JP2016107422A - Manufacturing method of curable kneaded material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a curable kneaded material for manufacturing the curable kneaded material which can be widely applied without being affected by compounding of a hydraulic setting composition and composition of admixture of a concentration reduction type and can suppress the deterioration of freeze-thaw resistance while reducing drying contraction strain of a cured body by using the admixture of a contraction reduction type.SOLUTION: A manufacturing method of a curable kneaded material for manufacturing the curable kneaded material made by kneading a hydraulic setting composition and water includes a first kneading process of kneading a hydraulic setting composition, admixture of a contraction reduction type, an antifoaming agent and water to manufacture the kneaded material and a second kneading process of kneading the kneaded material and an AE agent. Therein, in the first kneading process, used amount of the antifoaming agent is adjusted such that air amount of the kneaded material measured by JIS A 1128 (test method-air chamber pressure method using a pressure of air amount of fresh concrete) becomes less than 0.5% and, in the second kneading process, used amount of the AE agent is adjusted such that air amount of the curable kneaded material measured by JIS A 1128 (test method-air chamber pressure method using pressure of air amount of fresh concrete) becomes 5 to 7%.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a curable kneaded material for producing a curable kneaded material obtained by kneading a hydraulic composition and water.

  A curable kneaded material obtained by kneading a hydraulic composition (such as concrete) and water forms a cured product by curing with time. Since such a cured body shrinks upon drying, strain (dry shrinkage strain) is generated inside. Since such drying shrinkage strain causes a decrease in strength of the cured product, methods for reducing the drying shrinkage strain include shrinkage reducing agents and shrinkage reducing type admixtures (for example, shrinkage reducing type AE water reducing agents). Is known to be contained in a curable kneaded product.

  However, it is known that a shrinkage reducing agent or a shrinkage reducing type admixture generally reduces the freeze-thaw resistance of a cured product. For this reason, various methods for ensuring appropriate freeze-thaw resistance while using shrinkage reducing agents and shrinkage reducing type admixtures have been proposed. For example, there has been proposed a method of using a hydraulic composition in which a specific shrinkage reducing agent is used and the relationship between the unit amount of the shrinkage reducing agent and the unit amount of early-strength Portland cement is adjusted to a predetermined range (Patent Literature). 1). In addition, the blast furnace slag fine aggregate was used as a part of the hydraulic composition, and the relationship between the unit amount of the blast furnace slag fine aggregate, the unit amount of Portland cement, and the unit amount of the shrinkage reducing agent was adjusted to a predetermined range. A method using a hydraulic composition (see Patent Document 2) is known.

  Moreover, after knead | mixing curable kneaded material, water, and AE agent (air entraining agent) and forming a kneaded material, a shrinkage reducing agent is added and kneaded to this kneaded material (that is, a shrinkage reducing agent is added). A method of adjusting the timing to perform is also proposed (see Patent Document 3). In addition, a method using a shrinkage reducing agent (see Patent Documents 4 and 5) that does not reduce freeze-thaw resistance has been proposed.

JP2013-227179A JP 2012-116712 A JP 11-349367 A JP 2012-162436 A JP 2010-150085 A

  However, the methods of Patent Documents 1 and 2 are not methods that can be applied universally in various formulations of hydraulic compositions because it is necessary to adjust the formulation of the hydraulic composition to a predetermined one. Further, in the method of Patent Document 3, it is difficult to adjust the amount of air in the hard material, and appropriate freeze-thaw resistance cannot be obtained. Furthermore, since the shrinkage reducing agents of References 4 and 5 are configured to impart freeze-thaw resistance, it is difficult to use them in various hydraulic compositions as a general-purpose shrinkage reducing agent.

  Therefore, the present invention can be applied universally without being affected by the composition of the hydraulic composition and the composition of the shrinkage-reducing admixture, and the cured product can be dried using the shrinkage-reducing admixture. It is an object of the present invention to provide a method for producing a curable kneaded material for producing a curable kneaded material capable of suppressing a decrease in freeze-thaw resistance while reducing shrinkage strain.

  A method for producing a curable kneaded material according to the present invention is a method for producing a curable kneaded material for producing a curable kneaded material obtained by kneading a hydraulic composition and water, the hydraulic composition and A first kneading step of kneading a shrinkage-reducing admixture, an antifoaming agent, and water to produce a kneaded product; and a second kneading step of kneading the kneaded product and an AE agent. In the process, the amount of the antifoaming agent used is such that the amount of air in the kneaded material measured by JIS A 1128 (test method using air pressure of fresh concrete-air chamber pressure method) is less than 0.5%. In the second kneading step, the air amount of the curable kneaded material measured by JIS A 1128 (test method using air pressure of fresh concrete-air chamber pressure method) is 5 to 7%. The amount of AE agent used must be adjusted And features.

  According to such a configuration, by using the shrinkage-reducing admixture in the first kneading step, it is possible to reduce the drying shrinkage strain generated in the cured body obtained by curing the curable kneaded product. In addition, bubbles (hereinafter also referred to as first bubbles) are entrained in the kneaded product by using the shrinkage-reducing admixture. However, the defoaming agent is used in the first kneading step, so that the kneading is performed. The content of the first bubbles in the product is reduced to the above range. In the second kneading step, such a kneaded product and the AE agent are kneaded, so that a curable kneaded product containing bubbles entrained by the AE agent (hereinafter also referred to as second bubbles) in the above range is obtained. It is formed. That is, by using the antifoaming agent together with the shrinkage-reducing admixture in the first kneading step, it is possible to obtain a curable kneaded material in which the ratio of the first bubbles to the second bubbles is reduced.

  Here, the freeze-thaw resistance of the cured body decreases as the content of the first bubbles in the curable kneaded product increases. However, as described above, the ratio of the first bubbles to the second bubbles in the curable kneaded material is reduced, thereby freezing due to the use of the shrinkage-reducing admixture (that is, due to the inclusion of the first bubbles). A decrease in melting resistance can be suppressed.

  As described above, by performing the first kneading step and the second kneading step, the drying shrinkage strain of the cured product is reduced by using the shrinkage-reducing admixture, while the shrinkage-reducing admixture is used. Decrease in freeze-thaw resistance of the cured product can be suppressed. In addition, since it is possible to achieve both reduction of drying shrinkage strain and suppression of decrease in freeze-thaw resistance without being affected by the composition of the hydraulic composition and the composition of the shrinkage-reducing admixture, The method of the present invention can be applied universally to hard compositions and shrinkage-reducing admixtures of various compositions.

  As described above, according to the present invention, the present invention can be applied universally without being affected by the composition of the hydraulic composition and the composition of the shrinkage-reducing admixture, and the shrinkage-reducing admixture is used. Thus, it is possible to suppress a decrease in freeze-thaw resistance while reducing the drying shrinkage strain of the cured product.

  Hereinafter, embodiments of the present invention will be described.

  The method for producing a curable kneaded product according to the present invention is a method for producing a curable kneaded product obtained by kneading a hydraulic composition and water. Specifically, the method for producing a curable kneaded product according to the present invention includes a first kneading step of producing a kneaded product by kneading a hydraulic composition, a shrinkage-reducing admixture, an antifoaming agent, and water. And a second kneading step of kneading the kneaded product and the AE agent.

  The hydraulic composition used in the first kneading step is not particularly limited, and is composed of a hydraulic material that is hardened by contact with moisture and a coarse aggregate and / or fine aggregate ( Specific examples include concrete and mortar.

  The hydraulic material is not particularly limited. For example, ordinary Portland cement, early-strength Portland cement, ultra-early strength Portland cement, moderately hot Portland cement, low heat Portland cement, sulfate-resistant Portland cement, white Portland cement, etc. Various portland cements, blast furnace cement, silica cement, fly ash cement, eco cement, alumina cement, super-hard cement, grout cement, oil well cement, and the like. These can be used alone or in any combination.

  The coarse aggregate is not particularly limited, and examples thereof include mountain gravel, sea gravel, river gravel, crushed stone, limestone, blast furnace slag coarse aggregate, recycled coarse aggregate, lightweight coarse aggregate, and the like. The fine aggregate is not particularly limited. For example, land sand, mountain sand, sea sand, river sand, crushed sand, quartz sand, blast furnace slag fine aggregate, ferronickel slag fine aggregate, copper slag fine bone. Materials, electric furnace oxidation slag fine aggregates, ferrochrome fine aggregates, recycled fine aggregates, lightweight fine aggregates and the like.

  The shrinkage-reducing admixture is not particularly limited, but is preferably one that does not significantly adversely affect the strength of the cured product obtained by curing the curable kneaded product. For example, a polyglycol derivative, a glycol ether type Derivatives, polyether derivatives, polyalkylene glycol derivatives and the like may be mentioned, and a water reducing agent / AE water reducing agent containing these may be used. The shrinkage-reducing admixture may function as a water reducing agent or may not function as a water reducing agent.

  The antifoaming agent is not particularly limited, but is preferably one that does not adversely affect the strength and durability of the cured product, for example, a silicone-based antifoaming agent, a nonionic antifoaming agent, an alcohol-based antifoaming agent. , Fatty acid-based antifoaming agents, ether-based antifoaming agents, fatty acid ester-based antifoaming agents, phosphate ester-based antifoaming agents, polyether-based antifoaming agents, fluorine-based antifoaming agents, and the like.

  The AE agent is not particularly limited. For example, air entrainment capable of entraining fine closed cells in the kneaded product obtained in the first kneading step and entraining closed cells having a diameter of 250 μm or less, preferably 200 μm or less. Agents. Specifically, polyoxyalkylene alkyl ether sulfate, alkylbenzene sulfonate, polyoxyethylene alkylbenzene sulfonate, rosin soap, higher fatty acid soap, alkyl phosphate ester salt, polyoxyalkylene alkyl ether phosphate salt, JIS AE agent prescribed | regulated to A6204 etc. are mentioned.

  Examples of water include tap water, industrial water, ground water, river water, rain water, distilled water, and high-purity water for chemical analysis (ultra pure water, pure water, ion exchange water), and the like. In addition, it is preferable that water does not contain impurities, such as an organic substance, a chloride ion, a sodium ion, a potassium ion, which have a bad influence on the hydration reaction of a hydraulic material.

  The curable kneaded material may contain various admixtures. For example, a high-performance water reducing agent, a curing accelerator, a water reducing agent, an AE water reducing agent compatible with JIS A 6204 “Chemical admixture for concrete”. And high performance AE water reducing agent and fluidizing agent.

  In addition, the kneading apparatus used in the kneading operation in the first kneading step and the second kneading step is not particularly limited, and a biaxial mixer, a uniaxial mixer, a pan mixer, etc. A known mixer such as a gravitational mixer can be used.

  As described above, according to the method for producing a curable kneaded product according to the present invention, it can be applied universally without being influenced by the composition of the hydraulic composition and the composition of the shrinkage-reducing admixture. The decrease in freeze-thaw resistance can be suppressed while reducing the drying shrinkage strain of the cured product using a shrinkage-reducing admixture.

  Specifically, by using a shrinkage-reducing admixture in the first kneading step, it is possible to reduce drying shrinkage strain generated in a cured product obtained by curing the curable kneaded product. In addition, bubbles (hereinafter also referred to as first bubbles) are entrained in the kneaded product by using the shrinkage-reducing admixture. However, the defoaming agent is used in the first kneading step, so that the kneading is performed. The content of the first bubbles in the object is reduced. In the second kneading step, such a kneaded product and the AE agent are kneaded, so that a curable kneaded product containing bubbles entrained by the AE agent (hereinafter also referred to as second bubbles) is formed. That is, by using the antifoaming agent together with the shrinkage-reducing admixture in the first kneading step, it is possible to obtain a curable kneaded material in which the ratio of the first bubbles to the second bubbles is reduced.

  Here, the freeze-thaw resistance of the cured body decreases with an increase in the content of the first bubbles (bubbles coarser than the second bubbles) in the curable kneaded product. However, as described above, the ratio of the first bubbles to the second bubbles (bubbles finer than the first bubbles) in the curable kneaded material is reduced, which results from the use of the shrinkage-reducing admixture ( That is, it is possible to suppress a decrease in freeze-thaw resistance (due to the inclusion of the first bubbles).

  As described above, by performing the first kneading step and the second kneading step, the drying shrinkage strain of the cured product is reduced by using the shrinkage-reducing admixture, while the shrinkage-reducing admixture is used. Decrease in freeze-thaw resistance of the cured product can be suppressed. In addition, since it is possible to achieve both reduction of drying shrinkage strain and suppression of decrease in freeze-thaw resistance without being affected by the composition of the hydraulic composition and the composition of the shrinkage-reducing admixture, The method of the present invention can be applied universally to hard compositions and shrinkage-reducing admixtures of various compositions.

  In the first kneading step, the amount of air (the amount of first bubbles) in the kneaded material measured by JIS A 1128: 2005 (test method using air pressure of fresh concrete-air chamber pressure method) is 0.00. The amount of antifoaming agent used is adjusted to be less than 5% (preferably less than 0.1%, more preferably 0%). Further, in the second kneading step, the air amount (second bubble amount) of the curable kneaded material measured by JIS A 1128: 2005 (test method using air pressure of fresh concrete-air chamber pressure method) is 5 The amount of the AE agent used is adjusted to be -7% (preferably 5-6%). Thereby, the freeze-thaw resistance of the hardening body formed by hardening | curing the curable kneaded material obtained can be obtained.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<Materials used>
1. Hydraulic materials / ordinary pordoland cement:
(Sumitomo Osaka Cement, JIS R 5210 compliant product, density = 3.15 g / cm ³ , C ₃ S content = 56 mass%, C ₂ S content = 17 mass%, Al ₂ O ₃ content = 5 2% by mass, SO ₃ content = 1.9% by mass, Blaine specific surface area = 3400 cm ² / g, maximum particle size = 45 μm or less)

2. Water and tap water:
(Funabashi, Chiba)

3. Chemical admixture / AE water reducing agent:
(Manufactured by BASF Japan, product name: Pozzolith 15S, complex of lignin sulfonic acid compound and polycarboxylic acid ether, conforming to JIS A 6204)

・ Shrinkage-reducing admixture:
Shrinkage-reducing AE water reducing agent (manufactured by BASF Japan, product name: polyhide 15DS, complex of polycarboxylic acid ether compound and polyglycol derivative, JIS A 6204 compliant product)

・ AE agent:
(Manufactured by BASF Japan, product name: micro air 202, modified rosin acid compound anionic surfactant, JIS A 6204 compliant product)

・ Antifoaming agent:
(Manufactured by BASF Japan, product name: micro air 404, polyalkylene glycol derivative)

4). Coarse aggregate 1
・ Crushed stone 1505 from Kamiyama, Yamagata Prefecture:
(Table dry density = 2.68 g / cm ³ , water absorption = 2.57%, JIS A 5005 crushed stone 1505 compliant product)

5. Coarse aggregate 2
・ Crushed stones from Kamiyama, Yamagata Prefecture 2010:
(Table dry density = 2.65 g / cm ³ , water absorption = 2.17%, JIS A 5005 crushed stone 2010 compliant product)

6). Fine aggregate 1
・ Rough sand from Nagai, Yamagata Prefecture:
(Table dry density = 2.54 g / cm ³ , water absorption = 1.91%, conforms to gravel and sand in Annex A of JIS A 5308)

7). Fine aggregate 2
・ Fine sand from Sakata, Yamagata Prefecture:
(Surface dry density = 2.58 g / cm ³ , water absorption = 2.31%, suitable for gravel and sand in Annex A of JIS A 5308)

<Examples 1-3>
1. Preparation of Specimens Specimens used for the following measurements and tests were prepared. Specifically, a hydraulic composition composed of each of the above materials, the above water, the above-mentioned shrinkage-reducing AE water reducing agent, and the above antifoaming agent were kneaded to form a kneaded product. (First kneading step). Then, a curable kneaded material is prepared by adding the AE agent to the kneaded material and kneading (second kneading step), and using the curable kneaded material, a test specimen (in accordance with JIS A 1132) Specifically, a concrete specimen was prepared.

  The composition of each material constituting the hydraulic composition is as shown in Table 1 below. Moreover, the mixing | blending of the water with respect to each material which comprises a hydraulic composition is as showing in following Table 1. Further, the ratio (C ×%) to the hydraulic material in each of the shrinkage-reducing type AE water reducing agent, antifoaming agent and AE agent is as shown in Table 2 below. “W / C” in Table 1 below is the ratio of water to the hydraulic material, and “s / a” is the ratio of fine aggregate to the total amount of coarse aggregate and fine aggregate. The kneading in the first kneading step and the second kneading step was performed using a biaxial forced kneading mixer manufactured by Taiheiyo Kiko Co., Ltd.

2. Measurement of air amount JIS A 1128: 2005 (Test method by pressure of air amount of fresh concrete) The air amount of the kneaded material formed in the first kneading step and the air amount of the curable kneaded material formed in the second kneading step -Measured based on air chamber pressure method). The measurement results are shown in Table 2 below.

3. Durability Index A freezing and thawing test based on JIS A 1148 “Concrete Freezing and Thawing Test” (Method A) was performed on each of the above specimens, and the durability index of each specimen was calculated. The durability index of each specimen is shown in Table 3 below.

4). Drying Shrinkage Strain Tests based on JIS A 1129-2 “Measurement method for mortar and concrete length change—Part 2” were performed on each of the above specimens, and the dry shrinkage strain of each specimen was calculated. The drying shrinkage strain of each specimen is shown in Table 3 below.

5. Compressive strength A test based on JIS A 1108 “Method for testing compressive strength of concrete” was performed on each of the above specimens, and the compressive strength of each specimen was obtained. The compressive strength of each specimen is shown in Table 3 below. In addition, the compression strength ratio shown in Table 3 is a ratio of the compression strength of each Example and each Comparative Example to Comparative Example 1.

6). Inter-bubble coefficient The inter-bubble coefficient was calculated based on ASTM C 457 (linear traverse method) for each of the above specimens. The bubble spacing coefficient of each specimen is shown in Table 3 below.

<Comparative Example 1>
Except that a curable kneaded material was prepared by kneading a hydraulic composition, water, an AE water reducing agent, and an AE agent at the same time, a specimen was prepared in the same manner as each of the upper examples, and each measurement and test was performed. Went.

<Comparative Examples 2 and 3>
Except not having used an antifoamer, the test body was produced by the same method as each Example of the high-order, and each measurement and test were performed.

<Comparative Examples 4-6>
Specimens were prepared in the same manner as in the upper examples, except that the amount of air in the first kneading step and the second kneading step was as described in Table 2 below, and each measurement and test was performed.

<Comparative Examples 7 and 8>
Except that a curable kneaded material was prepared by simultaneously kneading a hydraulic composition, water, a shrinkage-reducing AE water reducing agent and an AE agent, a specimen was prepared in the same manner as in each of the upper examples, Each measurement and test was performed.

<Comparative Examples 9-11>
Specimens in the same manner as in the upper examples, except that a curable kneaded material was prepared by simultaneously kneading a hydraulic composition, water, a shrinkage-reducing AE water reducing agent, an antifoaming agent, and an AE agent. Were prepared, and each measurement and test were performed.

<Summary>
As shown in Table 3, when Comparative Example 1 is compared with each example and other comparative examples, it is recognized that each example and other comparative examples have less drying shrinkage strain. That is, the shrinkage-reducing AE water reducing agent is used like the curable kneaded material produced by the methods of the examples and other comparative examples, thereby reducing the drying shrinkage strain of the formed cured product. It is recognized that

  Moreover, as shown in Table 3, when Comparative Examples 2, 3, 7, and 8 were compared with each Example, each Example had a smaller bubble spacing coefficient than Comparative Examples 2, 3, 7, and 8, It can be seen that the durability index is high. Here, a smaller bubble spacing coefficient means higher freeze-thaw resistance, and a higher durability index means higher freeze-thaw resistance. That is, in each of the first kneading steps, a defoamed material was formed in the first kneading step as in each example, and in the second kneading step, the AE agent was added to the kneaded material and kneaded. Thus, a curable kneaded material that can improve the freeze-thaw resistance of the cured product can be obtained as compared to the case where no antifoaming agent is used.

  Moreover, as shown in Table 3, when Comparative Examples 9-11 are compared with each Example, each Example has a smaller bubble spacing coefficient and a higher durability index than Comparative Examples 9-11. Is recognized. That is, in each of the first kneading steps as in each example, a defoamed material was formed to form a kneaded product, and in the second kneading step, the AE agent was added to the kneaded material and kneaded. Thus, a curable kneaded material that can improve the freeze-thaw resistance of the cured product can be obtained as compared with the case where a defoaming agent and an AE agent are simultaneously kneaded to form a curable kneaded material.

  Moreover, as shown in Table 3, when Comparative Examples 4 to 6 and each Example are compared, the durability index of each Example exceeds 60. That is, as in each example, by setting the amount of air in the first kneading step and the second kneading step within the scope of the present invention, a curable kneaded material that can form a cured body exhibiting freeze-thaw resistance is obtained. Can do.

Claims (1)

A method for producing a curable kneaded material for producing a curable kneaded material obtained by kneading a hydraulic composition and water,
A first kneading step of kneading a hydraulic composition, a shrinkage-reducing admixture, an antifoaming agent and water, and a second kneading step of kneading the kneaded material and an AE agent. ,
In the first kneading step, an antifoaming agent is used so that the amount of air in the kneaded product measured by JIS A 1128 (test method using air pressure of fresh concrete-air chamber pressure method) is less than 0.5%. Usage is adjusted,
In the second kneading step, the air content of the AE agent is adjusted so that the air amount of the curable kneaded material measured by JIS A 1128 (test method using air pressure of fresh concrete-air chamber pressure method) is 5 to 7%. A method for producing a curable kneaded product, characterized in that the amount used is adjusted.