JPH0742151B2 - Cement-based cured product containing fiber-reinforced thermosetting plastic powder as an aggregate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a powdery fiber-reinforced thermosetting material obtained by crushing waste material of fiber-reinforced thermosetting plastic (FRP) into a part or all of aggregate. The present invention relates to a cement-based hardened body obtained by using plastic and mixing the aggregate with a cement-based inorganic material made of various cements or gypsum and adding at least water to cure the material.

In the present applicant, plastic has already been molded and
A solidified molded product refers to a cement-based cured product.
Not only cement products such as boards and blocks, but also all articles manufactured by hardening cement such as construction, civil engineering, and structures.

2. Description of the Related Art Cement-based hardened materials such as mortar products and concrete products are widely and widely used in the fields of construction and civil engineering in society today. And as the usage form, a plate,
There are various forms such as tubes, blocks and U-shaped grooves. These are made by the molding method, centrifugation method, casting method, and the like. These raw materials are fine aggregate, coarse aggregate, cement and the like. However, the problem of resource depletion has become a serious problem in this field as well. For example, river sand is desirable as a sand resource that is a fine aggregate, but sea sand has come to be used because it is difficult to obtain it. A large amount of fresh water is required to wash the sea sand, but the reality is that it is difficult to implement near the estuary. Therefore, since it is necessary to use even sand with seawater, when it is used for buildings etc., problems such as corrosion of reinforcing steel bars occur, and as a fine aggregate substitute for this. Raw materials were desired.

In addition, pumice and sand are used as aggregates in lightweight blocks used for housing fences and fences. Pumice stone is a volcanic ejecta that is cooled while containing a large amount of gas, and there are many voids inside, and many are light. However, this pumice stone has become difficult to obtain, and it has become necessary to collect it from geographically inconvenient and economically unprofitable points. Therefore, also in this field, it is eager to find a raw material as a new aggregate.

Conventionally, for plastic waste materials that have been separated and collected from general municipal waste, pyrolysis by high-temperature treatment, development of fish reefs,
Although research and development have been conducted on the effective use of agricultural film such as reuse, it is suitable for the waste material of fiber-reinforced thermosetting plastic, which is the most difficult to treat in industrial waste and causes pollution. There is no treatment method and illegal dumping has become a major social issue, and inexpensive landfills are reaching the limit because there are few suitable sites.

Problems to be Solved by the Invention Fiber-reinforced thermosetting plastic (FRP) is mainly composed of thermosetting resin, and glass fiber-reinforced plastic (GFRP), organic fiber-containing plastic or carbon is used as a reinforcing material. These wastes, such as plastics with fibers (CFRP), are hard to crush, and the thermosetting plastics are very difficult to cut.

There are various types of thermosetting resins used depending on the purpose.Unsaturated polyester resin, which is an iso type medium corrosion resistant resin,
Examples include bisphenol-based unsaturated polyester resin which is a high corrosion resistant resin, het acid-based unsaturated polyester resin which is an oxidation resistant resin, and epoxy resin which is a high corrosion resistant resin.

Even if GFRP is the only type of molded product, a bathroom unit,
Transportation equipment (cars and vehicles), boats, septic tanks, construction materials (flat, corrugated board, toilet bowls, miscellaneous goods, helmets), cooling towers, FRP types, etc.

Even for resin manufacturers, these industrial wastes have a very high dependency ratio of landfills in which outsourced trimming wastes, polymer residues, defective molding products, etc. are outsourced to resin manufacturers. It puts pressure on the management of SMEs.

From the user's point of view, the amount of waste generated by the residential lifts will steadily increase, and the unit bathroom alone will increase to 10 to 15 every year.
Over 10,000 tons of flat and corrugated sheets are landfilled each year, 220,000 coastal fishing boats and 100,000 leisure yachts are sequentially disposed of, and some are illegally dumped.

Thus, while being widely used for industrial purposes, these wastes have not been sufficiently investigated and treatment technologies and methods have not been established.

In view of such a current situation, the present invention is also from the viewpoint of pollution prevention,
This is an extremely effective means from the viewpoint of effective use of resources.By recycling the waste of fiber-reinforced thermosetting plastics as a resource and compounding it with a cement-based inorganic material, it is lightweight, strong and resistant to acid. Also, it aims at new utilization as a cement-based hardened material that is excellent in freeze-thawing.

Means for Solving the Problems In order to effectively use the fiber-reinforced thermosetting plastic as a resource for waste, it is necessary to use 10 mm by cutting and pulverizing.
It is necessary to make a powdery or granular form having a size of up to several μm. This was sufficiently possible with conventional techniques for general plastics, but it was extremely difficult to finely pulverize fiber-reinforced thermosetting plastics reinforced with glass fibers or the like. However, as a result of earnest research, it is possible to finely pulverize the fiber-reinforced thermosetting plastic to a size of about 40 μm by the crushing device developed by the inventor of the present application, as well as the reinforcing fiber. Became. For example, with glass fiber
GFRP contains a soft resin and a rigid glass fiber and is integrated, but there are many problems with this pulverization, and it was said to be impossible until now. If it is cut at a high speed, the heat generated will melt the resin and it cannot be cut. Also, if cutting at a low speed, workability will decline. For these reasons, it was necessary to develop a special cutting tool. However, this point could be solved by studying the cutting conditions and devising the shape of the blade. Therefore, as a result of research on the technique of dispersing powder of fiber-reinforced thermosetting plastic waste material in cement, mortar or concrete, it has become possible to produce a cement-based hardened product such as a mortar product or a concrete product.

Next, the structure of the present invention for solving the above-mentioned problems will be described.

First, the cement-based hardened product according to claim (1) is a cement-based cement composed of various cements or gypsum, and an aggregate containing a fiber-reinforced thermosetting plastic in which 90% or more of powder having a particle size of 100 μm or less in the particle size distribution. At least water is added to a material mixed with an inorganic material, and the material is molded and cured.

Further, the cement-based hardened product according to claim (2) is an aggregate containing a fiber-reinforced thermosetting plastic in which 90% or more of powder having a particle size of 100 μm or less is contained in a particle size distribution, and a cement-based cement composed of various cements or gypsums. In a cement-based cured product obtained by molding and curing at least water by adding a material mixed with an inorganic material, a carbon fiber sheet is laminated in the cement-based cured product.

This cement-based cured product has carbon fibers interposed for the purpose of imparting conductivity and weight reduction to the cured product, and a glass fiber sheet may be used if only the purpose of strengthening the strength is intended.

As an admixture added to the cement-based mixed material in addition to water, it is generally known that when mixed with cement, it is modified to have a strong stability, for example, a high-performance water reducing agent or potassium carbonate. There is an inorganic special cement admixture in which the above inorganic compounds are combined by a chemical reaction.

Action Each of the inventions of the present application is, as described above, a powder fiber-reinforced thermosetting plastic (hereinafter referred to as FRP powder) as a part or all of an aggregate, and the cement comprising the aggregate and various cements or gypsum. A cement-based cured product obtained by molding and curing at least water by adding at least water to a material mixed with a system-based inorganic material, and further comprising a carbon fiber sheet laminated in the cement-based cured product. In the cement-based hardened body such as blocks created based on
The FRP powder will be evenly dispersed, and since the FRP powder exhibits water repellency against water, it will reduce the water absorption rate of the cured product as a whole and will also have strong properties against freeze-thaw phenomenon. . Here, the freeze-thaw phenomenon means that the cement-based product is destroyed due to the expansion of the water during freezing due to repeated freezing and thawing of the water absorbed in the cement-based product in cold regions where the temperature difference is large every day. It refers to the phenomenon of being disabled.

In addition, since FRP powder showing high chemical resistance to acids such as sulfuric acid, hydrochloric acid, nitric acid, acetic acid, and various organic acids is uniformly arranged in the hardened cementitious body, it shows acid resistance. . This brings the gospel to cement-based structures caused by the damage of acid rain, which is now a very big social problem. That is, since the cement-based hardened body produced by the present invention exhibits high acid resistance, its performance does not deteriorate even if it is used by placing it in a place directly exposed to wind and rain, so its social spread. The effect is great.

Further, according to each invention of the present application, it is possible to recycle both industrial waste of fiber reinforced thermosetting plastics such as GFRP and resource depletion of cement-related aggregates, and to realize high functionality with high weight and high strength. It is possible to supply a hardened cementitious body such as various cement products having the same.

Examples Hereinafter, each invention of the present application will be specifically described based on Examples.

Cement products such as mortar and concrete are currently used in large quantities in all fields in society. One of them is the hollow block used for Hei and Fence. This is made from pumice, cement, sand, etc., but its compressive strength is specified to be 40 kgf / cm ² or more. Further, the decorative block is required to have a compressive strength of 80 to 130 kgf / cm ² or more. In the case of the present invention, even mortar containing FRP powder has a compressive strength of 200 kgf / cm ²
The above is possible, and it is fully applicable to this field. In addition, cement roof tile made by setting cement and sand is used in part. Since it is necessary that this tile does not break even if a person walks during work, the tile strength test method uses an actual tile, and the distance between fulcrums is set to 20 cm and a weight is applied to the center. In addition, it is required to have a strength of 100 kg or more. Converting this strength into bending strength, it is 45 kgf / cm ²
That's all. According to the invention, FRP powder is used instead of sand.
It was confirmed that this strength was maintained even if the content was up to about%.

One of the concrete products is slab concrete used for roads. The bending strength of this is 40kgf / cm ²
It is a degree. Again, use 20% FRP powder instead of sand.
It was possible to maintain sufficient strength even when mixed up to about 100%.

One of the more popular cement products is the interlocking block. This is used for road paving stones, cobblestones, etc. by fitting blocks that have been finished in any shape. This can be done by coloring the surface,
It is widely used by attaching tiles or giving unevenness. The strength required for this is 50 in bending.
kgf / cm ^2, which is 640kgf / cm ² at compression. In particular, in order to increase the compressive strength, when the raw material such as cement is filled in the mold, the mold is molded while being pressed. Even in the case of the present invention, bending strength and compressive strength can be sufficiently satisfied by applying a pressing operation.

As described above, the cement-based hardened body containing the FRP powder produced by the present invention can withstand practical use even if the FRP powder is mixed in an amount of about 20% to 50%, and in some cases about 70% instead of sand. The strength of the mortar is maintained, and various mortar products and concrete products can be manufactured.

What is particularly important here is that the apparent specific gravity of the fine powder of discarded fiber-reinforced thermosetting plastic such as GFRP is about 0.5, which is extremely smaller than that of sand having a specific gravity of about 2.5. Therefore, it is possible to provide a cement-based hardened material such as a cement product that is much lighter than conventional products. The thermal aspect of the specimen containing this FRP powder becomes a problem. To examine this, 40% FRP powder was used instead of sand.
% Of the mortar was placed in a dryer at 200 ° C. and heat-treated for 3 hours. The FRP used in this experiment was made from epoxy resin. Deformation temperature of epoxy resin is 70
Since the temperature was up to 150 ℃, it was treated at 200 ℃ higher than that, but it was not particularly greatly deformed or the strength was not reduced. Therefore, it can be said that at such a temperature, the heat resistance of the mortar and concrete products could be maintained. The cement-based inorganic material used in the present invention may be any of ordinary Portland cement, alumina cement, white cement and the like. It is also possible to use gypsum and water glass.

In order to further increase the mechanical strength of the cement-based hardened material containing FRP powder, fiber reinforcement was attempted. As the fiber, a carbon fiber that does not deteriorate in strength when placed in cement, and a sheet-like form was used. Sheet-shaped carbon fibers were laminated to produce a test piece having a content of 3 to 5%. The bending strength of the carbon fiber reinforced cement-based cured product containing no FRP powder was 400 kgf / cm ² . 10 FRP powder
Bending strength when added% is 420kgf / cm ^2, than the bending strength of the case without the FRP powder 20 kgf / cm ² and higher, it helped improve the strength. Add 20 FRP powder
The bending strength slightly decreased as the percentage increased. But FR
Even when P powder was mixed in 30% of the weight of cement, it showed a bending strength of 370 kgf / cm ² .

The carbon fiber content in this sample is almost the same as when it is used as a curtain wall for high-rise building, but since the bending strength is much higher than that,
It can also be used in that direction.

Further, the cement-based hardened body in which carbon fiber sheets are laminated and intercalated has an electric conductivity of about 10 ^-1 Ωcm as a property other than strength, and is therefore excellent in static electricity removing action and electromagnetic wave shielding property. Therefore, with respect to electromagnetic wave shielding against malfunctions of robots, troubles of medical devices and electronic devices, etc., it exhibits electric field shielding properties comparable to metals, and is also useful as a highly functional building material. It can also be used as a sheet heating element by devising the arrangement of carbon fiber sheets and adjusting the electric resistance.

In the examples of the present invention, FRP powder obtained by finely pulverizing an epoxy resin containing glass fiber was mainly used. When the fine powder was observed with a scanning electron microscope, the glass fiber was cut and the epoxy resin was also finely ground. When the particle size distribution of this fine powder was obtained,
As shown in Table 1, those with a particle size of 44 to 74 μm are most distributed, and some of them are fine powders with a size smaller than that (about several μm), and 90% or more of the powders have a particle size of 100 μm (0.1 mm) or less. Had occupied.

Example 1 FRP powder was mixed as a part of fine aggregate to prepare a mortar. Ordinary Portland cement is used as the cement, and standard sand is used as the sand. Water / cement (W / C) = 65%,
Specimens were made with aggregate (sand and FRP powder) / cement = 2. At that time, tests were conducted while changing the amount of FRP powder added to the aggregate to 10%, 20%, and 30% of the aggregate weight. Also, as the amount of FRP powder increases, the fluidity of mortar decreases, so a high-performance water reducing agent (Mighty FD), which is a type of admixture, may be used in an amount of 1 to 1.5% of the cement weight.
Added about. Mortar production is carried out according to JIS R5201, 4 ×
A 4 × 16 cm specimen was made. After curing in water for 8 days, bending strength and compressive strength were examined. The results are shown in Table 2.
If it contains no FRP, its bending strength is 54kgf / c.
The m ² and compressive strength were 230 kgf / cm ² . In contrast, the strength was slightly decreased with increasing amount of FRP powder, exhibited a compressive strength of flexural strength and 185kgf / cm ² of 35 kgf / cm ² even in the case of 30%. As the amount of FRP added increased, the weight of the test piece decreased.

Example 2 A mortar was produced with the same composition as in Example 1. Table 3 shows the results of obtaining properties such as mechanical strength after curing in water for 28 days. In this case, even if FRP was mixed with 20% of the amount of aggregate, the degree of decrease in strength was small, and the bending strength was 46 kgf / cm ² , which was almost the same as when FRP powder was not added. As the amount of FRP added increased, the amount of deflection in the center of the test piece also increased 2-3 times.

Example 3 An ultra-light mortar was manufactured by using Shirasu balloon as a part of fine aggregate. Cement (ordinary Portland cement)
Weigh 520g and use it as fine aggregate for Shirasu balloon (bulk density 0.3-0.33, apparent specific gravity 0.6-0.7, average particle size 50μ
m) and FRP powder (average particle size 44 μm). Aggregate at this time (Shirasu balloon and FRP powder) /cement=0.7. The amount of FRP powder added was set to an amount corresponding to 43%, 60%, and 75% of the total weight of the aggregate (shirasu balloon and FRP powder). To this, 370 g of water and a high-performance water reducing agent (Mighty FD) as an admixture were added by 3% of the cement weight. This was kneaded with a mortar mixer. W / C at this time = 71
%Met. After measuring the flow value, in the form (4 cm × 4 cm × 16
cm). After 2 days, it was removed from the mold and cured in water for 7 days to prepare a test piece. The specimen with FRP powder weight equivalent to 43% of the total aggregate weight had a bulk density of 0.8 g / cm ³ and bending strength of 20 kgf / cm ²
The compressive strength was 100 kg / cm ² .

Since the weight of the specimen taken out after curing in water was almost the same as the weight after air-drying, the water absorption rate of the specimen containing the FRP powder was zero or very small. A part of the test piece was put in water and sufficiently soaked in water. The sample was taken out of the water, and when it did not drip, it was placed in a freezer at -10 ° C for 12 hours. Then, the specimen was taken out of the freezer and left at room temperature for 12 hours. Then, it was put into water again, soaked in water, put in a freezer, and then cycled for 12 hours and 12 hours at room temperature, and the cycle of freeze-thawing was observed 10 times.

When the FRP powder was not contained, peeling occurred from the surface of the specimen during the first cycle, and a crack was formed in the center of the specimen at the third time, and the specimen was easily broken into two pieces by hand. In addition, the test piece was in a tattered state and could not maintain its shape.

On the other hand, the specimen containing FRP powder did not peel off from the surface of the specimen, internal destruction, or weathering, even after repeating 10 cycles. From these, it was proved that the specimen containing the discarded reinforced plastic powder has excellent properties against freeze-thawing.

Example 4 In an attempt to improve the properties of a cement-based cured product to which FRP was added, sheets (thin non-woven cloth) made of carbon fibers were laminated to form a cured product. In that case, the matrix was made from mortar using only sand-free cement paste.

As the carbon fiber, a sheet (thickness: 0.3 mm, basis weight: 33 g / m ² ) made of PAN-based high-performance carbon fiber was used. Predetermined amount of FRP
Carbon fiber sheet was impregnated into a cement paste with a given W / C ratio containing powder (10%, 20% and 30% of cement weight, which gives a resin / cement ratio of 0.1, 0.2 and 0.3) . 12 sheets of this carbon fiber sheet, thickness 6mm
A test piece (4 × 8 × 0.6 cm) was made by stacking in a mold of
Also in this case, the fluidity of the cement paste decreased as the amount of FRP added increased, so the W / C ratio was increased from 40% to 60%.

Each specimen was cured in water for 28 days and then the bending strength was determined.
The values are shown in Table 4. When 10% of FRP powder was added, a bending strength of 420 kgf / cm ² was shown, and the strength was rather higher than when no FRP powder was added (400 kgf / cm ² ). Therefore, the powder in this case acted as a fine aggregate for improving the strength. When the amount of FRP powder added was further increased, the bending strength of the specimen tended to decrease slightly.
Even if P powder is added at 30% of the cement weight, it has a bending strength of 370 kgf / cm ² , which is only 30 kgf / cm compared to the one without additive.
It was only a cm ² drop. It can be seen that the strength of the product is much higher than that of the mortar product of Example 2.

Example 5 Since carbon fiber has a particularly high tensile strength, an FRP powder-mixed cement hardened body in which the carbon fiber was arranged in one direction was produced by utilizing this characteristic. Forming 15 pitch-type high-performance carbon fibers (strand, 3K) impregnated with alumina cement paste (average particle size 2 μm, W / C = 30%) (width 0.8 cm, length 1)
5 cm, height 0.6 cm). 10%, 20% and 30% of the cement weight in the alumina cement paste
FRP powders corresponding to the above were dispersed respectively. After demolding
It was cured in water for 4 days to prepare a carbon fiber reinforced cement hardened body rod (0.8 × 0.6 × 15 cm). The carbon fiber content in this cured carbon fiber reinforced cement was 8 vol% in all cases.
Met. As shown in Table 5, the bulk density was 2.4 g / cm ³ when FRP powder was not added, but decreased as the amount added increased to 1.6 g / cm ³ when 30% was added. became. Further, the bending strength of the carbon fiber reinforced cement hardened body containing 30% of FRP powder was 420 kgf / cm ² . (Table 5) As a matter of course, if the amount of FRP powder added is reduced, carbon The flexural strength of the fiber-reinforced cement cured product was high, and it was 880 kgf / cm ² when 10% was added. From another experimental result, it has been found that the bending strength of the hardened cement product is further increased by increasing the carbon fiber content. For example, if the carbon fiber content is 15 vol%, the bending strength is 3000 kgf.
It was / cm ² . Therefore, even if it contains FRP powder,
It is clear that it shows a higher value than that shown in Table 5.

Example 6 With respect to the cement-based hardened body containing the FRP powder in which the carbon fiber sheets were laminated, the functionality other than the strength was examined. As the carbon fiber sheet, a sheet made of pitch-based carbon fiber was used. Specified W / C on 6 sheets of this carbon fiber sheet
Impregnated with the ratio cement paste (40% -60%) and thickness
Laminated in a 3 mm (15 cm x 15 cm) formwork. At that time, the specified content in the cement paste (10% of the amount of cement, 2
0%, 30% and 40%) FRP powder was added. In all cases, the carbon fiber content was about 5 vol%.
The specific resistance of each test piece was determined after being cured in water for 28 days.

The specific resistance was measured by applying a silver paste to both ends of the sample and applying a tester terminal thereto. Table 6 shows the measurement results. In the case of the examples, the specific resistance of the hardened cementitious material was about 10 ⁸ to 10 ⁹ Ωcm, but it was reduced to 0.35 Ω · cm by adding about 5 vol% of carbon fiber.

As for the electromagnetic wave shielding property of each sample, the electric field shielding property (dB) from the frequency of 50 MHz to 1000 MHz was measured by the Advantest method. The obtained results are shown in Table 6. The resistivity was decreased by adding carbon fiber. Since the hardened cement material became conductive, the electromagnetic wave shielding property was also extremely improved, and exhibited properties comparable to those of metals. Moreover, this property did not change even if the amount of FRP added increased to 40%.

EFFECTS OF THE INVENTION According to the present invention, powdered fiber-reinforced thermosetting plastic, that is, FRP powder as a part or all of the aggregate,
An excellent cement that is lightweight, has high mechanical properties such as strength and heat resistance, and is strong against freeze-thawing and acid resistance by being mixed with cement-based inorganic materials such as various cements or gypsum. A system hardened body can be provided.

Also, by laminating a carbon fiber sheet in this cement-based hardened material, mechanical properties can be further improved, and electrical conductivity and electromagnetic wave shielding properties can be obtained. OA rooms, hospitals, electronics-related factories Can be made useful as a building material.

Further, the present invention is not only economically excellent as such, but also contributes to the reuse of the fiber reinforced thermosetting plastic that becomes industrial waste as a resource, and greatly contributes to the protection of the global environment and pollution control. Is what you can do.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C04B 18:20 14:06 Z 14:16 14:38) A 111: 76 111: 94 (56) References JP-A-1-226758 (JP, A) JP-A-59-156947 (JP, A) JP-A-63-289163 (JP, A) JP-A-1-154997 (JP, A)

Claims (2)

[Claims] 1. 90% of powder having a particle size distribution of 100 μm or less
Cement-based hardened product obtained by molding and hardening by adding at least water to a material obtained by mixing aggregate containing fiber-reinforced thermosetting plastic powder occupying the above and cement-based inorganic material made of various cements or gypsum 2. 90% of powder having a particle size distribution of 100 μm or less
Aggregate containing fiber-reinforced thermosetting plastic powder occupying the above, and at least water is added to a material obtained by mixing a cement-based inorganic material made of various cements or gypsum,
A cement-based cured product obtained by molding and curing, characterized in that a carbon fiber sheet is laminated between the cement-based cured product.