JP2004131342A - Extruded part and method of producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing an extruded part, by which bending strength and toughness can be improved while maintaining high productivity, and to provide the extruded part used as a civil engineering structural member. <P>SOLUTION: The extruded part is produced by extruding under vacuum a mortar kneaded material containing cement, a pozzolana-based fine powder, aggregate, a quartz powder, needle-like particles, a polypropylene fiber, a water-soluble cellulose ether, a water-reducing agent, and water, and then subjecting the formed part to autoclave curing. A fiber having a specified size is used as the polypropylene fiber, and a water-soluble cellulose ether exhibiting viscosity of 10-100 Pa×s(20°C) when it is prepared as an aqueous solution of 2 mass % is used as the water-soluble cellulose ether. Further, the blending amounts of the water-soluble cellulose ether, the water-reducing agent, and water are 0.15-1.5 parts by mass, 0.3-0.7 parts by mass, and 20-30 parts by mass, respectively, to 100 parts by mass of the cement, and the blending amount of the polypropylene fiber is set to be 3-5 vol.%, based on the volume of the mortar. <P>COPYRIGHT: (C)2004,JPO

Description

【００２８】
一方、モルタル混練物および押出成形体について、以下の測定を行なった。
１）モルタル混練物：押出成形性の観察をし、良好な場合を「◯」、やや良好な場合を「△」、混練が困難な場合を「×」とし、３段階で評価した。
２）押出成形体：押出成形体を４５０×２５×１５００ｍｍに切断して供試体を作製し、支点間距離；１２００ｍｍの３等分点曲げ載荷試験により、曲げひび割れ強度および曲げたわみ４０ｍｍ時の曲げ強度を測定し、両者から残存曲げ耐力比（注）を算出した。
上記の結果を表１に併記した。
（注）「曲げ靱性」ともいう。計算式は、次のとおりである。
残存曲げ耐力比（％）＝［（曲げたわみ４０ｍｍ時の曲げ強度）／（曲げひび割れ強度）］×１００
【００２９】
表１、実施例１、２の測定結果から、ポリプロピレン繊維および水溶性セルロ−スエ−テルならびに配合割合をそれぞれ特定範囲に限定することにより、モルタル混練物の押出成形性および押出成形体の残存曲げ耐力比（曲げ靱性）が改良されることが確認された。
その結果、押出成形体を土木構造物用部材に使用できることが判明した。
一方、比較例１〜１０から、上記特定範囲から外れて製造された場合、押出成形性および／または残存曲げ耐力比が好ましくないことが認められた。
【００３０】
【発明の効果】
本発明は、オ−トクレ−ブ養生を行なってセメント押出成形体を製造するにあたり、原料の一部であるポリプロピレン繊維、水溶性セルロ−スエ−テルを限定し、かつ、使用原料およびその配合量を特定したことを特徴とし、これにより、高い生産性を維持しつつ、曲げ強度および靱性が改良されるという特性改良効果を奏した結果、該押出成形体が土木構造物用部材として使用できる、という用途拡大効果も生じた。
すなわち、本発明にしたがって製造された押出成形体は、道路構造物用部材、鉄道構造物用部材、海洋構造物用部材、地中構造物用部材、下水構造物用部材、土木構造物用埋設型枠および簡易スラブに使用できることとなった。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an extruded product and a method for producing the same, and more particularly to an extruded product capable of improving properties such as bending strength and toughness of the extruded product and a method for producing the same.
[0002]
[Prior art]
As an extruded product, there is known one produced by kneading cement, aggregate, pozzolanic fine powder, various powder particles, vinylon fiber, water reducing agent, water, etc., vacuum extruding and curing. . The molded article has characteristics such as relatively high strength and toughness.
However, since vinylon fiber is used as a raw material, the curing method has to rely on steam curing from the viewpoint of heat resistance, which requires a long production time and low productivity.
[0003]
Then, a method of blending polypropylene fibers without using vinylon fibers and performing autoclave curing has been considered.
Take an example. A cement composition such as cement, aggregate (eg, silica powder), reinforcing fiber (asbestos, pulp fiber, etc.), thickener (eg, methylcellulose), has a length of 3 to 12 mm and a thickness of 0.01 to 0.1 mm. Manufacture of cement board (use example: tile) which mixes, kneads, extrudes and cures autoclave by mixing 1 to 3% by weight of polypropylene fiber having a flat cross section of 02 mm and width of 0.05 to 0.3 mm. A method is disclosed (for example, Patent Document 1).
[0004]
[Patent Document 1]
JP-A-7-267709 (Claims 1 to 3, [0008] and [0010])
[0005]
[Problems to be solved by the invention]
However, the extruded body according to the above-mentioned conventional method can be used as a member for general buildings, but is used for members for civil engineering structures, for example, members for road structures, members for railway structures, members for sewage structures, and members for simple construction. A member requiring extremely high toughness, such as a slab, has a drawback that it cannot be used.
[0006]
The present invention has been made in consideration of the drawbacks of the above-mentioned conventional methods, and has made various studies on materials in order to use the extruded body as a member for civil engineering.
While maintaining high productivity,
An object of the present invention is to provide a method for producing an extruded body capable of improving bending strength and toughness, and to provide an extruded body used as a member for civil engineering structures.
[0007]
[Means for Solving the Problems]
The present invention is characterized in that the dimensions of the polypropylene fiber, the characteristics of the water-soluble cellulose ether, the raw materials used and the amounts thereof are generally specified, thereby achieving the above-mentioned object, and also being used in civil engineering structures. It has established a method for producing an extruded body that can be used.
[0008]
That is, the present invention (the method for producing an extruded body)
"·cement,
・ Pozzolanic fine powder,
・ Aggregate with maximum particle size of 2mm or less
A quartz powder having an average particle size of 3 to 20 μm,
Needle-like particles and / or flaky particles having an average particle size of 1 mm or less,
・ Polypropylene fiber,
・ Water-soluble cellulose ether,
Water reducing agents, and water,
In a method for producing an extruded body obtained by extruding a mortar kneaded product containing under vacuum in an autoclave,
1) 10 to 20 mm in length and 0.05 to 0.15 m in diameter as polypropylene fiber
m, and
A viscosity of 1 when prepared as a 2% by weight aqueous solution as a water-soluble cellulose ether;
Use a material exhibiting 0 to 100 Pa · s (20 ° C.), and
2) The compounding amounts of the water-soluble cellulose ether, water reducing agent and water are 0.15 to 1.5 parts by mass and 0.3 to 0.7 parts by mass, respectively, based on 100 parts by mass of the cement (in terms of solid content). And 20 to 30 parts by mass, and the amount of the polypropylene fiber is 3 to 5% by volume of the mortar volume. "
(Claim 1),
To the abstract, and
-The thing manufactured by the said manufacturing method is used as a member for civil engineering structures (Claim 2)
It is characterized by the following.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The extruded body manufactured by the present invention is a member for road structures, a member for railway structures, a member for marine structures, a member for underground structures, a member for sewage structures, a buried formwork for civil engineering structures and Used as a simple slab.
[0010]
Next, the raw materials used for producing the mortar kneaded material will be described.
Cement does not limit its variety. Portland cement such as ordinary Portland cement, early-strength Portland cement, medium heat Portland cement, low heat Portland cement, etc., mixed cement such as blast furnace cement, fly ash cement, other polymer cement, color cement, eco cement, etc. can be used. .
In particular, in addition to the above-mentioned purpose, it is preferable to use early-strength Portland cement when early strength is required on the construction period, and moderate heat Portland cement or low-heat Portland cement when long-term strength is required. .
[0011]
By mixing the pozzolanic fine powder, a microfiller effect and a cement dispersing effect are produced, and the pozzolanic fine powder has effects such as densifying the extruded product and improving the strength.
Examples of the pozzolanic fine powder having such an effect include silica fume, silica dust, fly ash, slag, volcanic ash, silica sol, precipitated silica, and the like.
Although fineness is not particularly limited, finer is preferable. Among them, silica fume and silica dust are preferred in terms of cost because they themselves have an average particle size of 1.0 μm or less and can be used as they are without pulverization.
The compounding amount is preferably 5 to 50 parts by mass, particularly preferably 15 to 35 parts by mass with respect to 100 parts by mass of cement, in view of kneading properties, extrudability and strength of the mortar.
[0012]
As the aggregate, conventional river sand, land sand, sea sand, crushed sand, quartz sand or a mixture thereof is used.
Aggregates having a maximum particle size of 2 mm or less are used. If it exceeds 2 mm, the strength is undesirably reduced. The preferred maximum particle size is 1.5 mm or less, more preferably 1.2 mm or less from the viewpoint of strength development.
The compounding amount is preferably from 50 to 250 parts by mass, more preferably from 80 to 180 parts by mass, based on 100 parts by mass of cement from the viewpoint of strength, resistance to cracks, etc. after curing, such as kneadability and extrudability of the raw material mixture. Is more preferred.
[0013]
Examples of the quartz powder include powders such as quartz and amorphous quartz, and silica-containing powders such as opal and cristobalite.
Fineness should be such that the average particle size is in the range of 3-20 μm. Outside this range, the strength is undesirably reduced. Those having a diameter of 4 to 10 μm are preferred in terms of strength.
The compounding amount is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass with respect to 100 parts by mass of cement, from the viewpoints of kneadability of the raw material mixture, extrudability of the kneaded material, strength after curing, and the like.
[0014]
Next, the acicular particles and the flaky particles will be described.
Examples of the acicular particles include wollastonite, bauxite, and mullite.
Examples of the flaky particles include mica flake, talc flake, vermiculite flake, and alumina flake.
These particles may be used alone or in combination.
Both the acicular particles and the flaky particles are blended having an average particle size (note) of 1 mm or less. If it exceeds 1 mm, the strength and the toughness of the extruded product are undesirably reduced (the needle-like particles preferably have a length / diameter ratio of 3 or more in order to increase the toughness).
The compounding amount (in the case of combined use, the total compounding amount) is from 1 to 35 parts by mass based on 100 parts by mass of cement from the viewpoints of kneading properties of the raw material mixture, extrudability of the kneaded product, strength after curing, toughness, and the like. Is preferable, and 2 to 25 parts by mass is more preferable.
(Note) In this specification, the “average particle size” refers to the maximum dimension of acicular particles and flaky particles (in the case of acicular particles, it is the length dimension).
[0015]
Polypropylene fibers have higher heat resistance than other organic fibers and can be autoclaved.
It is important that the fibers have a length of 10 to 20 mm and a diameter of 0.05 to 0.15 mm.
If the length is less than 10 mm, the toughness decreases, and if it exceeds 20 mm, the kneading property of the raw material mixture and the extrudability of the kneading material are reduced, and neither is preferable. If the diameter is less than 0.05 mm, the toughness decreases, while if it exceeds 0.15 mm, the extrudability decreases, and both are not preferred.
The blending amount of the polypropylene fiber is 3 to 5% by volume of the mortar volume. If the amount is less than 3% by volume, strength and toughness are undesirably reduced. On the other hand, if the amount is more than 5% by volume, extrudability is undesirably reduced.
[0016]
The water-soluble cellulose ether is blended as a thickening agent for the mortar kneaded material, and specific examples thereof include hydroxypropylmethyl cellulose (HPMC).
As the water-soluble cellulose ether, it is important to use a 2% by mass aqueous solution having a viscosity of 10 to 100 Pa · s (20 ° C.).
It is not preferable that the prepared 2% by mass aqueous solution contains a water-soluble cellulose ether having a viscosity outside the above range because the kneading property of the raw material mixture and the extrudability of the kneaded product are extremely reduced. A preferred water-soluble cellulose ether is hydroxypropylmethyl cellulose (HPMC).
[0017]
The amount of the water-soluble cellulose ether is 0.15 to 1.5 parts by mass based on 100 parts by mass of the cement.
If the compounding amount is less than 0.15 parts by mass, extrusion molding becomes difficult, while if it exceeds 1.5 parts by mass, the viscosity of the kneaded material increases, and the kneading properties and the extrudability are reduced, and neither is preferable.
[0018]
Water reducing agents include various water reducing agents such as lignin sulfonic acid type, naphthalene sulfonic acid type, alkyl allyl sulfonic acid type, melamine sulfonic acid type, polycarboxylic acid type and oxycarboxylic acid type (AE water reducing agent, high performance water reducing agent, Including high performance AE water reducing agents).
The compounding amount is 0.3 to 0.7 parts by mass (in terms of solid content) based on 100 parts by mass of cement. When the compounding amount is less than 0.3 parts by mass (solid content), the kneading property of the raw material mixture and the extrudability of the kneaded material are reduced, and when the compounding amount exceeds 0.7 parts by mass (solid content), Either case is not preferred because the strength is reduced.
In addition, as a water reducing agent, any of a liquid form and a powder form can be used.
[0019]
The amount of water is 20 to 30 parts by mass based on 100 parts by mass of cement. If the amount is less than 20 parts by mass, the kneadability of the raw material mixture and the extrudability of the kneaded material become difficult, and if the amount exceeds 30 parts by mass, the strength is reduced, and neither is preferred.
[0020]
Next, a method for manufacturing an extruded product will be described.
The above-mentioned raw materials are appropriately selected, blended and kneaded to produce a mortar kneaded material.
The kneading method is not particularly limited, but includes the following methods.
1) All raw materials to be blended are divided into a polypropylene fiber, a water-soluble cellulose ether, a water reducing agent and a water group, and a group of other raw materials other than the above, and the latter is put into a mixer. A method in which the raw materials of the former group are added to the mixture (premix), followed by kneading,
2) A method in which raw materials (excluding water) are charged into a mixer and mixed, and then water is charged and continuously kneaded (however, a water reducing agent is used in powder form);
3) a method in which each raw material is individually put into a mixer sequentially and kneaded,
And the like.
[0021]
For the kneading, a mixer for concrete kneading can be used. For example, there are an Erich mixer, an oscillating mixer, a pan-type mixer, a twin-screw mixer, and the like.
For the kneading, an Erich mixer having a large shearing force is preferable. When the raw material mixture is kneaded with an Erich mixer and then with a kneader roller, extrusion molding can be performed efficiently, and the most preferable mortar kneaded material is obtained.
[0022]
The mortar mixture is extruded under vacuum (1 to 60 mmHg).
As the extruder, for example, a single-screw or twin-screw continuous vacuum extruder is used.
[0023]
The molded raw extrudate is pre-cured and then autoclaved.
Autocure curing can shorten the curing time and improve productivity. The curing temperature is 105 to 150 ° C, preferably 110 to 130 ° C, and the curing time is 3 to 8 hours.
The pre-curing method includes, for example, a method of curing a raw extruded product at a temperature of 5 to 100 ° C. and a relative humidity of 50 to 100%, and a method of steam curing at 50 to 100 ° C. .
[0024]
The extruded body manufactured as described above has a bending crack strength of 20 MPa or more, and has extremely excellent toughness.
Therefore, the extruded product according to the present invention can be used for the above-mentioned civil engineering structural member.
[0025]
【Example】
Hereinafter, the present invention will be described with reference to examples.
The raw materials used are as follows.
1) Cement: Low heat Portland cement (manufactured by Taiheiyo Cement Corporation)
2) Pozzolanic fine powder: silica fume (average particle size: 0.25 μm)
3) Aggregate: silica sand No. 5 (maximum particle size 2.0 mm)
4) Quartz powder: average particle size 7 μm
5) Acicular particles: wollastonite (average particle size; 0.3 mm, length / diameter ratio = 4) 6) Polypropylene fiber:
Fiber A; length 12 mm, diameter 0.1 mm,
Fiber B; length 18 mm, diameter 0.1 mm,
Fiber C; length 12 mm, diameter 0.2 mm,
Fiber D; length 12 mm, diameter 0.043 mm,
7) Water-soluble cellulose ether: hydroxypropylmethylcellulose (HPMC), viscosity of a 2% by mass aqueous solution at 20 ° C .; 50 Pa · s
8) Water reducing agent: polycarboxylic acid-based high-performance water reducing agent 9) Water: tap water
(Examples 1 and 2, Comparative Examples 1 to 10)
A mortar kneaded product was manufactured using the above-mentioned raw materials.
That is, cement: 100 parts by mass, pozzolanic fine powder; 32, 5 parts by mass, aggregate: 120 parts by mass, quartz powder: 30 parts by mass, acicular particles: 24 parts by mass, and polypropylene fiber having the compounding amount shown in Table 1 The water-soluble cellulose ether was put into the Erich mixer at once, and the mixture was kneaded and kneaded with a water-reducing agent (in terms of solid content) and water having the compounding amount (parts by mass) shown in the same table, followed by kneading. The mixture was kneaded with a Darroller to obtain a kneaded mortar.
Then, the kneaded product was formed into a size of 450 × 3000 × 25 mm using a vacuum extrusion molding machine (manufactured by Mikami).
Next, after pre-curing for 40 hours under the conditions of 30 ° C. and relative humidity of 80%, autoclave curing was performed at 120 ° C. for 6 hours to produce an extruded body (member for road structure).
In Table 1, only the blending amount of the polypropylene fiber was indicated by "volume%" with respect to the total mortar volume.
[0027]
[Table 1]

[0028]
On the other hand, the following measurement was performed on the mortar kneaded material and the extruded product.
1) Kneaded mortar: Extrusion moldability was observed, and a good case was evaluated as “◯”, a slightly good case was evaluated as “△”, and a difficult kneading was evaluated as “x”, and evaluated in three steps.
2) Extruded body: The extruded body was cut into 450 × 25 × 1500 mm to prepare a test piece, and the bending crack strength and the bending at 40 mm of bending were determined by a cubic point bending load test of fulcrum distance: 1200 mm. The strength was measured, and the residual bending strength ratio (note) was calculated from both.
The results are shown in Table 1.
(Note) Also called "bending toughness". The calculation formula is as follows.
Residual bending strength ratio (%) = [(bending strength at bending of 40 mm) / (bending crack strength)] × 100
[0029]
From the measurement results of Table 1 and Examples 1 and 2, the extrudability of the mortar kneaded product and the residual bending of the extruded product were determined by limiting the polypropylene fiber, the water-soluble cellulose ether, and the mixing ratio to specific ranges, respectively. It was confirmed that the proof stress ratio (bending toughness) was improved.
As a result, it was found that the extruded product can be used as a member for civil engineering structures.
On the other hand, it was recognized from Comparative Examples 1 to 10 that, when manufactured out of the above specified range, the extrudability and / or the ratio of residual bending strength were not preferable.
[0030]
【The invention's effect】
The present invention limits the polypropylene fiber and the water-soluble cellulose ether, which are a part of the raw materials, to produce a cement extruded body by performing autoclave curing, and also uses the raw materials and the amounts thereof. It is characterized by the fact that, while maintaining high productivity, as a result of the characteristic improvement effect that the bending strength and toughness are improved, the extruded body can be used as a member for civil engineering structures, This also has the effect of expanding applications.
That is, the extruded body manufactured according to the present invention is a member for a road structure, a member for a railway structure, a member for an offshore structure, a member for an underground structure, a member for a sewage structure, a member for burying a civil structure. It can be used for formwork and simple slabs.

Claims (2)

Cement, pozzolanic fine powder, aggregate having a maximum particle size of 2 mm or less, quartz powder having an average particle size of 3 to 20 μm, needle-like particles and / or flaky particles having an average particle size of 1 mm or less, polypropylene fiber, water-soluble cellulosic A method for producing an extruded product obtained by extruding a mortar kneaded product containing a ter, a water reducing agent, and water under vacuum and then curing the autoclave.
1) A polypropylene fiber having a length of 10 to 20 mm and a diameter of 0.05 to 0.15 mm, and a water-soluble cellulose ether having a viscosity of 10 to 100 Pa · s (20 ° C), and
2) The compounding amounts of the water-soluble cellulose ether, water reducing agent and water are 0.15 to 1.5 parts by mass, 0.3 to 0.7 parts by mass (in terms of solid content) and 100 parts by mass of cement, respectively. 20 to 30 parts by mass and a blending amount of the polypropylene fiber is 3 to 5% by volume of the mortar volume. An extruded product, which is produced by the production method according to claim 1 and is used as a member for civil engineering structures.