JPH03265549A - Cement admixture and cement composition using the same - Google Patents

Abstract

PURPOSE:To obtain an admixture capable of imparting high strength to a cement composition and excellent in stability by calcining natural kaolin, halloysite or synthetic kaolin and specifying the amorphous part content and the diameter and sp.gr. of all the particles. CONSTITUTION:At least one kind of material among natural kaolin, halloysite and synthetic kaolin is calcined at 630-870 deg.C, and the calcined body is classified to obtain a cement admixture consisting essentially of an amorphous part, with the alumina-to-silica ratio controlled to 1.1-1.3, the diameter of all the particles to 8mum and the average particle diameter to 0.5-2.0mum and having 2.45-2.55 sp.gr. The admixture is added to cement by 5-30wt.% based on the total weight, and a thin aggregate, a water reducing agent and water are added and mixed to obtain a cement composition. The composition develops sufficient strength as in the case when a silica fume is used as the admixture and also develops high strength at an early stage, and the contraction due to drying is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cement admixture and a cement composition using the same, such as high-strength mortar or high-strength concrete.

<Prior Art> Conventional high-strength mortar is known to be a mixture of cement paste with a water-cement ratio of about 30%, an appropriate amount of fine aggregate, and silica hneem. Furthermore, high-strength concrete made by mixing such mortar with an appropriate amount of coarse aggregate is also known.

However, conventional products containing silica neem have high viscosity due to the silica neem. As a result, the fluidity when poured into a formwork is poor, resulting in poor workability.

Furthermore, since silica hneem is an ultrafine particle with a particle size of about 1/100 of that of cement, it scatters and is difficult to handle when used as is, so it is used in the form of granules. As a result, due to insufficient mixing time, dispersibility is poor and the desired quality cannot be obtained, and measures such as extending the mixing time are necessary to ensure quality.
The disadvantage was that the construction period was long.

On the other hand, as shown in JP-A No. 63-25256, alumina and silica are mainly used as admixtures in order to increase the alkali resistance to the glass fibers contained in the cement admixture material and to improve the strength. Some contain metakaolin as an ingredient.

<Problem to be solved by the invention> However, according to the above-mentioned known example, kaolinite is
It is obtained by heat treatment at 00 to 900°C, and usually such metakaolin has large variations in the particle size of the fine particles, with many particles having a particle size of less than 0.5 μm and more than 8 μm mixed together. There is. Particle size is 0.5μm
If it is less than 100%, the specific surface area is large and water absorption tends to increase accordingly, so when the water-to-cement ratio is low, a large amount of water reducing agent must be used, which has the disadvantage of being expensive. Further, as described above, there is a drawback that kneading and mixing takes time, resulting in a long construction period. On the other hand, if coarse particles with a particle diameter of more than 8 μl are mixed in, there are disadvantages in that required quality cannot be ensured, such as poor filling properties in concrete and failure to improve strength.

The present invention has been made in view of the above circumstances, and the invention of claim (1) provides a method for obtaining cement compositions such as high-strength mortar and high-strength concrete that does not require the development of high strength. In terms of workability, we have been able to provide cement admixtures that have low viscosity and high fluidity, and have excellent quality that is less affected by mixing time and other factors. The invention of claim (2) provides a high-quality, high-strength cement that can quickly develop high strength and has little shrinkage due to drying by using an appropriate amount of the cement admixture. The purpose is to obtain a composition.

<Means for Solving the Problems> In order to achieve the above-mentioned objects, the present invention provides a cement admixture according to the invention of claim No. At least one substance selected from 630-870℃
Calcined, alumina/silica composition ratio is 1.1 to 1.3
It is mainly composed of amorphous parts, and is classified so that the total particle size is 8 μm or less and the average particle size is 0.5 to 2.0 μm, and has a specific gravity of 2.45 to 2.55. It is characterized by being adjusted to.

Further, as the cement composition according to the invention of claim (2), at least one substance selected from the group consisting of natural kaolin, halloysite, and synthetic kaolin is used.
Calcined at 0 to 870℃, alumina/silica composition ratio is 1
．． Mainly composed of amorphous parts of 1 to 1.3, the total particle diameter is 8.
A cement admixture that has been classified so that the average particle diameter is 0°5 to 2.0μ and has a specific gravity of 2.45 to 2.55 is added to the internal cutting weight relative to the cement. It is characterized by the addition of 5 to 30% in terms of ratio, and the addition of fine aggregate, water reducing agent and water.

As a starting material for the cement admixture, any one of natural kaolin, halloysite, and synthetic kaolin may be used alone, or two or three of these may be used as a mixture.

Natural kaolin is a typical naturally occurring clay mineral and is more accurately called kaolinite. Af2S L Os
It is expressed by the chemical formula of (OH)4, and its theoretical value is 39.5% alumina (A1.03), silica (S i Oz
) 46.5%, water (H,0) 14.0%.

The crystal system is monoclinic, and it has a hexagonal plate-like particle shape under an electron microscope. Thermal properties are 100
It shows an endothermic peak due to the dehydration of attached water at the 'C' level, and water contained in the form of hydroxyl group OH creates a large endothermic peak around 600°C and dehydrates.

After the hydroxyl group OH is dehydrated, it becomes an amorphous state called metakaolin, and then an exothermic peak appears at 900 to 1000°C.

Commercial kaolin production involves removing the topsoil from a kaolin deposit, mining raw kaolin from the kaolin layer, and
Other impurities such as quartz and mica are removed. After this first refining step, the kaolin is made into a slurry and sent to a refining factory, where it is washed with water, dehydrated, and dried to become the first product.

The final product is then fired in horizontal or vertical kilns to improve whiteness, opacity, electrical insulation properties, strength, and durability.

Halloysite is a typical naturally occurring clay mineral and is included in the kaolin group, but it contains excessive water and has low crystallinity. AI, Sj, 0(OH)a ・2H
It is expressed by the chemical formula 20, but when it dries in nature, it goes through an intermediate hydrated state and changes to a state that contains almost no water between the eyebrows. The crystal system is a single-component system, and when viewed under an electron microscope, it takes the form of elongated, tubular particles. As for thermal properties, it exhibits an endothermic peak due to dehydration of interlayer water at about 100°C, and water contained in the form of hydroxyl group OH forms a large thermal peak around 550°C and dehydrates.

Does synthetic kaolin contain aluminum and silicon? A1-
Kaolin minerals are synthesized by methods such as organic complex decomposition methods and synthesis under hydrothermal conditions using natural minerals. The alumina/silica composition ratio is 1.1 to 1.3. If the composition ratio is less than 1.1, there are disadvantages such as a lack of strength development effect and the inability to obtain the required quality.
．． If it exceeds 3, there is a problem that the required quality cannot be obtained, such as a large amount of alumina, which delays the hardening of the cement.

The furnace temperature of the admixture is controlled at 630 to 870°C. The reason for this is that when the furnace temperature is below 630°C, the proportion of amorphous components that maintain their molecular structure is low, and therefore the pozzolanic reaction is difficult to occur;
This is because when the temperature exceeds 70°C, the molecular structure collapses, crystal transition occurs, recrystallization occurs and changes into another mineral, and the proportion of amorphous components becomes low, making it difficult for pozzolanic reactions to occur.

The above-mentioned admixture is classified so that the total particle size is 8 μm or less and the average particle size is 0.5 to 2.0 μm. This is because if coarse particles with a particle size exceeding 8 μm are mixed in, the filling properties in the concrete will be poor and the strength will not be improved, as described above.

On the other hand, if the average particle size is less than 0.5μ, as mentioned above, the amount of water reducing agent used increases when using a shrub-cement ratio.
Furthermore, there are conflicts that are difficult to knead. Moreover, if the thickness exceeds 2.0 μm, there is a problem that sufficient strength cannot be developed.

Further, the specific gravity of the admixture is adjusted to be 2.45 to 2.55. If the specific gravity is less than 2.45, the alumina/gluing force ratio will be affected and there will be no strength development effect, while if the specific gravity exceeds 2.55, the amount of alumina will increase, causing problems such as delayed curing.

When the above admixture is added to cement, it is added in an amount of 5 to 30% by weight relative to cement. This is because if it is less than 5%, the effect will be small, while if it exceeds 30%, the strength development effect will be reduced. Therefore, preferably 10 to 2
It is 0%.

Aggregates include general sand, gravel, crushed stone, and crushed sand, as well as silica, pyrite, hematite, magnetite, yellow jade, lawsonite, corundum, zenasite, spinel, beryl, whole stone, tourmaline, and granite. , andalusite, cross stone, zircon, calcined bauxite, silicon carbide, tungsten carbide, ferrosilicon nitride, silicon nitride, melting force, electrofused magnesia, cubic silicon nitride, iron powder, iron ball, heavy calcined banded rock, Hard aggregates such as great wall stone and fused alumina can be used.

As the water reducing agent, those containing as main components salts of naphthalene sulfonic acid formaldehyde condensates, salts of melamine sulfonic acid formaldehyde condensates, polymeric lignin sulfonates, polycarboxylate salts, etc. can be used.

As the cement, various Portland cements such as ordinary, early strength, ultra early strength, white, sulfate resistant, etc., as well as mixed cements containing blast furnace slag, fly ash, etc., can be used.

<Effect> As a result of various experiments, as mentioned above, the furnace temperature, alumina/
By using a cement admixture that has been refined by adjusting the composition ratio of silica, the maximum diameter of all particles, the average particle diameter, and the specific gravity, cement compositions such as high-strength mortar and high-strength concrete can be created even though the viscosity is relatively low. The inventors have discovered that it is possible to develop sufficient strength in the same way as when silica hneem is used as an admixture, and that high strength can be developed quickly and shrinkage due to drying can be reduced.

<Example> Next, an example of the present invention will be described in detail based on the drawings.

First, a kaolin slurry is prepared by mixing the raw material kaolin with water and a dispersant such as sodium tripolyphosphate.

Next, the particles are classified by specific gravity separation and centrifugation to adjust the average particle diameter to 1 to 2 μm and remove impurities.

After that, it is subjected to a grinding treatment and a classification treatment such that all particle diameters are 8 μI or less and the average particle diameter is 0.5 to 2 μI.

After that, after dehydrating and drying, 630-87
It is calcined in a controlled temperature range of 0°C, and has alumina and silica as its main components, and has an alumina/silica composition ratio of 1.1 to 1.3 and a specific gravity of 2.45 to 2.55. Refining cement admixtures.

Next, the results of an X-ray diffraction test conducted to verify the degree of amorphization of the cement admixture and comparative example will be described.

As the cement admixture in the example, the above-mentioned one was used,
As a comparative cement admixture, the following No. 1
Comparative Example and Second Comparative Example were used.

Kaolin, which is the starting material for the cement admixture in the above example, was used.

The kaolin used as the cement admixture in the above-mentioned example was not calcined, but simply calcined at 900 to 1000°C.

Equal amounts (500 mg) of each of the cement admixtures of the above examples, first comparative example, and second comparative example were packed in an aluminum sample holder, and powder X-ray diffraction method (reflection method) was performed.
The vertical axis shows the X-ray intensity, and the horizontal axis shows the X-ray diffraction angle (2θ=180°). The graph shown in is obtained.

The measurement conditions are as follows.

(1) X-ray generator manufactured by Rigaku Denki Co., Ltd.: RU-200B (rotating anode cathode type) .0°-0.15-1,06 detector:
Scintillation counter (3) Counting and recording device manufactured by Rigaku Denki Co., Ltd.: RAD-B type From the above results, the cement admixture of the example has a smaller diffraction peak than both the first and second comparative examples, and moreover, the diffraction peak is diffuse. It is clear that it has a high strength and a strong degree of amorphization, and that it is likely to cause a pozzolanic reaction when used as a cement admixture.

Next, examples and comparative examples of mortar will be described.

After mixing the cement admixture prepared and refined as described above with ordinary Portland cement as cement and standard Toyoura sand as aggregate for 15 seconds,
Chewpol HP-8 modified (manufactured by Takemoto Yushi Co., Ltd.), which is a high-performance water-reducing material, was mixed with water, stirred for 30 seconds, scraped off, and finally stirred for 120 seconds to obtain a mortar specimen. An omnimixer was used for both the above-mentioned drying and stirring.

A mortar specimen was obtained in the same manner as in the above example except that the cement admixture was omitted from the above example.

Silica hneem produced in Iceland was mixed as a cement admixture into the mol of the above-mentioned first comparative example, and a mortar specimen was obtained in the same manner as in the above-mentioned example.

The composition ratios of the cement admixture of the above example and the silica hneem of the second comparative example are shown in Table 1.

(Hereinafter, blank spaces) Table 1 (Mortar) The mortar formulation is as shown in Table 2.

Table 2 (Mortar) Using each of the mortar specimens mentioned above, the properties of mortar that have not hardened yet include air content (%: 1 based on the method of JIsA6201), temperature ("C: measured with a rod thermometer)" and flow value (ffim: based on the method of JIS A 5201) were measured, and the compressive strength (kgf/cffl) at 1 week, 4 weeks, and 8 weeks of age was measured.

The measurement results are shown in Table 3.

(Hereinafter, blank space) In addition, graphs comparing the amount of water reducing agent used, fluidity (flow value), and compressive strength described above are shown in Figures 2 and 3.
and FIG. 4, respectively.

From the above results, it is clear that the high-strength mortar according to the present invention can develop high strength earlier and obtain higher compressive strength than both the first and second comparative examples. In addition, it has excellent fluidity despite the addition of cement admixtures.

The strength of the second comparative example that used silica hneem as a cement admixture was lower than that of the first comparative example that did not use an admixture because the stirring conditions were the same. This is thought to be due to insufficient pulverization. That is, it is presumed that if pulverization is performed sufficiently, a strength close to that of the example can be obtained.

Next, high strength concrete will be explained.

Con r- A mixture of the cement admixture prepared and refined as described above, ordinary Portland cement as cement, Ogijima offshore sea sand (70%) and crushed sand from Ako (30%) as fine aggregate. Sand (specific gravity: 2.55, coarse grain ratio: 2.17),
Crushed stone from Ako (specific gravity: 2.63) as coarse aggregate
After mixing by dry kneading for 5 seconds, Chewpol HP-8 modified (manufactured by Monomoto Yushi Co., Ltd.) as a high-performance water reducing agent and water were mixed at a water-cement ratio of 30%, stirred for 30 seconds, and then scraped off. Finally, the mixture was stirred for 120 seconds to obtain two concrete specimens (NO, 1a, and lb, which will be described later). The amount of cement admixture added is 15% in internal cutting to cement. A single-shaft pan-type mixer was used for both the above-mentioned drying and stirring.

Con I-9 From the above-mentioned example, the cement admixture was omitted, and two concrete specimens (specimens No. 2a, 2b to be described later) were obtained in the same manner as in the above-mentioned example.

9. Silica hneem from Iceland was mixed as a cement admixture with the one in Comparative Example 1, and two concrete specimens (specimen No. 1 to be described later,
3a, 3b) were obtained.

・ Metakaolin was added as a cement admixture to Comparative Example 1 above (out of all particles, 15 particles had a particle size exceeding 8 μm).
Containing ~25%) was mixed, and a concrete specimen (specimen No. 4 to be described later) was mixed in the same manner as in the above example.
) was obtained.

Con 1 - Fine silica powder with an average particle size of 5 μm was mixed as a cement admixture with the material of Comparative Example 1, and a concrete specimen (specimen No. 5 to be described later) was prepared in the same manner as in the above Example.
I got it.

Con 1 - To the above Comparative Example 1, a cement admixture that had been simply calcined instead of the calcination treatment in the previous example was mixed, and a concrete specimen was prepared in the same manner as in the above example. (Specimen No. 016 to be described later) was obtained.

Table 4 shows the composition ratios of cement admixtures 2.3.4 and 5 in the above Examples and Comparative Examples.

(Hereinafter, blank spaces) Table 4 (Concrete) Table 5 shows the formulations of concrete for each of the above Examples and Comparative Examples 1.2.3.4 and 5.

(The following is a blank space) Table 5 (Concrete) Using each of the concrete specimens mentioned above, the properties of concrete that has not hardened yet include the amount of high performance water reducing agent used, slump value (cv), and air content (%: J■S A 6201
(based on the method of LISA 5201), temperature (°C: measured with a rod thermometer), and flow value (an: , based on the method of LISA 5201).

The measurement results are shown in Table-6. In addition, each specimen except the specimen of Comparative Example 5 had a slump value of 19.
Fig. 5 shows a graph comparing the average amount of high performance water reducing agent used when the slump value is set to 191 cm, and Fig. 6 shows a graph comparing the fluidity when the slump value is set to 191 cm. In these graphs shown in Table 1, Examples, Comparative Examples 1 and 2 each show values corrected based on the averaged value of the two values, and Comparative Examples 3 and 4 each show the values corrected based on the averaged value of the two values. The values are corrected based on the values in the table, and the values are as follows.

Example of usage amount of water reducing agent: 1.71, Comparative example 1: 1.13, Comparative example 2+
2.79 Comparative Example 3: 1.95, Comparative Example 4: 1.38
, Comparative Example 5: 1.90 Fluidity Example: 361, Comparative Example 1: 375, Comparative Example 2
: 314, Comparative Example 3: 299, Comparative Example 4:
335, Comparative Example 5: 530 (hereinafter referred to as blank space) The percentages shown above are also 1a; 2b; 4; The water reducing agents in Table 6 are expressed in (%) based on the weight of cement.

The material that reached the highest temperature for each specimen was investigated and found to be as follows.

11:25.1 b; 11:00.2 a; 13
:15.12:30.3 a; 15:20.3 b
; 14:00.13:35, 5; 15:30, 6
;14:00 Furthermore, the compressive strength (kgf/c-d) of each specimen at 1 week and 4 weeks of age, and the age of 1 week.
When the drying shrinkage rate (XIO-') was measured at 1 week, 4 weeks, 8 weeks, 3 months, 6 months, and 8 months, the results shown in Table 7 (a) and (b) were obtained. Ta. In addition, Fig. 7 shows a graph comparing the compressive strength of each specimen except for Comparative Example 5, and Fig. 8 shows a graph comparing the degree of change in drying shrinkage. A graph showing the relationship between compressive strength and cement water ratio (C/W) is shown in FIG.

In the graph comparing compressive strength, Example and Comparative Example 1
In each of Comparative Example 2 and Comparative Example 2, values obtained by averaging two types of values are shown. Further, in the graph comparing the degree of change in drying shrinkage, the values are shown based on the value 1a in Examples, the value 2a in Comparative Example 1, and the value 3a in Comparative Example 2.

(Hereinafter, blank space) Table 7 (a) Table (b) (Hereinafter, blank space) From the above results, the test specimens according to the examples of the present invention were compared to Comparative Examples 1.2.3.4 and 5. It was clear that high compressive strength could be developed at an early stage even when drying, and workability was improved.It was also clear that drying shrinkage was low and there were fewer cracks due to drying, improving quality.

Furthermore, in concrete using the admixture of the present invention,
When the compressive strength was measured by changing the water-to-cement ratio and the addition rate to cement (expressed as a percentage of the internal cutting weight ratio), the results shown in Table 8 were obtained. In addition, the graph showing the relationship between the cement admixture ratio and the compressive strength at a water-cement ratio of 25% for the specimens of the example is shown in the 10th graph.
In addition, FIG. 11 shows a graph showing the relationship between the cement admixture ratio and compressive strength at a water-cement ratio of 35%.

(The following is a blank space) Table 8 From these results, the addition rate of cement admixture to cement can be practically applied in the range of 5 to 30%, and 10 to 20%.
It is estimated that it can be suitably implemented within the range of %.

Next, the results of an experiment conducted to estimate the mechanism by which the strength of concrete can be increased by the cement admixture according to the present invention will be explained.

As the cement admixture, the cement admixture of the above-mentioned example, silica hneem, and the cement admixture of the above-mentioned second comparative example that was simply fired were used, and 1 g of each cement admixture was mixed with calcium hydroxide Ca (OH). !
Prepare samples by adding Ig and 30 g of simulated breathing water and dispersing with ultrasonic waves for 5 minutes.
Two months after the sample was completely gelled, the reaction product was identified by the same powder X-ray diffraction method as described above, and the results shown in FIG. 12 were obtained. Further, when the morphology was observed using an electron microscope (magnification: 5000 times), the results shown in FIG. 13 were obtained.

The above-mentioned pseudo breathing water contains 3.65 g of sodium hydroxide NaOH and potassium hydroxide KOH according to the composition ratio obtained based on the analytical values of cement breathing water.
8.02g, calcium hydroxide Ca (OH)! 1.
It was prepared by dissolving 27g in 11 parts of water.

The cement admixture of the above-mentioned example, silica hneem, and the cement admixture of the above-mentioned second comparative example, which was simply fired, were added to cement Ig and 30% of water.
When the reaction product was identified by powder X-ray diffraction method after 2 months as in the case described above, the first
The results shown in Figure 4 were obtained.

As a result of this experiment, the following was evident for each of the example sample, silica hneem sample, and second comparative example sample.

Example sample: As shown in Figures 12(a) and 14(a), crystallization reactions such as ettringite formation occur simultaneously with the pozzolanic reaction, and as shown in Figure 13(a). As can be seen, new crystals are generated by recrystallization.

Silica hneem sample: Fig. 12 (b) and Fig. 14 (
As shown in b), only a pozzolanic reaction occurs, and as shown in FIG. 13(a), no new crystals are generated.

Second Comparative Example: As shown in FIG. 12(c) and FIG. 14(C), most of the reactions are pozzolanic reactions, and
As seen in FIG. 13(c), although there is a change in morphology compared to the silica hneem sample, no new crystals are generated.

For these reasons, according to the present invention, the pozzolan reaction and
It is presumed that the simultaneous occurrence of crystal reactions such as ettringite formation makes it possible to improve initial strength, and that the generation of new crystals through recrystallization makes it possible to reduce shrinkage due to drying.

<Effects of the Invention> According to the present invention, there is no variation in particle size, the viscosity is low and there is no sticking ability, so the fluidity is high, and since it is easy to stir, it can be mixed well even in a short kneading time. It is not easily affected by the amount of mixing time, and can be quickly and easily poured into the mold, and it has become possible to obtain products of stable quality.

In addition, due to its high fluidity, it is possible to improve filling properties and easily finish the concrete surface.It also shortens the construction period and stabilizes and improves quality such as compressive strength and drying shrinkage. It became so.

In addition, using the above cement admixture, add 5 to 30% of the internal cutting weight ratio to cement to cement, and add aggregate,
High-strength mortar, which is a cement composition obtained by mixing a water-reducing agent and water, can develop high strength early and improve workability. It also has less drying shrinkage and stable quality, making it easier to use. Can develop strength. The same applies to high-strength concrete as a cement composition obtained by mixing coarse aggregate with this high-strength mortar.

[Brief explanation of drawings]

The drawings show examples of cement admixtures and cement compositions using the same according to the present invention, FIG. 1 is a graph showing the relationship between chi-ray diffraction angle and X-ray intensity, and FIG. P
Figure 3 is a graph comparing the usage of I, Figure 3 is a graph comparing fluidity, Figure 4 is a graph comparing compressive strength, Figure 5 is a graph comparing usage of high performance water reducing agent, 6th
Figure 7 is a graph comparing fluidity, Figure 7 is a graph comparing compressive strength, Figure 8 is a graph comparing the degree of change in drying shrinkage, and Figure 9 is a graph comparing compressive strength and cement water ratio. The graph showing the relationship, Figure 10, shows the water-cement ratio of 25%.
Figure 11 is a graph showing the relationship between the cement admixture ratio and compressive strength at a water-cement ratio of 35%.
Figure 2 is a graph showing the relationship between X-ray diffraction angle and X-ray intensity;
FIG. 13 is a photograph taken by an electron microscope, and FIG. 14 is a graph showing the relationship between X-ray diffraction angle and X-ray intensity. (cx '10)

Claims (2)

[Claims] (1) At least one substance selected from the group consisting of natural kaolin, halloysite, and synthetic kaolin.
Calcined at 0 to 870℃, alumina/silica composition ratio is 1
．． Mainly composed of amorphous parts of 1 to 1.3, the total particle diameter is 8.
A cement admixture characterized in that it has been subjected to a classification treatment to have an average particle diameter of 0.5 to 2.0 μm or less, and has been adjusted to have a specific gravity of 2.45 to 2.55. (2) At least one substance selected from the group consisting of natural kaolin, halloysite, and synthetic kaolin.
Calcined at 0 to 870℃, alumina/silica composition ratio is 1
．． Mainly composed of amorphous parts of 1 to 1.3, the total particle diameter is 8.
A cement admixture that has been classified to have an average particle size of 0.5 to 2.0 μm and has a specific gravity of 2.45 to 2.55 is used at an internal weight ratio to cement. 1. A cement composition characterized by adding 5 to 30% of fine aggregate, a water reducing agent, and water.