Concrete curing agent, and method of curing concrete using the same

Abstract

To provide a concrete curing agent capable of prolonging the setting delay time of concrete, and a curing method using the same.SOLUTION: The concrete curing agent formed of components including a polyether / polyol-based urethane polymer, a nanocluster derivative, zinc powder and clay mineral powder, is prepared by dissolving the components into water. The concrete curing agent is sprayed over the surface of placed concrete 1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a concrete curing agent and a concrete curing method using the same. [Background technology]

[0002] Poured concrete hardens through a hydration reaction between cement and water. Therefore, if the water in the concrete is lost through evaporation or other means before the concrete hardens, the cement and water will no longer be able to hydrate under optimal conditions.

[0003] In particular, in places exposed to direct sunlight, on hot days, or on windy days, the moisture in the surface layer of concrete evaporates rapidly, causing cracks due to drying shrinkage and plastic cracks on the surface of the concrete. Therefore, poured concrete needs to be cured to prevent the moisture in the concrete from evaporating until it hardens.

[0004] Conventional curing methods include sprinkler curing, in which water is sprayed onto the surface of the concrete, sheet curing, in which the surface of the concrete is covered with a sheet, and a method called sprinkler-sheet curing, which combines sprinkler curing and sheet curing. However, sprinkler curing is troublesome because it requires continuous water spraying. If water spraying is neglected, cracks will occur. Sheet curing and sprinkler-sheet curing have the problem that installing the sheet is troublesome and there is a risk that traces of the sheet curing will remain on the concrete.

[0005] Another conventional curing method is to spray a curing agent on the surface of the concrete. This method does not require the same management as water spray curing or sheet curing. Various curing agents have been proposed (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-87113 [Patent Document 2] Japanese Patent Application Publication No. 11-21184 Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventional curing agents have a short setting delay time, and there is a demand for curing agents with a long setting delay time.

[0008] Therefore, an object of the present invention is to provide a concrete curing agent that can extend the setting delay time of concrete, and a concrete curing method using the same. [Means for solving the problem]

[0009] The present invention was made in consideration of the above problems, and is (1) a concrete curing agent characterized by having polyether polyol-based urethane polymer and nanocluster derivative as its main components, and dissolving these main components in water.

[0010] (2) A concrete curing agent according to (1) above, characterized in that zinc dust and clay mineral powder are added to the main component.

[0011] (3) A concrete curing method characterized in that the step of spraying or applying the concrete curing agent described in (1) or (2) is carried out immediately after pouring the concrete and at the end of finishing the pouring of the concrete.

[0012] (4) A concrete curing method characterized in that the step of spraying or applying the concrete curing agent described in (1) or (2) is carried out after the concrete has been poured and finished, when initial cracks are discovered. [Effects of the Invention]

[0013] According to the present invention, the main components of a concrete curing agent are a polyether polyol-based urethane polymer, a surfactant that also serves as an excellent thickener and viscosity adjuster, and a nanocluster derivative, a functional amplifier. When an aqueous solution of this concrete curing agent, primarily composed of these components, is sprayed or applied to the surface of pre-hardened concrete, it penetrates into the concrete surface layer due to the surfactant's reduced surface tension (surface activity), resulting in a moisturized (water-retaining) state. Surfactant particles that enter the concrete surface layer are adsorbed to cement particles and cement hydrate particles, temporarily suppressing contact between the cement particles and water. This delays the formation of cement hydrate, which in turn delays the filling of the voids between the cement particles with the cement hydrate, ultimately delaying the solidification of the concrete.

[0014] Here, concrete curing agents whose main components are polyether polyol-based urethane polymers and nanocluster derivatives are able to maintain a moist state (water-retaining state) on the surface of concrete for a longer period of time compared to other surfactants due to factors such as their high viscosity. Therefore, compared to conventional curing agents, the surfactant particles inhibit contact between cement particles and water for a longer period of time, which is thought to extend the setting delay time of concrete. [Brief explanation of the drawings]

[0015] The drawings illustrate specific embodiments of the invention according to the present disclosure, including essential features of the invention as well as alternative and preferred embodiments. [Figure 1] FIG. 1 shows the present embodiment and is a diagram showing the composition, components, functions, etc. of a concrete curing agent. [Figure 2] FIG. 10 is a diagram illustrating the embodiment and explains the spraying of a concrete curing agent immediately after the concrete has been poured. [Figure 3] 1 is a diagram illustrating the embodiment and explaining the spraying of a concrete curing agent during concrete finishing. FIG. [Figure 4] FIG. 10 is a diagram illustrating the embodiment and explains the spraying of a concrete curing agent performed at the end of concrete finishing. [Figure 5] 1A is an overall view showing the state of concrete left to cure for five days after application at the end of concrete finishing, and FIG. 1B is an enlarged view of a main part of FIG. 1A. DETAILED DESCRIPTION OF THE INVENTION

[0016] Each embodiment will be described in detail below with reference to the accompanying drawings. In this example, a description of already known technologies will be omitted. Furthermore, the following examples illustrate devices and methods for embodying the technical idea of ​​the invention, and the technical idea of ​​the present invention is not limited to the following. Various modifications can be made to the technical idea of ​​the present invention within the scope of the matters described in the claims. In particular, it should be noted that the drawings are schematic and may differ from the actual product.

[0017] (concrete) First, we will explain the concrete 1. The concrete 1 to be poured is a fluid mixture of cement, fine aggregate, coarse aggregate, and water. The fine aggregate is, for example, sand. The coarse aggregate is, for example, gravel. The water is, for example, tap water or industrial water, and is not particularly limited.

[0018] (Concrete curing agent) The concrete curing agent of this embodiment is composed primarily of a polyether polyol-based urethane polymer and a nanocluster derivative (aqueous solution), and is prepared by dissolving zinc dust and clay mineral powder in water to form a concentrate. Figure 1 shows the composition, components, and functions of the concentrate for the concrete curing agent. The content of each component is as follows: polyether polyol-based urethane polymer: 5.0-7.5%, nanocluster derivative: 90-95%, zinc dust: 0.01% or less, and clay mineral powder: 0.01% or less. The polyether polyol-based urethane polymer is a compound with CAS registration number "7732-18-5." The clay mineral is a compound with CAS registration number "1332-58-7."

[0019] Polyether polyol-based urethane polymer is a surfactant that functions as a thickener and viscosity adjuster (moisturizer), allowing the aqueous solution of concrete curing agent to penetrate reliably into the surface of the concrete.

[0020] Furthermore, since the polyether polyol urethane polymer has excellent surface smoothness, it can be sprayed uniformly, and the moisture retention state (water retention state) of the surface layer of the concrete 1 is uniform.

[0021] Furthermore, polyether polyol-based urethane polymers are nonionic surfactants, meaning they have no electric charge. Therefore, they are chemically more stable than other surfactants, are less susceptible to the effects of pH and electrolytes, and have excellent foaming and emulsifying properties.

[0022] The nanocluster derivative ((H2O) x 10-12) is a functional additive, which enhances the various functions of polyether polyol urethane polymers.

[0023] Zinc powder (Zn) is a powder of metallic zinc. Substantial zinc powder is an efflorescence inhibitor and has high UV blocking properties.

[0024] The clay mineral powder is, for example, a mineral of 2 μm or less in size, and has a high affinity with water, causing the water to spread thinly. As a result, the concrete curing agent spreads evenly over the surface of the concrete 1 when sprayed.

[0025] Quality testing was carried out on the concrete curing agent, with the following results obtained. Visual inspection revealed that the appearance was a pale grey, transparent liquid. The unit volume mass was 1.0-1.1 (standard value: 1.0-1.1) based on the volume / weight formula. The hydrogen ion exponent (pH) was 8 (standard value: 7-8) based on pH reagent paper. The settling rate was visually determined to be 10 minutes or more (standard value: 10 minutes or more). From the above, it was shown that the unit volume mass, pH, and settling rate all met the standard values.

[0026] (Reasons for delayed setting of concrete) Next, the reason why the concrete curing agent causes delay in setting of the concrete 1 and the delay time is long will be explained.

[0027] When a concrete curing agent is sprayed on the surface of concrete 1 after it has been poured but before it hardens, the aqueous solution of the concrete curing agent penetrates into the concrete surface layer due to the surfactant's reduction in surface tension (surface activity), causing the concrete surface layer to become moist (water-retaining). The surfactant particles that enter the concrete surface layer are adsorbed to cement particles and cement hydrate particles, temporarily suppressing contact between the cement particles and water. This delays the formation of cement hydrate, which delays the filling of the voids between the cement particles, and ultimately the hardening of concrete 1.

[0028] Here, concrete curing agents whose main ingredients are polyether polyol-based urethane polymers and nanocluster derivatives can maintain a moist state (water-retaining state) on the surface of concrete for a longer period of time than other surfactants because the nano-sized particles improve water permeability. Therefore, compared to conventional curing agents, the surfactant particles inhibit contact between cement particles and water for a longer period of time, which is thought to extend the setting delay time of concrete.

[0029] (Construction method) Next, we will explain the application test conducted on a concrete curing agent. The test site was a concrete floor slab on the roof of a new building construction site in Tokyo. The test site area was 140m2 in total, with one 70m2 area and two other 70m2 areas. The minimum temperature was 18.8°C and the maximum 30.9°C. The average wind speed was 3m / s and the maximum was 6.0m / s. The concrete curing agent was applied by mixing 100g of the concentrate with 75 liters of water. The application method was to spray it over the entire concrete surface using a watering can.

[0030] First, immediately after the concrete was poured, as shown in Figure 2, concrete curing agent was spread using a watering can 2, while the concrete was leveled using a manual leveling tool called a tombo 3. The worker spread the agent over the entire surface of the concrete 1 using a funnel.

[0031] Next, when finishing the concrete, as shown in Figure 3, concrete curing agent was sprayed while the trowel 4, a mechanical leveling machine, was rotating. At this time, the surface condition of the concrete 1 was observed, and no cracks or other abnormalities were found.

[0032] Next, when the concrete finishing was completed, a concrete curing agent was sprayed using a watering can 2, as shown in Figure 4. After spraying, the concrete was left to cure for five days, but no cracks were observed overall, as shown in Figure 5. However, cracks were observed in one location on the 30 cm square and one location on the 10 cm square.

[0033] Since small cracks, which were incipient cracks, were discovered, concrete curing agent was sprayed onto the cracked areas using watering can 2.

[0034] The concrete curing agent's expansion components then act (clay mineral powder reacts with water), causing hydrated crystals to regenerate. These hydrated crystals cause small cracks to shrink or disappear. In other words, the concrete curing agent suppresses initial cracks.

[0035] (Effects of the embodiment) As explained above, the concrete curing agent is composed mainly of polyether polyol-based urethane polymer and nanocluster derivative, dissolved in water. Therefore, compared to conventional curing agents, the setting delay time of concrete 1 can be extended for the reasons mentioned above. As a result of extending the setting delay time of concrete 1 in this way, it has the effect of reliably preventing cracks caused by drying shrinkage, plastic cracks, and the like from occurring on the surface of concrete 1.

[0036] In addition to the main components mentioned above, concrete curing agents contain zinc powder and clay mineral powder.

[0037] Therefore, since the concrete curing agent contains zinc powder, it can prevent the efflorescence phenomenon of concrete.

[0038] The concrete curing agent spraying process is carried out immediately after pouring the concrete 1 and at the end of finishing pouring the concrete 1. Therefore, the concrete curing agent is sprayed onto the concrete 1 immediately after pouring, and the concrete curing agent penetrates into the surface layer of the concrete immediately after pouring, preventing cracks and the like due to lack of moisture in the surface layer of the concrete immediately after pouring.

[0039] A concrete curing agent is sprayed onto the concrete 1 after pouring and the concrete curing agent penetrates into the surface of the concrete after pouring, thereby preventing cracks and other problems caused by a lack of moisture in the surface of the concrete after pouring.

[0040] The concrete curing agent is sprayed when initial cracks are discovered after the concrete 1 has been poured. As described above, the expansion components of the concrete curing agent act (clay mineral powder and the like react with water) to regenerate hydrated crystals, thereby suppressing initial cracks.

[0041] In the above embodiment, the concrete curing agent is spread on the surface of the concrete 1 using the watering can 2, but it may also be applied to the surface of the concrete 1 using a brush or the like.

[0042] The concrete curing agent of the present invention can also be applied to mortar and the like.

[0043] Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments. [Explanation of symbols]

[0044] 1. Concrete

Claims

1. A concrete curing agent characterized by having polyether polyol-based urethane polymer and nanocluster derivative as its main components, the main components being dissolved in water.

2. 2. The concrete curing agent according to claim 1, further comprising zinc powder and clay mineral powder in addition to the main component.

3. 3. A method for curing concrete, comprising the steps of spraying or applying the concrete curing agent according to claim 1 immediately after pouring the concrete and at the end of finishing the pouring of the concrete.

4. 3. A method for curing concrete, comprising the step of spraying or applying the concrete curing agent according to claim 1 or 2, after concrete has been poured and finished, when an initial crack is discovered.

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