JP2012200947A - Production method of concrete with improved flowability, and concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce concrete with improved flowability without increasing paste (unit water amount or unit cement amount).SOLUTION: A mixture of water, cement, fine aggregates and coarse aggregates is used as cement concrete to be a base so that a slump value of ≥8 cm and ≤12 cm is achieved, and by kneading an admixture in which a thickener and a high performance AE water reducer are mixed, in the cement concrete, the flowability of the cement concrete is improved, and the slump value of >18 cm and ≤23 cm is obtained. As a thickener, the thickener containing glycol based, acrylic based and biopolymer based components are suitably used. As the high performance AE water reducer agent, a water reducer containing a polycarboxylic acid based component is suitably used.

Description

  The present invention relates to a method for producing concrete with increased fluidity without increasing the amount of paste, and a concrete structure constructed with this concrete.

  By reviewing the seismic design standards, rebars are arranged in high density even in general concrete such as viaduct substructures and box culverts. In particular, since the reinforcing bars of each member cross at the joint between the members, in the case of ordinary concrete (slump 8 cm to 12 cm) specified in the specifications of each ordering organization in a densely packed arrangement, the concrete is homogeneous. It is difficult to fill in a dense state, and there is a risk of defects such as beans.

  Generally, the concrete shown in the following (1) to (3) is used in order to surely fill the concrete even under such overcrowded reinforcement. That is, (1) concrete in which the unit water amount is increased in order to increase fluidity compared to ordinary concrete, and the unit amount of fine powder such as cement is increased in order to ensure material separation resistance accompanying the increase in fluidity; (2) Fluidized concrete obtained by adding a fluidizing agent to ordinary concrete; (3) High fluidity concrete that controls fluidity by slump flow is used. In addition, (4) special admixtures (such as coal ash) may be used.

  For example, Patent Document 1 discloses a method for lining concrete using medium-fluidity concrete (with a slump flow of 35 cm or more and 50 cm or less) that is superior in fluidity to ordinary concrete and easier in quality control than high-fluidity concrete. Are listed. The medium fluidity concrete described in this document is considered to be medium fluidity concrete belonging to the above (4) because an admixture such as stone powder or coal ash is used.

JP 2008-285843 A

  Consider the case of producing concrete with high fluidity in a general raw cleat factory. Here, when the unit cement amount and the unit water amount are increased as in (1) above (that is, when the paste amount is increased), the possibility of temperature cracking due to the heat of hydration accompanying the increase in the unit cement amount There is a problem that becomes high. There is also a problem that the possibility of cracking due to drying shrinkage increases as the unit water amount increases. Therefore, in the Japan Society of Civil Engineers, the amount of slump increase by the fluidizing agent is 5 to 8 cm as a standard. Furthermore, there is a problem in that there is a high possibility that the water tightness and durability of the structure will be reduced due to increased bleeding and cracking due to sedimentation.

  As described in (2) above, fluidized concrete using a fluidizing agent to improve fluidity has the following problems. According to the Japan Society of Civil Engineers standard, the slump of fluidized concrete is 18 cm in principle, and may not be filled with the above-described high-density reinforcing bar. In addition, when excessive slump is increased (increased fluidity) by the fluidizing agent, material separation occurs, and the water tightness and durability of the concrete may be reduced. Furthermore, noise and exhaust gas due to drum agitation when a fluidizing agent is mixed into an agitator vehicle on site will adversely affect the surrounding environment.

  When using high fluidity concrete in which fluidity is controlled by slump flow as in (3) above, there is a problem that the possibility of temperature cracking due to heat of hydration increases as the amount of unit cement increases. is there. Further, as described in (4) above, when a special admixture is used, there is a problem that a dedicated silo or a measuring instrument is required and the cost is increased.

  This invention is made | formed in view of such a situation, The main objective is to manufacture the concrete which improved fluidity | liquidity, without increasing paste (amount of unit water and unit cement amount).

  In order to solve the above-mentioned problems, the present invention is a method for producing a concrete having improved fluidity by mixing an admixture with cement concrete, and the cement concrete has a slump value of 8 cm or more and 12 cm or less. Water, cement, fine aggregate and coarse aggregate are blended, and the admixture is blended with a thickener and a high performance AE water reducing agent, and the cement concrete and the admixture The slump value is greater than 18 cm and not greater than 23 cm.

  According to the present invention, since the admixture in which the thickener and the high-performance AE water reducing agent are blended is used, the slump value can be made larger than 18 cm and smaller than 23 cm even in the case of blending with ordinary concrete. it can. That is, it is possible to produce concrete with improved fluidity without increasing the paste. As a result, generation of heat of hydration can be suppressed and the possibility of temperature cracking can be reduced as compared with concrete whose fluidity is increased by increasing the paste.

  In the above production method, the thickener is preferably selected from any one of a glycol thickener, an acrylic thickener, and a biopolymer thickener.

  In addition, the concrete structure according to the present invention is characterized by being constructed of concrete whose fluidity is improved by the above-described manufacturing method.

  According to the present invention, since an admixture having a water-reducing property and a thickening property is used, concrete with improved fluidity can be produced without increasing the paste. As a result, the amount of heat of hydration can be reduced and the possibility of temperature cracking can be reduced compared to concrete whose fluidity has been increased by increasing the paste.

It is a figure explaining the material and compounding ratio which are contained in each test body made into the test object. It is a figure explaining the detail of each material which comprises concrete. It is a figure explaining the result of a filling test. It is a figure explaining the result of a bleeding test. It is a figure explaining the result of a setting time test. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 1. FIG. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 2. FIG. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 2-2. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 3. FIG. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 4. FIG. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 5. FIG. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 6. FIG. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 7. FIG. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 7-2. It is a figure explaining the mode of the slump test with respect to the test body of the mixing | blending 8. FIG.

  Hereinafter, embodiments of the present invention will be described. In this embodiment, the properties of ready-mixed concrete were grasped by performing a filling test, a bleeding test, a setting time test, and a slump test on each of the test specimens No1 to No8 having the composition shown in FIG.

  First, the materials used in this test will be described. The materials used are shown in FIG.

As the cement (C), ordinary Portland cement manufactured by Taiheiyo Cement Co., Ltd. was used. The density of this ordinary Portland cement is 3.16 g / cm ³ . As the fine aggregate (S), land sand produced in Kisarazu, Chiba Prefecture was used. In this land sand, the surface dry density is 2.62 g / cm ³ , the water absorption is 1.39%, and the coarse particle ratio is 2.81. As the coarse aggregate (G), crushed stone produced in Ome, Tokyo was used. In this crushed stone, the surface dry density is 2.65 g / cm ³ , the water absorption is 1.00%, and the coarse particle ratio is 6.64.

  Regarding the admixture, the trade name “Pozoris No. 70” manufactured by BASF Pozzolith was used as the comparative AE water reducing agent (WR). This AE water reducing agent has a lignin sulfonic acid compound as a main component and is in a liquid state.

  Three types of high-performance AE water reducing agents (VA) containing a thickener component were used. The first type (VA1) is a trade name “Mighty 3000V” manufactured by Kao Corporation. This high-performance AE water reducing agent is a high-performance AE water reducing agent containing a glycol-based thickener component. The second type (VA2) is a trade name “Guronium” manufactured by BASF Pozzolith. This high-performance AE water reducing agent is a high-performance AE water reducing agent containing an acrylic thickener component. The third type (VA3) is a trade name “ADVA-FLOW” manufactured by Grace Chemicals. This high-performance AE water reducing agent is a high-performance AE water reducing agent containing a biopolymer thickener component.

  Moreover, the high performance AE water reducing agent which does not contain a thickener component was used as a comparative fluidizing agent (SP). In this embodiment, a trade name “Reobuild SP-8SV” manufactured by BASF Pozzolith is used. This fluidizing agent has a polycarboxylic acid compound as a main component and is in a liquid state.

  The above-mentioned high-performance AE water reducing agents (VA1 to 3) are also polycarboxylic acid-based high-performance AE water reducing agents. Other high-performance AE water reducing agents include naphthalene-based, melamine-based, and aminosulfonic acid-based ones, and all of them have lower water reduction than polycarboxylic acid-based high-performance AE water reducing agents. Moreover, since it has a setting delay property, it takes time to solidify. Therefore, in this embodiment, a polycarboxylic acid-based high-performance AE water reducing agent is used.

  In addition, as a AE assistant, a trade name “Micro Air 775S” manufactured by BASF Pozzolith was used. This AE auxiliary agent has a modified alkyl carbic acid compound-based anionic surfactant as a main component and is in a liquid form.

  Next, each specimen will be described with reference to FIG.

  In this test, a total of 10 types of test specimens composed of Formulations 1 to 8 (two types for Formulations 2 and 7) were produced. For convenience, in the following description, the formulation No. and the test specimen No. are aligned. For example, test body No1 means a test body made with formulation No1, and test body No7-2 means a test body made with formulation No7-2.

  A biaxial forced kneading mixer was used for the preparation of the test body. The kneading was carried out batchwise, and the kneading amount was 50 L per batch. For kneading, the aggregate and powder were added and kneaded for 10 seconds, and then the admixture and water were added and kneaded. The kneading time was 60 seconds for the test bodies using the AE water reducing agent (test bodies No1, No6, No8), and 90 seconds for the test bodies using the high-performance AE water reducing agent (other No test specimens). . After kneading, the mixture was allowed to stand for 3 minutes, and kneaded to perform various tests.

Each of the test bodies No1 to No5 is based on plain concrete with a slump of 8 cm, which is a slump of 21 cm or a slump of 23 cm. On the other hand, specimens Nos. 6 to 8 are all based on plain concrete with a slump of 12 cm, which is slump 21 cm or slump 23 cm. In addition, as compounding conditions of highly filled concrete, a unit water amount is 175 kg / m ³ or less, a unit cement amount is 270 kg / m ³ or more, and a water cement ratio is 60% or less. Hereinafter, the blending of each specimen is specifically described.

Specimen No1 is a comparative example and shows a blend of plain concrete with a slump of 8 cm. In this test body No1, the unit amount of water (W) is 155 kg / m ³ , the unit amount of cement (C) is 270 kg / m ³ , the unit amount of fine aggregate (S) is 824 kg / m ³ , and coarse aggregate The unit amount of (G) is 1060 kg / m ³ . As an admixture, AE water reducing agent (WR) is mixed in 0.25% of the cement amount, and AE auxiliary agent (AE) is mixed in 0.004% of the cement amount. The water cement ratio (W / C) is 57.4, the fine aggregate rate (s / a) is 44.0, the paste volume per unit amount (Vp) is 285 L / m ³ , and the coarse bone per unit amount The material volume (Vg) is 400 L / m ³ .

Specimen No. 2 is an example of a high-performance AE water reducing agent (VA1) containing a glycol-based thickener component, and is blended to make the slump from 8 cm to 21 cm. In this test body No2, the unit amount of water (W) is 155 kg / m ³ , the unit amount of cement (C) is 270 kg / m ³ , the unit amount of fine aggregate (S) is 955 kg / m ³ , and coarse aggregate The unit amount of (G) is 928 kg / m ³ . As the admixture, the above thickener-containing high performance AE water reducing agent (VA1) is mixed in 1.5% of the cement amount, and AE auxiliary (AE) is mixed in 0.0035% of the cement amount. The water cement ratio (W / C) is 57.4, the fine aggregate rate (s / a) is 51.0, the paste volume per unit amount (Vp) is 285 L / m ³ , and the coarse bone per unit amount The material volume (Vg) is 350 L / m ³ .

  Specimen No2-2 is an example of a high-performance AE water reducing agent (VA1) containing a glycol-based thickener component similar to Specimen No2, but tested in terms of blending the slump from 8 cm to 23 cm. It is different from the body No2. In this test body No. 2-2, 1.7% of the cement amount is mixed with the thickener-containing high performance AE water reducing agent (VA1), and 0.004% of the cement amount is mixed with the AE auxiliary agent (AE). Other blends are the same as those of the specimen No2.

Specimen No. 3 is an example of a high performance AE water reducing agent (VA2) containing an acrylic thickener component, and is blended to make the slump from 8 cm to 21 cm. In this test body No3, the unit amount of water (W) is 155 kg / m ³ , the unit amount of cement (C) is 270 kg / m ³ , the unit amount of fine aggregate (S) is 955 kg / m ³ , and coarse aggregate The unit amount of (G) is 928 kg / m ³ . As the admixture, the above thickener-containing high-performance AE water reducing agent (VA2) is mixed in 2.0% of the cement amount, and AE auxiliary (AE) is mixed in 0.0035% of the cement amount. The water cement ratio (W / C) is 57.4, the fine aggregate rate (s / a) is 51.0, the paste volume per unit amount (Vp) is 285 L / m ³ , and the coarse bone per unit amount The material volume (Vg) is 350 L / m ³ .

Specimen No. 4 is an example of a high-performance AE water reducing agent (VA3) containing a biopolymer thickener component, and is blended so that the slump is 8 cm to 21 cm. In this test body No3, the unit amount of water (W) is 155 kg / m ³ , the unit amount of cement (C) is 270 kg / m ³ , the unit amount of fine aggregate (S) is 955 kg / m ³ , and coarse aggregate The unit amount of (G) is 928 kg / m ³ . As the admixture, the above thickener-containing high-performance AE water reducing agent (VA3) is mixed with 1.4% of the cement amount, and AE auxiliary agent (AE) is mixed with 0.002% of the cement amount. The water cement ratio (W / C) is 57.4, the fine aggregate rate (s / a) is 51.0, the paste volume per unit amount (Vp) is 285 L / m ³ , and the coarse bone per unit amount The material volume (Vg) is 350 L / m ³ .

  Specimen No5 is a comparative example. Based on Specimen No1 (mixture of ordinary concrete with slump of 8 cm), a fluidizing agent (high-performance AE not containing a thickener component) is used to make the slump from 8 cm to 21 cm. Water-reducing agent; SP) is added afterwards. For this reason, the unit amount of water (W), cement (C), fine aggregate (S), and coarse aggregate (G) is the same as that of specimen No1. And the fluidizing agent (SP) is added 1.20% of the cement amount.

Specimen No. 6 is also a comparative example and shows a blend of ordinary concrete with a slump of 12 cm. In this specimen No. 6, the unit amount of water (W) is 162 kg / m ³ , the unit amount of cement (C) is 270 kg / m ³ , the unit amount of fine aggregate (S) is 832 kg / m ³ , and coarse aggregate The unit amount of (G) is 1033 kg / m ³ . As an admixture, AE water reducing agent (WR) is mixed in 0.25% of the cement amount, and AE auxiliary agent (AE) is mixed in 0.004% of the cement amount. The water cement ratio (W / C) is 60.0, the fine aggregate rate (s / a) is 44.9, the paste volume per unit amount (Vp) is 292 L / m ³ , and the coarse bone per unit amount The material volume (Vg) is 390 L / m ³ .

Specimen No7 is an example of a high-performance AE water reducing agent (VA1) containing a glycol-based thickener component, and is blended to make the slump from 12 cm to 21 cm. In this test body No7, the unit amount of water (W) is 162 kg / m ³ , the unit amount of cement (C) is 270 kg / m ³ , the unit amount of fine aggregate (S) is 936 kg / m ³ , and the coarse aggregate The unit amount of (G) is 928 kg / m ³ . As the admixture, the above thickener-containing high-performance AE water reducing agent (VA1) is mixed with 1.3% of the cement amount, and AE auxiliary agent (AE) is mixed with 0.003% of the cement amount. The water cement ratio (W / C) is 60.0, the fine aggregate ratio (s / a) is 50.5, the paste volume per unit amount (Vp) is 292 L / m ³ , and the coarse bone per unit amount The material volume (Vg) is 350 L / m ³ .

  Specimen No7-2 is an example of a high-performance AE water reducing agent (VA1) containing a glycol-based thickener component similar to Specimen No7, but tested in terms of blending slump from 12 cm to 23 cm. It is different from body No7. In this specimen No. 7-2, the thickener-containing high-performance AE water reducing agent (VA1) is mixed in 1.5% of the cement amount, and the AE auxiliary agent (AE) is mixed in 0.004% of the cement amount. Other blends are the same as those of the test body No7.

Specimen No. 8 is a comparative example and shows a concrete mix of 21 cm slump. In the specimen No8, water unit amount (W) is 180 kg / ^{m 3,} the cement unit amount of (C) is 314kg / ^{m 3,} the unit amount of 853kg / ^{m 3} of fine aggregate (S), coarse aggregate The unit amount of (G) is 928 kg / m ³ . As an admixture, AE water reducing agent (WR) is mixed in 0.25% of the cement amount, and AE auxiliary agent (AE) is mixed in 0.004% of the cement amount. The water cement ratio (W / C) is 57.4, the fine aggregate ratio (s / a) is 48.2, the paste volume per unit amount (Vp) is 324 L / m ³ , and the coarse bone per unit amount The material volume (Vg) is 350 L / m ³ .

  Hereinafter, each test will be described. First, the fillability test will be described. In the filling test, a test container having a chamber A and a chamber B partitioned by a partition is used, the partition is opened in a state in which the concrete to be tested is filled in the chamber A, and the concrete flows through a specified distance in the chamber B. Measure the time until. In this fillability test, it can be said that the shorter the time until the specified distance flows, the better the fillability.

  In this embodiment, 18.36 L (42.4 kg) of concrete was put into the A room. The rod-like vibrator (φ28 mm) was inserted while vibrating. After opening the partition, the time until the concrete flows 30 cm was measured. In addition, the filling property test was done about eight types of test bodies except test body No2-2 and No7-2. Hereinafter, the test results will be described.

  Please refer to FIG. 1B and FIG. In addition, the temperature (degreeC) in FIG.1 (b) is a test temperature in each test. As shown in FIG. 1 (b) and FIG. 3, the filling time for specimen No1 (concrete with slump 8 cm) was 68.1 seconds, and the filling time for specimen No6 (concrete with slump 12 cm) was 46.4 seconds. , And the filling time with specimen No. 8 (concrete of slump 21 cm) is 26.5 seconds. As described above, the shorter the filling time, the better the filling property. For this reason, if the filling time is around 26.5 seconds, it can be said that there is a filling property equivalent to that of concrete having a slump of 21 cm.

  The filling time for specimen No. 2 (flowable concrete using VA1) is 31.1 seconds, the filling time for specimen No. 3 (fluid concrete using VA2) is 23.8 seconds, and specimen No. 4 (using VA3) The filling time with fluid concrete is 29.0 seconds. In either case, the filling time for test body No1 is significantly shorter than 68.1 seconds, which is a value around the filling time for test body No8. From this, it can be said that the test bodies No2 to No4 have the same filling property as the concrete of the slump 21 cm.

  The filling time for specimen No. 5 (fluidized concrete added after SP) is 31.8 seconds, and the filling time for specimen No. 7 (fluid concrete using VA1) is 30.5 seconds. From these results, it can be said that the specimens No. 5 and No. 7 also have the same filling properties as the concrete having a slump of 21 cm.

  To summarize the above, paste (unit water amount or unit cement amount) can be added by adding thickener-containing high-performance AE water reducing agents (VA1 to VA3) as admixtures based on the blend of slump 8cm and 12cm ordinary concrete. It was confirmed that the fluidity could be increased without increasing, and the filling property could be made to the same level as the concrete equivalent to a slump of 21 cm. In other words, by using the thickener-containing high-performance AE water reducing agent (VA1 to VA3), it can be confirmed that the filling time of concrete can be shortened to 2/3 to 1/2 compared to ordinary concrete of slump 8cm to 12cm. It was. It was also confirmed that the filling property was increased to a slump equivalent to 21 cm by adding a high-performance AE water reducing agent (SP) based on the blend of plain concrete with a slump of 8 cm.

  Next, the bleeding test will be described. The bleeding test was performed according to JIS A 1123, and the bleeding rate was calculated. In addition, the bleeding test was also performed on 8 types of test specimens excluding the test specimens No2-2 and No7-2.

  As shown in FIG. 1 (b) and FIG. 4, the bleeding rate of specimen No1 is 4.6%, the bleeding rate of specimen No6 is 5.7%, and the bleeding rate of specimen No8 is 6.3%. is there. Regarding the bleeding rate, it can be said that the lower the bleeding rate, the higher the property of confining moisture in the concrete. That is, the amount of floating water can be reduced.

  Specimen No2 had a bleeding rate of 2.1%, Specimen No3 had a bleeding rate of 3.9%, Specimen No4 had a bleeding rate of 2.2%, and Specimen No7 had a bleeding rate of 3.4%. It was. All specimens had a bleeding rate lower than that of plain concrete having a slump of 8 cm. That is, it was confirmed that it has higher water retention than this ordinary concrete. Especially about test body No2, No4, it is below half the bleeding rate of the test body 1. FIG. From this, it can be said that the specimens No2 and No4 are concretes that are easy to fill and have extremely high water retention. In addition, the bleeding rate of test body No5 is 4.8%. From this result, it was confirmed that the water retention of the material in the specimen No. 5 is equivalent to or slightly damaged by the slump 8 cm ordinary concrete.

  To summarize the above, based on the mix of slump 8cm, 12cm ordinary concrete, adding high-performance AE water reducing agent (VA1 to VA3) containing thickener as an admixture increases the water retention without increasing the paste. It was confirmed that In particular, it was confirmed that by using a high-performance AE water reducing agent containing a glycol type (VA1) or a biopolymer type (VA3) as a thickener component (test bodies No2, No4), the water retention can be further increased. On the other hand, when a high-performance AE water reducing agent (SP) was added based on the blend of slump 8 cm ordinary concrete (test body No. 5), it was confirmed that the water retention was equal to or less than that of ordinary concrete.

  Next, the setting time test will be described. The setting time test was conducted in accordance with JIS A 1147, and the start time and end time were measured. In addition, the setting time test was done about four types, test body No1, No2, No3, No4.

  As shown in FIG. 1B and FIG. 5, the start time of the test specimen No1 is 6 hours and 15 minutes, and the end time is 8 hours and 30 minutes. And the start time of test body No2 is 6 hours and 25 minutes, the end time is 8 hours and 45 minutes, the start time in test body No3 is 8 hours and 35 minutes, and the end time is 11 hours and 10 minutes. Moreover, in the test body No4, the start time is 6 hours and 10 minutes, and the end time is 8 hours and 30 minutes. Specimens No2 and No4 had almost the same start time and termination time as specimen No1. For this reason, it was confirmed that the agglomerates in the same time as slump 8 cm ordinary concrete while using a thickener.

  Moreover, regarding test body No3, the start time was substantially the same as the end time of test body No1. From this, it was confirmed that the specimen No3 requires more time for setting than the specimen No1. However, if the start time of the test body No3 is 8 hours and 35 minutes and the end time is 11 hours and 10 minutes, it can be said that it is a time enough to withstand practical use. In addition, when the cellulose type thickener which is another kind of thickener is used, there exists knowledge that the start time is 16 hours and the end time is 18 hours. Compared to this time, it can be said that the setting time of the specimen No. 3 is sufficiently short.

  Next, the slump test will be described. The slump test was performed according to JIS A 1101, and the slump was measured in units of 0.5 cm. In addition, as specified in JIS A 5308, tolerance is recognized for slump. For example, a slump of 8 cm to 18 cm allows a difference of ± 2.5 cm, and a slump of 21 cm allows a difference of ± 1.5 cm. 6 to 15 are photographs of the state of the slump test performed on each specimen. In these drawings, reference numeral 1 indicates each of the test bodies No1 to No8, and reference numeral 2 indicates a measuring instrument. Reference numeral 3 denotes a flat plate.

  As for test body No1, as shown in FIG.1 (b), a slump value is 8.5 cm. As shown in FIG. 6, in the slump test, the test body No1 has a substantially conical shape, and the paste and the aggregate are integrated, that is, each material has moldability (plasticity; It can be seen that there is plasticity). The higher the moldability, the stronger the tendency to slowly collapse while maintaining integrity when the mold is removed. Moreover, at the time of construction, the higher the unity, the smoother the flow in the pump and the pipe, and the more difficult it becomes to block. Moreover, it can suppress that a bean plate (filling defect) arises.

  Regarding test bodies No2 to No4, as shown in FIG. 1B, the slump values are 20.5 cm, 21.0 cm, and 20.0 cm, respectively, which are within the tolerance of the slump of 21 cm. That is, in each test body No2-No4, it was able to be made into the slump 21cm, without increasing a paste, based on the mixing | blending of the plain concrete of slump 8cm. Moreover, the slump value of test body No2-2 is 23.0 cm. That is, it was possible to make the slump 23 cm without increasing the paste, based on the blend of plain concrete with a slump of 8 cm.

  As shown in FIG. 7, the specimen No2 has a ball shape in which the hemisphere is lightly crushed in the slump test. This indicates that the material integrity (plasticity) is high as in the previous bleeding test. As shown in FIG. 8, the specimen No. 2-2 has a disk shape whose side surface bulges in an arc shape in the slump test. Although it can be seen that the integrity is lower than that of the test body No2, it can be said that the corresponding integrity is maintained.

  As shown in FIG. 9, the specimen No. 3 has a substantially truncated cone shape in the slump test. It can be said that the integrity is lower than that of the test body 2 and slightly higher than that of the test body No2-2. It can be said that this result supports the result in the previous bleeding test. As shown in FIG. 10, the specimen No. 4 has an ellipsoidal shape like a rubber ball from which air has been removed in the slump test. From this shape, it can be seen that the integrity is the same as or higher than that of the test body No2.

  With respect to the specimen No. 5, as shown in FIG. 1B, the slump value is 20 cm, which is within the tolerance of the slump 21 cm. However, as shown in FIG. 11, this specimen No. 5 has a disk shape as if okonomiyaki was expanded. It can be understood that the integrity of the material is not high because the diameter is one or more times larger than that of the test body No. 2-2 and the circular shape is broken in a plan view. For this reason, it can be said that obstruction | occlusion easily arises in a pump or a pipe | tube, and a bean board will be easy to produce.

  With respect to the specimen No. 6, as shown in FIG. 1B, the slump value is 11.0 cm, which is within the tolerance of the slump of 12 cm. Then, as shown in FIG. 12, in the slump test, this specimen No. 6 has a tall truncated cone shape, and the paste portion and the aggregate are integrated in the same manner as the specimen No. 1 having a slump of 8 cm. I understand that.

  With respect to the specimen No. 7, as shown in FIG. 1B, the slump value is 20.5 cm, which is within the tolerance of the slump 21 cm. Moreover, the slump value of specimen No. 7-2 is 23.0 cm. That is, it was possible to make the slump 21 cm without increasing the paste, based on the blend of ordinary concrete of slump 12 cm. Similarly, it was possible to make the slump 23 cm without increasing the paste, based on the blend of plain concrete with a slump of 12 cm.

  As shown in FIG. 13, the specimen No. 7 has a thick disk shape partially broken in the slump test. Although it is considered that the integrity has been lost due to the fact that a part has collapsed, it is almost the same as the slump 21 cm specimen No. 8 (see FIG. 15), so the overall integrity is appropriate. It can be said that it has. As shown in FIG. 14, Specimen No. 7-2 has a flat disk shape in the slump test. Compared with the test body 5 in FIG. 11, the circular shape is maintained in a plan view, and the thickness gradually decreases from the central portion of the circle toward the peripheral portion. I can understand that

  With respect to the specimen No. 8, as shown in FIG. 1B, the slump value is 20.0 cm, which is within the tolerance of the slump of 21 cm. And as shown in FIG. 15, although this test body No8 is carrying out the truncated cone shape which a part collapse | crumbled in the slump test, it can be said that it has a suitable integrity as a whole. As shown in FIG. 1A, this is due to the fact that the unit water amount and the unit cement amount are larger than those of other test specimens.

  Summarizing this slump test, from the results of specimens No2, No3 and No4, using a thickener component-containing high performance AE water reducing agent (VA1 to VA3) based on the blend of ordinary concrete slump 8cm, paste It was confirmed that a concrete having a slump of 21 cm can be produced without increasing the thickness. Regarding the high-performance AE water reducing agent containing the thickener component, it was confirmed that a concrete having a slump of 21 cm can be produced regardless of whether it is a glycol type, an acrylic type or a biopolymer type.

  From the result of test body No. 2-2, the slump without increasing the paste by using a high-performance AE water reducing agent (VA1) containing a glycol-based thickener component based on the blend of slump 8 cm ordinary concrete. It was confirmed that 23 cm concrete could be manufactured. Since it has been confirmed that the specimens 2, 3 and 4 can produce 21 cm of slump concrete, the thickener component is an acrylic or biopolymer-based high-performance AE water reducing agent (VA2, VA3). It is understood that the concrete of slump 23cm can be manufactured.

  From the result of test body No5, when a fluidizing agent (SP) that does not contain a thickener component is post-added based on the blend of ordinary concrete of slump 8 cm, the slump can be 21 cm. It was confirmed that it was difficult to improve the sex (plasticity). In addition, when test body No5 and test body No8 are compared, test body No8 has higher integrity. This is understood to be related to the amount of cement and water that make up the paste.

  Moreover, from the result of the test body No7, slump without increasing the paste by using a high-performance AE water reducing agent (VA1) containing a glycol-based thickener component based on the blend of slump 12 cm ordinary concrete. It was confirmed that 21 cm of concrete could be manufactured. From the results of specimens No. 3 and No. 4, it is understood that even a high-performance AE water reducing agent (VA2, VA3) containing an acrylic or biopolymer thickener component can produce 21 cm of slump concrete. The

  Similarly, from the result of specimen No. 7-2, the paste is increased by using a high-performance AE water reducing agent (VA1) containing a glycol-based thickener component based on the blend of slump 12 cm ordinary concrete. It was confirmed that a concrete with a slump of 23 cm could be produced. From the results of specimens No. 3 and No. 4, it is understood that even a high-performance AE water reducing agent (VA2, VA3) containing an acrylic or biopolymer thickener component can produce a concrete with a slump of 23 cm. The

  The following was found from the results of the aforementioned tests (fillability test, bleeding test, setting time test, slump test).

  A high-performance AE water reducing agent containing a thickener component having water-reducing and thickening properties is added to ordinary concrete containing water, cement, fine aggregate and coarse aggregate so that the slump value is 8 cm to 12 cm. By adding, the fluidity of the concrete could be increased without increasing the paste, and the slump value could be greater than 18 cm and less than 23 cm.

  Compared with the concrete structure constructed with the concrete of the comparative example in which the fluidity (fillability) is increased by increasing the paste, the concrete structure constructed with the concrete of this embodiment reduces the amount of heat of hydration. It can be reduced, and distortion caused by expansion and contraction is suppressed. Moreover, the occurrence of bleeding can be suppressed. In addition, it is economical because the amount of cement and water used can be reduced.

  Moreover, since the concrete of this embodiment has high moldability (plasticity) compared with the concrete of a comparative example, it can flow smoothly in a pump and the inside of a pipe | tube, and can suppress obstruction | occlusion. Moreover, generation | occurrence | production of the beans board resulting from the filling defect of a paste part can be suppressed.

  The concrete of this embodiment uses what contains a glycol type, an acrylic type, or a biopolymer type component as a thickener. Thereby, it can be made to set in the setting time equivalent to the concrete which does not contain a thickener. In particular, when a thickener containing a glycol-based or biopolymer-based component is used, the thickener can be coagulated in a time comparable to concrete not containing the thickener.

  The above description of the embodiment is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof. For example, you may comprise as follows.

  Regarding cement concrete as a base, cement, fine aggregate, and coarse aggregate are not limited to those exemplified in the embodiment. If blended so that the slump value is not less than 8 cm and not more than 12 cm, concrete with improved fluidity can be produced even if there are some differences in the production area, particle size, and the like.

  In the above-described embodiment, the high-performance AE water reducing agent containing the thickener component has been exemplified, but the thickener and the high-performance AE water reducing agent may be constituted by different chemicals. In short, a thickener may be blended.

1 Specimen at the time of slump measurement (Specimen No1 to Specimen No8)
2 Measuring instrument 3 Flat plate

Claims (3)

A method for producing a concrete having improved fluidity by mixing an admixture with cement concrete,
The cement concrete is a mixture of water, cement, fine aggregate and coarse aggregate so that the slump value is 8 cm or more and 12 cm or less,
The admixture contains a thickener and a high-performance AE water reducing agent.
A method for producing concrete, characterized in that the cement concrete and the admixture are kneaded so that the slump value is greater than 18 cm and not greater than 23 cm.   The method for producing concrete according to claim 1, wherein the thickener is selected from any one of a glycol thickener, an acrylic thickener, and a biopolymer thickener.   A concrete structure characterized in that it is constructed of concrete having improved fluidity by the production method according to claim 1 or 2.