JP2018111631A - Fiber material for cement reinforcement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber material for cement reinforcement which has high convergence properties and excellent reinforcement effect, and to particularly provide to a fiber material for cement reinforcement which is excellent in a reinforcement effect relative to concrete or mortar having high viscosity.SOLUTION: A fiber material is covered with a resin, where a fiber constituting the fiber material is composed of a plurality of fiber strands. Preferably, the fiber material is obtained by twisting a plurality of fiber strands in a reverse direction, a twisting coefficient of second twist is 0.3 or more and a twisting coefficient of first twist is 0.3 to 3. Preferably, the resin is a resin containing an isocyanate compound as a component, and a resin containing polyol or epoxy compound as a component. Concrete or mortar molded body contains the above material.SELECTED DRAWING: None

Description

  The present invention relates to a fiber material suitable for cement reinforcement, and more particularly to a fiber material for cement reinforcement optimal for the production of concrete, mortar and the like.

Concrete or mortar moldings are used in large quantities in the construction and civil engineering fields because they are inexpensive in addition to excellent properties such as compressive strength, durability, and incombustibility. However, these molded products are brittle substances, and have the disadvantages that they are easily cracked or broken when stress such as tension, bending, or bending is applied.
In order to compensate for this drawback, reinforcement using an organic polymer such as aramid fiber is effective. By reinforcing with these fibers, mechanical properties such as bending strength and bending toughness of a cement molded body such as cement paste, mortar or concrete can be improved.

  However, when the reinforcing fiber is used in the form of a short fiber, the fiber length is short and the reinforcing effect is insufficient. When the fiber length of the short fiber was increased, there were problems of a decrease in dispersibility and entanglement between fibers. In order to obtain dispersibility, it is conceivable to use a monofilament type fiber having a large fiber diameter. However, the strength per fiber thickness is lowered, so that the reinforcing physical properties cannot be sufficiently exhibited.

  In order to solve these problems, Patent Document 1 discloses a method in which fibers (multifilaments) made up of a large number of thin filaments are bundled with a resin, and non-volatile oil is attached to the bundled fibers to improve the focusing property. It is disclosed. However, since the oil adheres to the fiber surface, there is a problem that the adhesive strength between the cement mortar or the concrete and the fiber decreases while exhibiting high sizing properties.

JP 2007-131464 A JP 2012-25603 A

  An object of the present invention is to provide a fiber material for cement reinforcement having a high convergence property and an excellent reinforcing effect, and particularly to provide a fiber material for cement reinforcing having an excellent reinforcing effect for highly viscous concrete or mortar. is there.

The fiber material for cement reinforcement of the present invention is a fiber material coated with a resin, and the fibers constituting the fiber material are composed of a plurality of fiber strands.
Furthermore, it is preferable that the fiber material is obtained by twisting a plurality of fiber strands in opposite directions, the twist coefficient of the lower twist is 0.3 or more, and the twist coefficient of the upper twist is 0.3 to 3. . Moreover, it is preferable that resin is resin which has an isocyanate compound as a structural component, and also resin is resin which has a polyol or an epoxy compound as a structural component in addition to an isocyanate compound.
Moreover, this invention includes the concrete or mortar molded object containing the fiber material for cement reinforcement of said invention.

  ADVANTAGE OF THE INVENTION According to this invention, the fiber material for cement reinforcement which is excellent in the concentrating property with respect to the concrete material or mortar with high convergence property, especially the cement reinforcement or mortar with high viscosity is provided.

Hereinafter, the present invention will be described in detail.
The fiber material for cement reinforcement of the present invention is a fiber material coated with a resin, and the fiber constituting the fiber material is a fiber material composed of a plurality of fiber strands.

Examples of fibers used in the reinforcing fiber material of the present invention include carbon fibers, glass fibers, steel fibers, ceramic fibers, asbestos fibers, and the like, aramid fibers, vinylon fibers, polypropylene fibers, polyethylene fibers, polyarylate fibers, poly Benzoxazole (PBO) fiber, nylon fiber, polyester fiber, acrylic fiber, vinyl chloride fiber, polyketone fiber, cellulose fiber, organic fiber such as pulp fiber, etc. can be mentioned, one of these or a combination of two or more Can be used. Of these, fibers made of para-aramid such as polyparaphenylene terephthalamide and copolyparaphenylene 3,4'oxydiphenylene terephthalamide are preferable because they have a greater reinforcing effect than other fibers, particularly copolyparaphenylene-3. , 4 'oxydiphenylene terephthalamide fiber is less deteriorated in mechanical properties even if it is kept in a strong alkaline atmosphere under high temperature and high pressure for a long time. Steam curing under high temperature and high pressure, for example, 180 ° C, pressure of about It is preferable because it has a high strength retention even under conditions of saturated steam of 10 kg / cm ² .

  The single yarn fineness of the fiber is desirably 0.5 to 100 dtex. If the fineness of the single yarn is less than 0.5 dtex, it becomes difficult to align the single yarn, and if the alignment is insufficient, the mechanical performance of the fiber cannot be fully utilized. In addition, adhesion spots of the resin serving as a sizing agent tend to occur between single yarns, and a predetermined sizing property may not be obtained. In particular, this tendency becomes remarkable when the number of single yarns is increased. On the other hand, when the fineness of the single yarn exceeds 100 dtex, the bonding area between the single yarns decreases, and it becomes difficult to maintain the bundling by the bundling agent, and the object of the present invention is not achieved. More preferably, the single yarn fineness of the bundled fibers is preferably 0.6 to 80 dtex, more preferably 0.7 to 60 dtex.

  The fiber material used in the present invention is composed of fiber strands in which single yarns as described above are assembled, and further uses a plurality of fiber strands. The number of single yarns constituting the fiber strand is preferably 50 to 3000 single fibers. Furthermore, it is preferable that the fiber strand is composed of 100 to 1500 single fibers. The fiber material of the present invention is finally composed of a plurality of fiber strands, but preferably 2 to 8, more preferably 2 to 4 fiber strands.

  Moreover, it is preferable that the fiber material for cement reinforcement of the present invention is a fiber material obtained by twisting a plurality of fiber strands in opposite directions. And as the twist coefficient, it is preferable that it is twisted within the range of the twist coefficient 0.3 or more by the lower twist, the untwisted by the upper twist, or the twist coefficient 0.3-3. Furthermore, the lower twist is preferably in the range of 0.5 to 3, and the upper twist is preferably the same or higher twist coefficient as the lower twist. Furthermore, it is preferable that both the lower twist and the upper twist have a twist coefficient of 2 or less. When the twisting coefficient is too large, a force perpendicular to the fiber axis direction due to the single yarns is more applied when pulled, and the strength tends to be lowered for fibers that are weak against bending. Moreover, the uniform impregnation property of resin used as a sizing agent is impaired, the elongation increases due to twisting and shrinkage, and the reinforcing property of cement mortar or concrete tends to be impaired. By being twisted within the range of the appropriate twisting factor, integration as a reinforcing material is enhanced when it is bundled with a resin, and even when kneaded in cement mortar or concrete, the bundling is maintained, and the fluidity of the material The workability can be ensured.

  In the present invention, the reinforcing material of the present invention (cement reinforcing fiber material) is mixed into cement mortar or concrete and cured by making the fibers into multiple twists in the range of an appropriate twisting factor. At this time, the cement mortar or the concrete of the reinforcing material enters the unevenness of the surface of the reinforcing material bundled by various twists, and there is an effect of improving the adhesive force between the reinforcing material and the cement mortar concrete. In addition, the interfacial adhesive force between the fiber bundle and the resin also increases as the unevenness of the surface of the fiber material increases, and the concrete reinforcing performance is improved.

In addition, as the direction of twisting, it is preferable to twist a plurality of twisted yarns subjected to a lower twist (S twist or Z twist) so that the upper twist is in the opposite direction to the lower yarn, and the fibers are difficult to unwind, There is a tendency that the convergence of the reinforcing fiber material is improved.
Here, the twisting coefficient in the present invention is indicated by the product of the number of twists per unit length and the square root of the fiber fineness, and the following formula described in ASTM D885; twisting coefficient = {twisting number ( Times / m) × √fiber fineness (tex)} / 1055.

  Moreover, it is preferable that the diameter of the fiber material for cement reinforcement comprised from the several fiber strand of this invention is the range of 0.05-5.0 mm. Moreover, it is preferable that it is a short fiber, and it is preferable that the length is the range of 1-50 mm. In particular, such a range is preferable from the viewpoint of reinforcing effects due to fiber mixing, that is, cracking suppression, and imparting high bending strength and high bending toughness. If the diameter of the bundled fiber reinforcement material is too small or the fiber length is too long, the fiber material is likely to be subjected to shearing force when kneaded in cement mortar or concrete, and the resin bundling cannot be maintained. , Unbundling tends to break up into single fibers and tend to impair the fluidity of the material. On the other hand, if the fiber length of the focused fiber is too short, the contact area between the fiber and cement mortar or concrete is small, or if the diameter is too large, the total contact surface area between the fiber and cement mortar or concrete per unit volume is small. Therefore, there is a tendency that a sufficient reinforcing effect cannot be obtained. As a more preferable shape, the diameter of the bundled fiber reinforcing material is preferably 0.1 to 3 mm. The fiber length is preferably 5 to 40 mm.

Moreover, it is preferable that the fiber used for this invention is high intensity | strength, More specifically, it is preferable that the tensile strength of a fiber is 7 cN / dtex or more. Furthermore, it is preferable that it is the range of 10-40 cN / dtex. Here, when the tensile strength of the fiber is too low, when a load is applied to the cement mortar or concrete, the bending strength of the molded product is small, or the fiber tends to break and cannot absorb the impact sufficiently. .
And as resin which coat | covers the fiber material of this invention, it is easy to osmose | permeate inside a fiber bundle, and it is easy to adhere a single yarn and a single yarn within a fiber bundle, and resin which has high toughness is preferable. For example, a resin containing an isocyanate compound as a constituent component is preferable. Specific examples include isocyanate resins, polyurethane resins, and crosslinked products of isocyanate and epoxy.

  More specifically, the isocyanate compound may be selected from aromatic diphenylmethane diisocyanate, toluene diisocyanate, aliphatic hexamethylene diisocyanate, and the like. It is preferable to use an aliphatic isocyanate having excellent permeability into the fiber bundle. Furthermore, an agent composed of a blocked isocyanate and an epoxy compound is preferable.

It is preferable that the adhesion amount of such resin is 3 to 15% by weight based on the total fiber weight. When the amount of adhesion is too small, the convergence is broken and the single fibers are scattered to tend to impair the fluidity of the material. This is because the fiber bundling by the bundling agent cannot be maintained when a shearing force is applied to the fiber during kneading with concrete or mortar. On the other hand, when there is too much adhesion amount, there exists a tendency for the intensity | strength of a fiber not to fully be utilized. When the adhesion amount is increased too much, the focusing property itself is not improved so much. Moreover, it is because the tensile strength of the bundling fiber per weight will fall by the increase in the apparent fineness of a fiber bundling body when the adhesion amount of resin increases.
Moreover, although resin, such as said isocyanate compound, contributes to fiber bundling, you may further coat | cover with the other resin in order to improve the adhesion performance with concrete or cement mortar on the surface.

  More specifically, as the fiber material for cement reinforcement of the present invention, in addition to the resin as described above, it is also preferable that a resin having an epoxy group as a constituent component exists on the surface of the fiber. Furthermore, from the viewpoint of cohesive strength and interfacial adhesive strength, acrylic-modified epoxy resin and bisphenol A type epoxy resin are preferable, and high performance is exhibited. In particular, a resin made of an acrylic-modified bisphenol A type epoxy resin is preferable. The adhesion amount of the epoxy resin is desirably 0.1 to 10% by weight based on the total fiber weight.

Such a fiber material for cement reinforcement of the present invention can be obtained by the following production method.
First, as the fiber material composed of a plurality of fiber strands, it is preferable to use multifilament long fibers in which single fibers are gathered, and a shape in which the single fibers are arranged in a plurality of pieces or tow-like long fibers. And as a method of attaching the resin used as a sizing agent in the present invention, such a fiber material is continuously fed from a bobbin or a beam creel and impregnated in a bag containing the sizing agent. And a method of attaching by a roller touch method, a method of spraying and attaching the sizing agent by a spray method, and the like. In particular, in order to uniformly adhere to the fiber, a method of impregnation in a cocoon containing a resin is preferable, and it is easy to adjust the amount of adhesion with a squeeze roll. In order to further impregnate and infiltrate the fiber bundle with the resin as the sizing agent, it is also preferable that the sizing agent is dispersed or dissolved in an aqueous system or an organic solvent and diluted. Moreover, it is preferable to use a water-based agent from the viewpoint of safety and work environment load. Furthermore, it is preferable to use a relatively low molecular weight compound with improved water solubility in order to ensure the penetration into the fiber bundle.

It is preferable that after the resin as a sizing agent is applied in this manner, a heat treatment is subsequently performed, and the dispersion medium of the sizing agent is dried and sometimes crosslinked by a heat treatment. The treatment apparatus is not particularly limited, and a contact type hot roller or the like can be used. Furthermore, when a non-contact type hot air drying furnace is used, the sizing agent can be operated without being attached to the apparatus or contaminated. Cheap. Moreover, it is preferable to dry at about 105-300 degreeC as a process temperature at this time, especially about 120-250 degreeC. Next, it is preferable to cut the obtained fiber material so as to have a predetermined fiber length by a known cutting machine.
The mixing rate of the fibers constituting the reinforcing fiber material of the present invention into cement mortar or concrete can be selected according to the purpose, but it is usually used in the range of 0.01 to 10.0% by volume. Is preferred.

  The reinforcing fiber material of the present invention is particularly effective for cement which is a binder for concrete and mortar, and is preferably used for concrete reinforcement and mortar reinforcement. The cement as the binder for concrete or mortar is selected in consideration of on-site construction conditions and the like, but the fiber material for cement reinforcement of the present invention can be combined with various cements. More specifically, for example, various portland cements such as normal, early strength, ultra-early strength, low heat, and moderate heat, and various mixed cements such as blast furnace cement in which fly ash and blast furnace slag are mixed with these various portland cements. Fast-hardening cement or the like can be used alone or in admixture of two or more.

The cement reinforcing fiber material of the present invention is preferably used as a concrete or mortar material together with the cement (binding material) as described above, and becomes a concrete or mortar molded body containing the cement reinforcing fiber material.
At this time, together with the reinforcing fiber material of the present invention, the reinforced furnace cement includes blast furnace slag powder, fly ash, silica fume, limestone powder, quartz powder, dihydrate gypsum, hemihydrate gypsum, anhydrous gypsum, and quicklime-based expansion. It is preferable to add known admixtures (binding materials) such as wood and calcium sulfoaluminate-based expansion materials. The blending ratio is not particularly limited, and various designs can be performed.

In particular, the fiber material for cement reinforcement of the present invention has high fiber convergence even in a process such as cement kneading, and breakage occurs even in kneading that produces a high shearing force such as concrete or mortar with a low water / binder ratio. It was difficult to occur and did not hinder the fluidity and workability of the material. Further, the concrete or mortar molded product reinforced with the fiber material for cement reinforcement of the present invention does not cause abrupt fiber breakage even when the applied stress increases, and therefore greatly improves the bending fracture energy of the molded product. there were.
The use of the concrete or mortar molded body containing the cement reinforcing fiber material of the present invention is not particularly limited, and can be widely applied to general civil engineering and architectural uses.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Various evaluations in the examples were measured as follows.

(1) Fiber length and fineness Measured according to JIS-L-1015.
(2) Fiber tensile strength It measured based on ASTM D885.
(3) Fiber bundle diameter and fiber bundle length of bundled fiber bundles After treating with resin, the treated fiber bundle (treated yarn) cut with the digital caliper (manufactured by A & D Co., Ltd.) The fiber bundle length was measured.

(4) Convergence after Cement Kneading In the following Examples and Comparative Examples, after kneading the cement, the unwinding of the reinforcing material in the cement mortar or concrete was visually confirmed and evaluated as follows. In particular, it was defined as untwisting that twisting is easy at the center of a short fiber, but bulging occurs from the end to the center of the short fiber by untwisting at the center.
○: 2 or less of the fiber bundles that were unwound in 10 pieces.
(Triangle | delta): The fiber bundle which thawed out of 10 is 3 or more and 8 or less.
X: Of 10 fibers, 9 or more fiber bundles were dissolved.

(5) Fluidity of raw cement In the following examples and comparative examples, a slump cone (height 15 cm, lower surface inner diameter 10 cm, upper surface inner diameter) on a horizontally disposed 50 cm square aluminum plate following the kneading step (4) above. The raw cement was poured into a 5 cm conical column with a hollow inside, and the slump cone was slowly pulled up vertically. At this time, raw cement spreads circularly on the aluminum plate. The diameter of the expanded circle at this time, or when the circle is distorted, an arithmetic average of the shortest diameter and the longest diameter was measured as a flow value. This flow value reflects the fluidity of raw cement.

(6) Compressive strength and bending fracture energy of mortar moldings Using the cement obtained in the following examples and comparative examples, a raw cement was placed in a mold having a width of 40 mm, a height of 40 mm, and a length of 160 mm, A specimen was produced by curing at 20 ° C. and 90% RH until the material age was 28 days. The above specimen was subjected to three-point bending measurement according to “JIS-R-5201”. More specifically, using a tensile compression tester for 10 tons (manufactured by TOYO BALDWIN, UNIVERSAL TESTING INSTRUMENT MODEL UTM 10t), the center of the fulcrum distance of 10 cm is compressed at a speed of 2 mm / min. The secondary yield point stress when the specimen was destroyed was calculated.

[Example 1]
As a fiber as a reinforcing material, a copolymer type aramid fiber strand (copolymer type aromatic polyamide fiber, “Technora” manufactured by Teijin Ltd., 1670 dtex, 1000 filament, tensile strength 24.5 cN / dtex) is used, and a twisting machine is used. The fiber is subjected to a lower twist (S direction) so that the twist coefficient is 2, and two fiber strands are combined so as to have the total fineness in the table, and the upper twist is reversed so that the twist coefficient is 1. (Z direction) and sorbitol polyglycidyl ether type epoxy compound (manufactured by Nagase ChemteX Corporation, “EX614B”), dimethylpyrazole block hexamethylene diisocyanate (manufactured by Baxenden, “Trixene aqua 201”, dimethyl as a sizing agent resin component Pyrazole block-HDI trimer) A fiber bundle to which a sizing agent was applied at a temperature of 200 ° C. after being immersed in a blending solution having a total solid content of 10% by weight, mixed at a ratio of 50% by weight and 50% by weight, respectively, and then dried at 200 ° C. Obtained. Then, after dipping in a 10% solids weight aqueous dispersion containing a carboxyl group-containing acrylic-modified bisphenol A type epoxy resin (DIC Corporation, “Dick Fine EN”) as a finishing coating agent resin component, the temperature It was dried at 200 ° C., treated with an agent so that the amount of coating agent attached to the fiber was 3% by weight, and the fiber material was cut into 30 mm to obtain a reinforcing material. The diameter of the obtained treated fiber bundle was 0.7 mm.

  13.9 g of the obtained fiber material for cement reinforcement, 951 g of low heat Portland cement (manufactured by Taiheiyo Cement Co., Ltd.), 220 g of silica fume (manufactured by Elchem AS), fine aggregate (manufactured by Sanei Silica Co., Ltd., “No. 6 silica sand”) 541 g, fine aggregate (manufactured by Sanei Silica Co., Ltd., “Silica Sand SP80”), 193 g of water, and a mortar mixer (manufactured by Marui, MIC-362, capacity: 5 L) at a stirring speed of 140 rpm for about 3 minutes The mixture was kneaded to obtain raw cement (mortar). Table 1 shows the results of evaluating the mortar molded body obtained by curing the raw cement.

[Example 2, Comparative Examples 1 and 2]
It implemented similarly to Example 1 and evaluated except having changed the twist structure of Example 1, the twist coefficient, and the use fiber into the thing of Table 1. FIG. The results are also shown in Table 1.

Claims (6)

  A fiber material for cement reinforcement, which is a fiber material coated with a resin, and a fiber constituting the fiber material is composed of a plurality of fiber strands.   The fiber material for cement reinforcement according to claim 1, wherein the fiber material is obtained by twisting a plurality of fiber strands in opposite directions.   The fiber material for cement reinforcement according to claim 1 or 2, wherein the twist coefficient of the lower twist is 0.3 or more and the twist coefficient of the upper twist is 0.3 to 3.   The fiber material for cement reinforcement according to any one of claims 1 to 3, wherein the resin is a resin containing an isocyanate compound as a constituent component.   The fiber material for cement reinforcement according to claim 4, wherein the resin is a resin containing a polyol or an epoxy compound as a constituent component in addition to the isocyanate compound.   A concrete or mortar molded body containing the fiber material for cement reinforcement according to any one of claims 1 to 5.