TWI383966B - Conservatives for cement structures - Google Patents

Description

Cement curing agent Field of invention

The present invention relates to a cement structure covering curing agent, and more particularly to a coating curing agent which inhibits evaporation of water by coating the surface of the cement structure and thereby can increase the strength of the cement structure.

Background of the invention

In order to fully exert the performance of a cement structure such as mortar or concrete, a curing method for suppressing moisture loss from the surface of the cement has been used, and methods such as water spray curing, film curing, and sheet curing are generally used.

However, in the period of high temperature and rapid evaporation of water, water spray maintenance must increase the number of water sprays and constitute complicated work. Moreover, sheet maintenance must increase the sheet simultaneously with the increase of construction area, and there is a large area application. Difficult, and at the same time has the disadvantage of being difficult to cope with the form.

Moreover, although the coating film curing does not have the above problems, the conventional coating film curing agent uses a resin coating film curing agent such as epoxy, acrylic acid or urethane, and the coating film curing agent has a solvent, The use of the two-liquid type is complicated or the film is hard and it is difficult to cater for the deformation of the cement structure.

With respect to such a problem, Patent Document 1 discloses a coating film curing agent comprising an aqueous solution containing cellulose, and Patent Document 2 discloses a curing coating composed of an aqueous synthetic resin dispersion or the like. However, these water evaporation inhibition effects are not sufficient.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-244255

[Patent Document 2] JP-A-2005-162534

Invention

In view of the above, an object of the present invention is to provide a coated curing agent which can be used by a simple method and which has an excellent effect of suppressing moisture evaporation on the surface of a cement structure and thereby improving the strength of the cement structure.

The cement structure of the present invention is coated with or coated with a coating curing agent for a cement structure, and an oily component is contained in a coating curing agent (hereinafter also referred to simply as a coating curing agent), and has a melting point of 70 ° C or less. Further, it is a semi-solid or solid oily component at room temperature, and is composed of one or more selected from the group consisting of higher fatty acids, higher alcohols, fats and oils, and hydrocarbons.

The oily component is preferably a penetration of 10 or more at 25 °C.

Further, the coating material for a cement structure according to the present invention may be an oil-in-water emulsion dispersion in which the oil component is dispersed in water by using a surfactant.

According to the coated curing agent of the present invention, the water loss rate can be reduced, whereby the hydration reaction of the cement can be promoted and the initial strength developability can be improved, so that the crack prevention effect can be enhanced by the increase in the drying shrinkage reduction effect. In turn, the durability of the cement structure can be improved.

The best form for implementing the invention

The oil component used in the present invention is composed of one or more selected from the group consisting of a hydrophobic compound composed of a higher fatty acid, a higher alcohol, a fat, and a hydrocarbon, and is semi-solid at normal temperature. Shape or solid. Here, the term "semi-solid or solid" means non-liquid, and more specifically, in accordance with Article 69 of the "Rules for the Limitation of Hazardous Materials" of the Japanese Prime Minister's Decree. In the confirmation test of the liquid definition, it takes 90 seconds or more at 20 °C. Further, these oily components are formed to have a melting point of 70 ° C or lower.

When the oily component is preferably at a penetration of 10 or more at 25° C., the water loss suppressing effect is further improved, and the strength development effect of the cement structure can be further improved.

Preferable examples of the oil component include a higher fatty acid having a carbon number of 12 to a carbon number of 16 or a higher alcohol, and specific examples thereof include lauric acid, myristic acid, palmitic acid, stearic acid, and lauryl alcohol. Myristyl alcohol, cetyl alcohol, stearyl alcohol. Other preferred examples include waxes such as beeswax, cetyl wax, lanolin, paraffin wax, and paraffin wax. Among them, since the deformation of the cement structure is excellent, it is preferably semi-solid at room temperature. The lanolin and paraffin fat of the substance.

The coating curing agent of the present invention may be applied by heating the oil component directly or as needed, or may be an oil-in-water emulsion dispersion in which the oil component is dispersed in water by using a surfactant. When the two are compared, the former is superior in the effect of suppressing water evaporation, and the latter is excellent in workability.

In the case of the former, the heating can be carried out in a state in which the oily component is easily applied, and the heating temperature can be appropriately determined depending on the type of the oil component, the cement structure to be coated, the working environment, and the like.

In the latter case, the oil-in-water emulsion dispersion can be prepared by a method which has heretofore been used to prepare the same dispersion. In other words, the surfactant which is used to disperse the oil component and is used as the oily emulsified dispersion in water can be used without any particular limitation as long as it does not adversely affect the performance of the coating curing agent of the present invention, and an anionic system can be used. And a nonionic surfactant, wherein a nonionic surfactant is preferably used. Further, the preparation method may be a method in which water is added little by little and phase-converting emulsification method using phase conversion; natural emulsification using self-emulsifying dispersibility in a large amount of water; using a homogenizer or a rubber mill Forced emulsification method such as machine action.

In order to obtain good workability, the coating curing agent of the present invention preferably has a viscosity of 10,000 mPa. s or less, and more ideally 500mPa. s to 5000mPa. s.

Additives such as a clay mineral or a soap-like viscosity modifier may be appropriately added to the coated curing agent of the present invention within the range not departing from the object of the present invention.

The coated curing agent of the present invention is applied by coating or spreading on the surface of the cement structure. The amount of coating or dispersion is not particularly limited. However, it is preferably from 50 g/m ² to 500 g/m from the viewpoint that the desired effect can be obtained without causing waste of the coating curing agent and the workability is also good. ² and more desirably 100 g/m ² to 300 g/m ² .

A general method can be used for the method of coating or spreading the coated curing agent on the surface of the cement structure. For example, in the coating, a bristles or a drum which can apply the oily component or the dispersion thereof to the surface of the cement structure can be used. Further, a hand pump sprayer, a mechanical sprayer, or the like can be used for the dispersion.

Example

Hereinafter, the present invention will be more specifically illustrated by the examples, but the present invention is not limited to the following examples.

[Example 1 to Example 5, Comparative Example 1 to Comparative Example 6]

The oily component shown in Table 1 and the polyoxyethylene lauryl ether as a nonionic surfactant were put into water and stirred, and the oily component was 20% by weight (purity) and 10% by weight of the nonionic surfactant. The coating curing agent for the oil-type emulsified dispersion, however, Comparative Example 1 was used as a blank sample. The melting point of the oil component or the like to be used and the penetration at 25 ° C are simultaneously shown in Table 1. Further, the melting point and the penetration degree are measured in advance according to JIS K2235 (petroleum wax).

The obtained coating curing agent was used, and the amount of moisture loss and compressive strength of the cement test body were measured as follows. Further, the results are simultaneously shown in Table 1.

Water loss: using a simple mold frame of Φ50mm×100mm, the mortar is cemented (cement/sand = 1/3, W/C=60%), and is cured in a constant temperature and humidity chamber at 20 ° C and 60% RH. 24 hours. After demolding, the aforementioned coating curing agent was applied to the surface of the mortar by bristles at 200 g/m ² . The sample was placed in a constant temperature and humidity chamber at 20 ° C and 60% RH, and the weight of the test body after 1 day, 2 days, 3 days, 5 days, and 7 days was measured, and then dried by a dryer at 100 ° C for 4 days. The weight of the test body was measured. The amount of water loss (g/m ² ) was calculated from the weight before drying, the weight after drying, and the volume of the test body.

Further, the compressive strength was measured in accordance with JIS A1108 "Test method for compressive strength of concrete".

[Embodiment 6, Example 7]

The oily component shown in Table 1 was heated to 35 ° C and applied to the surface of the cement test body at a ratio of 40 g/m ² using a rubber shovel. With respect to the cement test body, the amount of water loss and the compressive strength were measured in the same manner as described above. Further, the results are collectively shown in Table 1.

As shown in Table 1, the examples showed a small amount of water loss and excellent compressive strength from 1 day to 7 days after the comparison with the comparative examples.

Industry availability

The coated curing agent of the present invention can be used for various cement structures used in civil engineering and construction fields, such as tunneled concrete for concrete, walls or floors of general structures, and the like.

Claims (3)

A coating material for a cement structure, which is coated or dispersed in a cement structure, and characterized in that it comprises an oily component selected from the group consisting of lauric acid, cetyl alcohol, lanolin, paraffin wax and beeswax. One or more of the constituent groups. The coating curing agent for a cement structure according to the first aspect of the invention, wherein the oily component has a penetration degree of 25 or more at 10 °C. The coating curing agent for a cement structure according to the first or second aspect of the invention is the oil-in-water emulsion dispersion in which the oil component is dispersed in water by using a surfactant.