CN102680397A - Device for testing binding force of reinforcing steel bar and concrete - Google Patents

Abstract

The invention relates to a test device for the adhesion between steel bars and concrete, which includes steel bars, a cylindrical base PVC pipe, a built-in circular steel plate, an external circular steel plate, a base PVC pipe and an adhesive tape. The external circular steel plate passes through The adhesive tape is fixedly connected to the outer wall of the bottom of the cylindrical base PVC pipe to form a cylindrical barrel device. The base PVC pipe is placed on a horizontal plane, and the cylindrical barrel device is placed on the base PVC pipe. The described The steel bar passes through the external circular steel plate and the base PVC pipe in order to reach the horizontal surface. After the concrete pouring is completed, the internal circular steel plate is passed through the steel bar and built into the base PVC pipe to correct the center position of the steel bar. Compared with the prior art, the invention has the advantages of simple manufacture, high precision and low cost.

Description

A device for testing the bonding strength of steel bars and concrete

technical field

The invention relates to the field of an experimental test device for the performance of civil engineering materials, in particular to a test device for the bonding force between steel bars and concrete.

Background technique

Reinforced concrete structure is one of the most widely used structural forms in modern civil engineering structures. With the passage of structural service time and the erosion of the service environment, the materials continue to age, the structural performance degrades, and the service life decreases. The durability of reinforced concrete structures It has become a key issue for the sustainable development of buildings. A large number of studies have shown that there are many factors that affect the durability of reinforced concrete structures, such as steel corrosion, concrete freeze-thaw damage, and concrete alkali-aggregate reaction. The most important factor of deterioration. The bonding force between steel bars and concrete is the key factor to ensure their work together. Corrosion of steel bars in concrete reduces the mechanical properties of steel bars, destroys the interface bonding force between steel bars and concrete, and seriously reduces the safety and applicability of reinforced concrete structures. and durability, how to scientifically and effectively evaluate the loss of cohesive force, scholars at home and abroad have taken various specimens to carry out the pull-out test of steel bars, and the cylindrical concrete matrix is the most suitable test piece for the stress distribution around the steel bar, but how to Ensuring that the steel bars are vertically arranged in the concrete matrix is a key factor that restricts the accuracy and success of the test measurement.

At present, there are two types of devices used for testing the bonding force between steel bars and concrete: squares and cylinders, and squares are mostly processed with wooden templates, which are processed into squares of the same size and then assembled. Under the condition of the overall strength of the square device, it is difficult to ensure the dimensional accuracy, and it is difficult to fix the position of the steel bar accurately. During the concrete vibration process, the formwork is easy to crack, so the experimental error is relatively large; And the plastic cylindrical device, the steel bar is fixed by the hoisting method and the bottom embedding method to ensure that the steel bar is in the center of the cylinder. The hoisting method is to place the formwork equidistantly on the level ground, bind and fix the steel bars on the cross bars respectively, and place the steel bars respectively at the center of the formwork. Poor; the bottom embedding method is based on a thick plank, and a round hole the size of the diameter of the steel bar is processed on the plank, the steel bar is fixed in the round hole, and then the cylindrical formwork is placed and the concrete is poured. , it is difficult to ensure the central position of the reinforcement. According to the above analysis, the above experimental devices all have the characteristics of complicated manufacturing steps, low test accuracy, and difficulty in practical application. Therefore, a device that ensures that the steel bar is in the center of the cylindrical concrete, has high experimental test accuracy, and is easy to operate and apply is needed. To meet the test work of the current large-scale experiment.

Contents of the invention

The purpose of the present invention is to provide a simple, high-precision and low-cost testing device for the adhesion between steel bars and concrete in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

A kind of steel bar and concrete bonding force testing device, it is characterized in that, comprise steel bar, cylindrical matrix PVC pipe, built-in circular steel plate, external circular steel plate, cylindrical base PVC pipe and adhesive tape, described external circular The shaped steel plate is fixedly connected to the outer wall of the bottom of the cylindrical base PVC pipe through an adhesive tape to form a cylindrical barrel device. The base PVC pipe is placed on a horizontal plane, and the cylindrical barrel device is placed on the base PVC pipe. The steel bars pass through the external circular steel and the base PVC pipe in turn to reach the horizontal plane;

The uniformly mixed concrete is poured into the cylindrical matrix PVC pipe, and vibrated evenly and densely. After the concrete is poured, the built-in circular steel plate is passed through the steel bar and built into the matrix PVC pipe to correct the center position of the steel bar. During this process, lightly tap the side of the cylindrical base PVC pipe to ensure that the concrete is dense, and finally remove the built-in circular steel plate from the upper part of the steel bar;

After the test piece is made, after three days of curing according to the standard method, the formwork is removed. First, the outer circular steel plate is taken out, and then a gap is cut longitudinally along the cylindrical matrix PVC pipe with a cutting machine, and the cylindrical matrix PVC pipe is taken out. .

The reinforcing bars include threaded steel and smooth round steel.

The outer circular steel plate is a steel plate with a thickness of 2mm, its diameter is the outer diameter of the cylindrical matrix PVC pipe, and a central circular hole with a diameter of the steel bar is provided.

The built-in circular steel plate is a steel plate with a thickness of 2mm, its diameter is the inner diameter of the cylindrical matrix PVC pipe, and a central circular hole with a diameter of the steel bar is provided.

The base PVC pipe has a smaller diameter than the cylindrical base PVC pipe.

Compared with the prior art, the present invention has the following advantages:

(1) The experimental device is simple to make. According to the test design requirements, the base PVC pipe is selected and cut into cylindrical standard sections of equal length. The combination can be tested, and it is easy to carry out a large number of experimental research work;

(2) The experimental device has high precision. During the concrete pouring process, the central position of the steel bar in the concrete is fixed by the center hole of the upper and lower circular steel plates. Therefore, the steel bar will not be deflected during the concrete vibration process. shift;

(3) It can effectively reduce the test cost, the PVC pipe is cheaper than the wooden template, and the round steel plate can be recycled;

(4) The experimental device is easy to operate and apply, requiring less personnel to complete all the experimental work.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the structural representation of steel bar of the present invention;

Fig. 3 is the structural representation of cylindrical base PVC pipe of the present invention;

Fig. 4 is a structural schematic diagram of a built-in circular steel plate of the present invention;

Fig. 5 is a schematic structural view of an external circular steel plate of the present invention;

Fig. 6 is the structural representation of the base PVC pipe of the present invention;

Fig. 7 is a structural schematic diagram of the adhesive tape of the present invention.

Detailed ways

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

Example

As shown in FIG. 1 , a test device for the adhesion between steel bars and concrete includes a steel bar 1 , a cylindrical base PVC pipe 2 , a built-in circular steel plate 3 , an external circular steel plate 5 , a base PVC pipe 6 and an adhesive tape 7 .

As shown in Figure 2, it is steel bar 1, including threaded steel and smooth round steel.

As shown in Figure 3, it is a cylindrical matrix PVC pipe 2. The diameter of the concrete matrix is determined according to the requirements of the test design, and then the type of the cylindrical matrix PVC pipe 2 is determined. According to the height of the concrete matrix, the PVC pipe is cut into a standard of equal length. section, and maintain the flatness of the cut surface.

As shown in Figure 4, it is a built-in circular steel plate 3, which is processed into a circle by using a 2mm thick steel plate. The diameter of the built-in circular steel plate 3 is the inner diameter of the cylindrical PVC pipe 2, and the diameter of the central circular hole 4 is the diameter of the steel bar 1. .

As shown in Figure 5, it is an external circular steel plate 5, which is processed into a circle by using a 2mm thick steel plate. The diameter of the external circular steel plate 3 is the outer diameter of the cylindrical PVC pipe 2, and the diameter of the central circular hole 4 is the steel bar 1 diameter.

As shown in Figure 6, it is a cylindrical base PVC pipe 6, and the diameter of the cylindrical base PVC pipe 6 is smaller than the cylindrical matrix PVC pipe 2. According to the loading length of the steel bar 1, the height of the base PVC pipe 6 is determined, and Maintain the flatness of the cut surface.

As shown in Figure 7, it is an ordinary adhesive tape 7.

Below is the concrete construction process of the embodiment of the present invention:

(1) Place the external circular steel plate 5 on the bottom of the cylindrical matrix PVC pipe 2, and firmly connect the external circular steel plate 5 and the cylindrical matrix PVC pipe 2 with adhesive tape 7 to form a cylindrical barrel device .

(2) The cylindrical base PVC pipe 6 is placed on the level ground, the center of the cylindrical barrel device is symmetrically placed on the upper part of the cylindrical base PVC pipe 6, and the steel bar 1 is passed through the outer circular steel plate 5 Central circular hole 4, and reaches level ground surface.

(3) Pouring the uniformly stirred concrete into the cylindrical matrix PVC pipe 2, and vibrating it evenly and densely, passing the built-in circular steel plate 3 through the steel bar 1, and putting it in the cylindrical matrix PVC pipe 2, to the steel bar 1 During this process, lightly tap the side of the cylindrical matrix PVC pipe 2 to ensure that the concrete is dense, and finally remove the built-in circular steel plate 3 from the upper part of the steel bar 1 and recycle it.

(4) After the test piece is made, after three days of curing according to the standard curing method, the formwork is removed. First, the outer circular steel plate 5 is taken out, and then a slit is longitudinally cut out along the cylindrical matrix PVC pipe 2 with a cutting machine, namely The cylindrical base PVC pipe 2 can be taken out, and the external circular steel plate 5 and base PVC pipe 6 can be recycled to the next batch of tests.

It can be seen from the above-mentioned embodiments that the manufacturing process of the steel bar-concrete adhesion test device is simple, easy to operate and apply, low in cost, high in test accuracy, and can meet the requirements of large-scale tests at present.

Claims (5)

1. reinforcing bar and concrete binding force test device; It is characterized in that; Comprise reinforcing bar, cylindrical base pvc pipe, built-in circular steel plate, external circular steel plate, cylindrical base pvc pipe and adhesive tape; Described external circular steel plate is fixedly connected with cylindrical base pvc pipe bottom outer wall through adhesive tape, forms the cylindrical tube body device, and described pedestal pvc pipe places on the surface level; Described cylindrical tube body device is positioned on the pedestal pvc pipe, and described reinforcing bar arrives surface level after passing external circular steel and pedestal pvc pipe successively;

With the concrete that stirs, build in the cylindrical base pvc pipe, and it is evenly closely knit to vibrate; After concreting is accomplished, built-in circular steel plate is passed reinforcing bar, and be built in the matrix pvc pipe; Proofread and correct center to reinforcing bar, in this process, knocks cylindrical base pvc pipe side gently; Guarantee concrete compaction, at last built-in circular steel plate is taken out from reinforcing bar top;

After test specimen completes, after three days, carry out form removal, at first external circular steel plate is taken out, vertically cut out a slit with cutting machine along the cylindrical base pvc pipe then, the cylindrical base pvc pipe is taken out according to the standard method maintenance.

2. a kind of reinforcing bar according to claim 1 and concrete binding force test device is characterized in that, described reinforcing bar comprises screw-thread steel and light face round steel.

3. a kind of reinforcing bar according to claim 1 and concrete binding force test device is characterized in that, the steel plate that described external circular steel plate is a 2mm thickness, and its diameter is the external diameter of cylindrical base pvc pipe, and is provided with the center hole that diameter is a bar diameter.

4. a kind of reinforcing bar according to claim 1 and concrete binding force test device is characterized in that, the steel plate that described built-in circular steel plate is a 2mm thickness, and its diameter is the internal diameter of cylindrical base pvc pipe, and is provided with the center hole that diameter is a bar diameter.

5. a kind of reinforcing bar according to claim 1 and concrete binding force test device is characterized in that the diameter of described pedestal pvc pipe is less than the cylindrical base pvc pipe.

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