JP2006257669A - Concrete member excellent in explosion-proof properties - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete member which not only prevents large-scale destruction of a building from explosion of an explosive substance such as powder but also minimizes scattering of concrete fragments caused by explosion impact, to thereby reduce human damage in the building. <P>SOLUTION: The concrete member is formed of a concrete portion and a sheet stuck at least to one surface or embedded at least in one surface of the concrete portion, and excellent in explosion-proof properties. The sheet is formed of high-strength fibers and has a tensile strength of 1.5 GPa or more and a tensile modulus of 40 GPa. Preferably the sheet formed of the high-strength fibers satisfies the following conditions. (1) Both the warp and woof of the sheet have a tensile strength of 200 N/cm or more, and an elongation of 10% or less, (2) a strength ratio of the warp to the woof falls in the range of 0.5 or more and 2.0 or less, and (3) an elongation ratio of the warp to the woof falls in the range of 0.33 or more and 3.0 or less. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a concrete member constituting a pillar, wall, beam, or the like of a building, and more particularly to a technique for preventing destruction of a concrete member or explosion of a building due to explosive explosion.

Conventionally, many techniques for improving the explosion resistance of concrete and mortar have been proposed. However, those that attempt to improve the explosion resistance in a high temperature environment such as a fire (see, for example, Patent Documents 1, 2, and 3). ), Those that are intended to prevent the destruction of structures against sudden impacts caused by earthquakes (see, for example, Patent Documents 4 and 5), those that relate to protection performance against impacts, collisions, or projectiles (see Patent Document 6), etc. No proposals have been made from the viewpoint of refractory explosion resistance and human protection.
In recent years, conflicts have occurred in various parts of the world due to conflicts between nations, religions, and ethnic groups, and the destruction of buildings due to bombs and explosives has occurred frequently, and there have also been explosions involving the explosion of dangerous materials. . When explosives explode in the vicinity of concrete, the surface on the explosion side and the concrete part on the back side are partially peeled off by the energy. The speed of debris scattered at that time is extremely fast, and in the worst case, if the volume of the peeled part is large, the force to restrain the main bar is lost, which may lead to the destruction of the building. A proposal from the viewpoint of human protection is required.
JP 2002-193654 A JP 2002-326857 A JP 2004-026631 A JP 2000-192671 A Japanese Patent Laid-Open No. 11-031516 Japanese National Patent Publication No. 11-512842

The present invention not only suppresses large-scale destruction of buildings due to explosion of explosives such as explosives, but also prevents human damage inside the building by suppressing scattering of concrete fragments due to explosion impact. A concrete member is to be provided.

That is, the present invention employs the following configuration in order to achieve the above-described problems.
(1) Concrete with excellent explosion resistance, characterized in that a sheet of high-strength fibers having a tensile strength of 1.5 GPa or more and a tensile modulus of elasticity of 40 GPa or more is pasted or embedded on at least one surface of a concrete member. Element.
(2) The concrete member excellent in explosion resistance according to (1), wherein the sheet comprising high-strength fibers has the following characteristics (a) to (c).
(A) Tensile strength is 200 N / cm or more and elongation is 10% or less.
(B) The strength ratio of the weft direction to the warp direction is 0.5 or more and 2.0 or less.
(C) The elongation ratio of the weft direction to the warp direction is 0.33 or more and 3.0 or less.
(3) It is characterized in that short fibers made of high strength fibers having a tensile strength of 1.5 GPa or more and a tensile elastic modulus of 40 GPa or more are mixed in the concrete so that the volume content is 1.0% or more and 8.0% or less ( A concrete member having excellent explosion resistance as described in 1) or (2).
(4) The concrete member excellent in explosion resistance according to any one of (1) to (3), wherein the sheet composed of high-strength fibers is a woven fabric or a non-woven fabric.
(5) The sheet made of high-strength fibers is a biaxial mesh-like sheet with a gap between threads, and the distance between the threads is 10 mm or more and 30 mm or less (1) to (4) A concrete member having excellent explosion resistance according to any one of the above.
(6) The concrete member excellent in explosion resistance according to any one of (1) to (5), wherein two or more sheets made of high-strength fibers are laminated and pasted.
(7) When 100 g of explosive is contacted and exploded on the back side of the concrete to which the sheet is attached, the concrete part on the side to which the sheet is attached does not peel off. (1) to (6) Concrete with excellent explosion resistance as described.
(8) The high-strength fiber is an ultrahigh molecular weight polyethylene fiber having an average polymerization molecular weight of 1 million or more and a fiber density of 0.95 to 0.98 g / cm ³ , according to any one of (1) to (7) Concrete member with excellent explosion resistance.

Since the sheet | seat which consists of a high strength fiber is affixed on the at least single side | surface of a concrete structure part, or this invention is embedded, the effect which suppresses destruction of the concrete building with respect to the explosion impact force of an explosive is high. In other words, when an explosive explodes near a concrete structure, the concrete structure usually has a higher risk of injury to the person inside the structure because the concrete peels off the back side where the explosion occurred. However, according to the present invention, since concrete peeling on the back side is suppressed, it is effective in reducing human damage and preventing collapse of the concrete building.

Hereinafter, the present invention will be described in detail.
The concrete member of the present invention can reduce the peeling volume of concrete due to the explosive impact force of explosives because a sheet made of high-strength fibers is attached or embedded on the surface of the concrete structure.
The high strength fiber used for the sheet in the present invention is required to have physical properties of a tensile strength of 1.5 GPa or more and a tensile elastic modulus of 40 GPa or more. When concrete peels due to the blasting impact force, an abrupt tensile or shearing force is generated at the interface between the part to be peeled and the base material. However, in the concrete member of the present invention, the deformation of the concrete due to the blasting impact force is high. The strong fiber sheet is pressed down and plays the role of reducing the peel volume within the amount of deformation that does not break. For this reason, the physical properties required for high-strength fibers are physical properties that are difficult to break and that are difficult to stretch, and the difficulty of breaking provides a strong resistance against peeling and breakage of concrete. The tensile strength is required to be 1.5 GPa or more, preferably 2.5 GPa or more. Further, the difficulty of elongation is a force for suppressing deformation of the concrete, and the tensile elastic modulus is required to be 40 GPa or more, preferably 70 GPa or more.

The type of fiber used in the present invention is not limited as long as it satisfies the above tensile strength and tensile modulus values. Fibers that satisfy this physical property include ultra high molecular weight polyethylene fibers, polybenzobisoxazole (PBO) fibers, aramid fibers, polyarylate fibers, vinylon fibers for organic fibers, and carbon fibers, glass fibers, boron fibers, and alumina for inorganic fibers. Examples of fibers and metal fibers include steel fibers and stainless fibers. Of these, ultra-high molecular weight polyethylene fibers are most suitable. This fiber is stable even in an alkali, has no corrosion such as rust, has high strength and elastic modulus, and has a low specific gravity, so that a lightweight structure can be obtained. However, since the heat resistance is low, it is preferable to use fibers having excellent heat resistance such as PBO fibers and aramid fibers when the structure is cured at a high temperature in a high-pressure kettle.

Examples of the shape of the sheet include a woven fabric, a non-woven fabric, and a sheet (generally referred to as a UD sheet) in which fibers are arranged in the 0 ° and 90 ° directions without crossing the fibers.
As the woven fabric, there are many patterns in which warp yarns and weft yarns such as plain weave, twill weave, and satin weave intersect, but the pattern is not limited as long as workability is not hindered.
Non-woven fabrics include a type in which spun yarn is entangled with needles, water flow, air flow, etc., a type in which long fibers are randomly stacked and pressed (spunbond), or a mesh in which the yarns are spaced at regular intervals. Arrange the yarns so that they are vacant, and maintain the 90 ° angle with the yarns so that the yarns cross alternately up and down, and at regular intervals so that the yarns are spaced apart. The type that hardened is also mentioned.
Another example is a sheet in which fibers are arranged in three axes at a crossing angle of 60 °.
The unidirectionally arranged sheet is a sheet made by arranging fibers in one direction while opening multifilaments, and arranging the fibers in one direction in a similar manner so as to form an angle of 90 ° thereon. Can be mentioned.

The physical properties of the sheet composed of high-strength fibers are preferably at least 200 N / cm or more, more preferably 250 N / cm or more, and the elongation is preferably 10% or less in both the longitudinal direction of the sheet. More preferably, it is 8% or less. In addition, it is preferable that the sheet has a balance between the background strength and the difference is small. If the background strength is not balanced and the difference is large, the reinforcement effect only in the strong direction is exhibited, but the reinforcement effect in the weak direction is remarkable. As a result, the effect of suppressing the deformation of the concrete on the surface is significantly impaired. Therefore, the sheet used in the present invention preferably has a small balance in the physical properties of the weft, and the ratio of the strength in the weft direction to the warp direction (the weft strength / the warp strength) is from 0.5 to 2.0 and the elongation In this case, it is preferable that the strength ratio of the weft direction to the warp direction (latitude / elongation) is 0.3 or more and 3.0 or less.

Among the sheets in the present invention, a mesh-like sheet is preferable. The mesh sheet preferably has a yarn interval of 5 mm to 100 mm, more preferably 10 mm to 50 mm. When the yarn interval is too wide, it is difficult to maintain the sheet shape, and the handleability tends to be reduced. Also, as the fiber cross-sectional shape, the thickness of the sheet is reduced, the amount of binder used can be reduced, the adhesive area at the intersection increases, and it becomes easier to maintain the sheet shape. The shape is preferred. The most preferable reason for the mesh-like sheet is that when adhering with a binder such as concrete, mortar, or organic resin, the binder on the front and back of the sheet comes into contact due to the presence of voids, and the adhesion strength is increased. When the adhesion strength is increased, it is considered that the strength and elastic modulus of the sheet can be effectively used, and the effect of suppressing deformation of concrete is easily exhibited.

In the case where the sheet according to the present invention is applied to existing concrete, a method of attaching the attached surface with a sander or the like, and attaching with an organic resin binder such as an epoxy resin or an inorganic binder such as polymer mortar can be used. After roughening the surface with a sander or the like, a method of coating the organic resin binder or inorganic binder thinly, attaching a sheet thereon, further coating the organic resin binder or inorganic binder, and fixing the sheet is preferable. By this method, the binders on the front and back of the sheet come into contact with each other and are cured, whereby the adhesive force is increased and the sheet can be firmly fixed. At this time, it is possible to obtain higher performance by using a plurality of sheets. The number of sheets to be stacked is preferably at least 2 and at most 8 sheets. If it exceeds 8, there is a problem that the price increases.

In the case of newly producing concrete in the present invention, it is possible to employ a method in which a plurality of sheets are stacked and fixed on a formwork, and the concrete is poured into the sheet. Of course, the sheet may be affixed after the concrete is cured without being fixed to the mold. The number of sheets to be stacked is preferably at least 2 and at most 8 sheets.

As the cement used when newly making concrete, normal Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, medium-strength Portland cement, and the like can be used, but are not limited to the above-mentioned cement, and various cements can be used. Can be used. Also, fly ash, silica, blast furnace slag fine powder, or the like can be used in order to increase the fluidity of the concrete paste and obtain concrete strength.

As concrete in the present invention, ordinary raw concrete can be used, but it is preferable to use concrete containing short fibers. This is because the mixing of the short fibers improves the tensile and bending properties of the mortar and also improves the toughness, so that it can be expected that the concrete itself is difficult to break during blasting. The characteristics of the mixed short fibers are preferably a tensile strength of 1.5 GPa or more and a tensile modulus of 40 GPa or more, and the above-mentioned high strength fibers shortened can be used. The tensile properties of the short fibers have a great relationship with improving the tensile performance and bending performance of the concrete, and the higher the value of the short fibers, the higher the value of the concrete.

The mixing ratio of short fibers is preferably 1.0% by volume or more. As the upper limit for mixing fibers, if the amount of fibers is excessively large, lumps and agglomeration occur, workability deteriorates and the effect of mixing is not obtained, so 8.0 volume% or less is preferable, 6.0 volume% or less It is more preferable that If the mixing ratio of the short fibers is too small, improvement in the tensile properties and bending performance of the concrete cannot be expected.
By using concrete with short fibers, the number of sheets to be embedded or pasted can be reduced, and performance can be expected from at least one sheet.

Concrete structures that can employ the concrete members of the present invention include buildings such as apartments and buildings, container-like things such as warehouses, roads and runways, harbor quays and breakwaters, and generally manufactured secondary products. However, the present invention is not particularly limited, and can be used for buildings where threats due to explosives such as terrorism are assumed.

When considering local damage to buildings that are subjected to explosive loads such as explosives, explosive sources can be broadly classified into three categories. That is, when a building explodes at a very close distance (close proximity explosion), when it explodes on the surface of a building (contact explosion), and when it explodes inside a building member. Among these, the contact explosion can be used as a reference in other cases in evaluating damage to a building.

The concrete having excellent explosion resistance according to the present invention can be evaluated by a model contact explosion test. For example, if you put 100 g of explosives in direct contact with the back side of the concrete with the sheet attached (the side without the sheet attached) and blast (contact explosion), the concrete on the side with the attached sheet will bulge. Even if it shows the characteristic which does not peel off.

Hereinafter, the present invention will be described specifically by way of examples.
(Measurement of physical properties of organic fibers)
The tensile strength and tensile modulus of the multifilament organic fiber were determined using 5t Tensilon manufactured by Orientec Co., Ltd., at a tensile speed of 100 mm / min and a distance between chucks of 200 mm. Further, the tensile strength and tensile modulus of the fiber chip after the resin processing were measured in the same manner.

(Sheet tensile test)
The sheet was cut into a strip of 5 cm width, wound around a chuck, fixed so as not to slip, and the tensile strength was measured using 5t Tensilon manufactured by Orientec. The measurement conditions were a tensile speed of 100 mm / min and a chuck-to-chuck distance of 200 mm. The elongation was measured with a video measure with a marked line on the sheet while the sheet was stretched.

(Preparation of concrete specimen)
Add the normal Portland cement and ground granulated blast furnace slag, aggregate 30 seconds, add water for 90 seconds, add water for 90 seconds, and add fibers at this stage, and mix for 3 minutes. Concrete specimens were prepared. The size of the specimen was 60 cm in length and width, and the thickness was 10 cm. Inside, the deformed reinforcing bars SD295A (D10) were placed vertically and horizontally at 12 cm intervals and 5 cm in the thickness direction (see Fig. 1). ). Regarding the curing, compressing was carried out for 14 days after placement, and then air-curing was performed for 14 days.

(Explosion resistance test)
The contact explosion method was carried out to explode the explosion source on the surface of the structure.
In other words, the procedure for the blasting work is to install 100 g of gunpowder at the center of the concrete specimen, and the specimen is fixed to a height of 14.5 cm from the ground using two types of square materials (see Fig. 2). went. The explosive used was SEP composed of 65% pen slit (PETN) and 35% paraffinic. The explosive had a density of 1.3 g / cm ³ and an explosion speed of 6900 m / sec.

(Evaluation of blast peeling part)
About the evaluation of the part which peeled after the blasting, it was made into three items, a diameter, depth, and volume.
About the diameter, the diameter was measured with respect to the specimen in four directions of the vertical direction, the horizontal direction, and both bias directions, and the average value was expressed as an average diameter. About the depth, the deepest part was measured with calipers. As for the peeled volume, water was poured into the peeled trace, and the poured volume was examined. The exfoliation volume part on the side where the explosive was installed was referred to as “crater”, and the exfoliation volume part on the back side thereof was referred to as “spole” (see FIG. 3).

Example 1
A sheet (trade name Cybermesh; manufactured by Toyobo Co., Ltd.) in which ultrahigh molecular weight polyethylene fibers 1320T having a tensile strength of 2.8 GPa and a tensile modulus of 91 GPa are arranged in two directions in the background at 10 mm intervals and the intersections are bonded with urethane resin. Concrete was cast with the formulation shown in Table 1, and after curing for 28 days, the two sheets were pasted with polymer mortar containing short fibers. After the surface of the concrete has been roughed with a sander, the mortar containing short fibers is applied to a thickness of 3 mm, two sheets are pasted before drying, and the mortar containing short fibers is immediately applied 3 mm thick from the top. did. As the mortar, ultrahigh molecular weight polyethylene fibers (trade name Dyneema (R); manufactured by Toyobo Co., Ltd.) mixed with 1.5% by volume of 9 mm short fibers were used.
After applying the sheet, the concrete specimen was obtained by curing for 35 days. Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Example 2)
After casting concrete with the composition shown in Table 1 and curing for 28 days, two sheets of the same sheet as in Example 1 were pasted in the same manner as in Example 1 using epoxy resin instead of polymer mortar. . The thickness of the epoxy resin was 4 mm, and no short fibers were mixed in the epoxy resin.
After sticking the sheet, it was cured for 33 days to obtain a concrete specimen. Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Example 3)
Concrete was cast with the composition shown in Table 1 and cured for 28 days. The concrete was mixed with 1.0% by volume of 30 mm short fibers obtained by impregnating and curing ultra high molecular weight polyethylene fibers (trade name Dyneema (R); manufactured by Toyobo Co., Ltd.) with an epoxy resin. This short fiber had a tensile strength of 2.3 GPa and a tensile modulus of 48 GPa. Further, when placing concrete, one sheet same as that in Example 1 was placed and embedded in the mold so as to be 10 mm from the surface.
The explosive test was conducted by installing explosives on the side far from the sheet in the obtained specimen. Table 2 shows the evaluation results of the part peeled after the blasting.

Example 4
Concrete was cast with the composition shown in Table 1 and cured for 28 days. Thereafter, one sheet same as that in Example 1 was attached with a polymer mortar mixed with 1.5% by volume of 9 mm-long short fibers of ultrahigh molecular weight polyethylene fibers (trade name Dyneema (R); manufactured by Toyobo Co., Ltd.). At this time, the thickness of the polymer mortar was 6 mm, and the sheet was placed in the middle portion of 3 mm. A polymer mortar sandwiching such a sheet was applied to both sides of the concrete. A concrete specimen was obtained after curing for 35 days after construction.
Explosives were placed on the obtained specimen and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Example 5)
A woven sheet obtained by weaving ultra high molecular weight polyethylene fiber 440T having a tensile strength of 2.8 GPa and a tensile modulus of 91 GPa into a plain weave structure (15 warps per inch, both warp and weft) was obtained. Concrete was cast according to the formulation shown in Table 1, and after curing for 28 days, two woven sheets were pasted with polymer mortar containing short fibers. At this time, the thickness of the polymer mortar was 6 mm, and two woven sheets were stacked on the middle 3 mm portion. As the mortar, ultrahigh molecular weight polyethylene fibers (trade name Dyneema (R); manufactured by Toyobo Co., Ltd.) mixed with 1.5% by volume of 9 mm short fibers were used. After applying the sheet, the concrete specimen was obtained by curing for 35 days.
Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Example 6)
This is a method in which ultra high molecular weight polyethylene fibers with a tensile strength of 3.7 GPa and a tensile modulus of 126 GPa are arranged in one direction while opening, and the fibers are further arranged in one direction while opening to form a 90 ° crossing angle. Then, a sheet laminated in four layers was produced, and a laminated sheet (trade name SB2) in which this sheet was sandwiched between thermoplastic films was produced. Concrete was cast with the composition shown in Table 1, and after curing for 28 days, two of the laminated sheets were pasted with polymer mortar containing short fibers. The thickness of the polymer mortar at this time was 6 mm, and two laminated sheets were stacked on the middle 3 mm portion. As the mortar, ultrahigh molecular weight polyethylene fibers (trade name Dyneema (R); manufactured by Toyobo Co., Ltd.) mixed with 1.5% by volume of 9 mm short fibers were used. After applying the sheet, the concrete specimen was obtained by curing for 35 days.
Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Comparative Example 1)
Concrete was cast with the composition shown in Table 1 and cured for 28 days. However, the sheet was not attached, and only a polymer mortar (no short fibers mixed) was applied to only one side with a thickness of 6 mm, followed by curing for 35 days to obtain a concrete specimen. Explosives were placed on the obtained specimen and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Comparative Example 2)
Concrete was cast with the composition shown in Table 1 and cured for 28 days. However, the sheet was affixed with two sheets of nylon fiber 1370T having a tensile strength of 0.8 GPa and a tensile elastic modulus of 4.5 GPa arranged in two directions in the background at 10 mm intervals and overlapping one side only with urethane resin. The same polymer mortar as in Example 1 was used as the binder, but the short fibers were not mixed, and the sheet was affixed so that the sheet was placed in a portion of 6 mm thickness and 3 mm. A concrete specimen was obtained after curing for 35 days. Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Comparative Example 3)
Concrete was cast with the composition shown in Table 1 and cured for 28 days. However, the fiber mixed in the concrete was prepared by adding 1.0% by volume of a net-like polypropylene fiber (55 mm in length). The physical properties of this fiber were a catalog value, a tensile strength of 0.6 GPa, and a tensile modulus of 3.5 GPa. From there, one sheet used in Comparative Example 2 was attached using a polymer mortar not mixed with fiber as a binder. The mortar thickness was 6 mm, and a sheet was placed in the middle 3 mm. A concrete specimen was obtained after curing for 35 days. Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Comparative Example 4)
A sheet of ultra high molecular weight polyethylene fiber 1320T having a tensile strength of 2.8 GPa and a tensile modulus of 91 GPa was arranged in two warp and warp directions at 10 mm intervals and weft yarns at 50 mm intervals. Concrete was cast according to the formulation shown in Table 1, and after curing for 28 days, the two sheets were pasted with polymer mortar. At this time, the thickness of the polymer mortar was 6 mm, and two sheets were stacked on the middle 3 mm portion. After applying the sheet, the concrete specimen was obtained by curing for 35 days. Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

(Comparative Example 5)
Nylon fiber 1320T with a tensile strength of 2.8 GPa and a tensile modulus of 91 GPa and ultrahigh molecular weight polyethylene fiber 1320T at 10 mm intervals and a tensile strength of 0.8 GPa and a tensile modulus of elasticity of 4.5 GPa are arranged in two directions at 10 mm intervals and made of urethane resin. The sheet | seat which made the intersection point adhere | attach was produced. Concrete was cast according to the formulation shown in Table 1, and after curing for 28 days, the two sheets were pasted with polymer mortar. At this time, the thickness of the polymer mortar was 6 mm, and two sheets were stacked on the middle 3 mm portion. After applying the sheet, the concrete specimen was obtained by curing for 35 days. Explosives were installed on the side of the obtained specimen on which the sheet was not attached, and a blast test was conducted. Table 2 shows the evaluation results of the part peeled after the blasting.

Although the tensile strength and elongation of the sheets of Examples 1 to 6 and Comparative Examples 1 to 5 and the evaluation results of the blast test are shown in Table 2, the surface on which the sheet is particularly attached in this example is swelled. The destruction or peeling of what was seen was not observed.

From Examples 1 to 6 and Comparative Examples 1 to 5, it can be seen that the concrete of the present invention has an effect of reducing the peeling volume of the concrete against explosion of explosives. It can also be seen that when concrete containing short fibers is used, similar performance can be obtained even if the number of sheets used is reduced.

The present invention is effective not only for explosions caused by terrorism, but also for preventing the collapse of concrete buildings in the event of an explosion and minimizing human damage to people inside the building. This is effective for industrial conservation.

It is a figure which shows the dimension of a concrete test body. It is a figure which shows typically the state of the blasting test of a concrete specimen. It is a figure which shows the outline | summary of how to obtain | require each dimension of the damage (crater, spall) of the concrete test body after a blast test.

Claims (8)

A concrete member excellent in explosion resistance, characterized in that a sheet made of high-strength fibers having a tensile strength of 1.5 GPa or more and a tensile modulus of elasticity of 40 GPa or more is attached or embedded on at least one surface of the concrete member. The concrete member excellent in explosion resistance according to claim 1, wherein the sheet made of high-strength fibers has the following characteristics (a) to (c).
(A) Tensile strength is 200 N / cm or more and elongation is 10% or less.
(B) The strength ratio of the weft direction to the warp direction is 0.5 or more and 2.0 or less.
(C) The elongation ratio of the weft direction to the warp direction is 0.33 or more and 3.0 or less. The short fibers made of high-strength fibers having a tensile strength of 1.5 GPa or more and a tensile modulus of elasticity of 40 GPa or more are mixed in the concrete so that the volume content is 1.0% or more and 8.0% or less. 2. Concrete member excellent in explosion resistance according to 2. The concrete member excellent in explosion resistance according to any one of claims 1 to 3, wherein the sheet made of high-strength fibers is a woven fabric or a nonwoven fabric. The sheet made of high-strength fibers is a biaxial mesh-like sheet with an interval between yarns, and the interval between the yarns is 10 mm or more and 30 mm or less. Concrete member with excellent explosion resistance. The concrete member excellent in explosion resistance according to any one of claims 1 to 5, wherein two or more sheets made of high strength fibers are laminated and pasted. The explosion-proof property according to any one of claims 1 to 6, wherein the concrete part on the side where the sheet is affixed does not peel off when 100 g of explosive is contacted and exploded on the back side of the concrete affixed with the sheet. Excellent concrete member. The high-strength fiber is an ultrahigh molecular weight polyethylene fiber having an average polymerization molecular weight of 1 million or more and a fiber density of 0.95 to 0.98 g / cm ³ , and has excellent explosion resistance according to any one of claims 1 to 7 Concrete parts.