JP3598247B2 - Specimen preparation apparatus and specimen preparation method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus and a method for preparing a specimen for a low-temperature crack resistance test of an asphalt mixture or the like.
[0002]
[Prior art]
A material obtained by solidifying asphalt alone or as a binder (hereinafter referred to as asphalt mixture) or a concrete material has a property of shrinking with a decrease in temperature. Free shrinkage is restrained by being constrained by the ground, existing buildings, internal buried objects, and the like. When the stress generated inside the material exceeds an allowable value, the material cracks.
[0003]
In particular, low-temperature cracking of a material using asphalt alone or asphalt mixture has become a problem in road pavement in a cold region, a dam wall type dam, a water channel, and the like.
[0004]
As a test method for accurately and efficiently evaluating low-temperature crack resistance, there is a low-temperature crack resistance test using a ring-shaped restrained specimen. The restraint specimen for the low-temperature crack resistance test of a fluid asphalt simple material was prepared by placing asphalt into a ring outside the annular restraint and integrating the restraint with the material. ing.
[0005]
In the case of asphalt mixture, when preparing test specimens, a method of dropping a weight on a cylindrical specimen and compacting it, or compacting a flat specimen with a roller compactor, The method of cutting was used.
[0006]
[Problems to be solved by the invention]
However, conventionally, in the case of an asphalt mixture material, a ring-shaped specimen could not be produced successfully because the fluidity of the asphalt mixture was small. Further, when preparing a rod-shaped specimen having a narrow width, it was difficult to compact the rod to a uniform density with a weight drop or a roller.
[0007]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a manufacturing apparatus and a method for manufacturing a specimen for a low-temperature crack resistance test of a material having low fluidity at a uniform density. To provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, a first aspect of the present invention provides a disk-shaped bottom mold in which a ring-shaped recess is formed, a ring-shaped restraint plate, a ring-shaped outer mold, and an outer mold. And a frame retaining ring, a disc-shaped inner presser plate is provided above the restraining plate, and a ring-shaped outer presser plate is provided above the outer mold frame. The test material is loaded in a ring shape between them, a ring-shaped compaction ring is provided on the test material, and the compaction ring is vibrated by a vibration compaction device to compact. This is a sample preparation apparatus.
[0010]
In the second invention, a ring-shaped restraining plate, a ring-shaped outer mold, and an outer mold-frame retaining ring are provided in the recess of the disk-shaped bottom mold in which a ring-shaped recess is formed, A disk-shaped inner holding plate is provided above the restraining plate, a ring-shaped outer holding frame is provided above the outer forming frame, and a ring-shaped test is performed between the restraining plate and the outer forming frame. A material is loaded , a ring-shaped compaction ring is provided on the material under test, and the compaction ring is vibrated by a vibration compaction device while rotating the compaction ring to compact the specimen. .
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a ring-shaped specimen manufacturing apparatus 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view thereof. FIG. 3 is a diagram showing a ring-shaped specimen 3.
[0013]
The bottom mold 100 has a disk shape, and a concave portion 138 is provided concentrically inside. A plurality of fixing bolt holes 112 (four places in FIG. 1) are provided on the outer peripheral convex part 136 of the bottom formwork, and a plurality of fixing bolt holes 114 are provided (two places in FIG. 1) on the inner convex part 140. Can be In the recess 138, a plurality of (four in FIG. 1) bolts 116 are provided for removing the ring-shaped specimen 3 from the bottom mold. The unframed bolt hole 116 is located at a position where the restraint plate 104 is arranged, and is a penetrated hole. The ring-shaped specimen 3 is removed by inserting a bolt into the unframed bolt hole 116 and pushing out the restraint plate 104.
[0014]
The outer frame fixing L-shaped ring 102 has an L-shaped cross section and is an integrated ring for fixing the outside of the outer frame 104, and is engaged with both the outer convex portion 136 and the concave portion 138 of the bottom frame 100. Do not place.
[0015]
The outer frame 104 is a ring-shaped metal, and is disposed in the recess 138 of the bottom frame 100 in contact with the outer frame retaining L-shaped ring 102. The outer frame 104 is formed of several pieces so that it can be easily removed from the ring-shaped specimen 3. For example, in the present embodiment, the outer frame 104 is formed of three pieces.
[0016]
The restraining plate 106 also has a ring shape, is in contact with the inner convex portion 140 of the bottom mold 100, and is disposed on the innermost peripheral side in the concave portion 138. The ring-shaped specimen 3 shown in FIG. 3 is one in which a material to be tested (asphalt mixture 200) is cast outside the restraining plate 106. In the manufacturing process, the ring-shaped specimen 3 can be removed from the bottom mold 100 by pushing the bottom 118 (four places in FIG. 1) of the restraint plate 106 with the bolts inserted from the bolt holes 116 for removing the frame. it can.
[0017]
The outer holding plate 108 is a donut-shaped flat plate, and fixes the outer mold frame 104 between the recessed portion 138 of the bottom mold frame 100 from above and below. A plurality of fixing bolt holes 120 (four places in FIG. 1) are provided on the outer holding plate 108, and between the fixing bolt holes 112 of the bottom form 100 by nuts 124, 128 and bolts 126. Combine and fix. FIG. 1 shows a case in which four bolts are used to connect the outer holding plate 108 for fixing the outer formwork 104 and the bottom formwork 100.
[0018]
The inner holding plate 110 is a circular flat plate, and fixes the restraining plate 106 between the recess 138 of the bottom mold frame 100 from above and below. A plurality of fixing bolt holes 122 (two locations in FIG. 1) are provided on the inner holding plate 110, and are fixed between the fixing bolt holes 114 of the bottom form 100 by nuts 130, 134 and bolts 132. Combine and fix. FIG. 1 shows a case where two bolt connections are used to connect the inner holding plate 110 for fixing the restraining plate 106 and the bottom formwork 100.
[0019]
Now, in the present embodiment, the asphalt mixture 200 is driven between the restraining body 106 and the outer mold 104. Then, as shown in FIG. 2, after the surface is leveled, a ring-shaped compaction ring 204 is placed on the asphalt mixture 200. Further, the asphalt mixture 200 is compacted while rotating the compaction ring 204 in the circumferential direction by using the vibration compaction device 206 to obtain the ring-shaped specimen 3 having a desired density. Note that a tamper or the like is used as the vibration compaction device 206.
[0020]
The dimensions of the compaction ring 204 are set such that the compaction ring 204 rotates while maintaining a gap between the restraint plate 106 and the outer mold frame 104 when the vibration compaction device 206 operates.
[0021]
Next, a method for producing the ring-shaped specimen 3 using this apparatus will be described with reference to FIGS.
[0022]
Here, the asphalt mixture used in the experiment was a dense particle asphalt mixture in which the maximum particle size of the coarse aggregate was 13 mm and the amount of asphalt added was 8.2% (FIG. 4).
[0023]
First, the outer frame fixing L-shaped ring 102 is fitted into the outer peripheral convex portion 136 and the concave portion 138 of the bottom mold 100, and the outer frame 104 is set in contact with the inside thereof. Further, the restraint plate 106 is installed at the innermost portion of the concave portion 138 in contact with the outer periphery of the inner convex portion 114 of the bottom formwork 100.
[0024]
Next, the upper part of the outer formwork 104 is held down by the outer holding plate 108, and the outer holding plate 108 and the bottom formwork 100 are joined at a plurality of places (four places in FIG. 1) with the bolts 126 and the nuts 124 and 128. The outer mold 104 is fixed so as not to be displaced by vibration.
[0025]
Similarly, the upper side of the restraining plate 106 is held down by the inner holding plate 110, and the inner holding plate 110 and the bottom form 100 are joined at a plurality of places (two places in FIG. 1) by the bolts 132 and the nuts 130 and 134. The restraint plate 106 is fixed so as not to be displaced by vibration.
[0026]
The weight of the asphalt mixture to be inserted is measured so that the density when the asphalt mixture reaches a predetermined height after compaction becomes a target value. Then, a predetermined amount of the asphalt mixture is driven into a ring-shaped gap between the constraint plate 106 and the outer mold frame 104.
[0027]
After leveling the surface of the asphalt mixture 200, the compaction ring 204 is placed on the asphalt mixture 200. As the compaction ring 204 used in this experiment, the one in which the distance between the constraint plate 106 and the outer mold frame 104 is 0.5 mm is used. If the interval is too small, the compaction ring 204 does not rotate during vibration compaction, and compaction with sufficient kneading cannot be performed.
[0028]
The vibration compaction device 206 is placed on the compaction ring 204 and the top surface of the asphalt mixture 200 is compacted by rotating the compaction ring 204.
[0029]
After the asphalt mixture 200 is cooled to room temperature, the inner holding plate 110, the outer holding plate 108, the outer frame fixing L-shaped ring 102, and the outer frame 104 are removed.
[0030]
Next, a member such as a bolt is screwed into the unframed bolt holes 116 (four locations in FIG. 1) of the bottom mold 100, and the bottom 118 (four locations in FIG. 1) of the restraint plate 106 is pushed out. Remove the frame 100. Thus, the ring-shaped specimen 3 of the asphalt mixture integrated with the restraining plate 106 is manufactured.
[0031]
The ring-shaped specimen 3 of the asphalt mixture produced in the above-described steps is used for a low-temperature crack resistance test, and is generated due to a difference in shrinkage between the restraining plate 106 and the asphalt mixture 200 when the temperature becomes low. It is a test object for detecting cracks.
[0032]
Now, it was confirmed whether the porosity and density of the asphalt mixture 200 of the ring-shaped specimen 3 produced in the present embodiment were uniform. First, the restraining plate 106 was removed from the ring-shaped specimen 3, the ring-shaped asphalt mixture 200 was divided into two equal parts vertically, and each of the upper and lower rings was further divided into eight equal parts to produce a total of 16 divided asphalt mixture pieces.
[0033]
The porosity and density of this mixture piece were measured, and the variation in the degree of compaction inside the specimen was investigated. FIG. 5 shows the measurement results of the porosity / density. Although there is a part where the porosity is smaller in the upper part than in the lower part, it can be seen that the porosity is less than 2% in almost all of the mixture pieces, indicating that it is sufficiently compacted. confirmed.
[0034]
This apparatus has made it possible to prepare a ring-shaped specimen with a material having a low fluidity such as an asphalt mixture, which was conventionally difficult. In addition, a ring-shaped specimen can be manufactured by uniformly compacting at a density equal to or higher than a predetermined density, and a low-temperature cracking resistance test of an asphalt mixture can be performed.
[0035]
Next, an apparatus and a method according to a second embodiment will be described with reference to FIGS. FIG. 6 is an exploded view showing an apparatus for manufacturing the rod-shaped specimen 5, and FIG. 7 is a view showing an apparatus for manufacturing the rod-shaped specimen 5.
[0036]
In the step of manufacturing the rod-shaped specimen 5, first, a bolt 334 is inserted into a hole 338 provided in the bottom mold 308 and holes 336 and 337 provided in the long side outer frames 300 and 302, and the nut 332 is used to stop the bolt. (In FIG. 6, the bottom mold frame 308 and the long side outer frames 300 and 302 are stopped by six holes.) Next, a bolt 326 is inserted into a hole 330 provided in the bottom mold 308 and a hole 328 provided in the short side outer frame 304, and is fixed with a nut 324. Similarly, the bottom mold 308 and the short side outer frame 306 are similarly inserted with bolts in the holes and fastened with nuts (in FIG. 6, the bottom mold 308 and the short side outer frames 304, 308 are formed by four holes). Stopped). Further, a bolt 318 is inserted into a hole 320 provided in the short side outer frame 304 and a hole 322 provided in the long side outer frame 300, and is fixed with a nut 316. Similarly, a bolt 340 is inserted into a hole 321 provided in the short side outer frame 304 and a hole 323 provided in the long side outer frame 302, and fixed with a nut 342. Similarly, the short side outer frame 306 is fixed between the long side outer frames 300 and 302 with bolts and nuts (in FIG. 6, the long side outer frames 300 and 302 and the short side outer frames 304 and 308 are totaled 8). It is stopped by two holes.)
[0037]
Then, the bottom mold 308, the long side outer frames 300 and 302, and the short side outer frames 304 and 306 form a box-shaped container 315 having an open top.
[0038]
Next, the restraint plate 310 is arranged on the bottom mold 308, and the asphalt mixture 312 is driven thereon.
[0039]
The top surface of the asphalt mixture 312 is leveled, a compaction plate 314 is placed, and the compaction plate 314 is linearly reciprocated on the asphalt mixture 312 using a vibration compaction device and compacted.
[0040]
After compacting the asphalt mixture 312 and cooling it to room temperature, the long side outer frames 300 and 302, the short side outer frames 304 and 306, and the bottom mold 308 are removed to obtain the rod-shaped specimen 5.
[0041]
In addition, since it becomes impossible to restrain when sliding at the boundary between the constraint plate 310 and the asphalt mixture 312 during the low-temperature cracking test, the surface of the constraint plate 310 used for the rod-shaped specimen 5 (the boundary with the asphalt mixture 312) is provided with irregularities. deep.
[0042]
The constraint plate 310 shown in FIG. In the restraint plate 310a shown in FIG. 9, a wavy uneven portion 406 is provided on the upper surface.
[0043]
This device has made it possible to make rod-shaped specimens with less flowable materials such as asphalt mixtures. In addition, a rod-shaped specimen can be manufactured by uniformly compacting at a predetermined density or more, and a low-temperature crack resistance test of the asphalt mixture can be performed.
[0044]
The present invention is not limited to the asphalt mixture, but can be applied to the preparation of a specimen made of a material such as asphalt alone or concrete.
[0045]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a manufacturing apparatus and a method for manufacturing a specimen for a low-temperature crack resistance test of a material having low fluidity at a uniform density.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a ring-shaped specimen manufacturing apparatus 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the ring-shaped specimen manufacturing apparatus 1. FIG. FIG. 4 is a diagram showing the composition of the asphalt mixture. FIG. 5 is a diagram showing the porosity / density measurement results of the ring-shaped asphalt mixture. FIG. 6 is a configuration diagram of a rod-shaped specimen 5 manufacturing apparatus. FIG. 8 is a view showing a manufacturing apparatus. FIG. 8 is a view showing a restraining plate 310 of a rod-shaped specimen. FIG. 9 is a view showing a restraining plate 310a of a rod-shaped specimen.
DESCRIPTION OF SYMBOLS 1 ... Ring-shaped specimen preparation apparatus 3 ... Ring-shaped specimen 5 ... Rod-shaped specimen 100 ... Bottom mold 102 ... Outer mold stop L-shaped ring 104 ... Outer mold 106, 310, 310a ... Restriction plate 108 ... Outer holding plate 110 ... Inner holding plate 116 ... Bolt holes 126, 132 ... Bolts 112, 114, 120, 122 ... Fixing bolt holes 200, 312 ... Asphalt mixture (material under test)
204 ... compaction ring 206 ... vibration compaction device 315 ... box-shaped container 300, 302 ... long side outer frame 304, 306 ... short side outer frame 308 ... bottom mold 318, 326, 334 ... bolt

Claims (6)

A ring-shaped restraining plate, a ring-shaped outer frame, and an outer frame stopper ring are provided in the recess of the disk-shaped bottom frame in which the ring-shaped recess is formed,
Providing a disc-shaped inner holding plate above the restraining plate,
A ring-shaped outer frame holding plate is provided on the upper side of the outer frame,
The test material is loaded in a ring shape between the restraining plate and the outer mold frame,
Providing a ring-shaped compaction ring on the test material,
A specimen manufacturing apparatus characterized in that the compaction ring is vibrated and compacted by a vibration compaction apparatus. The specimen manufacturing apparatus according to claim 1, wherein a hole is provided in a position of the disc-shaped bottom form in which the concave portion is formed, where the restraining plate is arranged. 2. The apparatus according to claim 1, wherein the material to be tested is an asphalt mixture, asphalt alone, or concrete. A ring-shaped restraining plate, a ring-shaped outer frame, and an outer frame stopper ring are provided in the recess of the disk-shaped bottom frame in which the ring-shaped recess is formed,
Providing a disc-shaped inner holding plate above the restraining plate,
A ring-shaped outer frame holding plate is provided on the upper side of the outer frame,
The test material is loaded in a ring shape between the restraining plate and the outer mold frame,
Providing a ring-shaped compaction ring on the test material,
A method for preparing a specimen, wherein the compaction ring is vibrated by a vibration compaction device while being compacted . A hole is provided at a position where the restraining plate of the disc-shaped bottom form in which the concave portion is formed is arranged,
5. The method according to claim 4, wherein a member is pushed into the hole to push out the restraining plate to obtain the material to be tested integrated with the restraining plate . The method according to claim 4, wherein the test material is an asphalt mixture, asphalt alone, or concrete.

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