JP4090772B2 - Cement composition - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cement composition, and more particularly, to a cement composition that can be used for a mortar filler for reinforcing steel joints and the like, and is excellent in strength development, fluidity, and non-shrinkage.
[0002]
[Prior art]
Conventionally, in order to improve the strength of the cement composition, a method of reducing the water / cement ratio using a water reducing agent has been taken. However, when the water / cement ratio is approximately 30% by weight or less, sufficient fluidity cannot be obtained and workability is lowered. Therefore, a grout material composition (Japanese Patent Laid-Open No. 09-263438) is proposed that has high fluidity even at low water volume by holding a small amount of water in advance in hydraulic cement, and can exhibit high strength with a compressive strength of 80 MPa or more. Has been. In addition, using ultra fine powder (silica fume), high-performance water reducing agent, and heavy aggregate, a grout mortar composition that secures a compressive strength of about 100 MPa (Japanese Patent Laid-Open No. 06-293549), or using early-strength cement, A grout material having a compressive strength of about 100 MPa (Japanese Patent Laid-Open No. 11-49549) has been proposed.
[0003]
However, for example, in filling mortars used for reinforced joints, with the recent increase in size and aseismic performance of reinforced concrete structures, high strength with a compressive strength of 120 MPa or more is desired while ensuring predetermined fluidity. It has become. Therefore, none can be said to have sufficient performance. Moreover, when naphthalenesulfonic acid formalin high condensate was used as a high-performance water reducing agent, it was difficult to maintain good fluidity for a long time, so satisfactory workability could not be obtained.
[0004]
Furthermore, a technique for producing high-strength concrete having a compressive strength of 120 MPa or more using a water-reducing agent mainly composed of a water-soluble vinyl copolymer having high water-reducing performance (Japanese Patent Laid-Open No. 06-191918) has also been proposed. . However, as in this technology, when ultrafine powder such as silica fume is blended with a cement composition with a very low water / binder ratio, the amount of cure shrinkage increases significantly, making it difficult to ensure no shrinkage. There was a problem of becoming.
[0005]
[Problems to be solved by the invention]
In view of the above problems, the present invention is suitable as a filler for reinforcing steel joints by having good and stable fluidity, high compressive strength, and good non-shrinkage, and a material other than water. An object of the present invention is to provide a cement composition that can be supplied in the form of a premix.
[0006]
[Means for solving the problems]
  In order to achieve the above object, the cement composition of the present invention comprises high belite cement and, A silica fume, a cement dispersant mainly composed of a polycarboxylic acid-based polymer compound having a polyalkylene glycol chain, either a lime-based admixture or an organic shrinkage reducing agent or both, a foaming agent,A fine aggregate having a specific gravity of 3.4 or more and a water absorption of 0.5 to 1.5%.containsA cement composition, wherein the kneaded product of the cement composition with water can maintain a flow value of 200 mm or more (static flow using a flow cone defined in JIS R 5201) for 60 minutes or more after kneading, In addition, the hydrated cured body of the mixture has a compressive strength (based on JIS R 5201) of 28 days of age of 120 MPa or more, and an expansion coefficient (based on JIS C-F533) of 0 to 1 up to 7 days of age. %WhenBecomeIt is characterized by that.
[0010]
In addition, all of the cement composition according to the present invention is suitable as a filler for reinforcing steel joints.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1. About performance
〔Liquidity〕
The cement composition of the present invention is required to maintain a flow value of 200 mm or more after kneading with water for 60 minutes or more after kneading. In the filling of reinforcing bar joints, which is the main purpose of the cement composition of the present invention, it is necessary to completely fill the filling mortar in the narrow gap between the reinforcing bar and the joint. Fluidity (flow value of 200 mm or more) is required. Furthermore, since the filling operation is usually performed on a plurality of reinforcing bar joints, a predetermined fluidity is maintained until the filling operation for a plurality of reinforcing bar joints is completed after a predetermined amount of filling mortar (cement composition) is manufactured. It is necessary to maintain (flow value of 200 mm or more), and if the fluidity retention time of 60 minutes or more after kneading can be secured, the filling operation can be performed without any trouble.
[0012]
〔Strength〕
In the cement composition of the present invention, it is essential that the compressive strength of the hydrated cured body at the age of 28 days is 120 MPa or more. In recent years, reinforced concrete structures have been made more durable (earthquake resistant) and lighter (reduced amount of reinforcing bars) through the use of high-strength reinforcing bars, etc. This is a very important issue. In order to further increase the durability and weight of reinforced concrete structures in the future, a filling mortar having a high strength of compressive strength of 120 MPa or more is desired (conventional filled mortar has a compressive strength of about 60 MPa, and a maximum of about 100 MPa. ).
[0013]
[Non-shrinkage]
It is essential that the cement composition of the present invention has an expansion rate of 0 to 1% up to 7 days of age. In the reinforcing bar joint, if a void is generated between the reinforcing bar and the filling mortar or between the fitting and the filling mortar, the connection strength is not preferable. Even if the filling state is good, if the filling mortar shrinks during the hydration hardening process, voids are formed and the connection strength is lowered. Therefore, the filling mortar needs to have no shrinkage (expansion rate of 0% or more). is there. Furthermore, as the filled mortar, those having a slight expansibility are preferable, but since excessive expansion can cause a decrease in strength, the expansion rate is preferably approximately 1% or less.
[0014]
2. About materials used
In the present invention, high belite cement is contained as an essential component. The high belite cement is a cement in which the content of alite, which is the main component of ordinary portland cement, is reduced and the belite content is further increased than moderately heated portland cement. Belite (2CaO · SiO as high belite cement)₂) Containing 40% by weight or more can be suitably used. In particular, the belite content is 50% by weight or more, and the brain specific surface area is 4500 cm.²/ G or less is preferable. This is because it is suitable for securing a good fluidity for a long time when the water / binder ratio is low.
[0015]
  In the present invention, silica fume is used to ensure good fluidity at low water / binder ratioDo. Among them, silica fume having an average particle size of 0.20 μm or less and a carbon content of less than 1.5% by weight can be suitably used. When the average particle size is 0.20 μm or less, it is easy to ensure good fluidity even when the water / binder ratio is extremely low (approximately 24% or less). Further, when the carbon content is less than 1.5% by weight, it is easy to stably ensure good fluidity for a long time even with such a low water / binder ratio.
[0016]
  Also, to obtain good fluidity stably,Mainly composed of polycarboxylic acid polymer compound with polyalkylene glycol chainUse cement dispersant. Cement dispersants based on polycarboxylic acid polymer compounds maintain fluidization performance and fluidity compared to dispersants based on naphthalene sulfonate formalin high condensate and melamine sulfonate formalin high condensate. It is because the nature is high.
[0017]
The cement dispersant mainly composed of the polycarboxylic acid-based polymer compound having a polyalkylene glycol chain can also be used in powder form by dry-dispersing the dispersant solution. Examples of such a polymer compound include a group -COOM (M represents a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or an organic amine) and a (meth) acrylic acid copolymer having a polyalkylene glycol chain, Or a polyalkylene glycol alkenyl ether-maleic anhydride copolymer (however, excluding polyvalent metal salts) is preferred. The polyalkylene glycol chain is preferably a C 2-4 polyalkylene glycol chain, more preferably —O (CH₂CH (R^aO)_bIt is shown by-. Where R^aRepresents a hydrogen atom or a methyl group, and b is preferably 2 to 200. Further, it is preferable to add a reducing inorganic compound such as nitrite and a reducing organic compound such as an amine compound to the above-mentioned liquid before dry powderization. Each of these addition amounts (solid content) is preferably 0.01 to 2.5% by weight of the solid content of the polycarboxylic acid polymer compound. Moreover, it is preferable to adjust said liquid to pH 7-9. The method for dry powdering is not particularly limited, but it is preferably carried out while kneading and stirring. (The dispersant for a powdery hydraulic composition described in JP 2001-002788 A can be used as the cement dispersant of the present invention). As described above, by using a powdery cement dispersant, an easy-to-handle cement composition capable of supplying materials other than water in the form of a premix can be obtained.
[0018]
  The cement composition according to the present invention contains either a lime-based admixture or an organic shrinkage reducing agent or both in order to obtain no-shrinkage.Do.
  The lime-based admixture can be used to form a solid and high-strength cured body while suppressing self-shrinkage and improving non-shrinkage. As the lime-based admixture, a lime-based expansion material generally used for mortar concrete and a lime-based admixture used as a hardening accelerator when producing concrete products can be used. A mixed pulverized product of clinker containing a crystal and gypsum is preferable. The clinker preferably contains 50 to 92% by weight of CaO. In addition, clinker is a major mineral composition of 3CaO · SiO.₂-2CaO · SiO₂-CaO-porosity, 3CaO.SiO₂-CaO-porosity, 2CaO · SiO₂Those containing one or more selected from the group consisting of -CaO-porosity are preferred. As the gypsum, any of anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum can be used. As for the mixing ratio of clinker and gypsum, it is preferable to mix 5 to 50 parts by weight of gypsum with 100 parts by weight of clinker (including those described in JP 2001-39748 A).
[0019]
The organic shrinkage reducing agent can be used to suppress self-shrinkage and improve non-shrinkage and to form a solid and high-strength cured body. Examples of the organic shrinkage reducing component constituting the organic shrinkage reducing agent include those having an alkylene oxide polymer represented by the following formula (1) in the skeleton of the chemical structure.
R¹O (AO)_nR²    ... (1)
Where R¹And R²Is independently of each other a hydrogen group, an alkyl group, a phenyl group, a cycloalkyl group, etc., and A is one alkylene group having 2 to 3 carbon atoms or two alkylene groups randomly or block-polymerized. , N is an integer of 2-20. Especially R²An organic shrinkage reducing agent in which is a hydrogen group can be suitably used (including those described in Japanese Patent Publication No. 59-3430).
[0020]
As an organic shrinkage reducing agent, an inorganic or organic powdery body having oil absorption is impregnated with, for example, a liquid organic shrinkage reducing agent component of the above-mentioned components in advance, and a powdery material in a powder form is used. By using it, an easy-to-handle premix product is obtained. As the inorganic powder, fibrous magnesium oxide can be used, and as the organic powder, phenol resin or the like can be used (including those described in JP-A-2-164754).
[0021]
The organic shrinkage reducing agent is generally used for reducing the drying shrinkage of a cement cured body. The drying shrinkage of a hardened cement body is generally considered to cause tensile stress in the capillary of the hardened body due to the formation of a meniscus by drying, which causes elastic volume shrinkage of the hardened body. The organic shrinkage reducing agent has an action of reducing the surface tension of water in the voids of the cured body, whereby the tensile stress in the capillary is lowered and the shrinkage is reduced. On the other hand, the mechanism of self-shrinkage is thought to be due to self-drying as the hydration progresses, causing tensile stress in the capillaries of the cured body to shrink the volume. It is also effective in reducing self-shrinkage.
[0022]
  The cement composition according to the present invention ensures the non-shrinkage at the initial age,Blowing agentContainsDo. In the present invention, as described above, the shrinkage is reduced by using a lime-based admixture, an organic shrinkage reducing agent, or the like, but it is not possible to secure sufficient non-shrinkage particularly at the initial age. . Therefore, in order to make the expansion rate (JSCE-F533) up to 7 days of age 0 to 1%,Blowing agentIs used.Blowing agentIs added to the cement composition, during hydration, the gas generated inside the cement composition is trapped inside as the hardening progresses. As the amount of this gas increases, it becomes the internal pressure, which counteracts the shrinkage phenomenon caused by the hydration reaction of high belite cement, and can more effectively suppress the shrinkage, even at the initial age. High non-shrinkage can be ensured.Blowing agentFor example,,A granular material (Japanese Patent Publication No. 60-4150) obtained by heating a metal powder such as aluminum powder or a carbon compound such as fluid coke which is a by-product of petrochemicals can be used..
[0023]
  The cement composition of the present invention comprises:By ensuring non-shrinkage, for example, when used as a filler for a reinforcing bar joint, the risk of a decrease in connection strength due to shrinkage can be eliminated.
[0024]
In the cement composition of this invention, a specific fine aggregate is contained as an essential component. That is, as a fine aggregate, a kneaded product of a cement composition and water can maintain a flow value of 200 mm or more after kneading for 60 minutes or more, and a hydrated cured body of the kneaded product has a compressive strength (120 MPa or more). Use a material that is easy to obtain properties having a material age of 28 days. Such a fine aggregate has a specific gravity of 3.4 or more, preferably 3.7 to 7, and a water absorption of 0.5 to 1.5%, preferably 0.6 to 1.4%. Can be suitably used. By setting the specific gravity to 3.4 or more, even if the water / binder ratio is low, stable fluidity can be obtained over time and high compressive strength can be obtained. Further, by setting the water absorption rate to 1.5% or less, a stable fluidity with time can be obtained even when the water / binder ratio is low. On the other hand, strength development can be improved by making a water absorption rate into 0.5 or more. Here, the water absorption rate is a value expressed as a percentage by dividing the water absorption amount of the aggregate (the amount of water contained in the surface dry aggregate) by the aggregate mass in the absolutely dry state. In addition, the water absorption test method was performed according to JIS A 1109 “Specific gravity and water absorption test method of fine aggregate”.
Any fine aggregate can be used as long as it satisfies the specific gravity and water absorption rate. Generally, fine aggregates such as river sand, sea sand, land sand, crushed sand, quartz sand, magnetite sand, iron sand and metal aggregates are often outside the above specific gravity and water absorption range. Can be suitably used for mixed sand adjusted so as to satisfy the specific gravity and water absorption rate. Further, in order to obtain good filling properties when the cement composition of the present invention is used as a filler for reinforcing steel joints, the maximum particle size of the fine aggregate is preferably less than 3 mm.
[0025]
If the characteristic shown in Claim 1 is ensured, the cement composition of the present invention may contain other components other than the above components, for example, a thickener, an antifoaming agent, a rust preventive agent and the like as necessary. It may be included.
[0026]
3. About their blending ratio in preferred materials
In order to show an example of the blending ratio, preferred systems for achieving this object include high belite cement, silica fume, fine aggregate, cement dispersant, lime-based admixture and organic shrinkage reducing agent. Taking up the foaming agent, the blending ratio is shown.
(1) Mixing ratio of high belite cement and silica fume
In the present invention, the blending ratio when the high belite cement and silica fume are used in combination is preferably blended at a weight ratio of cement / silica fume = 90/10 to 98/2. Even when the water binder ratio is extremely low (approximately 26% or less), a kneaded material having a relatively low viscosity can be obtained. Therefore, good flowability (flow value of 200 mm or more “static using a flow cone defined in JIS R 5201”) It is easy to ensure a sufficient flow rate (holding flow of 60 minutes or more) and good strength development (compression strength “JIS R 5201” of material age 28 days is 120 MPa or more). A more preferable blending ratio is high belite cement / silica fume = 92/8 to 97/3 in weight ratio.
[0027]
(2) Mixing ratio of cement dispersant
In the case of using a dispersant containing a polycarboxylic acid polymer compound having a polyalkylene glycol chain as a main component, the blending ratio is usually 0 with respect to a total of 100 parts by weight of high belite cement and silica fume as the active ingredient amount. .1 to 2 parts by weight, preferably 0.5 to 1.5 parts by weight. By setting the blending amount of the dispersant to 0.1 parts by weight or more, good fluidity can be ensured even when the water binder ratio is extremely low (generally 26% or less). In addition, when the amount is 2 parts by weight or less, there is no delay in curing, and good fluidity can be ensured.
[0028]
(3) Mixing ratio of lime based admixture and organic shrinkage reducing agent
The blending ratio of the lime-based admixture is usually 1 to 10 parts by weight, preferably 3 to 8 parts by weight with respect to 100 parts by weight as a total of the high belite cement and silica fume. By reducing the amount of lime based admixture to 1 part by weight or more, the self-shrinkage that becomes noticeable when the water binder ratio is low is effectively reduced in the cement composition containing silica fume. Can do. Moreover, by making it 10 parts weight or less, the danger of the strength fall by deterioration of fluidity or excessive expansion | swelling can be decreased very much.
[0029]
The blending ratio in the case of using an organic shrinkage reducing agent is usually 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight with respect to a total of 100 parts by weight of high belite cement and silica fume as the amount of active ingredients. is there. By making the blending amount of the organic shrinkage reducing agent 0.5 parts by weight or more, in the cement composition blended with silica fume, it is possible to effectively reduce self-shrinking that becomes noticeable when the water binder ratio is low. it can. Moreover, the danger of the intensity | strength fall by a setting delay can be decreased very much by setting it as 5 weight part or less.
[0030]
The lime-based admixture and the organic shrinkage reducing agent can also be used together. In that case, the blending ratio of each is not particularly limited and can be added within the above range, but when used alone. It can reduce according to the ratio to use together compared with a mixture ratio.
[0031]
(4) Foaming agentofMixing ratio
  Blowing agentIn the case of metal powder, the blending ratio is preferably 0.0001 to 0.002 parts by weight with respect to a total of 100 parts by weight of high belite cement and silica fume, and is obtained by heat treatment of a carbon-based compound such as fluid coke. In the case of a granular material, 0.1 to 5 parts by weight is preferable. Within this range, good shrinkage resistance can be ensured in the cement composition using the combination of materials of this example without causing a decrease in strength due to excessive expansion. Also foaming agentIsTwo or more types can also be used in combination, in which case, the mixing ratio of each is not particularly limited and can be added within the above range, but the ratio used in combination compared to the mixing ratio when used alone Can be reduced depending on
[0032]
(5) Mixing ratio of fine aggregate
The blending ratio of the fine aggregate is preferably 40 to 120 parts by weight with respect to 100 parts by weight of the total high belite cement and silica fume. Within this range, the cement composition can be easily kneaded even when the amount of water is reduced, and since there is little increase in viscosity after kneading, good fluidity can be ensured. A more preferable blending ratio is 60 to 100 parts by weight.
[0033]
In the present invention, in order to achieve both high compressive strength and good and stable fluidity, the amount of water to be added is, for example, in the above blending example, from 16 to 100 parts by weight with respect to a total of 100 parts by weight of high belite cement and silica fume. 24 weight% is preferable and 18-22 weight% is more preferable.
[0034]
4). Manufacturing method and others
The cement composition of the present invention is prepared by pre-mixing the above materials by a conventional method at a factory, for example, and is usually supplied to the construction site in the form of bagging or the like. And kneaded. The kneading method is not particularly limited. Moreover, the apparatus used for kneading is not particularly limited, and a conventional mixer such as a hand mixer, a pan-type mixer, a biaxial kneading mixer, and a tilting mixer can be used. Although the use of the cement composition of the present invention is not particularly limited, it is preferably used for a reinforcing steel joint filler. The method of use is the same as that of a conventional mortar filler for reinforcing steel joints and is not particularly limited.
[0035]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited to these. In addition, the material used for the Example and the comparative example is as follows.
[0036]
[Materials used]
(1) Cement
Table 1 shows the chemical components and specific surface areas of the cements used in the examples and comparative examples.
[0037]
[Table 1]
[0038]
(2) Silica fume
Silica fume with an average particle size of 0.14 μm and a carbon content of 0.50% was used in the examples and comparative examples.
[0039]
(3) Cement dispersant
(A) Powdered cement dispersant mainly composed of a polycarboxylic acid polymer compound (abbreviation: A)
54 mol% sodium methacrylate, 7 mol% sodium methallylsulfonate, 8 mol% methyl acrylate, 16 mol% methoxypoly (n = 40) ethylene glycol methacrylate and 15 mol% methoxypoly (n = 23) ethylene glycol methacrylate In order to adjust pH, 75.2 g of a 10 wt% aqueous sodium hydroxide solution is added to each 800 g of an aqueous solution having a molecular weight of 11900 and having a molecular weight of 11900 as a main component and a solid content concentration of 45%. Then, 0.5 parts by weight of sodium sulfite and triethanolamine were added to 100 parts by weight of the solid content of the polymer compound, followed by stirring for 3 minutes. This was put into a kneader-type kneader / stirrer having a treatment volume of 1 L, and concentrated and dried while kneading under a reduced pressure of 90 ° C. and 30 torr. The obtained powder was pulverized with a pulverizer and classified to produce a powder (A) having a particle size of 50 to 500 μm. The water content of the powder was 2.1% by weight.
[0040]
(B) Conventional powdered cement dispersant (abbreviation: B)
As a comparative example, a naphthalene sulfonic acid formalin highly condensed product (Mighty 100 manufactured by Kao Corporation) was used.
[0041]
(4) Lime-based admixture
Table 2 shows the main chemical components and specific surface areas of the lime-based admixtures used in the examples and comparative examples.
[0042]
[Table 2]
[0043]
(5) Organic shrinkage reducing agent
As the organic shrinkage reducing agent, trade name: Tetragard PW (60% active ingredient powdery organic shrinkage reducing agent, main component: oxyalkylene alkyl ether) (manufactured by Taiheiyo Materials Co., Ltd.) (abbreviation: TG) was used. .
[0044]
(6) Foaming agent
  Blowing agentAs a trade name, PERMANENT LIFE AGGREGATE (a carbon-based foaming agent mainly composed of a granular material obtained by heating a carbon-based compound) (manufactured by INTERNATIONAL CONSTRUCTION PRODUCTS RESEARCH INC.) (Abbreviation: PL) was used.
[0045]
(7) Fine aggregate
Table 3 shows the average particle diameter, specific gravity and water absorption rate of the fine aggregates used in the comparative examples. Moreover, the fine aggregate of the mixed sand obtained by mixing these fine aggregates was used in Examples and Comparative Examples. Table 4 shows the average particle diameter, specific gravity, and water absorption.
[0046]
[Table 3]
[0047]
[Table 4]
[0048]
[Method for producing cement composition]
Each of the above materials is premixed in advance so as to achieve the blending amounts shown in Table 5, and a predetermined amount of water is added to 100 parts by weight of the base material, using a hand mixer (rotation speed 1100 rpm), 3 A cement composition was prepared by kneading for a minute.
[0049]
[Table 5]
[0050]
〔Test method〕
{Circle around (1)} Flowability: Using a flow cone defined in “JIS R 5201 (Cement physical test method)”, a stationary flow without dropping motion of the table was measured from immediately after kneading until 60 minutes had elapsed. Table 6 shows the measurement results.
(2) Compressive strength: Compressive strength at a material age of 28 days was measured according to “JIS R 5201 (physical test method for cement)”. Table 6 shows the measurement results.
(3) Expansion rate: The expansion rate up to 7 days of age was measured according to the Japan Society of Civil Engineers standard "PC grout test method (container method) (JSCE-F533)". Table 6 shows the measurement results.
[0051]
[Table 6]
[0052]
As shown in Table 6, Examples 1 to 13 maintained a flow value of 200 mm or more for 60 minutes or more after kneading, and were able to stably obtain high fluidity. Moreover, the compressive strength on the age of 28 days was 120 MPa or more, and a high strength could be obtained. Furthermore, the expansion rate until the age of 7 days was 0 to 0.5%, and good no-shrinkage could be obtained.
[0053]
On the other hand, Comparative Examples 14, 15, 19 and 21 using a fine aggregate having a specific gravity of 3.3 or less have a flow value of 180 mm or less after kneading and cannot stably obtain high fluidity, Also, the compressive strength was less than 120, and high strength could not be obtained. In addition, Comparative Examples 16 to 18 and 20 using fine aggregates having a specific gravity of 3.4 or more but a water absorption rate of less than 0.5 are stable at a flow value of 210 mm or more after kneading for 210 minutes. High fluidity was obtained, but the compressive strength was less than 120, and high strength could not be obtained.
[0054]
Moreover, the comparative example 22 which did not use a foaming agent etc. became expansion coefficient -0.5% or less, and was not able to acquire non-shrink property. Further, Comparative Example 23, in which neither a lime-based admixture nor an organic shrinkage reducing agent was used, had an expansion coefficient of 0% or less and no shrinkage was obtained, and the compressive strength was less than 120, and high strength was also obtained. I couldn't. Further, Comparative Example 24 in which a cement dispersant mainly composed of a polycarboxylic acid polymer compound was not used, Comparative Example 25 in which silica fume was not used, and Comparative Example 26 in which no high belite cement was used. The flow value for 60 minutes after kneading was less than 140 mm, and high fluidity could not be obtained stably.
[0055]
【The invention's effect】
As described above, according to the present invention, it has good fluidity, high compressive strength, and good non-shrinkage, and materials other than water can be supplied in the form of a premix. A cement composition can be provided.

Claims (2)

High belite cement, silica fume, cement dispersant mainly composed of polycarboxylic acid polymer compound having polyalkylene glycol chain, and / or lime-based admixture or organic shrinkage reducing agent And a cement composition containing a foaming agent and a fine aggregate having a specific gravity of 3.4 or more and a water absorption of 0.5 to 1.5% ,
A kneaded product of this cement composition with water can maintain a flow value of 200 mm or more for 60 minutes or more after kneading, and the hydrated cured body of the mixture has a compressive strength of 120 MPa or more at a material age of 28 days. And a cement composition having an expansion rate of 0 to 1% up to 7 days of age . The cement composition according to claim 1 , wherein the cement composition is used for a filler for reinforcing steel joints.