JP4519245B2 - High-strength concrete members for high-speed traffic system structures - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-strength concrete member such as a reinforced concrete or a prestressed concrete used for a structure constituting a high-speed traffic system such as a super-high-speed railway or a linear motor car.
[0002]
[Prior art]
Conventionally, concrete structures such as reinforced concrete and prestressed concrete, which are economical and highly durable and can reduce noise, have been used as land transportation system structures such as railways, as well as steel structures. In particular, for long bridges and elevated roadways, higher strength members are required due to the demand for weight reduction of members, and high strength concrete members that use a high-performance water reducing agent to reduce the water-cement ratio, and those Prestressed concrete members and the like in which prestress is introduced have been used.
[0003]
On the other hand, in order to improve the brittleness, which is a defect of a concrete member, to prevent cracking and to improve toughness, it has also been performed to mix fibers into concrete. And as a technology to achieve the improvement of concrete properties by combining these various strength enhancement technologies, in JP-A-11-246255, in addition to cement, metal fibers, aggregate particles, pozzolanic reaction particles, dispersants, A technique for improving mechanical behavior such as toughness and ductility by adding a component capable of improving the toughness of the matrix is disclosed.
[0004]
[Problems to be solved by the invention]
In order to satisfy the desire to reach the destination in a shorter time, the speeding up of the land transportation system is advancing more and more in recent years. High-speed traffic systems exceeding 350 km / h for rail-type traffic systems and over 500 km / h for linear motor car systems are being put into practical use from the experimental stage. In such a high-speed traffic system, extremely severe conditions are imposed not only on the function and structure of the vehicle itself that runs at high speed, but also on civil engineering structures such as the running road that forms the basis of the system. The strength, toughness, durability, etc. of the structure are natural, but in addition, in order to maintain the ride comfort of passengers traveling at high speeds and ensure safety, the traveling roads, etc. High dimensional stability is required.
[0005]
In this regard, in conventional concrete structures, creep strain due to continuous load during the period from construction to service due to its own weight, etc. cannot be ignored, and in order to reduce irregularities in pier height and deflection of girders, etc. Predict the deformation due to creep and determine the amount of design rise, and when the creep progresses after completion, the rise displacement decreases, so that the displacement of each part is minimized at the creep convergence value. Predictive design and construction were performed with great care. However, in field construction, the progress of creep was greatly affected by process changes, temperature, humidity, etc., and it was often difficult to obtain the expected effect. Therefore, there has been a demand for a high-strength concrete member having such a property that the creep itself can be greatly reduced while improving the strength and toughness.
[0006]
[Means for Solving the Problems]
In view of the above-mentioned problems, the inventors based on the results of extensive research on a high-strength concrete member having a property capable of greatly reducing the creep itself, the high-strength concrete member for a high-speed traffic system structure of the present invention. It came to complete. The main point is that the cement, pozzolanic reaction particles, aggregate particles, dispersants, fibers, inorganic powders, as well as fibrous particles or flaky particles are appropriately combined to produce a mechanical behavior such as strength and toughness. In addition to the conventionally known properties such as high strength and high toughness, there is an unexpected property that the creep is remarkably reduced, and by applying this, the high strength that greatly reduces the creep itself It is in finding that a concrete member can be obtained.
[0007]
That is, the present invention firstly consists of a hardened body of a blend containing at least cement, pozzolanic fine powder, aggregate having a particle size of 2 mm or less, water, and a water reducing agent. A high-strength concrete member for a system structure has a basic configuration. Moreover, 2nd is a high-strength concrete member for high-speed traffic system structures characterized by including any 1 type, or 2 or more types of a metal fiber, organic fiber, and carbon fiber in the said compound. Moreover, it is the high-strength concrete member for high-speed traffic system structures containing the inorganic powder with an average particle diameter of 3-20 micrometers in the said 1st or 2nd compound as the 3rd, It is a high-strength concrete member for high-speed traffic system structures containing fibrous particles or flaky particles having an average particle size of 1 mm or less in the second or third blend. Further, the high strength for a high speed traffic system structure according to any one of the first to fourth concrete members, wherein prestress is introduced by either a pre-tension method or a post-tension method. The concrete member is the fifth form. And the high-speed traffic system is a linear motor car or a high-strength concrete member for a high-speed traffic system structure according to any one of the first to fifth high-speed traffic system structures is also included in the present invention.
[0008]
ADVANTAGE OF THE INVENTION According to this invention, the concrete member suitable for the high-speed traffic system structure of the high dimensional accuracy in which the displacement by creep is remarkably small on top of high intensity | strength and high toughness can be obtained. The high-strength concrete members for high-speed traffic system structures described here include bridges and viaduct concrete girders, piers, abutments, arches, piles, side walls of tracks, tracks, track slabs, floor boards, and magnetic levitation functions. Although a module board etc. are assumed, it is not limited to these.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The kind of cement used in the present invention is not limited. Various portland cements such as ordinary portland cement, early-strength portland cement, intermediate heat portland cement, low heat portland cement, mixed cements such as blast furnace cement and fly ash cement can be used.
[0010]
In the present invention, when trying to improve the early strength of concrete, it is preferable to use early-strength Portland cement, and when improving the fluidity of concrete, use moderately hot Portland cement or low heat Portland cement. It is preferable.
[0011]
Examples of the pozzolanic fine powder include silica fume, silica dust, fly ash, slag, volcanic ash, silica sol, and precipitated silica. In general, silica fume or silica dust has an average particle size of 1.0 μm or less and is preferably used as the pozzolanic fine powder of the present invention because it does not need to be pulverized.
[0012]
By blending the pozzolanic fine powder, the concrete is densified by the micro filler effect and the cement dispersing effect, and the compressive strength is improved. On the other hand, as the amount of pozzolanic fine powder added increases, the amount of unit water increases. Therefore, the amount of pozzolanic fine powder added is preferably 5 to 50 parts by weight with respect to 100 parts by weight of cement.
[0013]
In the present invention, an aggregate having a particle size of 2 mm or less is used as an essential component.
The aggregate having a particle size of 2 mm or less means that the 85% (weight) cumulative particle size is 2 mm or less, and does not prevent the inclusion of an aggregate component larger than 2 mm. Specifically, river sand, land sand, sea sand, crushed sand, quartz sand, and mixtures thereof can be used. The blending amount of the aggregate is preferably 50 to 250 parts by weight, more preferably 80 to 180 parts by weight with respect to 100 parts by weight of cement, from the workability and separation resistance of the concrete, the strength after hardening and the resistance to cracking, and the like. preferable.
[0014]
Moreover, you may mix | blend the coarse aggregate used for normal high-strength concrete other than the above-mentioned aggregate with a particle size of 2 mm or less. Specific examples include gravel such as river gravel, mountain gravel, land gravel, sea gravel, hard sandstone, andesite, crushed stone such as limestone, slag aggregate, artificial lightweight aggregate, etc. is not.
[0015]
As the water reducing agent, a lignin-based, naphthalenesulfonic acid-based, melamine-based, or polycarboxylic acid-based water reducing agent, an AE water reducing agent, a high-performance water reducing agent, or a high-performance AE water reducing agent can be used. Among these, it is preferable to use a high performance water reducing agent or a high performance AE water reducing agent. The amount of the water reducing agent added is preferably 0.5 to 4.0% by weight in terms of solid content with respect to cement, from the fluidity and separation resistance of concrete, the strength after curing, and the cost.
[0016]
In the present invention, the water / cement ratio is preferably 10 to 35% by weight, more preferably 15 to 30% by weight, from the viewpoint of fluidity and separation resistance of concrete, strength and durability of the cured body, reduction of creep, and the like.
[0017]
In the present invention, from the viewpoint of increasing the bending strength of the cured body, it is preferable to include one or more of metal fibers, organic fibers, and carbon fibers in the blend.
Examples of the metal fibers include steel fibers and amorphous fibers, among which steel fibers are excellent in strength and are preferable from the viewpoint of cost and availability. The metal fiber preferably has a diameter of 0.01 to 1.0 mm and a length of 2 to 30 mm. If the diameter is less than 0.01 mm, the strength of the fiber itself is insufficient, and it is easy to break when subjected to tension. When the diameter exceeds 1.0 mm, the number of the same compounding amount decreases, and the bending strength of the concrete decreases. If the length exceeds 30 mm, fiber balls are likely to occur during kneading. If the length is less than 2 mm, the adhesive strength with the matrix is lowered and the bending strength is lowered.
[0018]
The blending amount of the metal fiber is preferably less than 4% of the concrete volume after setting, and more preferably less than 3.5%. The content of the metal fiber is determined from the viewpoints of fluidity and bending strength of the cured body. In general, when the content of the metal fiber is increased, the bending strength is improved. On the other hand, since the unit water amount is increased in order to ensure fluidity, the content of the metal fiber is preferably the above amount.
[0019]
Examples of the organic fiber include vinylon fiber, polypropylene fiber, polyethylene fiber, and aramid fiber. The organic fiber or carbon fiber preferably has a diameter of 0.005 to 1.0 mm and a length of 2 to 30 mm. The organic fiber or carbon fiber content is preferably less than 10% of the concrete volume after setting, and more preferably less than 7%. In the present invention, any two or more of metal fibers, organic fibers, and carbon fibers may be used in combination.
[0020]
In the present invention, it is preferable to include an inorganic powder having an average particle size of 3 to 20 μm, more preferably an average particle size of 4 to 10 μm, from the viewpoint of increasing the filling density of the cured body, improving strength, and reducing creep. Examples of inorganic powders include quartz powder, limestone powder, oxide powder such as Al2O3, carbide powder such as SiC, nitride powder such as SiN, etc. Among them, quartz powder is cost and stability of the quality of the cured product. From the point of view, it is preferable. Examples of the quartz powder include quartz, amorphous quartz, opal and cristobalite silica-containing powders, and the like. The blending amount of the inorganic powder is preferably 50 parts by weight or less, more preferably 20 to 35 parts by weight with respect to 100 parts by weight of cement, from the fluidity of concrete, the strength of the cured body, and the like.
[0021]
In the present invention, from the viewpoint of increasing the toughness of the cured body and effectively dispersing the load loaded on the cured body and reducing creep, fibrous particles or flaky particles having an average particle size of 1 mm or less are used. It is preferable to include. Here, the particle size of the particle is the size of the maximum dimension (particularly, the length of the fibrous particle). Examples of fibrous particles include wollastonite, bauxite, mullite, and examples of flaky particles include mica flakes, talc flakes, vermiculite flakes, and alumina flakes. The blending amount of the fibrous particles or the flaky particles is preferably 35 parts by weight or less, more preferably 10 to 25 parts by weight with respect to 100 parts by weight of cement in view of the fluidity of concrete, the strength and toughness of the hardened body. In addition, it is preferable to use a fibrous particle having a needle-like degree represented by a length / diameter ratio of 3 or more from the viewpoint of increasing the toughness of the cured body.
[0022]
In the present invention, the concrete kneading method is not particularly limited. Moreover, the apparatus used for kneading is not particularly limited, and a conventional mixer such as an omni mixer, a pan-type mixer, a biaxial kneading mixer, and a tilting cylinder mixer can be used.
[0023]
The above-mentioned kneaded concrete is filled into a formwork in which reinforcing materials such as reinforcing bars and continuous fibers are placed, molded, cured and cured, and the high-strength concrete member for the high-speed traffic system structure of the present invention is manufactured. can do. In addition, a shaping | molding method is not specifically limited, It can carry out by conventional shaping | molding methods, such as casting. Also, the concrete curing method is not particularly limited, and normal temperature curing, steam curing, or the like may be performed.
[0024]
Furthermore, in the present invention, in the process of manufacturing a concrete member according to the above method, prestress can be introduced into the member by a pretensioning method that is usually performed, or is normally performed after the concrete of the member is hardened. It is also possible to introduce prestress into the member by the post-tension method. When prestress is introduced into the concrete member according to the present invention, since creep is greatly reduced, there is an advantage that loss of prestress can be greatly reduced.
[0025]
In addition, in concrete with a reduced water-cement ratio as used in the present invention, dimensional changes due to self-shrinkage cannot be ignored, but the effect can be reduced by taking measures such as adding a shrinkage reducing agent as necessary. It is possible to suppress.
[0026]
【Example】
Hereinafter, the hardening body which comprises the concrete member of this invention is demonstrated by an Example.
1. Materials used 1) Cement: Low heat Portland cement (manufactured by Taiheiyo Cement Co., Ltd.)
2) Pozzolanic fine powder; silica fume (average particle size 0.2 μm)
3) Aggregate: 2: 1 (weight ratio) mixture of silica sand 4 and silica sand 4 4) Metal fiber: Steel fiber (diameter: 0.2 mm, length: 15 mm)
5) High-performance AE water reducing agent; polycarboxylic acid-based high-performance AE water reducing agent 6) Water; tap water 7) Quartz powder; Average particle size 7 μm
8) Fibrous particles; wollastonite (average length 0.3 mm, length / diameter ratio 4)
[0027]
2. Formulation Example 1
Low heat Portland cement; 100 parts by weight silica fume; 32.5 parts by weight aggregate; 120 parts by weight quartz powder; 30 parts by weight wollastonite; 24 parts by weight high-performance AE water reducing agent; 1.0% by weight (based on cement solids)
Water / cement ratio: 22% by weight
Steel fiber: 2% of concrete volume
[0028]
Example 2
Low heat Portland cement; 100 parts by weight silica fume; 32.5 parts by weight aggregate; 120 parts by weight high-performance AE water reducing agent; 1.0% by weight (vs. cement solids)
Water / cement ratio: 25% by weight
[0029]
3. Test method 1) Kneading method Each material is put into a biaxial kneader at once. Kneading 2) Cylindrical specimen with 10cm diameter and 20cm height and prismatic specimen with 10x10x40cm 3) Compressive strength test method Specimen: Cylindrical specimen: Curing condition: Demolded after 24 hours (20 ° C), cured for 20 days at 20 ° C under water, strength measurement: JIS A 1108 method was followed.
4) Bending strength test method-Specimen: prismatic specimen-Curing conditions: Pre-formation (20 ° C) 24 hours after demolding, 28-day 20 ° C water curing-Strength measurement: JIS A 1106 method was followed.
5) Creep test method ・ Specimen: Cylindrical specimen ・ Test method: JIS draft Concrete compression creep test method (draft) was followed.
(Loading material age 28 days, loading stress 60 MPa, test material age 1000 days)
[0030]
4). Test result Example 1
1) Compressive strength: 230 MPa
2) Bending strength: 47 MPa
3) Creep coefficient: 0.20
Example 2
1) Compressive strength: 150 MPa
2) Bending strength: 21 MPa
3) Creep coefficient: 0.31
The values of the creep coefficients of the cured bodies of Examples 1 and 2 are both 1/5 or less of ordinary concrete and 1/3 or less of ordinary high-strength concrete, and the creep is greatly reduced. Therefore, the high-strength concrete member manufactured by using the cured body formulation of the present embodiment can greatly reduce creep and stabilize the dimensional accuracy.
[0031]
【The invention's effect】
As described in detail above, the present invention is a high-strength concrete member having properties such as high strength and high toughness, and a property that the creep is greatly reduced. This will greatly contribute to the improvement of construction efficiency and reduction of construction costs.

Claims (5)

At least, cement 100 parts by weight pozzolanic substance fine powder 5-50 parts by weight, 50 to 250 parts by weight of 85 wt% cumulative particle diameter of 2mm or less of the aggregate, 10 to 35 weight parts of water, water reducing agent (in terms of solid content) 0.5% to 4.0 parts by weight , 2% to less than 4% of the concrete volume after setting metal fibers having a diameter of 0.01 to 1.0 mm and a length of 2 to 30 mm, and an average particle size of 3 to 20 μm A high-strength concrete member for a high-speed traffic system structure with a low creep and a high dimensional accuracy, characterized in that it is a cured product of a blend containing 20 to 50 parts by weight of an inorganic powder. The blend further comprises organic fibers having a diameter of 0.005 to 1.0 mm and a length of 2 to 30 mm, and less than 10% of the concrete volume after setting, and / or a diameter of 0.005 to 1.0 mm and a length of 2 to 2. The high-strength concrete member for a high-speed traffic system structure with low creep and high dimensional accuracy according to claim 1, comprising 30 % of carbon fiber less than 10% of the concrete volume after setting . At least, cement 100 parts by weight, pozzolanic substance fine powder 5 to 50 parts by weight, and 50 to 250 parts by weight of 85 wt% cumulative particle diameter of 2mm or less of the aggregate, 10 to 35 parts by weight of water, water reducing agent (in terms of solid content) 0.5% to 4.0 parts by weight , 2% to less than 4% of the concrete volume after setting metal fibers having a diameter of 0.01 to 1.0 mm and a length of 2 to 30 mm, and an average particle size of 3 to 20 μm 20 to 50 parts by weight of an inorganic powder, and a low creep high dimensional accuracy high, characterized in that pre-stress is introduced by either a pre-tension method or a post-tension method. High-strength concrete member for speed traffic system structures. The blend further comprises organic fibers having a diameter of 0.005 to 1.0 mm and a length of 2 to 30 mm, and less than 10% of the concrete volume after setting, and / or a diameter of 0.005 to 1.0 mm and a length of 2 to 2. The high-strength concrete member for high-speed traffic system structures with low creep and high dimensional accuracy according to claim 3, comprising less than 10% of 30 mm of carbon fiber after setting .   The high-strength concrete member for a low creep high-speed traffic system structure according to any one of claims 1 to 4, wherein the high-speed traffic system is a linear motor car or a railway.