CN106759283A - A kind of ECC die trials and its application method - Google Patents

Abstract

The invention discloses an ECC test mold, which comprises a base plate and side plates fixed on both sides of the base plate, a plurality of partitions are arranged between the side plates along the extending direction of the side plates, and a plurality of fixed partitions are arranged on the inner side of the side plates. The groove of the plate, a cover plate is detachably arranged on the outer side of the side plate, there is a gap between the cover plate and the partition, and a top plate is arranged on the top of the side plate to cover the partition. The parts in contact between the test mold and the test piece are coated with polytetrafluoroethylene, or sprayed with a release agent. On the one hand, it avoids the adhesion between the test piece and the test mold, which is beneficial to the removal of the mold. On the other hand, it can ensure the surface of the ECC test piece Flat and smooth, less air bubbles; easy to assemble and disassemble, strong and durable.

Description

A kind of ECC trial mold and its application method

technical field

The invention relates to the field of civil engineering, in particular to an ECC test mold and a using method thereof.

Background technique

Engineered Cementitious Composite (ECC for short) is a fiber cement-based composite material with remarkable strain hardening properties, the ultimate tensile strain is above 3%, and the ultimate crack width is less than 100 μm. Due to its excellent bending and tensile properties, ECC materials have attracted more and more attention from scholars at home and abroad.

The flow characteristics of freshly mixed ECC are different from ordinary concrete and mortar, mainly because the surface is difficult to smooth and easy to form concave and convex surfaces during the molding process of ECC. If the test piece with uneven surface is directly used for tensile and bending mechanical tests, on the one hand, it will cause stress concentration at the contact points on the uneven surface, which will affect the experimental results; on the other hand, the uneven surface will also affect the surface. Observation of saturated fractures. Some scholars will smooth the uneven surface before the experiment, which leads to other problems: 1. The grinding process is complicated and wastes a lot of time; 2. A large amount of concrete and fiber debris are produced during the grinding process, which affects the health of the grinder; 3. If the strength is not well controlled during grinding, it will cause damage to the ECC test piece; 4. The thickness of the test piece after grinding is not easy to control.

The uniformity of fiber dispersion in ECC has a great influence on the dispersion of mechanical properties such as tensile and bending. After the ECC is evenly stirred, during the molding process, the disturbance to the freshly mixed ECC material should be minimized, or an equal degree of disturbance should be caused to each ECC specimen, so as to ensure the stability of the mechanical properties of the ECC material to the greatest extent.

Therefore, it is necessary to study a special trial mold for ECC and a method for ECC molding.

Contents of the invention

In order to solve the above problems, the present invention proposes an ECC test mold and its use method. The present invention has a simple structure, is convenient to disassemble, is strong and durable, is very suitable for concrete laboratories, and can ensure the stability of the mechanical properties of ECC materials to the greatest extent.

In order to achieve the above object, the present invention adopts the following technical solutions:

An ECC trial mold, comprising a bottom plate, side plates fixed on both sides of the bottom plate, several partitions are arranged between the side plates along the extending direction of the side plates, and a plurality of grooves for fixing the partitions are arranged on the inner side of the side plates A cover plate is detachably arranged above the outer side of the side plate, there is a gap between the cover plate and the partition, and a top plate is provided on the top of the side plate to cover the partition.

The part of the ECC test mold that is in contact with the test piece is coated with polytetrafluoroethylene, or sprayed with a release agent.

The top plate is combined with the bottom plate by bolts.

The bottom plate is made of cast iron or non-deformable polymer material, and the top surface of the bottom plate is coated with polytetrafluoroethylene or sprayed with a release agent.

The shape of the bottom plate is rectangular, and there are several equally spaced bolt holes on one pair of sides, which are tapped for fixing the bolts of the side plate, and several equally spaced bolt holes on the other pair of sides , to do tapping processing, used to fix the bolts of the top plate.

The side plate is made of cast iron or non-deformable polymer material, and the inner side of the side plate is coated with polytetrafluoroethylene or sprayed with a release agent.

Each side plate is provided with equidistant bolt holes corresponding to the number of bolt holes of the bottom plate, and the side plate is fixed on the bottom plate by inner bolts.

The length of the bolt hole is suitable, and when the bolt is tightened, the head of the bolt just enters the side plate as a whole.

On the inner side of the side plate, grooves for fixing the partition are arranged at equal intervals, and the grooves are vertically integrated as a whole, and the outside of the side plate is provided with a horizontally penetrating L-shaped cover plate groove for fixing the cover plate.

The shape of the cover plate is double L-shaped, and the width of the cover plate ensures that the bolts on the side plate are covered. When in use, the double-L-shaped cover plate is inserted laterally into the L-shaped cover plate groove of the side plate to ensure that the side plate Bolts on the board are not filled with extruded ECC.

The side plate material is cast iron or non-deformable polymer material, and the quantity is determined according to the quantity of ECC specimens produced by each test mold.

The two sides of the separator in contact with the ECC test piece are coated with polytetrafluoroethylene, or sprayed with a release agent, and the separator has an additional distance of 1 to 3 mm relative to the side plates.

A sufficient gap is left between the separator and the cover to serve as a channel for the ECC to extrude from both sides.

The material of the top plate is cast iron or non-deformable polymer material, and the bottom surface of the top plate is coated with polytetrafluoroethylene, or sprayed with a release agent.

The length of the top plate is equal to the length of the partition plate, and the width of the top plate is equal to the width of the bottom plate. A pair of sides in the length direction are respectively provided with several equidistant bolt holes, which are fixed with the bottom plate by bolts.

Based on the above method of using the test mold, use bolts to fix the side plate on the bottom plate, insert the cover plate from the horizontal direction, cover the bolts, insert the partition plate into the groove of the side plate, and the bottom plate, partition plate and side plate are combined to form a test piece Pour the freshly mixed ECC directly into the middle of the test piece tank, let the ECC flow and fill the test piece tank through vibration, and the overall height is 3-5mm above the partition, cover the top plate, squeeze through the top plate and go back and forth horizontally Move and extrude the excess ECC. When the top plate touches the partition, stop the top plate extrusion and horizontal back and forth movement, and clean the extruded ECC specimen; fix the top plate and the bottom plate together with bolts, remove the mold after a period of time, and disassemble the test piece. Die, take out the test piece, clean up the mold test.

The beneficial effects of the present invention are:

1) The contact parts between the test mold and the test piece are coated with polytetrafluoroethylene or sprayed with a release agent. On the one hand, it can avoid the adhesion between the test piece and the test mold, which is beneficial to the demoulding, and on the other hand, it can ensure that the ECC test The surface of the piece is smooth and smooth, with few air bubbles;

2) Embed the hexagon socket bolts inside the side plate, and seal the bolt holes with the cover plate, so as to facilitate the cleaning of the extruded ECC.

3) The partition is 1~3mm higher than the side plate, and there is a space in front of the partition and the cover to provide an extrusion channel for the ECC.

4) Squeeze the top plate downward and move back and forth horizontally to squeeze out excess ECC, which can ensure that the top surface of the produced ECC test piece is smooth and has less air bubbles.

5) The test mold is easy to assemble and disassemble, durable and very suitable for concrete laboratories.

Description of drawings

Fig. 1 is the top view of the combination of the trial mold bottom plate, side plate and partition plate;

Fig. 2 is the front view after the test mold side plate and cover plate are combined;

Fig. 3 is a top view of the cover plate.

detailed description:

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, an ECC trial mold includes a bottom plate, a side plate is fixed with bolts at both ends of the bottom plate, a cover plate is placed on the top of the two side plates, and there are grooves on the inner sides of the two side plates. The partition plate is inserted into the groove, topped with the top plate, and the top plate is combined with the bottom plate through bolts.

The bottom plate is made of cast iron or non-deformable polymer material, and the quantity is 1 piece. The top surface of the bottom plate is coated with polytetrafluoroethylene or sprayed with a release agent. The shape of the top surface is rectangular, and there are three equally spaced bolt holes on one pair of sides, and they are tapped to fix the bolts of the side plate. There are three equidistant bolt holes on the other pair of sides, which are also tapped, and are used to fix the bolts of the top plate.

The side plate is made of cast iron or non-deformable polymer material, the quantity is 2 pieces, and the inside of the side plate is coated with polytetrafluoroethylene or sprayed with a release agent. There are 3 equally spaced bolt holes on each side plate, and the side plate can be fixed on the bottom plate by hexagon socket bolts. When the bolt is tightened, the head of the bolt should just enter the side plate as a whole. On the inner side of the side plate, the grooves for fixing the partition are arranged at equal intervals, and the grooves are vertically integrated as a whole. The outer side of the side plate is provided with a horizontally through "L"-shaped cover plate groove, and the "double L"-shaped cover plate is inserted laterally into the "L"-shaped cover plate groove during use.

As shown in Figure 2, the material of the cover plate is cast iron, the quantity is 2 pieces, and the shape is "double L". The width of the cover plate is advisable to just cover the bolts. When in use, insert the "double L"-shaped cover plate laterally into the "L"-shaped cover plate groove to ensure that the bolts on the side plate are not filled by the extruded ECC.

The material of the partition is cast iron or non-deformable polymer material, the quantity is determined according to the number of ECC specimens made by each test mold, and the two sides of the partition that are in contact with the ECC specimens are coated with polytetrafluoroethylene, or sprayed to release the mold agent. The height of the partition is 1~3mm higher than the side plate, and there is enough gap between the partition and the cover to serve as a channel for ECC to extrude from both sides.

As shown in Figure 3, the material of the top plate is cast iron or non-deformable polymer material, the quantity is one piece, and the bottom surface of the top plate is coated with polytetrafluoroethylene or sprayed with a release agent. The length of the top plate is equal to the length of the partition, and the width of the top plate is equal to the width of the bottom plate. Three equally spaced bolt holes are respectively opened on a pair of sides in the length direction, and are fixed with the bottom plate by bolts.

A method for using an ECC mold trial, the specific steps are as follows:

1) Fix the side plate to the bottom plate with hexagon socket bolts;

2) Insert the cover plate horizontally to cover the bolts;

3) Insert the separator into the groove of the side plate, and the bottom plate, the separator and the side plate are combined to form a specimen groove;

4) Pour the freshly mixed ECC directly in the middle of the test piece tank, and let the ECC flow and fill the test piece tank through vibration by hand or with the help of a vibrating table, and the overall height is 3-5mm higher than the partition;

5) Cover the top plate, and squeeze it downwards vigorously, and half of it moves back and forth in a small horizontal direction in multiple directions, in order to squeeze out excess ECC;

6) When the top plate touches the partition, stop the top plate extrusion and horizontal back and forth movement;

7) Clean the extruded ECC specimen with a scraper;

8) Bolt the top and bottom plates together.

9) Remove the mold after 24 hours, disassemble the test mold according to the reverse order of 1) ~ 8), take out the test piece, clean the test mold, and assemble it in the normal order.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (10)

1. A kind of ECC trial mold, it is characterized in that: comprise base plate, be fixed on the side plate of base plate both sides, be provided with some dividing plates along side plate extending direction between described side plate, the inboard of described side plate is provided with several A groove for fixing the partition, a cover plate is detachably arranged above the outer side of the side plate, there is a gap between the cover plate and the partition, and a top plate is provided on the top of the side plate to cover the partition. 2. A kind of ECC trial mold according to claim 1, characterized in that: the top plate is combined with the bottom plate by bolts. 3. A kind of ECC trial mold as claimed in claim 1 or 2, characterized in that: the bottom plate material is cast iron or non-deformable polymer material, and the top surface of the bottom plate is coated with polytetrafluoroethylene, or sprayed to release the mold agent. 4. A kind of ECC trial mold as claimed in claim 1, characterized in that: the material of the side plate is cast iron or a polymer material that is not easily deformed, and the inner side of the side plate is coated with polytetrafluoroethylene or sprayed with a release agent ; Each side plate is provided with equidistant bolt holes corresponding to the number of bolt holes of the bottom plate, and the side plate is fixed on the bottom plate by inner bolts. 5. An ECC test mold according to claim 2 or 4, characterized in that: the length of the bolt hole is adapted, and when the bolt is tightened, the head of the bolt just enters the side plate as a whole. 6. A kind of ECC trial mold as claimed in claim 1, characterized in that: the inner side of the side plate, the grooves for fixing the partition are arranged at equal intervals, the grooves are vertically integrated, and the outer side of the side plate There is a horizontally through L-shaped cover plate groove for fixing the cover plate. 7. A kind of ECC trial mold as claimed in claim 1, characterized in that: the shape of the cover plate is double L-shaped, the width of the cover plate is guaranteed to cover the bolts on the side plate, and the double-L-shaped cover plate is laterally Insert it into the L-shaped cover groove of the side panel. 8. A kind of ECC test mold as claimed in claim 1, it is characterized in that: the two sides of described separator and ECC specimen contact are coated with polytetrafluoroethylene, or spray release agent, and separator is opposite to the side panels have an additional distance; Or there is enough space between the separator and the cover to serve as a channel for the ECC to extrude from both sides. 9. A kind of ECC mold trial as claimed in claim 1, characterized in that: the material of the top plate is cast iron or non-deformable polymer material, and the bottom surface of the top plate is coated with polytetrafluoroethylene or sprayed with a release agent. 10. Based on the method of using the test mold according to any one of claims 1-9, it is characterized in that: use bolts to fix the side plates on the bottom plate, insert the cover plate from the horizontal direction, cover the bolts, and place the partition plate Inserted into the groove of the side plate, the bottom plate, the partition plate and the side plate are combined to form a specimen tank, and the freshly mixed ECC is directly poured into the middle of the specimen tank, and the ECC is allowed to flow and fill the specimen tank through vibration, and the overall height Extrude the partition, cover the top plate, and squeeze out the excess ECC. When the top plate touches the partition, stop the extrusion of the top plate and move back and forth horizontally, and clean up the extruded ECC specimen; fix the top plate and the bottom plate together, and remove it after a period of time. Die, disassemble the test mold, take out the test piece, clean up the test mold.