JP2001261414A - Concrete with self-wetting curing function and its construction method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To obtain concrete that is lightweight and has excellent strength and durability. SOLUTION: In concrete comprising water, cement-containing binder, aggregate and admixture, JI is used as admixture.
Use AE water reducing agent or high performance AE water reducing agent according to SA 6204, and use all or part of concrete aggregate as JIS
The crushing load according to Z 8841 is 1000-2000N,
1.4-1.8, water absorption using 12 to 20% of the artificial bone material, water cement ratio is 25 to 55%, each as yet solidified no unit volume weight of the concrete is 1.8-2.1 t / m ³ Concrete having a self-humidifying curing function characterized by blending materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete in which various properties are exhibited by imparting a self-wetting curing function and other functions to an aggregate to be mixed with concrete, and a method of applying the same.

[0002]

2. Description of the Related Art In general, concrete must be cured so as not to dry rapidly after completion of the casting and until hydration of the cement and hardening of the concrete have sufficiently proceeded. For this reason, for example, in “JASS 5 Reinforced Concrete Work” of the Architectural Institute of Japan Standard Specification and Commentary (hereinafter abbreviated as “Nikken Specification”),
After concrete is poured, it is required to cure for several days. In this case, the moist curing includes leaving the mold for a predetermined period (from 3 days or more to 10 days or more depending on the type of cement), watering, spraying water, and the like.

[0003] For this reason, in building construction, a covering material such as a weir board (a form in contact with concrete) or the like is kept for a predetermined period, and water is sprayed or sprayed. Due to the fact that the dam cannot be kept for a certain period of time, and that watering and spraying also affect the next work process and are often difficult to implement, the problem of concrete curing is an important requirement for concrete work. However, it is often subject to construction restrictions.

[0004] In the "JASS 5 Reinforced Concrete Work" of the above-mentioned Nikken specifications, a design standard in the case of using lightweight concrete is indicated. According to this, the maximum design standard strength of lightweight concrete is 36 N /. mm ²
It is prescribed. This conventional artificial lightweight aggregate is a specific gravity of about 1.30, since crushing load according to JIS Z 8841 is about 500 N, due to the difficulty to obtain a light-weight concrete in excess of 36N / mm ^2. For this reason, the use of lightweight concrete in places where strength is required is limited, and construction of lightweight concrete structures is often difficult.

[0005]

SUMMARY OF THE INVENTION One object of the present invention is to provide a concrete which can be cured by itself even when external supply water is cut off.

[0006] Another object of the present invention is to obtain a concrete which is light in weight and can exhibit high strength.

Another object of the present invention is to obtain concrete capable of simultaneously achieving lightweight, high flow and high strength.

[0008] Another object of the present invention is to obtain a highly durable concrete which has a higher strength and a smaller drying shrinkage than ordinary concrete, and furthermore, the progress of neutralization is small.

[0009]

Means for Solving the Problems One object of the present invention is to use an AE water reducing agent or a high-performance AE water reducing agent in accordance with JIS A 6204 as an admixture in a concrete comprising water, cement-containing binder, aggregate and admixture. The crushing load in accordance with JIS Z 8841 is used for all or part of the concrete aggregate.
1000-2000N, specific gravity of absolute dryness 1.4-1.8, water absorption rate 12-20
% Of artificial aggregate, water-cement ratio is 25-55%, unit mass of concrete not yet set is 1.8-2.1
It has been found that this can be achieved by concrete having a self-wetting curing function, which is characterized by blending each material so as to have a t / m ³ . This concrete can exhibit sufficient strength even if the dam is removed from the concrete one day after casting in place.

Another object of the present invention is to provide a concrete comprising water, cement-containing binder, aggregate and admixture, wherein an AE water reducing agent or a high-performance AE water reducing agent according to JIS A 6204 is used as the admixture, The crushing load according to JIS Z 8841 is 1000 to 20 as all or part of the aggregate.
00N, absolute dry specific gravity 1.4 ~ 1.8, water absorption 12 ~ 20% using artificial aggregate, water cement ratio 25 ~ 55%, unit mass of concrete not yet solidified 1.8 ~ 2.1 t / m ^Three
Each material is blended so that the slump flow is 45c
m, which is achieved by mixing high-fluidity concrete of at least m. This high-fluidity concrete is light in weight and can exhibit high strength in which the compressive strength of the hardened body exceeds 36 N / mm ² . By further adding fly ash or silica fume to the concrete, it is possible to further improve the compressive strength, reduce the drying shrinkage, and suppress the progress of the neutralization depth.

[0011] Another object of the present invention is to use an AE water reducing agent or a high-performance AE water reducing agent in accordance with JIS A 6204 as an admixture in concrete comprising water, cement-containing binder, aggregate and admixture. As all or part of
Using artificial aggregate with a crushing load according to JIS Z 8841 of 1000-2000N, specific gravity of absolute dryness of 1.4-1.8, and water absorption of 12-20%,
When the water-cement ratio is 25-55%, the unit volume mass is 1.8-
Achieved by a method of manufacturing high-strength lightweight concrete, characterized by compounding each material to 2.1 t / m ³ , kneading concrete, and curing the obtained unconsolidated concrete using an insulating formwork. According to this, the tensile strength can be remarkably improved as compared with concrete using ordinary aggregate.

[0012] Another object of the present invention is to use an AE water reducing agent or a high-performance AE water reducing agent in accordance with JIS A 6204 as an admixture in a concrete comprising water, cement-containing binder, aggregate and admixture. As all or part of
Using artificial aggregate with a crushing load according to JIS Z 8841 of 1000-2000N, specific gravity of absolute dryness of 1.4-1.8, and water absorption of 12-20%,
When the water-cement ratio is 25-55%, the unit volume mass is 1.8-
This is achieved by a mass concrete construction method which comprises mixing each material so as to be 2.1 t / m ³ , kneading concrete, and constructing a mass concrete structure with the obtained concrete which has not yet solidified. The mass concrete has improved tensile strength as compared with ordinary concrete and can reduce temperature cracks.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Concrete according to the present invention is a concrete having a self-wetting curing function (self-curing concrete), a lightweight and high-strength concrete, depending on the aggregate and admixture to be used. , Lightweight, high-flow, high-strength concrete, and high-durability concrete, all of which have the same characteristic as artificial bone having a specific strength, specific gravity, and water absorption as all or part of the aggregate. The point is to use wood. Therefore, this artificial aggregate will be described first.

Conventional artificial lightweight aggregates have a specific gravity of about 1.30, and a crushing load in accordance with JIS Z 8841 is 500 N.
Compressive strength of 36 N / mm ²
In general, it has been difficult to obtain lightweight concrete that exceeds the standard. In other words, the lack of strength of the aggregate itself led to a decrease in the strength of concrete. On the other hand, since the aggregate having high strength is relatively dense, the specific gravity is high and it is difficult to reduce the weight. For this reason, it is not always easy to achieve both light weight and strength, but in the present invention, the crushing load according to JIS Z 8841 is in the range of 1000 to 2000 N, and the absolute dry specific gravity is 1.4 to 2000 N.
It is characterized in that an artificial aggregate having a water absorption ratio in the range of 1.8 and 12 to 20% is used.

An artificial aggregate having such physical properties is obtained by using, for example, coal ash and shale as raw materials, and mixing these powders in a predetermined ratio, for example, a weight ratio of coal ash: shale = 5: 5 to 7: 3. , And granulated by adding water or a binder, firing the granulated product at a high temperature (1100 ° C. or more), and appropriately adjusting the firing conditions and the cooling process from the firing temperature. . The obtained fired product can be separated into fine aggregate and coarse aggregate by pulverizing and classifying it.

A typical example of the production of such an artificial aggregate is as follows. Coal ash coarse powder (a) produced as a by-product of a thermal power plant having the following chemical components and fine shale powder ( b)
Are mixed at a weight ratio of (a) :( b) of approximately 6: 4, a binder is added, and the mixture is granulated. The mixture is calcined in a rotary kiln at about 1100 to 1200 ° C., and the cooling process is performed. At about 100-200 ° C. in water. The obtained fired product can be roughly crushed and classified to separate into a fine aggregate of 5 mm or less and a coarse aggregate of 5 to 15 mm.

(A) Chemical composition (mass%) of coal ash SiO ₂ : about 54%, Al ₂ O ₃ : about 29%, Fe ₂ O ₃ + FeO: about 4.5%, CaO: about 3.5% MgO: about 1.0% Ignition loss: about 4.7%

(B) Chemical composition (mass%) of shale SiO ₂ : about 70%, Al ₂ O ₃ : about 13%, Fe ₂ O ₃ + FeO: about 4.2%, CaO: about 1.6% MgO : About 1.6% Loss on ignition: about 5.6%

The thus obtained coarse aggregate having a size of 5 to 15 mm has an absolute dry specific gravity of 1.52, a hot water absorption of 15%,
A crushing load of 1130 N according to JIS Z 8841 is shown. Here, the hot water absorption refers to a value obtained by measuring the water absorption in a surface drying state at room temperature after water cooling from 100 to 200 ° C. in the firing process of the artificial aggregate. For fine aggregates of 5 mm or less, absolute dry specific gravity = 1.61, hot water absorption = 15
%. Although it is difficult to measure the crushing load of fine aggregate, it can be seen that it is equivalent to that of coarse aggregate. Also, 10
When the pore size distribution of the coarse particles of 15 mm was examined by the mercury intrusion method, the results shown in FIG. 1 were obtained. As can be seen from the results of FIG. 1, the pore volume is almost evenly distributed in the pore radius of 50 to 6000 nm, and the cumulative pore volume (total pore volume) reaches about 110 m ³ / g. This is
It can be seen that while having a low specific gravity, it contributes to high strength and acts to enhance water retention performance.

Not only in this representative example, but according to the same principle,
By selecting the raw materials and properly controlling the firing conditions, the crushing load in accordance with JIS Z 8841 is in the range of 1000 to 2000 N,
It is possible to produce artificial aggregates with a specific gravity in the range of 1.4 to 1.8 and a water absorption in the range of 12 to 20%. By using this artificial aggregate, self-curing concrete), light weight and high strength Concrete, lightweight, high-flow, high-strength concrete and highly durable concrete can be manufactured.

The crushing load of the artificial aggregate used in the present invention is 10
If it is less than 00 N, sufficient concrete strength exceeding 36 N / mm ² cannot be obtained. Conversely, if it exceeds 2000 N, a sufficient amount of pores cannot be secured, and therefore the specific gravity is large and the water absorption rate is undesirably reduced. . Therefore, the crushing load of the artificial aggregate used in the present invention is 1000 to 2000 N, preferably 1000 to 1500 N, and more preferably 1100 to 1300 N. If the specific gravity of the artificial aggregate is less than 1.40, it is difficult to secure a crushing load of 1000 N or more, and the specific gravity becomes 1.
If it exceeds 80, weight reduction cannot be achieved and water absorption rate is 1
Since it becomes difficult to secure 2% or more, the absolute specific gravity of the artificial aggregate used in the present invention is 1.40 to 1.80, preferably 1.50 to 1.80.
It should be 1.70. If the water absorption is less than 12%, the self-curing function and the improvement effect on the neutralization and drying shrinkage of concrete will not be sufficiently exhibited, and if it exceeds 20%, it will be difficult to secure a crushing strength of 1000N or more with a specific gravity of 1.80 or less. Therefore, the water absorption of the artificial aggregate used in the present invention is 12
It is preferably about 20%. Note that this water absorption rate is actually 100 to 200 as described above depending on the manufacturing history.
In the case of water-cooled from ℃, it can be expressed as a percentage of the retained water amount contained in the surface-dried state (hot water absorption) of the product thus produced. Regarding the pore size distribution, as can be seen from the above-mentioned representative example, the pore radius is 50 to 60.
Total pore volume) of about 110m ³ / g in nm, is good in the range of preferably 90~130m ³ / g.

[0022] Such an artificial aggregate is used as a whole or a part of the concrete aggregate to have a water cement ratio of 25 to 55%,
By mixing kneading concrete using AE water reducing agent or high performance AE water reducing agent according to JIS A 6204 as admixtures with unit volume weight of the fresh concrete is formulated to be 1.8~2.1 t / m ^3, a lightweight In addition, concrete having a self-wetting curing function can be obtained. This concrete can exhibit the same compressive strength as that obtained by subjecting concrete using ordinary aggregate to standard underwater curing, even if the weir is removed from the concrete one day after casting. That is, even though it is lightweight concrete, the same compressive strength as that of ordinary concrete can be achieved without standard curing. Further, the concrete according to the present invention is suppressed in neutralization and exhibits low shrinkage, so that a structure excellent in durability can be obtained.

Further, when mixing the lightweight aggregate concrete having a unit volume mass of 1.8 to 2.1 t / m ³ using the artificial aggregate, adjusting the water-cement ratio and using a high-performance AE water-reducing material. When the slump flow is 45 cm or more of high-fluidity concrete, it is lightweight and high-fluidity,
36 N / mm, which was difficult with conventional lightweight concrete
High-strength concrete with a compressive strength exceeding ² can be obtained, and at the same time, weight reduction, high fluidity, and high strength that cannot be achieved using ordinary aggregate can be achieved.

Furthermore, when fly ash or silica fume is blended as an admixture with the concrete of the present invention, the action of densifying the concrete is added to the action of self-wetting and curing.
High strength concrete with high strength and thermal crack resistance can be obtained.

Furthermore, the concrete according to the present invention exhibits higher compressive strength and higher tensile strength than concrete using ordinary aggregate when hardened in an adiabatic curing form or when cast as mass concrete. As a result, high quality concrete with improved crack resistance can be obtained.

Representative examples of concrete having a self-wetting curing function, lightweight, high-strength concrete, lightweight, high-flow, high-strength concrete and high-durable concrete manufactured using such artificial aggregates will be described below. The content of the present invention will be specifically described.

[0027]

[Example 1]: Concrete having a self-wetting curing function. The characteristics of the concrete of the present invention are shown below in comparison with ordinary concrete.

[0028] Materials used 1) Cement: ordinary Portland cement (specific gravity 3.16) 2) Fine aggregate 1: land sand (specific gravity 2.60) 3) Fine aggregate 2: absolute dry specific gravity = 1.16, hot water absorption = 15%, particle size = Granules of 5 mm or less. This is because artificial bone with a specific gravity of 1.52, absolute water absorption of 1.52, hot water absorption of 15%, and crushing load of 1130N in accordance with JIS Z 8841 (coal ash and shale fine powder having the chemical component values described in the text are obtained under the above conditions. (A calcined product obtained by sintering and cooling) is crushed and classified to obtain a powdery material of 5 mm or less. 4) Coarse aggregate: 4-1) In the case of ordinary concrete: crushed stone (specific gravity 2.6
5) 4-2) In the case of the concrete of the present invention ... specific gravity of absolute dryness = 1.5
2, hot water absorption = 15%, crushing load according to JIS Z 8841 = 113
0N artificial aggregate (fired product obtained by sintering and cooling coal ash having the chemical component values described in the text and fine shale powder under the above conditions)
15 to 5 mm coarse particles obtained by crushing and classifying 5) Admixture: AE water-reducing agent among chemical admixtures for concrete specified in JIS A 6204 (trade name: Pozoris No. 70)

[0029] Test items and test method Using the above materials, kneading the concrete of the present invention with the concrete shown in Table 1 at a water cement ratio of 50%, slump test, air volume test, compressive strength test, drying shrinkage test, A neutralization test and a concrete moisture content test were performed. The test method is as follows.

1) Slump test: In accordance with JIS A 1101. 2) Air volume test: In accordance with JIS A 1101. 3) Compressive strength test: The test was performed in accordance with JIS A 1108, except that the curing conditions of the specimen were changed to three types (a) to (c). Curing condition (a): Standard water curing Curing condition (b): After curing for one day in a mold, remove the mold and remove it from the air to cure in air in a room at 20 ° C and 60% humidity Curing condition (c): Mold After curing for 7 days, the mold is removed and aerial curing is performed in a room at a temperature of 20 ° C. and a humidity of 60%. 4) Concrete moisture content test: Both concretes were subjected to the pre-curing described in (a) to (c) above. At the specified age
After measuring the mass (W1) of the specimen containing water, the specimen was dried for 10 days in a drying oven at 105 ° C., and the mass (W2) after the drying was measured, and 100 × (W1−W2). /
The water content was calculated according to the formula of W1. 5) Drying shrinkage test: According to JIS A 1129. 6) Neutralization test: Architectural Institute of Japan, "High Durable Reinforced Concrete Design, Construction, Guidelines, and Explanations", Architectural Institute of Japan 199
1 year version, pages 179 to 184, according to the accelerated neutralization test method for concrete (draft).

Table 2 shows the test results of the fresh properties (slump, air amount, temperature, unit volume mass). Fig. 2 shows the results of compressive strength test (relation between curing conditions and compressive strength).
Fig. 3 shows the results of the test of the moisture content of concrete (the relationship between the age and the water content of the concrete), Fig. 4 shows the results of the drying shrinkage test (the relationship between the material and the drying shrinkage), and Fig. 5 shows the neutralization test. (The relationship between the material and the depth of neutralization).

[0032]

[Table 1]

[0033]

[Table 2]

[0034] In the formulation of Table 1, ordinary concrete of the present invention concrete and B ₁ A ₁ is obtained by equalizing the total aggregate volume of fine aggregate + coarse aggregate, cement, water, A
E The composition of the water reducing agent is the same. Its Fresh properties, as seen in Table 2, towards the present invention concrete A ₁ is higher slump value and air content, whereas unit volume mass is usually concrete B ₁ in 2.3t / m ^3, in concrete a ₁ of the present invention is 1.9 t / m ³ and weight.

[0035] From the results of FIG. 2, when compared with those of the age of 28 days, the compressive strength of the present invention concrete A ₁ that of stripping the mold 1 day shows a 45N / mm ² degree, which is usually concrete B ₁ Is almost the same value as that obtained by curing in standard water. Also, when compared with a material of 91 days of age, the compressive strength of A ₁ which was left on the mold for 1 day shows about 48 N / mm ² ,
Which is about 1.3 times higher than those ones of B ₁ was of stripping the mold 1 day is about 38N / mm ^2, is substantially equal to that of the B ₁ was of stripping the mold 7 days.

Thus, the concrete A of the present invention
₁ means that the mold can be removed from the mold in one day, and then the strength can be expressed well without external water supply.
It is clear that it has a self-moisturizing curing function (self-curing action), and the same quality as when ordinary concrete is sufficiently cured even if the mold is left on the site for one day and no curing water is supplied. It can be seen that site work can be streamlined and construction can be facilitated.

From the results shown in FIG.₁
Is more apparent. example
For example, the concrete A of the present invention which has been cured for one day₁(■
The moisture content at 7 days old is 8%.
Normal concrete B cured under water₁(With ○)
Of about 6.5%. That is, the concrete of the present invention
A ₁Then, even without external makeup water,
Sufficient water is ensured at the early age when hydration enhancement is particularly marked.
And this water acts as curing water.
(Ie, by the self-curing effect), as shown in FIG.
It can be considered that this contributed to the increase in the compressive strength.

Further, the concrete A ₁ of the present invention promotes the hydration of the cement for a long time under the same curing condition than the ordinary concrete B ₁ due to the self-wetting curing action (black coating in FIG. 2). The ones with a mark have a higher moisture content at all ages than those with a white one),
It can be considered that the hydration product densifies. The results in FIGS. 4 and 5 demonstrate this. That is, the present invention concrete A ₁ is compared to plain concrete B _1, since it has been halved neutral depth as drying shrinkage as seen in FIG. 4 has halved, also seen in FIG. 5 ,
It can be seen that the self-wetting curing action results in a concrete with low drying shrinkage and excellent durability, which is hardly neutralized.

Example 2 Light Weight, High Strength, High Fluidity Concrete The properties of the concrete of the present invention are shown below in comparison with ordinary concrete.

[0040] Materials used 1) Cement: Ordinary Portland cement (specific gravity 3.16) 2) Fine aggregate: land sand (specific gravity 2.60) 3) Coarse aggregate: 3-1) In the case of ordinary concrete: crushed stone (specific gravity 2.6)
5) 3-2) In the case of the concrete of the present invention ... specific gravity of absolute dryness = 1.5
2, hot water absorption = 15%, crushing load according to JIS Z 8841 = 113
0N artificial aggregate (fired product obtained by sintering and cooling coal ash having the chemical component values described in the text and fine shale powder under the above conditions)
15 to 5 mm coarse particles obtained by crushing and classifying 4) Admixture: High-performance AE water reducing agent among the chemical admixtures for concrete of JIS A 6204 (trade name: Pozoris SP-8)
N) 5) Admixture: coal ash (fly ash) or silica fume

[0041] Test items and test methods Using the above materials, water cement ratio (water binder ratio) =
The concrete A ₂ , A ₃ and A ₄ of the present invention were mixed with 35% of the ordinary concrete B ₂ having the composition shown in Table 3 and subjected to a slump test, a slump flow test, an air volume test, and a compressive strength test. The test method is as follows.

1) Slump test: According to JIS A 1101. 2) Slump flow test: According to JASS 5T-303. 3) Air volume test: In accordance with JIS A 1101. 4) Compressive strength test: In accordance with JIS A 1108.

Table 4 shows the test results of the fresh properties of each concrete (slump, slump flow, air volume, temperature,
(Mass per unit volume). FIG. 6 shows the results of the compressive strength test of each concrete.

[0044]

[Table 3]

[0045]

[Table 4]

In the composition shown in Table 3, the concretes A _{2 to} A ₄ of the present invention and the ordinary concrete B ₂ were fine aggregate + coarse aggregate +
The total aggregate volume of the (admixture) is equal, and the blends of cement (binder), water, and high-performance AE water reducing agent (ratio to binder) are also equal. Its Fresh properties, as seen in Table 4, the present invention concrete A ₂ to A ₄ are compared to plain concrete B _2, while the slump is substantially equal, high flow and slump flow value increased both Is shown. In particular, the present invention concrete A ₂ not incrementally added to the powder such as fly ash and silica fume shows high fluidity is noteworthy. Further, the concrete of the present invention has a high air volume, a low unit mass and a low weight.

[0047] From the results of FIG. 6, the compressive strength of the high-flow concrete A ₂ of the present invention is ordinary concrete B ₂ equivalent to that of 65N / mm ² (age of 28 days), 80 N / mm ² (age of 90 days) It can be seen that it has a high strength that far exceeds the design standard strength of 36 N / mm ² , which is difficult to use a normal artificial lightweight aggregate.

[0048] A particular, in the present invention Concrete A ₄ were added the present invention concrete A ₃ and silica fume were added fly ash exhibits high compressive strength than ordinary concrete B _2, light weight and high strength are achieved at the same time Further, it has a unique property of being excellent in fluidity. The concrete A ₃ and A ₄ showed higher strength than B ₂ and A _2, filling effect and pozzolanic reaction effect that fine powder is filled in the gap portion between the aggregate may be seen to have contributed. That is, the voids at the interface between the hardened cement and the aggregate are densified, and high strength is developed. In addition,
All of the specimens subjected to the measurement of the compressive strength were cured in standard water, but as seen in Example 1 above,
The present invention Concrete A ₂ to A ₄ has a self-moist curing function. Therefore, what the densification A ₃ and A _4, which is achieved, the B ₁ .about.B ₂ further than the A ₁ to A _2, is further drying shrinkage is reduced and suppressed progression of neutralization depth It is clear that the concrete has high strength and high durability.

Example 3 High Tensile Strength Light Weight Concrete The properties of the concrete of the present invention are shown below in comparison with ordinary concrete.

[0050] Materials used 1) Cement: ordinary Portland cement (specific gravity 3.16) 2) Fine aggregate 1: land sand (specific gravity 2.60) 3) Fine aggregate 2: absolute dry specific gravity = 1.16, hot water absorption = 15%, particle size = Granules of 5 mm or less. This is artificial bone with absolute dry specific gravity = 1.52, hot water absorption = 15%, crushing load = 1130N according to JIS Z 8841 (coal ash and shale fine powder having the chemical component values described in the text are described in the text. A sintered product obtained by sintering and cooling under the conditions) is crushed and classified, and is a powdery material of 5 mm or less. 4) Coarse aggregate: 4-1) In the case of ordinary concrete: crushed stone (specific gravity 2.6
5) 4-2) In the case of the concrete of the present invention ... specific gravity of absolute dryness = 1.5
2, hot water absorption = 15%, crushing load according to JIS Z 8841 = 113
0N artificial aggregate (fired product obtained by sintering and cooling coal ash having the chemical component values described in the text and fine shale powder under the above conditions)
15 to 5 mm coarse particles obtained by crushing and classifying 5) Admixture: High-performance AE water reducing agent among concrete admixtures for concrete of JIS A 6204 (trade name: Pozoris SP-8)
N) 6) Admixture: coal ash (fly ash) or silica fume

[0051] Test items and test methods Using the above materials, water cement ratio (water binder ratio) =
Ordinary concrete B ₃ of the formulations shown in Table 5 with 50%, kneading the present invention concrete A _5, A ₆ and A _7, for its fresh properties, slump test was carried out air volume test. In addition, measurement of temperature history, compressive strength test, and tensile strength test when simple adiabatic curing was performed were performed. The test method is as follows.

1) Slump test: In accordance with JIS A1101. 2) Air volume test: In accordance with JIS A 1101. 3) Compressive strength test: According to JIS A 1108. 4) Insulation curing: Ten specimens obtained by driving concrete into a cylindrical form having a diameter of 10 cm and a height of 20 cm were set in a styrene foam container shown in FIG. The upper surface was sealed and cured so that water did not evaporate. A thermocouple was embedded at the center of one of these specimens, the history of the internal temperature of the concrete was measured, and when the concrete temperature returned to room temperature, each specimen was taken out of the container and kept at a predetermined age. It was sealed and cured in a room at 60 ° C. × 60%.

Table 6 shows the test results (slump, air amount, temperature, unit volume mass) of the fresh properties of each concrete. FIG. 8 shows the results of the compressive strength test of each concrete adiabatically cured, and FIG. 9 shows the results of the tensile strength test of each concrete adiabatically cured.

[0054]

[Table 5]

[0055]

[Table 6]

In the composition shown in Table 5, the concretes A _{5 to} A ₇ of the present invention and the ordinary concrete B ₃ were fine aggregate + coarse aggregate +
The total aggregate volume of the (admixture) is equalized, and the blending of cement (binder), water, and high-performance AE water reducing agent (ratio to binder) does not change much. Its Fresh properties, as seen in Table 6, the present invention concrete A ₂ to A ₄ are, except a lighter than ordinary concrete B _2,
There is no significant difference in slump or air volume. However, although the concrete of the present invention was lighter in weight than ordinary concrete, as shown in FIG. 8 and FIG. 9, the result that the compressive strength and tensile strength were higher than that of ordinary concrete was obtained.

[0057] That is, as seen in FIG. 8, the compressive strength of the concrete A ₅ of the present invention is higher than that of ordinary concrete B _3, concrete A ₆ and A ₇ of the present invention show a higher compressive strength . Similarly, as seen in FIG. 9, the tensile strength of the concrete A ₅ to A ₇ of the present invention is 1.3 to 1.5 times higher than that of ordinary concrete B _3.
This is because, in the concrete of the present invention, which has sufficient curing water inside, when adiabatic curing is performed, the high-temperature state due to the heat of hydration is favorably maintained. As a result, the hydration of the cement and the pozzolanic reaction are accelerated, and the concrete is densified. It is thought that it depends. Therefore, the concrete of the present invention has a special property that the compression strength and the tensile strength increase when the curing proceeds in an adiabatic form in which the supply of the curing water from the outside is cut off. Since it also appears in mass concrete, it means that when applied to a heat-insulating formwork or casting of mass concrete, concrete with increased tensile strength and reduced temperature cracks can be obtained.

[0058]

As described above, according to the present invention, a concrete having a self-wetting curing action is provided, and the concrete is lightweight. In addition, it is possible to manufacture a lightweight, high-flow, high-strength concrete with unprecedented performance, such as high fluidity and high strength, and prevention of temperature cracking.

[Brief description of the drawings]

FIG. 1 is a table and a graph showing an example of the distribution of the pore radius of the artificial aggregate used in the present invention.

FIG. 2 is a diagram comparing the compressive strengths of concrete A and ordinary concrete B according to the present invention with different curing methods.

FIG. 3 is a diagram showing the change over time in the water content of concrete A and ordinary concrete B according to the present invention.

FIG. 4 is a diagram showing a change over time in the drying shrinkage ratio of concrete A and ordinary concrete B according to the present invention.

FIG. 5 is a diagram showing a change with time of the neutralization depth of concrete A and ordinary concrete B according to the present invention.

FIG. 6 is a diagram comparing the compressive strengths of concrete A and ordinary concrete B according to the present invention.

FIG. 7 is a schematic cross-sectional view for explaining a curing method of an adiabatic curing test.

FIG. 8 is a diagram comparing the compressive strengths of the concrete A according to the present invention and the ordinary concrete B that have been adiabatically cured.

FIG. 9 is a diagram comparing the tensile strength of concrete A and ordinary concrete B according to the present invention that have been adiabatically cured.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 14:04 C04B 14:04 A 14:02 14:02 B 20:00) 20:00) B 103: 30 103: 30 103: 32 103: 32 111: 40 111: 40 (72) Inventor Hiroshi Kasai 2-9-1-1, Tobita-Sen, Chofu-shi, Tokyo Kashima Construction Co., Ltd. (72) Inventor Kazuhiko Inagaki Tokyo 3-7-1, Nishishinjuku, Shinjuku-ku Kashima Construction Co., Ltd. Kanto Branch F-term (reference) 4G012 PA04 PA27 PB04 PC02 PC11 PC12 PC14 4G019 DA04 LA02 LB01 LC13 LD02

Claims (6)

[Claims] 1. In a concrete comprising a binder, an aggregate and an admixture containing water and cement, JI is used as an admixture.
Use AE water reducing agent or high performance AE water reducing agent according to SA 6204, and use all or part of concrete aggregate as JIS
The crushing load according to Z 8841 is 1000-2000N,
1.4-1.8, water absorption using 12 to 20% of the artificial bone material, water cement ratio is 25 to 55%, each as yet solidified no unit volume weight of the concrete is 1.8-2.1 t / m ³ Concrete having a self-humidifying curing function characterized by blending materials. 2. A binder, aggregate containing water and cement, and
In cast-in-place construction of concrete containing admixture,
AE water reducer or high performance according to JIS A 6204 as admixture
Using AE water reducing agent, JIS as all or part of aggregate
 The crushing load according to Z 8841 is 1000-2000N,
Use artificial aggregate with 1.4 ~ 1.8, water absorption 12 ~ 20%, water
When the cement ratio is 25-55%, the unit mass is 1.8-2.
1 t / m ^ThreeMix each material so that it becomes concrete
Knead and beat the resulting concrete that has not yet set.
After installation, the crest plate is removed from the crust plate one day of age.
Concrete construction method. 3. A concrete comprising a binder, an aggregate and an admixture containing water and cement, wherein JI is used as an admixture.
Use AE water reducing agent or high performance AE water reducing agent according to SA 6204, and use all or part of concrete aggregate as JIS
The crushing load according to Z 8841 is 1000-2000N,
1.4-1.8, water absorption using 12 to 20% of the artificial bone material, water cement ratio is 25 to 55%, each as yet solidified no unit volume weight of the concrete is 1.8-2.1 t / m ³ Lightweight concrete that contains materials and exhibits high fluidity with a slump flow of 45 cm or more and compressive strength of the cured body exceeding 36 N / mm ² . 4. The lightweight concrete according to claim 3, further comprising fly ash or silica fume. 5. A concrete comprising a binder, an aggregate and an admixture containing water and cement, wherein JI is used as an admixture.
Using AE water reducer according to SA 6204 or high performance AE water reducer, crush load according to JIS Z 8841 is 1000-2000N, absolute dry specific gravity is 1.4-1.8, water absorption is 12-20% as all or part of aggregate. Water-cement ratio of 25 ~
Mixing and mixing concrete so that the unit volume mass becomes 1.8 to 2.1 t / m ³ under 55%, and curing the obtained unconsolidated concrete using an insulating formwork. Manufacturing method of high-strength lightweight concrete. 6. A concrete comprising a binder, an aggregate and an admixture containing water and cement, wherein JI is used as an admixture.
Using AE water reducer according to SA 6204 or high performance AE water reducer, crush load according to JIS Z 8841 is 1000-2000N, absolute dry specific gravity is 1.4-1.8, water absorption is 12-20% as all or part of aggregate. Water-cement ratio of 25 ~
Characterized in that 55% of the unit volume weight under the 1.8-2.1 t / m ³ and comprising as by blending each material kneading the concrete, in yet harden not concrete obtained for construction of massive concrete structure Mass concrete construction method.