concrete pavement> The method for preventing cracks in concrete pavement of this embodiment is characterized by spraying onto concrete pavement an impregnating agent containing at least one of sodium silicate and potassium silicate, lithium silicate, and water, and having a dry solids concentration of 25 to 30 mass%.
[0016] In this embodiment of the method for preventing cracks in concrete pavement, a predetermined impregnating agent is sprayed to prevent cracks from occurring in the concrete pavement, and even if cracks do occur, the cracks can self-heal. The predetermined impregnating agent contains at least one of sodium silicate and potassium silicate, lithium silicate, and water, with a dry solids concentration of 25 to 30% by mass. In this embodiment, the impregnating agent penetrates the surface layer of the concrete pavement when sprayed on the surface. Among the components of the impregnating agent, lithium silicate remains in a solid state, while at least one of sodium silicate and potassium silicate reacts with calcium hydroxide in the concrete via water to form CSH gel (calcium silicate hydrate). Therefore, by modifying the surface layer of the concrete, a crack prevention effect is achieved. Furthermore, sodium silicate or potassium silicate re-reacts semi-permanently when water is supplied, thereby providing a long-term self-healing effect on cracks. Conversely, even in areas where water is not supplied, a refractory solid can be produced to seal cracks. Furthermore, by setting the dry solids concentration of the impregnating agent to 25 to 30 mass %, cracks in the concrete pavement can be effectively prevented, and even if cracks do occur, the cracks can be self-healed. First, the impregnating agent used in the method for preventing cracks in concrete pavement according to this embodiment will be described below.
[0017] As described above, the impregnating agent used in this embodiment contains at least one of sodium silicate and potassium silicate, lithium silicate, and water, and has a dry solids concentration of 25 to 30 mass %. Each component will be described in detail below.
[0018] [Sodium silicate, potassium silicate] It performs almost the same function as sodium silicate and potassium silicate. That is, after the impregnating agent is sprayed on concrete pavement, sodium silicate and / or potassium silicate dissolve in water such as rain and can fill cracks. Furthermore, by repeatedly reacting with calcium hydroxide, a component of concrete pavement, it can fill voids over the long term. Then, sodium silicate and / or potassium silicate solidify while adhering to the cracks, thereby sealing them sufficiently.
[0019] In this embodiment, the content of sodium silicate in the impregnating agent is preferably 50 to 65% by mass, more preferably 55 to 65% by mass. The same applies to the preferred content of potassium silicate. Note that sodium silicate and potassium silicate may be used alone or in combination. When sodium silicate and potassium silicate are used in combination, the total content of both is preferably the same as the content when each is used alone.
[0020] [Lithium silicate] Unlike sodium silicate or potassium silicate, lithium silicate becomes a poorly soluble solid as it dries. Once solidified, it is difficult to dissolve in water and maintains its solid state. Therefore, lithium silicate becomes a poorly soluble solid and can fill voids. In other words, after the impregnating agent is sprayed on the concrete pavement, lithium silicate contributes to improving the filling rate as a poorly soluble solid.
[0021] In this embodiment, from the viewpoint of improving the filling rate for cracks, the mass ratio of lithium silicate to at least one of sodium silicate and potassium silicate is preferably 10:1 to 18:1, more preferably 10:1 to 15:1, and even more preferably 10:1 to 12:1.
[0022] In this embodiment, the impregnating agent preferably further contains colloidal silica. By including colloidal silica in the impregnating agent, an improvement in the filling rate can be expected. The content of colloidal silica in the impregnating agent is preferably 5 to 15 mass%, more preferably 8 to 15 mass%, and even more preferably 10 to 15 mass%.
[0023] The above-described impregnating agent can be prepared by adding at least one of sodium silicate and potassium silicate, lithium silicate, and, if necessary, other components to water and stirring the mixture.
[0024] In this embodiment, the impregnating agent is sprayed onto the concrete pavement, but there is no particular limitation on the spraying method. 2 The amount is preferably 150 to 250 g per serving. After the impregnation agent is sprayed, it is preferable to prevent the surface from coming into contact with moisture until the surface is dry.
[0025] <Concrete pavement repair methods> The concrete pavement repair method of this embodiment is characterized by spraying onto the concrete pavement an impregnating agent containing at least one of sodium silicate and potassium silicate, lithium silicate, and water, and having a dry solids concentration of 25 to 30 mass%.
[0026] In the concrete pavement repair method of this embodiment, cracks in the concrete pavement can also be repaired by spraying a predetermined impregnating agent. The predetermined impregnating agent is the same as the impregnating agent used in the concrete pavement crack prevention method described above, containing at least one of sodium silicate and potassium silicate, lithium silicate, and water, with a dry solids concentration of 25 to 30% by mass. In this embodiment, when the impregnating agent is sprayed on the surface of the concrete pavement, it penetrates into the cracks, and the lithium silicate fills the cracks as a solid, while at least one of the sodium silicate and potassium silicate reacts with calcium hydroxide in the concrete via water to form CSH gel (calcium silicate hydrate), which then fills the cracks. In this way, cracks in the concrete pavement are repaired. Furthermore, even if cracks occur in the future, the sodium silicate or potassium silicate will re-react semi-permanently when water is supplied, allowing the cracks to be sealed for a long period of time. Furthermore, by setting the dry solid content of the impregnating agent to 25 to 30 mass %, cracks in concrete pavement can be repaired effectively.
[0027] The impregnating agent and its application in the concrete pavement repair method of this embodiment are the same as those in the concrete pavement crack prevention method of this embodiment, including preferred aspects. Therefore, the description of the impregnating agent and its application in the concrete pavement crack prevention method of this embodiment applies to this impregnating agent and its application. Therefore, the description of the impregnating agent and its application will be omitted here. [Example]
[0028] The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to these examples.
[0029] [Example 1] (1) Preparation of concrete specimens A concrete specimen with a diameter of 10 cm and a thickness of 6 cm was prepared, which was integrated with a VP pipe (rigid polyvinyl chloride pipe). A load was applied to the side of the specimen, and approximately linear cracks with an average width of 0.2 mm or less were introduced.
[0030] (2) Preparation of Impregnating Agent 1 10,000 g of the sodium silicate solution and 5,000 g of the lithium silicate solution were added to 5,000 g of purified water and stirred to prepare Impregnating agent 1. The dry solid concentration of Impregnating agent 1 was 25 mass %.
[0031] The impregnating agent 1 prepared as above was spread on the prepared concrete specimen at a rate of 0.2 kg / m 2 The concrete specimens were then air-cured at a temperature of 20°C, and the surfaces of the concrete specimens were observed using a microscope immediately after spraying the impregnating agent 1, one week after spraying, and four weeks after spraying. Photographs of the surfaces are shown in Figures 1(a) to 1(c). Figure 1(a) is a photograph taken immediately after spraying the impregnating agent, Figure 1(b) is a photograph taken one week after spraying, and Figure 1(c) is a photograph taken four weeks after spraying. Figures 1(a) to 1(c) show that cracks were visible immediately after spraying, but that the cracks had been sealed one week and four weeks after spraying due to the formation of CSH gel.
[0032] [Example 2] Impregnating agent 1 was sprayed onto concrete specimens in the same manner as in Example 1, except that air curing was changed to cyclic curing, and crack evaluation was performed. Photographs of the surface of the concrete immediately after spraying of impregnating agent 1, one week after spraying, and four weeks after spraying are shown in Figures 2(a) to 2(c). Figures 2(a) to 2(c) show that cracks were visible immediately after spraying, but that the cracks had been sealed by the formation of CSH gel one week and four weeks after spraying.
[0033] [Comparative Example 1] (1) Preparation of Impregnating Agent 2 Impregnating agent 2 was prepared by adding 7,200 g of sodium silicate solution and 3,600 g of lithium silicate solution to 9,200 g of purified water and stirring. The dry solids concentration of impregnating agent 2 was 20 mass%. Next, in the same manner as in Example 1, impregnating agent 2 was sprayed onto a concrete specimen, and a crack evaluation was performed. Photographs of the surface of impregnating agent 2 taken immediately after spraying, one week after spraying, and four weeks after spraying are shown in Figures 3(a) to 3(c). From Figures 3(a) to 3(c), cracks are visible immediately after spraying, one week after spraying, and four weeks after spraying.
[0034] Comparative Example 2 Impregnating agent 2 was sprayed onto concrete specimens in the same manner as in Comparative Example 1, except that air curing was changed to cyclic curing, and crack evaluation was performed. Photographs of the surface of the specimen immediately after spraying impregnating agent 2, one week after spraying, and four weeks after spraying are shown in Figures 4(a) to (c). Figures 4(a) to (c) show that CSH gel was formed on the specimen surface one week after spraying, and that the cracks were sealed four weeks after spraying.
Claims
1. A method for preventing cracks in concrete pavement, comprising spraying onto the concrete pavement an impregnating agent containing at least one of sodium silicate and potassium silicate, lithium silicate, and water, and having a dry solids concentration of 25 to 30 mass %.
2. 2. The method for preventing cracks in concrete pavement according to claim 1, wherein the mass ratio of the lithium silicate to at least one of the sodium silicate and the potassium silicate is 0.5 to 0.
8.
3. 3. The method for preventing cracks in a concrete pavement according to claim 1 or 2, wherein the impregnating agent further comprises colloidal silica.
4. A method for repairing a concrete pavement, comprising spraying onto the concrete pavement an impregnating agent containing at least one of sodium silicate and potassium silicate, lithium silicate, and water, and having a dry solids concentration of 25 to 30 mass %.
5. 5. The method for repairing a concrete pavement according to claim 4, wherein the mass ratio of the lithium silicate to at least one of the sodium silicate and the potassium silicate is 0.5 to 0.
8.
6. 6. The method for repairing a concrete pavement according to claim 4 or 5, wherein the impregnating agent further comprises colloidal silica.