JP2020011871A - Concrete having durability - Google Patents

Abstract

To provide concrete having excellent durability.SOLUTION: The concrete according to the present invention is characterized in that copper slag is contained as fine aggregate at 15% by volume or more and 35% by volume or less based on all fine aggregates, and satisfies the following requirements: (A) when the freeze-thaw test is conducted, a relative dynamic elastic modulus of elasticity at 300 freeze-thaw cycles is 70% or more; and (B) when the freeze-thaw test is conducted, a change rate of the relative dynamic elastic modulus of elasticity between 0 and 300 freeze-thaw cycles is within 10%.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to durable concrete, which includes copper slag in a part of fine aggregate.

  Concrete is widely used as a main material of civil engineering buildings because of its economy, workability, strength, durability, and the like. Concrete is mainly composed of coarse aggregate (gravel), fine aggregate (sand), cement, and water, mixed well and poured into ready-mixed concrete into a formwork (usually called pouring). ), Cured. Coarse aggregate refers to aggregate having a particle size of about 50 mm or less, and fine aggregate refers to aggregate having a particle size of about 5 mm or less.

  As sand as fine aggregate constituting concrete, for example, crushed sandstone obtained by crushing sandstone is known. Sand has properties required for fine aggregate for concrete, such as strength (hardness), physical and chemical stability, harmlessness, appropriate particle size, large surface composition with high adhesive strength, and required weight. Therefore, it is suitably used as a fine aggregate.

  However, it is known that concrete using only sand as fine aggregate has a problem that, for example, drying shrinkage easily occurs. For this reason, for example, limestone aggregate having a shrinkage reducing effect is used together at a predetermined ratio, but there is a problem that limestone aggregate is expensive. On the other hand, slag fine aggregates such as copper slag have also been used as alternative fine aggregates. Since these alternative fine aggregates have different characteristics from sand, they are usually used in place of a part of sand used as fine aggregate.

  Now, the use of copper slag as an alternative fine aggregate is specified in JIS as a fine aggregate for concrete. As the copper slag, granulated blast furnace slag, refined steel slag, and the like are used (see, for example, Patent Document 1), and various characteristics of the slag have been studied. For example, the drying shrinkage rate is also evaluated as one of the properties (for example, see Non-Patent Document 1).

  However, no research has been made on the durability of concrete containing copper slag, which has been used as a substitute for fine aggregate.

  Concrete is an element forming the basis of a structure such as a house or a building by holding a reinforcing bar or the like, and is generally exposed to outside air, rainwater, or the like. For this reason, it is required that the concrete constituting the structure has excellent durability and also has good durability stably over a long period of time.

JP-A-2002-179451

Keisuke Ishimaru, Hiroyuki Mizuguchi, Chinori Hashimoto, Takao Ueda, Kazuhiro Fujita, Masaaki Omi "Properties of concrete using copper slag and Class II fly ash as a part of fine aggregate" "Materials" (J. Soc Mat. Sci., Japan), Vol.54, No.8, pp.828-833, Aug.2005

  The present invention has been proposed in view of such circumstances, and has as its object to provide concrete having excellent durability.

[1] The first invention of the present invention is a concrete which contains copper slag as fine aggregate at 15% by volume or more and 35% by volume or less with respect to all fine aggregates and satisfies the following requirements.
(A) When a freeze-thaw test is performed, the relative dynamic elastic modulus at a freeze-thaw cycle of 300 cycles is 70% or more, and
(B) The rate of change in the relative kinematic elasticity from 0 to 300 cycles of the freeze-thaw cycle during the freeze-thaw test is within 10%.

[2] The second invention of the present invention is the concrete according to the first invention, which further satisfies the following requirements.
(C) When the accelerated neutralization test was performed, the neutralization depth at the accelerated material age of 26 weeks was 20 mm or less, and
(D) When the accelerated neutralization test is performed, the neutralization rate coefficient expressed by the neutralization depth with respect to the square root of the accelerated age from 0 to 0.5 years is 30 or less.

  [3] The third invention of the present invention is the concrete according to the first or second invention, wherein the copper slag has a particle size classification of 2.5 mm or less according to JIS A5011-3.

  [4] A fourth invention of the present invention is a method for producing concrete containing copper slag in a part of fine aggregate, wherein the fine aggregate is 15% by volume or more and 35% by volume or less based on all fine aggregates. A process of mixing fine copper, copper slag, and fine aggregate, kneading the fine aggregate, coarse aggregate, and a cement paste having a water / cement ratio of 40% to 50%. It is a manufacturing method of.

  According to the present invention, an object is to provide concrete having excellent durability.

It is a graph which shows the measurement result of the relative dynamic elastic modulus by a freeze-thaw test. It is a graph which shows the measurement result of the accelerated neutralization depth at the time of performing the accelerated neutralization test about the concrete of Test example 1-Test example 5 and Comparative example 1. Based on the accelerated neutralization depth measured for the concretes of Test Examples 1 to 5 and Comparative Example 1, the neutralization rate coefficient from 0 years (0 weeks) to 0.5 years (26 weeks) of the accelerated material age It is a graph which shows the result of having calculated. It is a graph which shows the measurement result of the accelerated neutralization depth at the time of performing the accelerated neutralization test about the concrete of Test Example 6-Test Example 9 and Comparative Example 2. Based on the accelerated neutralization depth measured for the concretes of Test Examples 6 to 9 and Comparative Example 2, the neutralization rate coefficient from 0 years (0 weeks) to 0.5 years (26 weeks) of accelerated material age It is a graph which shows the result of having calculated.

  Hereinafter, a specific embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following embodiment at all, and changes the gist of the present invention. It can be carried out with appropriate changes within a range not to be performed. In this specification, the notation “X to Y” (X and Y are arbitrary numerical values) means “X or more and Y or less”.

≪1. Durable concrete≫
Concrete according to the present embodiment is a durable concrete, including copper slag in a part of fine aggregate, for the total fine aggregate consisting of natural fine aggregate and copper slag fine aggregate, The copper slag fine aggregate is contained at a ratio of 15% by volume or more and 35% by volume or less, and satisfies a specific requirement as an index measured by a freeze-thaw test.

  Specifically, (A) the freeze-thaw cycle when the freeze-thaw test was performed, the relative kinematic elastic modulus at a freeze-thaw cycle of 300 cycles was 70% or more, and (B) the freeze-thaw test was performed. Satisfies the requirement that the rate of change of the relative dynamic elastic modulus from 0 cycle to 300 cycles is within 10%.

[Copper slag fine aggregate]
In the concrete according to the present embodiment, copper slag is used as a part of the fine aggregate (partially substitute fine aggregate). This copper slag is generated by the copper smelting operation, and is formed by combining iron in the copper concentrate with limestone, silica, and the like in the copper smelting process, and mainly includes FeO, SiO ₂ , and CaO. The molten slag is made into a granulated and crushed product by water cooling.

Examples of the composition of the copper slag include iron oxide (FeO) 45 mass% to 55 mass%, silicic acid (SiO ₂ ) 30 mass% to 36 mass%, calcium oxide (CaO) 2 mass% to 7 mass%, and aluminum oxide. (Al ₂ O ₃ ) 3 mass% to 6 mass%. It has high strength, is physically and chemically stable, and is mainly used as a raw material for cement, a raw material for civil engineering work (filling material, etc.), an abrasive for sandblasting, and a fine aggregate for concrete. The standard for using copper slag as concrete aggregate (copper slag fine aggregate) is specified in JIS A5011-3 “Concrete aggregate Part 3 Copper slag” (1997).

  The particle size of the copper slag used for a part of the fine aggregate conforms to the particle size classification of the copper slag fine aggregate in JIS A5011-3. For example, a copper slag having a particle size of 1.2 mm is called CUS1.2. ing. The sieving test in JIS A5011-3 is further specified in JIS A1102 (Aggregate sieving test method), and has a nominal size of 10 mm, 5 mm, 2.5 mm, 1.2 mm, 0.6 mm, 0.3 mm, 0 mm This is a test method using a .15 mm sieve, and the mass% of the material passing through each sieve is specified.

  The classification according to the particle size of the copper slag fine aggregate in JIS A5011-3 is classified into four levels of CUS5, CUS2.5, CUS1.2, and CUS5-0.3. In the concrete according to the present embodiment, The particle size of the copper slag is preferably 2.5 mm or less according to the particle size classification specified in JIS A5011-3. If the particle size is larger than CUS2.5, the durability may be reduced, and the bleeding amount may be increased to lower the workability.

  The content of copper slag is 15% by volume or more and 45% by volume or less based on the total fine aggregate. Further, it is preferably from 20% by volume to 40% by volume, and more preferably from 35% by volume to 45% by volume. When the copper slag accounts for 15% by volume or more and 45% by volume or less based on the total fine aggregate, the durability can be improved.

[Other fine aggregates]
As other fine aggregate, conventionally known crushed sand such as crushed sandstone and lime sand, lightweight fine aggregate (melasite sand), natural fine aggregate such as mountain sand and land sand can be used, and is not particularly limited. . Note that lime fine aggregate, which is a fine aggregate mainly composed of lime, is particularly effective because it is effective in drying shrinkage.

[Coarse aggregate]
The constituent material of concrete is mainly composed of the fine aggregate described above, coarse aggregate, and cement paste composed of water and cement. In addition, the fine aggregate and the coarse aggregate are collectively referred to as aggregate.

  The coarse aggregate is not particularly limited, and known gravel, crushed stone, and the like can be appropriately used.

[Water and cement]
Further, water and cement are not particularly limited, and conventionally known water and cement can be appropriately used. For example, as the cement, ordinary Portland cement, early-strength Portland cement, moderate heat Portland cement, Portland cement such as white Portland cement, blast furnace cement, silica cement, mixed cement such as fly ash cement, special cement such as alumina cement, etc. Can be used.

  Further, in a cement paste composed of water and cement, the water / cement ratio (W / C ratio), which is a mixing ratio of the water and cement, is not particularly limited, but is in a range of 40% to 50%. Is particularly preferred. As will be described in detail in Examples below, in the production of concrete, by setting the water / cement ratio to 50% or less, the durability of the obtained concrete is further improved. More specifically, neutralization can be suppressed, rust and the like can be stably prevented over a long period of time, and good durability can be maintained.

Incidentally, the copper slug is known to be low water absorption, amount that is mixed with copper slag at a rate in part on a predetermined fine aggregate, reduced unit water content of concrete (water required per concrete 1 m ³⁾ is I do. For this reason, since the amount of cement is reduced and the calorific value is reduced, cracks after hardening hardly occur. Even in this case, there is no effect on concrete strength and the like.

[Other materials]
In the concrete according to the present embodiment, if necessary, various additives may be added as other materials as long as the effect on the durability of the concrete is not impaired. Examples of the additive include a water reducing agent (AE agent) and the like.

[Index based on freeze-thaw test]
Now, a freeze-thaw test is known as a test relating to durability of concrete. The present inventors have found that there is a specific relationship between indices measured by freeze-thaw tests in concrete that has durability and that can maintain the durability stably for a long period of time. .

  The freeze-thaw test is an in-water freeze-thaw test method specified in JIS A 1148: 2010. This freeze-thaw test artificially repeats the freeze-thaw action on a concrete specimen a predetermined number of times, and measures an index of concrete durability based on the degree of retention of a relative dynamic elastic modulus (durability index). It is a test. The relative dynamic elastic modulus (%) is an index indicating the degree of decrease in the dynamic elastic coefficient before and after the freeze-thaw test.

  Specifically, in this freeze-thaw test, a concrete specimen having a prism shape of 100 mm x 100 mm x 400 mm was prepared, and the specimen was fixed in a wooden tub in a water tank, and the water tank was filled with water and the test specimen was completely submerged. Let it stand for 24 hours, then drain to a water depth of 3-5 mm. Then, in this state, the temperature was reduced to 0 ° C., cooled to −20 ° C. in 30 minutes, and maintained at −20 ° C. for 2 hours. After raising the temperature to + 20 ° C. over 2 minutes and maintaining the temperature at + 20 ° C. for 2 hours, the operation of cooling again over 30 minutes to 0 ° C. and returning to the same condition as the first was defined as one cycle (freeze-thaw cycle). Perform 300 cycles.

The concrete according to the present embodiment is characterized by satisfying the following requirements as an index represented by a freeze-thaw test.
(A) The relative kinematic elasticity coefficient is 70% or more when the freeze-thaw test is performed at 300 freeze-thaw cycles, and (B) The freeze-thaw cycle is 0 to 300 cycles when the freeze-thaw test is performed. The rate of change of the relative dynamic elastic modulus up to 10%

  In the freeze-thaw test, if the relative kinematic elastic modulus when the freeze-thaw cycle is 300 cycles is 70% or more (requirement (A)), it can be said that the durability of the concrete is good. Further, the relative dynamic elastic modulus at 300 freeze-thaw cycles is preferably 80% or more, more preferably 90% or more.

  Further, in satisfying the requirement (A), in the freeze-thaw test, if the rate of change of the relative kinematic elastic modulus from 0 to 300 in the freeze-thaw cycle is within 10%, it is stable for a long period of time. It can be said that the concrete can maintain good durability in general.

  Further, although not an essential requirement, in the freeze-thaw test, it is preferable that the change rate of the relative kinematic elastic modulus from 150 to 300 freeze-thaw cycles be within 5%. The freeze-thaw cycle from 150 cycles to 300 cycles means a severer second half cycle in which the freeze-thaw test was repeated. Therefore, it can be said that the durability is further enhanced when the rate of change of the relative kinetic elasticity coefficient in the freeze-thaw cycle from 150 cycles to 300 cycles is within 5%.

  Here, FIG. 1 is a graph showing a measurement result of a relative dynamic elastic modulus by a freeze-thaw test. The freeze-thaw test was performed by a method based on JIS A 1148: 2010, and Table 1 below shows the measured values of the relative dynamic elastic modulus. Test Examples 1 to 5 are test examples using concrete manufactured by mixing copper slag (CUS) into a part of fine aggregate, and Comparative Example 1 is a fine aggregate made of crushed sand and lime. It is a test example using concrete using concrete (concrete not containing copper slag).

  In the production of the concrete of each test example, the water / cement ratio was 55%, 50%, 55%, 50%, 45%, 50% in order from Comparative Example 1, Test Example 1 to Test Example 5, respectively. And In addition, the mixing ratio of copper slag (CUS) is shown in the graph.

  As can be seen from the graph of FIG. 1, in the concrete not containing copper slag, although the relative kinematic elasticity coefficient in the freeze-thaw cycle of 300 cycles was 70%, it was higher than the concrete in which copper slag was mixed at a predetermined ratio. Was low.

  Also, in concrete containing copper slag, the rate of change of the relative kinematic elastic modulus from 0 to 300 freeze-thaw cycles is within 10%, and the rate of change after 150 cycles (from 150 cycles to 300 cycles). Was also within 10%. On the other hand, in the case of the concrete containing no copper slag, the relative dynamic elastic modulus was significantly reduced from around 150 cycles, and the rate of change from 150 cycles to 300 cycles exceeded 10%.

[Index based on accelerated neutralization test]
As another test relating to durability of concrete, an accelerated neutralization test is known. In general, in a structure made of concrete, the concrete has alkalinity and oxidation of reinforcing bars and the like inside the concrete is prevented.However, concrete is affected by the action of carbon dioxide contained in the air and rainwater. Neutralization gradually proceeds inward from the surface, and when the neutralization progresses and reaches the reinforcing steel, rust prevention performance on the reinforcing steel is lost and rust is generated. When rust is generated, the reinforcing bar swells, and the expanded reinforcing bar presses the concrete around the reinforcing bar, causing cracks in the concrete.

  The present inventors have satisfied the specific indices (requirements) measured by the freeze-thaw test described above, and further improved the durability by satisfying the specific indices measured by the accelerated neutralization test. In addition, it has been found that the concrete can stably maintain durability.

  The accelerated neutralization test is an accelerated neutralization test method for concrete specified in JIS A 1153. In the accelerated neutralization test, the neutralization depth was measured based on “Method for measuring neutralization depth of concrete” specified in JIS A 1152.

Specifically, in the accelerated neutralization test, under the environment of a temperature of 20 ° C. ± 2 ° C., a relative humidity of 60 ± 5%, and a CO ₂ concentration of 5 ± 0.2%, for example, the accelerated material age is 0 weeks (0 years). ) To 26 weeks (0.5 years), forcibly neutralize the concrete specimen.

The concrete according to the present embodiment is not an essential requirement, but more preferably satisfies the following requirement as an index represented by the accelerated neutralization test.
(C) When the accelerated neutralization test was performed, the neutralization depth at the accelerated material age of 26 weeks was 20 mm or less, and
(D) When the accelerated neutralization test is performed, the neutralization rate coefficient expressed as the neutralization depth with respect to the square root of the accelerated age from 0 to 0.5 years of the accelerated age is 30 or less.

  In the accelerated neutralization test, if the neutralization depth at the accelerated age of 26 weeks is 20 mm or less (requirement (C)), the neutralization is effectively suppressed to prevent rust and the like, and the durability of the concrete is reduced. Can be said to be good.

  In addition, in satisfying the requirement (C), in the accelerated neutralization test, neutralization expressed as the neutralization depth with respect to the square root of the accelerated age from 0 to 0.5 years When the carbonization rate coefficient is 30 or less, it can be said that neutralization can be suppressed for a long period of time, and good durability can be stably maintained. The neutralization rate coefficient is an index (coefficient) indicating the rate of neutralization of concrete. The neutralization depth of concrete is proportional to the square root of the number of years elapsed. (Mm), and when the material age is t (year), it is expressed by a relational expression of C = A√t. The coefficient A in this relational expression corresponds to the neutralization rate coefficient (mm / √ year).

  Here, FIG. 2 is a graph showing the measured results of the accelerated neutralization depth when the accelerated neutralization test was performed on the concretes of Test Examples 1 to 5 and Comparative Example 1. FIG. 3 shows the accelerated neutralization depth measured for the concretes of Test Examples 1 to 5 and Comparative Example 1, based on the accelerated material age of 0 years (0 weeks) to 0.5 years (26 weeks). FIG. 5 is a graph showing the result of calculating the neutralization rate coefficient in FIG. The accelerated neutralization test was performed by a method in accordance with JIS A 1153 and JIS A 1152. Table 2 below shows actual measured values of the accelerated neutralization depth, and Table 3 below shows the neutralization rate coefficient. Is the calculated value.

  As shown in the graph of FIG. 2, in any of the concretes, when the accelerated neutralization test was performed, the neutralization depth at the accelerated material age of 26 weeks was 20 mm or less. However, regarding the neutralization rate coefficient represented by the depth of neutralization with respect to the square root of the accelerated age from 0 years to 0.5 years of the accelerated age, there is a large difference depending on whether copper slag is mixed or not. In the concrete containing no copper slag, the carbonation rate coefficient greatly fluctuated between the accelerated material age of 0 years and 0.5 years.

  It is also found that the neutralization rate coefficient varies greatly depending on the water / cement ratio at the time of concrete production. When the water / cement ratio is 50% or less, the neutralization rate coefficient is about 30 or less. It turned out that.

  FIG. 4 is a graph showing measurement results of the accelerated neutralization depth when the accelerated neutralization test was performed in the same manner as in FIG. 2, and the above Test Examples 1 to 5 and Comparative Example 1 7 shows test results for concretes of Test Examples 6 to 9 and Comparative Example 2 using crushed sand different from crushed sand which is a natural fine aggregate used for concrete of Example 1. The same copper slag was used. In addition, FIG. 4 is based on the accelerated neutralization depth measured for the concretes of Test Examples 6 to 9 and Comparative Example 2, and from 0.5 years (26 weeks) to 0 years (0 weeks) of the accelerated material age. FIG. 5 is a graph showing the result of calculating the neutralization rate coefficient in FIG.

  Comparative Example 2 is concrete containing crushed sand and lime at a ratio of 70:30 as fine aggregate. Further, Test Examples 6 to 8 are concretes containing crushed sand and copper slag (CUS) at a ratio of 70:30 as fine aggregate, and Test Example 9 is crushed sand and copper slag as fine aggregate. Concrete containing 80:20. The accelerated neutralization test was carried out by a method based on JIS A 1153 and JIS A 1152. Table 4 below shows actual measured values of the accelerated neutralization depth, and Table 5 below shows the calculation of the neutralization rate coefficient. Value.

  As shown similarly in the graph of FIG. 3, in any of the concretes, when the accelerated neutralization test was performed, the neutralization depth at the accelerated material age of 26 weeks was 20 mm or less. However, regarding the neutralization rate coefficient represented by the depth of neutralization with respect to the square root of the accelerated age from 0 years to 0.5 years of the accelerated age, there is a large difference depending on whether copper slag is mixed or not. In the concrete containing no copper slag, the carbonation rate coefficient greatly fluctuated between the accelerated material age of 0 years and 0.5 years.

  Further, it is understood that the neutralization rate coefficient varies greatly depending on the water / cement ratio at the time of concrete production. When the water / cement ratio is 50% or less, the neutralization rate coefficient is about 20 or less. It turned out that.

{2. Concrete manufacturing method コ ン ク リ ー ト
In the method for producing concrete according to the present embodiment, a predetermined amount of copper slag is mixed as a part of fine aggregate to produce copper slag. Specifically, this concrete manufacturing method is to prepare fine aggregate by mixing copper slag at a predetermined ratio with respect to all fine aggregate as fine aggregate, and prepare the fine aggregate and coarse aggregate. And kneading with cement paste.

(Fine aggregate preparation process)
In the fine aggregate preparation step, fine aggregate composed of copper slag and natural fine aggregate to be configured as a part of the fine aggregate is prepared. The mixing ratio of the copper slag is set to be 15% by volume or more and 35% by volume or less based on the total fine aggregate.

  Further, as the copper slag, a copper slag having a particle size of 2.5 mm or less according to JIS A5011-3 is used. According to such a copper slag, it is easy to handle, it is easy to mix with the coarse aggregate, and the durability of the obtained concrete is improved.

(Kneading process)
In the kneading step, the fine aggregate prepared in the fine aggregate preparation step is kneaded with water, cement, and coarse aggregate, which are constituent materials of concrete, to obtain a kneaded material.

  Here, the mixing ratio (water / cement ratio) of water and cement is in the range of 40% to 50%. As described above, by including copper slag as a part of fine aggregate and kneading it with a cement paste having a water / cement ratio in the range of 40% to 50%, the durability of the obtained concrete can be increased. . Specifically, by setting the water / cement ratio to 50% or less, particularly when the accelerated neutralization test is performed on concrete, the neutralization depth at the accelerated material age of 26 weeks is 20 mm or less. And when the accelerated neutralization test was performed, the neutralization rate coefficient represented by the neutralization depth with respect to the square root of the accelerated age from the accelerated age of 0 to 0.5 years was 30. The following is obtained. In such concrete, neutralization can be stably suppressed over a long period of time to prevent rust and the like, and good durability can be maintained. If the water / cement ratio is less than 40%, the amount of water becomes too small, the viscosity increases, and the workability during concrete construction deteriorates.

  The fine aggregate ratio (s / a), which is the ratio of the volume of the fine aggregate to the total aggregate (fine aggregate and coarse aggregate), can be appropriately determined without any particular limitation. Generally, it is in the range of 40% to 50%.

  The kneading method in the kneading step is not particularly limited, and kneading can be performed by a known method. Specifically, for example, it can be carried out in a mixer such as a horizontal biaxial forced kneading mixer, a cement paste made of water and cement, a fine aggregate containing copper slag, and a coarse aggregate, The mixture is charged into the mixer and stirred for about 30 seconds, and then, if necessary, water containing a chemical such as an admixture and a water reducing agent is charged into the mixer and stirred for about 90 seconds.

(Curing process)
In the hardening step, concrete is obtained by curing and curing the kneaded material obtained in the kneading step.

Specifically, in the curing step, the kneaded material is formed into a predetermined shape according to the purpose, and a hydration reaction proceeds to cure and cure. Curing means securing an appropriate temperature and humidity, and protecting it from external force such as drying and freezing. As the curing method, for example, a method of immersing the molded concrete in water or a method of spraying water, a method of covering with a wet mat or the like, and the like. May go. In addition, the treatment time for curing and curing is not particularly limited, and can be appropriately set according to the strength of the target concrete.

Claims (4)

Including copper slag at 15% by volume or more and 35% by volume or less based on all fine aggregates as fine aggregate,
A concrete characterized by satisfying the following requirements.
(A) When a freeze-thaw test is performed, the relative dynamic elastic modulus at a freeze-thaw cycle of 300 cycles is 70% or more, and
(B) The rate of change in the relative kinematic elasticity from 0 to 300 cycles of the freeze-thaw cycle during the freeze-thaw test is within 10%. The concrete according to claim 1, further satisfying the following requirements.
(C) When the accelerated neutralization test was performed, the neutralization depth at the accelerated material age of 26 weeks was 20 mm or less, and
(D) When the accelerated neutralization test is performed, the neutralization rate coefficient expressed by the neutralization depth with respect to the square root of the accelerated age from 0 to 0.5 years is 30 or less.   The concrete according to claim 1, wherein the copper slag has a particle size of 2.5 mm or less according to a particle size classification defined in JIS A5011-3. A method for producing concrete containing copper slag in a part of fine aggregate,
A fine aggregate is prepared by mixing copper slag at a ratio of 15% by volume or more and 35% by volume or less with respect to all fine aggregates as fine aggregate, and the fine aggregate, coarse aggregate, and water / cement ratio are prepared. And kneading the cement paste with 40% to 50%,
Concrete manufacturing method.

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