Retarder and concrete joint treatment method

Abstract

To provide a setting retarder that achieves efficiency of construction joint work, and a placing joint treatment method for concrete.SOLUTION: A setting retarder applied to a surface of concrete in placing joint treatment of the concrete has a function of exhibiting a predetermined setting retarding action by staying on the surface of the concrete located in a position to which the setting retarder is applied right after the placement. The setting retarder contains a base compound having the setting retarding action, wherein a relative density of the base compound may be larger than that of bleeding water. Moreover, the setting retarder may have a component that has high viscosity by reacting with the bleeding water or the concrete.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a set retarder and a method for treating concrete joints. [Background technology]

[0002] Conventionally, when constructing a concrete structure, a joint treatment is carried out (see, for example, Patent Document 1). If the joint treatment is not carried out properly, it can become a weak point in the structure and affect durability. A typical joint treatment involves spraying a set retarder on the joint where bleeding has subsided, and then carrying out a laitance treatment the following day. Figure 4 shows an example of a typical conventional joint treatment procedure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-256804 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional set retarders work by being sprayed on concrete that has settled after bleeding has flowed out or receded (dried). Therefore, the set retarder can only be sprayed on concrete after the bleeding has settled. This requires workers to wait a certain amount of time (e.g., 1 to 3 hours) after concrete pouring is complete until the bleeding settles, resulting in inefficient work.

[0005] The present invention has been made in view of the above, and aims to provide a set retarder and a concrete joint treatment method that can improve the efficiency of joint treatment work. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the set retarder of the present invention is a set retarder that is applied to the surface of concrete during concrete joint processing, and is characterized by having the function of remaining on the surface of the concrete at the applied position and exhibiting a predetermined set retarding effect when applied to the surface of the concrete immediately after pouring.

[0007] Another set retarder according to the present invention is characterized in that, in the above-mentioned invention, it contains a base agent having a set retarding effect, and the specific gravity of this base agent is greater than that of the bleeding water.

[0008] Another set retarder according to the present invention is characterized in that, in the above-mentioned invention, it contains a component that reacts with bleeding water or concrete to increase viscosity.

[0009] Another setting retarder according to the present invention is characterized in that it is a thickening setting retarder composed of compound A having a setting retarding effect and compound B which is one or more alkali-thickening type thickeners whose aqueous solution viscosity increases in an alkaline environment, in the above-mentioned invention.

[0010] Another setting retarder according to the present invention is characterized in that, in the above-mentioned invention, the compound A is composed of one or more of hydroxycarboxylic acid, lignosulfonic acid, phosphonic acid, humic acid and / or salts thereof, or sugars and polyols.

[0011] Another setting retarder according to the present invention is characterized in that, in the above-mentioned invention, compound B is an acrylic thickener, and the setting retarder is composed of one or more thickeners whose aqueous solution viscosity at 5% active ingredient is 10 mPa s or less at pH = 5 and 200 mPa s or more at pH = 12.

[0012] Another setting retarder according to the present invention is characterized in that in the above-mentioned invention, the composition of the compound A and the compound B is 10 / 90 to 60 / 40 in weight ratio.

[0013] Another set retarder according to the present invention is the one described above, which can be applied to concrete with a surface area of ​​1 m 2 It is characterized by being used by spraying 150ml to 1500ml per unit.

[0014] Furthermore, the concrete joint treatment method according to the present invention is characterized in that the setting time of the concrete is adjusted by applying the above-mentioned set retarder to the surface of the concrete immediately after it has been poured. [Effects of the Invention]

[0015] The set retarder according to the present invention is a set retarder applied to the surface of concrete during concrete joint processing, and when applied to the surface of concrete immediately after pouring, it remains on the surface of the concrete at the applied position and has the function of exerting a predetermined set retarding effect, so it can be sprayed on the surface of the concrete immediately after pouring, eliminating the waiting time immediately after pouring that was previously required. Therefore, it has the effect of improving the efficiency of the joint processing work.

[0016] In addition, another set retarder according to the present invention contains a main agent with a set retarding effect, and since the specific gravity of this main agent is greater than that of the bleeding water, the main agent of the applied set retarder settles in the bleeding water and is not washed away by the bleeding water. Therefore, it remains on the surface of the concrete where it is applied, and can exert the desired set retarding effect.

[0017] In addition, the set retarder according to the present invention contains a component that reacts with bleeding water or concrete to increase viscosity, so the applied set retarder does not become viscous and is not washed away by bleeding water, but remains on the surface of the concrete where it is applied, thereby achieving the desired set retarding effect.

[0018] Furthermore, the other set retarder according to the present invention is a thickening set retarder composed of compound A, which has a set retarding effect, and compound B, which is one or more types of alkali thickening type thickeners whose aqueous solution viscosity increases in an alkaline environment, and therefore has the effect of remaining on the surface of the concrete where it is applied and exhibiting the desired set retarding effect.

[0019] Furthermore, according to another set retarder of the present invention, the compound A is composed of one or more of hydroxycarboxylic acid, lignosulfonic acid, phosphonic acid, humic acid and / or salts thereof, or sugars and polyols, and therefore, the retarder remains on the surface of the concrete where it is applied and can exert a predetermined set retarding effect.

[0020] In addition, according to another set retarder of the present invention, compound B is an acrylic thickener, and is composed of one or more thickeners whose aqueous solution viscosity at 5% active ingredient is 10 mPa s or less at pH = 5 and 200 mPa s or more at pH = 12, thereby achieving the effect of remaining on the surface of the concrete where it is applied and exhibiting the desired set retarding effect.

[0021] In addition, according to another set retarder of the present invention, the composition of the compound A and the compound B is 10 / 90 to 60 / 40 in weight ratio, so that it can remain on the surface of the concrete at the applied position and exhibit a predetermined set retarding effect.

[0022] Furthermore, according to another set retarder of the present invention, the surface area of ​​concrete is 1 m 2 Since 150ml to 1500ml is sprayed per unit, it remains on the surface of the concrete where it is applied and has the effect of exerting the desired setting retarding effect.

[0023] Furthermore, according to the concrete joint treatment method of the present invention, the above-mentioned setting retarder is applied to the surface of the concrete immediately after pouring to adjust the setting time of the concrete, thereby achieving the effect of improving the efficiency of the joint treatment work. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram showing the procedure of an embodiment of the method for treating concrete joints according to the present invention. [Figure 2] FIG. 2 is a diagram showing an example of the spraying state of the setting retarder. [Figure 3] Figure 3 is a comparison diagram of the washing depth depending on the spray timing. [Figure 4] FIG. 4 is a schematic diagram showing an example of a conventional jointing process. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the set retarder and concrete joint treatment method according to the present invention will be described in detail with reference to the drawings, but the present invention is not limited to these embodiments.

[0026] (Retarder) First, an embodiment of the setting retarder according to the present invention will be described. The set retarder according to this embodiment is sprayed (applied) on the surface of concrete during concrete joint processing, and when sprayed on the surface of concrete immediately after pouring, it remains on the surface of the concrete at the sprayed position and exerts the desired set retarding effect. Normally, concrete produces excess water, known as bleeding water, within a certain period of time (for example, about 3 hours) after being poured. The set retarder according to this embodiment is not washed away by the bleeding water even under such circumstances, but remains on the surface of the concrete and exerts the desired set retarding effect.

[0027] The set retarder contains a base agent with a set retarding effect, and the base agent can be configured with a specific gravity greater than that of the bleeding water. In this way, the base agent of the sprayed set retarder settles in the bleeding water and is not washed away by the bleeding water. Therefore, it remains on the surface of the concrete where it is sprayed, and can exert the desired set retarding effect.

[0028] Furthermore, the set retarder can be composed of a component that reacts with the alkaline components of the bleeding water or concrete to increase viscosity. In this way, the sprayed set retarder becomes viscous and does not wash away with the bleeding water. Therefore, it remains on the surface of the concrete where it is sprayed, and can exert the desired set retarding effect.

[0029] As the above-mentioned component, for example, a synthetic polymer-type alkaline thickener can be used. By adding this alkaline thickener to a commercially available set retarder (main component), the set retarder of the present invention can be obtained. When the set retarder of the present invention is sprayed on concrete immediately after pouring, the alkaline thickener contained in the set retarder comes into contact with the highly alkaline concrete surface and reacts, causing the set retarder to become highly viscous overall. As a result, the main component is not washed away by the bleeding water, but remains on the concrete surface, thereby achieving the desired set retarding effect.

[0030] The retarder of the present invention is not limited to the above, and may be any material that, when sprayed on the surface of concrete immediately after pouring, remains on the surface of the concrete at the sprayed position and exerts a predetermined setting retarding effect.

[0031] According to this embodiment, the agent can be sprayed onto the surface of concrete immediately after pouring. This eliminates the need for the waiting time required for bleeding to subside immediately after pouring, which was previously required. This improves the efficiency of the joint processing work. Furthermore, since it is not dependent on the shape of the concrete to be sprayed, it can be applied to the construction of various concrete structures.

[0032] In the above embodiment, a thickening retarder may be used, which is composed of Compound A, which has a set retarding effect, and Compound B, which is one or more alkali thickening type thickeners whose aqueous solution viscosity increases in an alkaline environment. Even in this case, the thickening retarder can remain on the surface of the concrete where it is applied and exhibit the desired set retarding effect.

[0033] Compound A may be composed of one or more of hydroxycarboxylic acid, lignosulfonic acid, phosphonic acid, humic acid and / or their salts, or sugars and polyols. Compound B may be an acrylic thickener, and may be composed of one or more thickeners whose aqueous solution viscosity at 5% active ingredient is 10 mPa·s or less at pH=5 and 200 mPa·s or more at pH=12. The weight ratio of Compound A and Compound B may be, for example, 10 / 90 to 60 / 40. The setting retarder may be, for example, a thickener that can be used to thicken concrete for 1 m of surface area of ​​concrete. 2 It may be used by spraying 150 ml to 1500 ml per spray.

[0034] (Set retarder composition) Next, an embodiment of the setting retarder composition will be described. In a first embodiment, the present invention provides a retarder composition for cement-based building materials, said composition comprising, in each case relative to the total weight of the composition: a) 3 to 13 wt % of at least one retarder selected from the group consisting of sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, lignosulfonic acids, phosphoric acids, phosphonic acids, boric acids, and salts thereof; b) 10-20 wt % of at least one thickener selected from alkali-swellable polymers, and c) The remainder is water.

[0035] A set retarder in the context of the present invention is a chemical substance or mixture of chemical substances that slows the hydration of cementitious building materials after the addition of mixing water compared to when such a set retarder is not added. In particular, set retarders affect the hydration reaction at an early age and reduce the increase in compressive strength.

[0036] The at least one retarder is present in the composition of the present invention in an amount of 3 to 13 wt %, preferably 5 to 10 wt %, particularly preferably 8 wt %, based on the total weight of the composition. According to an embodiment, the at least one retarder is selected from the group consisting of sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, lignosulfonic acids, phosphoric acids, phosphonic acids, boric acids and salts thereof.

[0037] In the present invention, sugar acids are monosaccharides having a carboxyl group, such as aldonic acid, urosonic acid, uronic acid, or aldaric acid. Aldonic acid is preferred. Examples of sugar acids useful in the present invention include, but are not limited to, glyceric acid, xylonic acid, gluconic acid, ascorbic acid, neuraminic acid, glucuronic acid, galacturonic acid, iduronic acid, tartaric acid, mucic acid, and saccharinic acid. Sugar acids may exist as free acids or as salts. In some embodiments, sugar acid salts are salts with metals from Groups IIa, IIa, IIb, IIb, IVb, and VIIIb of the Periodic Table of the Elements. Preferred sugar acid salts are salts of alkali and alkaline earth metals, iron, cobalt, copper, or zinc. Particularly preferred are salts of monovalent metals such as lithium, sodium, and potassium.

[0038] The sugar in the present invention is a carbohydrate having an aldehyde group. In a particularly preferred embodiment, the sugar belongs to the group of monosaccharides or disaccharides. Examples of sugars include, but are not limited to, glyceraldehyde, threose, erythrose, xylose, lyxose, arabinose, ribose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, fructose, sorbose, lactose, maltose, sucrose, lactulose, trehalose, cellobiose, chitobiose, isomaltose, palatinose, mannobiose, raffinose and xylobiose.

[0039] The sugar alcohol in the present invention is a polyhydric alcohol that can be derived from sugar through oxidation-reduction reaction.Therefore, sugar alcohol belongs to the class of alditol.Examples of sugar alcohols include, but are not limited to, ethylene glycol, glycerol, diglycerol, threitol, erythritol, pentaerythritol, dipentaerythritol, xylitol, ribitol, arabitol, sorbitol, sorbitan, isosorbide, mannitol, dulcitol, fucitol, iditol, inositol, volemitol, lactitol, maltitol, isomalt, maltotriitol, maltotetriitol, and polyglycitol.

[0040] In the present invention, a hydroxycarboxylic acid is a carboxylic acid containing an OH-moiety in the same molecule. Examples of hydroxycarboxylic acids include, but are not limited to, malic acid, citric acid, isocitric acid, tartaric acid, tartronic acid, mandelic acid, salicylic acid, lactic acid, tannic acid, and humic acid. Preferred hydroxycarboxylic acids are citric acid, tartaric acid, and lactic acid. Hydroxycarboxylic acids exist as free acids or salts. According to an embodiment, the salt of a hydroxycarboxylic acid is a salt with ammonium or a metal from group IIa, IIa, IIb, IIb, IVb, or VIIIb of the periodic table of the elements. Preferred salts of hydroxycarboxylic acids are alkali metal salts, alkaline earth metal salts, or ammonium salts.

[0041] The phosphoric acid of the present invention is a derivative of phosphoric acid. The phosphoric acid may be free phosphoric acid, a phosphoric acid oligomer, and / or a phosphoric acid polymer, such as diphosphate, triphosphate, or tetraphosphate. The phosphoric acid may be protonated, partially deprotonated, or fully deprotonated. Fluorinated phosphoric acid is also possible. Examples of suitable phosphoric acids are trisodium orthophosphate, tetrasodium pyrophosphate, sodium hexametaphosphate, and disodium fluorophosphate. The phosphoric acid may refer to an ester of phosphoric acid or an ester of one of its oligomers. Examples of phosphoric acid esters include, but are not limited to, mixed esters with the above-mentioned hydroxycarboxylic acids and / or sugar acids, mixed esters with carboxylic acids, especially mixed esters with fatty acids, alkyl esters, aryl esters, and esters with polyalkylene glycols.

[0042] The phosphonic acid may be mono-, di-, tri-, tetra-, penta-, or hexa-phosphonic acid, as well as their oligomers and / or esters. Preferably, the phosphonic acid has an organic functional group. The phosphonate may exist in a protonated, partially deprotonated, or fully deprotonated state. Examples of suitable phosphonic acids are 1-hydroxyethylidene-1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 3-aminopropylphosphonic acid, aminotri(methylenephosphonic acid), and diethylenetriaminoepenta(methylenephosphonic acid).

[0043] The preferred borate salts in the present invention are salts of boric acid, boric acid or borax.

[0044] Sodium gluconate as the at least one set retarder is a particularly preferred embodiment.

[0045] The at least one thickening agent is selected from alkali-swellable polymers.

[0046] It is also possible to use mixtures of different alkali-swellable polymers.The at least one thickener is present in the composition according to the invention in an amount of from 10 to 20 wt.%, preferably from 12 to 17 wt.%, relative to the total weight of the composition.

[0047] According to a preferred embodiment, at least one thickener is an alkali-swellable polymer, preferably an alkali-swellable polymer emulsion. The alkali-swellable polymer is a carboxylic acid-functional copolymer that can be produced by free-radical emulsion polymerization of ethylenically unsaturated monomers. The alkali-swellable polymer is a preferential copolymer of (meth)acrylic acid and an ester of (meth)acrylic acid. The copolymer of (meth)acrylic acid and an ester of (meth)acrylic acid may contain additional monomer units such as propylene, butadiene, styrene, vinyl chloride, vinyl alcohol, and / or an ester of vinyl alcohol, such as vinyl acetate. The most preferred copolymer in the present invention is a copolymer of methacrylic acid and an ester of acrylic acid, particularly a copolymer of methacrylic acid and an ethylene ester of acrylic acid in a molar ratio of about 1:1. The copolymer is an anionic-charged polymer. Generally, the alkali-swellable polymer has a high molecular weight, such as a number average molecular weight Mn of 10,000 to 10,000,000 g / mol, preferably 10,000 to 1,000,000 g / mol, and particularly preferably 30,000 to 500,000.

[0048] The glass transition temperature (Tg) of the alkali-swellable polymer is not particularly limited and can vary over a wide range. The Tg of the alkali-swellable polymer, measured according to ASTM D3418, is within the range of -20°C to +90°C. The alkali-swellable polymer thickens upon absorption of water and swelling, and the thickening occurs depending on the pH change from low to high. At low pH, the copolymer is insoluble in water, but becomes neutralized and soluble at high pH, ​​resulting in thickening. Mixtures of two or more alkali-swellable polymers are also possible.

[0049] Particularly preferred alkali-swellable polymers are aqueous emulsions, also known as ASE (alkali-soluble / swellable polymer emulsions). Preferred ASEs have a solids content of 10 to 40 wt%, particularly 25 to 35 wt%. The alkali-swellable polymer emulsions of the present invention exhibit effective thickening at pH >5, more preferably pH >7, and particularly pH >8.

[0050] Alkali-swellable polymers can also be hydrophobically modified. This is typically done by incorporating a small number of hydrophobic macromonomers into the polymer. Such macromonomers are esters of (meth)acrylic acid and hydrophobic alcohols, styrene derivatives, or nonionic surfactants. The molecular weight of the hydrophobically modified alkali-swellable polymer is typically lower than that of the ASE polymers mentioned above. Hydrophobically modified alkali-swellable polymers are preferentially used as aqueous emulsions, also known as HASE (hydrophobically modified alkali-soluble polymer emulsions).

[0051] Suitable ASEs and HASEs are available under the brand names Acrysol from Dow Chemical, Acryset from Nippon Shokubai, or Rheovis from BASF.

[0052] Pigments can be used to add color to the set retarder composition of the present invention. This is useful for identifying the location where the set retarder composition has already been applied during application. Suitable pigments are organic or inorganic pigments. Organic dyes can also be used. Suitable pigments are known to those skilled in the art. In one embodiment, titanium dioxide (TiO2) is used as the pigment. In another embodiment, an azo pigment is used as the pigment. In yet another embodiment, fluorescein, rhodamine, or a derivative thereof is used as the pigment. Pigments can be used in the set retarder formulation of the present invention in an amount of 1 wt% or less, based on the total weight of the set retarder composition.

[0053] In a second embodiment, the present invention relates to a retarder composition for cement-based building materials, said composition comprising: a) 3 to 13 wt% of at least one cement hydrating agent selected from the group consisting of sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, lignosulfonic acids, phosphates, phosphonic acids, borates, and salts thereof; b) 10-20 wt % of at least one thickener selected from the group consisting of alkali-swellable polymers; c) optionally 20 to 90 wt. %, preferably 50 to 90 wt. %, in particular 67 to 87 wt. % of at least one filler, d) 0-1 wt% pigment; e) Composed of 0 to 1 wt% preservative and the remainder water.

[0054] In a third embodiment, the present invention relates to a method for producing a washed finish concrete, comprising the steps of: a) contacting a surface of an unhardened cementitious building material with a set retarder composition as described above; b) allowing the cementitious building material to harden while the surface is in contact with the set retarder composition; and c) removing the set retarder composition and residual material from the concrete surface.

[0055] (Method of processing concrete joints) Next, an embodiment of the concrete joint treatment method according to the present invention will be described. The concrete joint treatment method according to this embodiment involves spraying the above-mentioned set retarder on the surface of the concrete immediately after it has been poured to adjust the setting time of the concrete. Specifically, as shown in FIG. 1, first, a set retarder having the above-mentioned functions is prepared in advance (Step S1). Next, the set retarder is sprayed immediately after the concrete is poured (Step S2). This eliminates the need to wait a predetermined time (e.g., 1 to 3 hours) after pouring is completed until bleeding settles, as in the conventional method. An example of the spraying situation is shown in FIG. 2(1).

[0056] After that, after a predetermined time has elapsed (for example, the next day), jointing processing is performed using a water jet or the like (step S3). An example of the completion of jointing processing is shown in FIG. 2(2).

[0057] As described above, according to this embodiment, the agent can be sprayed on the surface of the concrete immediately after pouring, eliminating the need for waiting time until bleeding subsides immediately after pouring. This improves the efficiency of the joint processing work. Furthermore, since it is not dependent on the shape of the concrete to be sprayed, it can be applied to the construction of various concrete structures.

[0058] (Verification of the effects of the present invention) Figure 3 compares the washout depth depending on the spray timing of the set retarder between the developed product and a conventional product. The washout depth is the depth of the concrete surface that could be removed with a high-pressure washer the day after pouring (20 hours after pouring). The conventional product shown in the legend is a conventional set retarder that is commercially available (hereinafter referred to as the commercial product), and the developed product is a set retarder to which the above-mentioned alkaline thickener has been added to this commercial product. The spraying timings are as follows: spraying immediately after pouring (spraying immediately after pouring), spraying 1 hour after pouring, spraying 2 hours after pouring, spraying 3.5 hours after pouring (standard spraying timing for commercial products), and spraying 4.5 hours after pouring. The graph for the developed product sprayed immediately after pouring corresponds to an example of the present invention, and the other graphs correspond to comparative examples.

[0059] As shown in this figure, this example (spraying immediately after pouring) achieves a washout effect equal to or greater than that of standard spraying of commercially available products, even though it is sprayed immediately after pouring. Therefore, this example makes it possible to eliminate the waiting time required immediately after pouring concrete, which was previously required. This makes it possible to improve the efficiency of the joint processing work.

[0060] As explained above, the set retarder according to the present invention is a set retarder that is applied to the surface of concrete in concrete joint processing, and when applied to the surface of concrete immediately after pouring, it remains on the surface of the concrete at the applied position and has the function of exerting a predetermined set retarding effect, so it can be sprayed on the surface of the concrete immediately after pouring, eliminating the waiting time immediately after pouring that was previously required. Therefore, the efficiency of the joint processing work can be improved.

[0061] In addition, another set retarder according to the present invention contains a main agent with a set retarding effect, and since the specific gravity of this main agent is greater than that of the bleeding water, the main agent of the applied set retarder settles in the bleeding water and is not washed away by the bleeding water. Therefore, it remains on the surface of the concrete where it is applied, and can exert the desired set retarding effect.

[0062] In addition, the set retarder according to the present invention contains a component that reacts with bleeding water or concrete to increase viscosity, so the applied set retarder does not become viscous and is not washed away by bleeding water, but remains on the surface of the concrete where it is applied, thereby achieving the desired set retarding effect.

[0063] Furthermore, another set retarder according to the present invention is a thickening set retarder composed of compound A, which has a set retarding effect, and compound B, which is one or more alkali thickening type thickeners whose aqueous solution viscosity increases in an alkaline environment, so it can remain on the surface of the concrete where it is applied and exert the desired set retarding effect.

[0064] Furthermore, according to another set retarder of the present invention, the compound A is composed of one or more of hydroxycarboxylic acid, lignosulfonic acid, phosphonic acid, humic acid and / or salts thereof, or sugars and polyols, and therefore can remain on the surface of the concrete where it is applied and exhibit a predetermined set retarding effect.

[0065] In addition, according to another set retarder of the present invention, compound B is an acrylic thickener, and is composed of one or more thickeners whose aqueous solution viscosity at 5% active ingredient is 10 mPa s or less at pH = 5 and 200 mPa s or more at pH = 12, so that it remains on the surface of the concrete where it is applied and can exert the desired set retarding effect.

[0066] In addition, according to another set retarder of the present invention, the composition of the compound A and the compound B is 10 / 90 to 60 / 40 in weight ratio, so that the retarder can remain on the surface of the concrete at the applied position and exhibit a predetermined set retarding effect.

[0067] Furthermore, according to another set retarder of the present invention, the surface area of ​​concrete is 1 m 2 It is used by spraying 150ml to 1500ml per unit, so it remains on the surface of the concrete where it is applied and can exert the desired setting retarding effect.

[0068] Furthermore, according to the concrete joint treatment method of the present invention, the above-mentioned setting retarder is applied to the surface of the concrete immediately after pouring to adjust the setting time of the concrete, thereby achieving the effect of improving the efficiency of the joint treatment work.

[0069] Furthermore, according to the concrete joint treatment method of the present invention, the above-mentioned setting retarder is applied to the surface of the concrete immediately after it is poured, thereby adjusting the setting time of the concrete, thereby making it possible to improve the efficiency of the joint treatment work. [Industrial Applicability]

[0070] As described above, the set retarder and concrete joint treatment method according to the present invention are useful for concrete joint treatment, and are particularly suitable for improving the efficiency of joint treatment work.

Claims

1. A set retarder applied to the surface of concrete in concrete joint treatment, When applied to the surface of concrete immediately after pouring, it remains on the surface of the concrete at the applied position and has the function of exerting a predetermined setting retardation effect. A thickening retarder comprising a compound A having a setting retarding effect and a compound B which is one or more alkali thickening type thickeners whose aqueous solution viscosity increases in an alkaline environment, A setting retarder characterized in that the composition of the compound A and the compound B is 10 / 90 to 60 / 40 by weight ratio.

2. 2. The setting retarder according to claim 1, comprising a base agent having a setting retarding effect, the base agent having a specific gravity greater than that of the bleeding water.

3. 3. The set retarder according to claim 1, further comprising a component that reacts with bleeding water or concrete to increase viscosity.

4. The setting retarder according to any one of claims 1 to 3, characterized in that the compound A is composed of one or more of oxycarboxylic acid, lignosulfonic acid, phosphonic acid, humic acid and / or salts thereof, or sugars and polyols.

5. The set retarder according to any one of claims 1 to 4, characterized in that the compound B is an acrylic thickener, and is composed of one or more thickeners whose aqueous solution viscosity at 5% active ingredient is 10 mPa s or less at pH = 5 and 200 mPa s or more at pH = 12.

6. Concrete surface area 1m ２ The setting retarder according to any one of claims 1 to 5, characterized in that it is used by spraying 150 ml to 1500 ml per unit time.

7. A method for treating concrete joints, comprising applying the set retarder according to any one of claims 1 to 6 to the surface of concrete immediately after pouring to adjust the setting time of the concrete.

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