CN104198684B - Concrete transmission performance test system and method - Google Patents

Abstract

The invention discloses a concrete transmission performance testing system and method, which relate to the field of research and testing of concrete durability, and the main purpose is to test the concrete transmission performance under the condition of loading a constant compressive stress on a concrete test block. The main technical solution of the present invention is: a concrete transmission performance testing system, including: four tie rods, and a lower pressure plate, a limit valve, a middle pressure plate, a spring, an upper pressure plate, A constant compressive stress loading device composed of washers and nuts; and a solution circulation supply device composed of a solution tank, a constant flow pump, a water tank and three anti-corrosion hoses. Wherein, the distance between the lower pressure plate and the middle pressure plate is greater than the height of the concrete test block; each limit valve, washer and nut are provided on each pull rod; an elastic component is arranged under the middle pressure plate, and one end of the component is connected to the middle The lower surface of the pressure plate is in contact with the other end of which is in contact with the concrete test block.

Description

Concrete transmission performance test system and method

technical field

The invention relates to the field of research and testing of concrete durability, in particular to a concrete transmission performance testing system and method.

Background technique

The performance of concrete depends to a large extent on the number, size and distribution of pores in the cement paste, the performance of the aggregate, and the performance of the interface between the paste and the aggregate. Concrete structures are inevitably affected by external factors such as load and environment during service, and these factors will lead to changes in the transmission properties of concrete, thereby affecting the durability of concrete structures.

In the previous studies on the influence of load on concrete performance, the preload was mainly used once, and then the concrete was tested for transportability after unloading. However, this method cannot simulate the continuous load of concrete in the actual environment, so the test There are large errors in the reliability of the data. Another method is to apply a continuous load to the concrete while conducting a transmission test, but there are few studies on this method at present, mainly due to the limitation of the test loading device. Because the loading devices used to apply constant compressive stress have shortcomings such as limited loading stress level and stability, cumbersome operation steps, and large errors, which will eventually affect the accuracy of test results, and these loading devices apply bending loads. The loaded sample is subjected to two completely different loads of compressive stress and tensile stress on both sides of the neutral layer, which cannot simulate the situation of a single constant compressive stress in the actual environment, nor can it meet the requirements of easy disassembly, easy replacement and maintenance, and accurate measurement requirements. And there is currently no suitable solution supply device for testing the transportability of concrete under the application of continuous load.

Contents of the invention

In view of this, embodiments of the present invention provide a concrete transmission performance testing system and testing method, the main purpose of which is to test the concrete transmission performance under the condition of loading a constant compressive stress on the concrete test block.

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

On the one hand, an embodiment of the present invention provides a concrete transmission performance testing system, which includes: a constant compressive stress loading device for placing a concrete test block and a solution circulation supply device.

The solution circulation supply device includes a solution tank, a constant flow pump, a water tank and three anti-corrosion hoses. The other end of the flow pump is connected to the water tank through an anti-corrosion hose, and the other end of the water tank is connected to another anti-corrosion hose inserted into the solution tank to form a loop for circulating the solution.

The opening of the water tank is in sealing contact with the concrete test block placed in the constant compressive stress loading device, so that the circuit for circulating the solution is a closed circuit.

As in the aforementioned concrete transmission performance testing system, the constant compressive stress loading device includes:

Four pull rods, and a lower pressing plate, a limit valve, a middle pressing plate, a spring, an upper pressing plate, a washer and a nut which are threaded sequentially on the pulling rods from bottom to top.

The lower pressing plate is used to place the concrete test block, and the distance between the lower pressing plate and the middle pressing plate is greater than the height of the concrete test block.

A limit valve, a washer and a nut are respectively arranged on each pull rod, and the limit valve is used to fix the middle pressure plate, spring and upper pressure plate which move downward due to gravity before the concrete test block is added.

A contact part is arranged under the middle pressure plate, one end of the contact part is in contact with the lower surface of the middle pressure plate, and the other end is in contact with the concrete test block, and the contact part is used to uniformly compress the compressive stress of the middle pressure plate Pass it to the concrete test block, so that the concrete test block is evenly stressed.

As in the aforementioned concrete transmission performance testing system, the contact part in the concrete constant compressive stress loading device is a spherical roller.

The upper part of the spherical roller is semicircular and the lower part is rectangular.

There is a groove smaller than the semicircle at the center of the medium pressure plate, the height of which is half the thickness of the medium pressure plate, and smaller than the radius of the semicircle.

Most of the semicircle of the spherical roller is embedded in the middle pressure plate and can rotate freely in it, and the lower surface of the rectangle is in contact with the concrete test block.

As in the aforementioned concrete transmission performance testing system, the contact parts in the concrete constant compressive stress loading device are elastic parts;

The elastic component includes a base and an elastic mechanism arranged on the upper surface of the base; the lower surface of the base is fully in contact with the concrete test block; the top of the elastic mechanism is in contact with the lower surface of the middle pressure plate.

As in the concrete transmission performance testing system mentioned above, the tension gauges in the concrete constant compressive stress loading device are all provided with strain gauges, and the strain gauges are arranged between the middle pressure plate and the lower pressure plate.

As in the aforementioned concrete transmission performance testing system, the springs are disc springs, and the quantity on each pull rod is 40.

As in the aforementioned concrete transmission performance testing system, the upper platen is divided into upper and lower parts:

The upper surface of the upper part is higher than the upper surfaces of the four pull rods when the nut is screwed to the bottom;

The lower half is provided with 4 circular holes matching the four pull rods.

As in the aforementioned concrete transmission performance testing system, the constant compressive stress loading device includes:

Four pull rods, and a lower pressure plate, a middle pressure plate, a spring, an upper pressure plate, a washer and a nut that are threaded on the pull rods in sequence from bottom to top.

The lower pressing plate is used to place the concrete test block, and the distance between the lower pressing plate and the middle pressing plate is greater than the height of the concrete test block.

One washer and one nut are respectively arranged on each tie rod.

On the other hand, an embodiment of the present invention provides a concrete transmission performance testing method, which is applied to the above-mentioned concrete transmission performance testing system, and the method includes:

Fix the 4 limit valves in the constant compressive stress loading device as upward as possible on the tie rod;

Put the concrete test block between the lower pressure plate and the middle pressure plate, release the limit valve after placing it, adjust the position of the concrete test block so that the lower surface of the contact part at the lower end of the middle pressure plate fully contacts the concrete test block;

The constant compressive stress loading device is placed on a pressure testing machine, the upper surface of the upper pressing plate fully contacts the upper pressing plate of the pressure testing machine, and the lower pressing plate fully contacts the lower pressing plate of the pressure testing machine;

Start the pressure testing machine and continue to pressurize until the strain value displayed on the strain gauge attached to the side of the pull rod of the device reaches the predetermined requirement, stop loading, and control the load of the pressure testing machine to stabilize;

Tighten the 4 nuts evenly and slowly. During the process of tightening the nuts, the spring is gradually compressed and begins to store energy. The load displayed by the pressure testing machine gradually decreases. Remove it from the testing machine and connect it to the solution circulation supply device;

Assemble the solution circulation supply device, select a smooth side of the concrete test block, and seal and fix the water tank in the solution circulation supply device on this side;

Put the solution in the solution tank and seal it, place a weighing instrument under it to record its initial weight, weigh and record it every fixed period of time during the test, and start the constant flow pump to make the solution flow in the solution circulation supply device Circulation, so that the solution can continuously contact the concrete side;

After the predetermined test time is reached, the transmission performance of the concrete is tested according to the solution transmission rate and penetration depth.

Concrete transmission performance test method as previously mentioned, described according to the transmission performance of testing concrete with solution transmission rate and depth of penetration comprises:

Calculate the decrease rate of the solution mass according to the results of the weighing test to obtain the solution transfer rate.

After removing the concrete test block and splitting it horizontally along a section where the water tank is installed, the penetration depth of the solution is tested by the chromogenic method.

The transport performance of concrete was characterized by solution transport rate and penetration depth.

The concrete constant compressive stress loading device in the concrete transmission performance test system provided by the embodiment of the present invention fixes the upper pressing plate by nuts, and then uses the elastic deformation energy storage of the disc spring to load the concrete test block with a large load of constant compressive stress. At the same time, through the contact parts set under the middle pressure plate, the constant compressive stress loaded by the device is more stable. After using the limit valve, the placement of the concrete test block is more convenient. Since the whole device is connected in series by four tie rods Formed, so that the overall structure of the device is simple, easy to disassemble and maintain. However, the concrete transmission performance test system provided by the embodiment of the present invention can simulate the real working conditions of concrete components such as different levels of constant compressive stress and solution erosion in actual engineering through the cooperation of the constant compressive stress loading device and the solution circulation supply device. Combined with the concrete transmission performance test method provided by the embodiment of the present invention, the data results tested by the test system are more valuable for engineering reference.

Description of drawings

Fig. 1 is a schematic structural diagram of a concrete transmission performance testing system provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of another concrete transmission performance testing system provided by the embodiment of the present invention;

3 is a schematic structural view of a concrete constant compressive stress loading device provided by an embodiment of the present invention;

Fig. 4 is a side view and a top view of the spherical roller of the constant compressive stress loading device provided by the embodiment of the present invention;

5 is a top view and a side view of the pressure plate in the constant compressive stress loading device provided by the embodiment of the present invention;

Fig. 6 is a structural schematic diagram of another concrete constant compressive stress loading device provided by the embodiment of the present invention;

Fig. 7 is a side view of the pull rod of the constant compressive stress loading device provided by the embodiment of the present invention;

Fig. 8 is a top view and a side view of the lower platen of the constant compressive stress loading device provided by the embodiment of the present invention;

9 is a side view and a top view of the upper platen of the constant compressive stress loading device provided by the embodiment of the present invention;

Fig. 10 is a side view and a top view of the limit valve of the constant pressure stress loading device provided by the embodiment of the present invention.

detailed description

The present invention is described in detail below in conjunction with accompanying drawing and embodiment, but accompanying drawing and embodiment are all only for illustrating the technical scheme of the present invention, wherein the concrete structure of each component, connection mode etc. all can be changed to some extent, Any equivalent transformation or improvement made on the basis of the technical solution of the present invention shall not be excluded from the protection scope of the present invention.

An embodiment of the present invention provides a concrete transmission performance testing system, as shown in FIG. 1 , comprising: a constant compressive stress loading device for placing a concrete test block and a solution circulation supply device.

Concrete constant compressive stress loading device, as shown in Figure 3, the device includes: four tie rods 8, and a lower pressure plate 9, a limit valve 7, a middle pressure plate 5, a spring 4, Upper platen 3, washer 2 and nut 1.

Wherein, the lower pressing plate 9 is used to place the concrete test block, and the distance between the lower pressing plate 9 and the middle pressing plate 5 is greater than the height of the concrete test block;

A limit valve 7, a washer 2 and a nut 1 are provided on each pull rod, and the limit valve 7 is used to fix the middle pressure plate 5, spring 4 and upper pressure plate 3 that move downward due to gravity before the concrete test block is added;

A contact part 6 is arranged below the middle pressure plate 5, and one end of the contact part is in contact with the lower surface of the middle pressure plate 5, and the other end is in contact with the concrete test block. The compressive stress is transmitted to the concrete test block, so that the concrete test block is evenly stressed.

The solution circulation supply device includes a solution tank 10, a constant flow pump 11, a water tank 12 and three anti-corrosion hoses 13, the solution is packed into the solution tank 10 and sealed, and two anti-corrosion hoses 13 are inserted in the solution tank 10, one of which is The root is connected to the constant flow pump 11, and the other end of the constant flow pump 11 is connected to the water tank 12 through an anti-corrosion hose, and the other end of the water tank 12 is connected to another anti-corrosion hose inserted into the solution tank 10 to form a circuit for circulating the solution; The opening of the water tank 12 is in sealing contact with the concrete test block placed in the constant compressive stress loading device, so that the circuit for circulating the solution is a closed circuit.

The constant compressive stress loading device in the concrete transmission performance testing system may be the above-mentioned constant compressive stress loading device for concrete, or other forms of constant compressive stress loading device, which are not limited by specific embodiments of the present invention.

When the constant compressive stress loading device is the above-mentioned constant compressive stress loading device, the water tank 12 of the solution circulation supply device in the concrete transmission performance testing system provided by the embodiment of the present invention and the concrete sample placed on the constant compressive stress loading device block seal connection.

The embodiment of the present invention also provides a concrete transmission performance testing system, as shown in Figure 2, the concrete constant compressive stress loading device is:

Four pull rods 26, and the lower pressing plate 27, the middle pressing plate 25, the spring 24, the upper pressing plate 23, the washer 22 and the nut 21 which are sheathed on the pulling rods in order from bottom to top; wherein, the lower pressing plate 27 is used to place the concrete test block, The distance between the lower pressure plate 27 and the middle pressure plate 25 is greater than the height of the concrete test block, and a washer 22 and a nut 21 are respectively arranged on each tie rod.

The solution circulation supply device in the concrete transmission performance test system is the same as the solution circulation supply device in the concrete transmission performance test system provided by the aforementioned embodiment of the present invention, and also passes through the water tank 12 and the concrete placed on the constant compressive stress loading device The test block is hermetically connected.

As shown in Figure 1, the contact part of the concrete constant compressive stress loading device in the concrete transmission performance test system can be a spherical roller or an elastic part. The specific embodiment of the present invention does not limit this, as long as it can play One end is in contact with the upper surface of the concrete test block, and the other end is in contact with the intermediate pressure plate. When the intermediate pressure plate moves downward, the compressive stress can be completely and evenly transmitted to the concrete test block.

When the contact part is a spherical roller, as shown in Figure 4, the upper part of the spherical roller is a semicircle and the lower part is a rectangle, and there is a center of the lower surface of the middle pressure plate 5 which is smaller than the semicircle. Groove, as shown in Figure 5, the height of this groove is half of the thickness of the medium pressure plate, and less than the radius of the semicircle, so that most of the semicircle of the spherical roller 6 is embedded in the medium pressure plate 5 and can be in it Rotating freely, the rectangular lower surface of the spherical roller 6 is in contact with the upper surface of the concrete test block.

When the contact part is an elastic part, as shown in Figure 6, the contact part arranged under the middle pressure plate 5 can be an elastic part, and the elastic part includes a base and an elastic mechanism arranged on the upper surface of the base, wherein the base The lower surface is in full contact with the concrete test block, and the top of the elastic mechanism is in contact with the lower surface of the middle pressure plate 5 .

Strain gauges 20 are installed on the four tie rods of the above-mentioned concrete constant compressive stress loading device. As shown in FIG. 3 , the strain gauges 20 are pasted between the middle pressure plate 5 and the lower pressure plate 9 .

Further, the spring used in the above-mentioned concrete constant compressive stress loading device is a disc spring, which is also called a Belleville washer. It is different from ordinary springs. The main characteristics of the disc spring are: high modulus of elasticity, short stroke , convenient combination, easy maintenance and replacement, high safety performance, etc., especially able to bear a huge load in a small space. Disc springs have large variable performance per unit volume, especially when superimposed combinations are used, due to the surface frictional resistance, the effects of absorbing impact and dissipating energy are obvious. After the calculation of the device according to the applied load range, 40 disc springs of 40*20.4*1.5*1.15mm can be used in combination on each pull rod, but the specific embodiment of the present invention does not limit this, and can Set the number of disc springs according to specific usage requirements, for example, 30 or 35.

In the above-mentioned concrete constant compressive stress loading device, four tie rods 8 pass through the round holes on the four corners of the lower pressure plate 9 respectively, and the diameter of the lowermost section of the tie rods 8 is larger than that of the upper part, as shown in Figure 7, and this section The height will be less than half of the thickness of the lower pressing plate 9, and the round holes on the four corners of the lower pressing plate 9 are matched with the lower end of the pull rod 8. The aperture of the lower part is large and the aperture of the upper part is small. As shown in Figure 8, the two wear sleeves Use after connection to achieve mutual fixation; the four corners of the middle pressure plate 5 and the upper pressure plate 3 are provided with round holes, the diameter of which is larger than the diameter of the upper part of the pull rod 8, and the limit valve 7, the middle pressure plate 5, and the disc spring 4 And the upper platen 3 passes through the upper end of the pull rod 8 in turn, and is set between the four pull rods 8 and can slide up and down. The upper end of the pull rod 8 is fixed with the washer 2 and the nut 1, and the upper edge of the pull rod 8 is higher than the upper edge of the nut 1. along.

As shown in Figure 7 and Figure 9, there is a section of thread on the upper end of the pull rod 8 in Figure 7 to match the nut 1, and the length of this section of thread is less than the total height of the upper platen 3 in Figure 9, so as to ensure the height of the upper platen 3 of the device. The upper surface can always be in contact with the lower surface of the upper platen of the pressure testing machine during the pressurization process, so that the pressurization operation can be performed by means of the pressure testing machine.

As shown in Figure 10 and Figure 7, the diameter of the circular hole at the center of the limit valve 7 in Figure 10 is consistent with the diameter of the upper end of the pull rod 8 in Figure 7, and the two are matched, and the limit valve 7 can be fixed on the On the pull rod 8.

In the concrete constant compressive stress loading device in the above-mentioned concrete transmission performance testing system, the nuts 1 used are locknuts.

Based on the above-mentioned concrete transmission performance testing system, an embodiment of the present invention provides a concrete transmission performance testing method, which specifically includes the following steps:

1. Fix the four limit valves in the constant compressive stress loading device upwards on the tie rods as much as possible, so that the distance between the lower platen and the middle platen is greater than the height of the concrete test block.

2. Put the concrete test block between the lower pressure plate and the middle pressure plate, release the limit valve after placing it, adjust the position of the concrete test block so that the lower surface of the contact part at the lower end of the middle pressure plate fully contacts the concrete test block.

3. Place the constant compressive stress loading device on the pressure testing machine, the upper surface of the upper platen of the device fully contacts the upper platen of the pressure testing machine, and the lower platen of the device fully contacts the lower platen of the pressure testing machine.

4. Start the pressure testing machine and continue to pressurize until the strain value displayed on the strain gauge attached to the side of the pull rod of the device reaches the predetermined requirement, stop loading, and control the pressure testing machine to stabilize the load.

5. Tighten the 4 nuts evenly and slowly. During the process of tightening the nuts, the disc spring is gradually compressed and begins to store energy. The load displayed by the pressure testing machine gradually decreases. When the load of the pressure testing machine is exactly 0, the disc spring Just compressed to the predetermined position, then the constant compressive stress loading device can be removed from the pressure testing machine and connected to the solution circulation supply device.

6. After assembling the solution circulation supply device, select a smooth side of the concrete test block, and seal and fix the water tank in the solution circulation supply device on this side.

7. After putting the solution into the solution tank and sealing it, place a weighing instrument under it to record its initial weight. During the test, weigh and record it every fixed period of time, and start the constant flow pump at the same time to make the solution in the solution Circulate in the circulation supply so that the solution is continuously in contact with the concrete side.

8. After the predetermined test time is reached, test the transmission performance of the concrete according to the solution transmission rate and penetration depth.

Among them, when testing the transmission performance of concrete according to the solution transmission rate and penetration depth, the following methods can be used, but not limited to, including:

Calculate the reduction rate of the solution mass according to the weighing test results to obtain the solution transmission rate;

After removing the concrete test block and splitting along a section of the installation water tank transversely, test the penetration depth of the solution by color development method;

The transport performance of concrete was characterized by solution transport rate and penetration depth.

The concrete constant compressive stress loading device provided by the embodiment of the present invention fixes the upper pressure plate 3 through the nut 1, and then utilizes the elastic deformation energy storage of the disc spring 4 to load a large load of constant compressive stress on the concrete test block, and at the same time pass through the middle pressure plate The contact part 6 arranged under the 5 makes the constant compressive stress loaded by the device more stable. After the limit valve 7 is adopted, the placement of the concrete test block is more convenient. Since the whole device is connected in series by four tie rods 8 As a result, the overall structure of the device is simple and easy to disassemble and maintain. However, the concrete transmission performance test system provided by the embodiment of the present invention can simulate the real working conditions of concrete components such as different levels of constant compressive stress and solution erosion in actual engineering through the cooperation of the constant compressive stress loading device and the solution circulation supply device. Combined with the concrete transmission performance test method provided by the embodiment of the present invention, the data results tested by the test system are more valuable for engineering reference.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (6)

1. a concrete transmission performance test system, it is characterised in that including: place concrete test block Constant compressive stress charger and solution circulation-supplied device；

Constant compressive stress charger, including:

Four pull bars, and sequence from low to uper part be set on pull bar lower platen, limit valve, center platen, bullet Spring, top board, packing ring and nut；

Described lower platen is used for placing concrete test block, and the distance between described lower platen and center platen is more than described The height of concrete test block；

Described limit valve, packing ring and nut arrange one on every pull bar, and described limit valve is for fixing not Center platen, spring and the top board moved down due to gravity before adding concrete test block；

One elastomeric element, one end of described elastomeric element and medium pressure plate are set below medium pressure plate Lower surface contacts, and the other end contacts with concrete test block, and described elastomeric element is used for middle pressure in pressure process The compressive stress Transmit evenly of plate, to concrete test block, makes concrete test block uniform force；Wherein, described elasticity Parts include base and are arranged on the elastic mechanism of this base upper surface；The lower surface of described base and described coagulation Soil test block is fully contacted；The top of described elastic mechanism contacts with the lower surface of medium pressure plate；

Solution circulation-supplied device is soft including a solution tank, a constant flow pump, a water tank and three anticorrosions Pipe, solution loads sealing in solution tank, inserts two anticorrosion flexible pipes in solution tank, and wherein one connects constant flow pump, The constant flow pump other end is hose connection to water tank by an anticorrosion, and the other end of water tank connects the another of insertion solution tank A piece anticorrosion flexible pipe, forms a loop making solution circulate；

The opening of described water tank is in sealing contact with the concrete test block placed in constant compressive stress charger, makes The loop of described solution circulation is closed circuit.

Concrete transmission performance test system the most according to claim 1, it is characterised in that described mixed Be provided with strain gauge on pull bar in solidifying native constant compressive stress charger, described strain gauge be arranged on described in Between pressing plate and lower platen.

Concrete transmission performance test system the most according to claim 2, it is characterised in that described bullet Spring is disk spring, and the quantity on its every pull bar is 40.

Concrete transmission performance test system the most according to claim 3, it is characterised in that on described Pressing plate is divided into upper and lower two parts:

The upper surface of top half is higher than the upper surface of described four pull bars when described nut is screwed to minimum；

The latter half has 4 circular holes matched with described four pull bars.

5. a concrete transmission performance test method, is applied to according to any one of the claims 1-4 Concrete transmission performance test system, it is characterised in that including:

4 limit valves in constant compressive stress charger are upwards fixed on pull bar as far as possible；

Concrete test block is put between lower platen and center platen, after placing, unclamps limit valve, adjust concrete Test block position allows the elastomeric element lower surface of center platen lower end be fully contacted concrete test block；

Being placed on pressure testing machine by described constant compressive stress charger, described top board upper surface fully connects Touch pressure testing machine top board, described lower platen is fully contacted pressure testing machine lower platen；

Start pressure testing machine persistent pressure, until the dependent variable of display in the strain gauge that device pull bar side is pasted Value reaches pre-provisioning request, stops loading, controls pressure testing machine load stable；

Uniformly tightening 4 nuts lentamente, during fastening nut, spring is gradually started accumulation of energy by compression, The load that pressure testing machine shows is gradually reduced, when pressure testing machine load is just 0, by constant compressive stress Connection solution circulation-supplied device taken off from pressure testing machine by charger；

Assemble described solution circulation-supplied device, select a smooth side of concrete test block, by described molten Tank seal in liquid circulation-supplied device is fixed on this side；

Thereunder place a weighing instrument after loading solution sealing in solution tank and record its initial weight, test During every fixing a period of time weigh record once, start constant flow pump, make solution in solution circulation-supplied Device circulates, makes solution can continuously contact this concrete side；

According to the transporting testing concrete by solution transfer rate and length of penetration after reaching predetermined test period Energy.

Method the most according to claim 5, it is characterised in that described according to by solution transfer rate and The transmission performance of length of penetration test concrete includes:

Calculate the minimizing speed of solution quality according to experiment of weighing result, obtain solution transfer rate；

Concrete test block is unloaded after one section of horizontal splitting of installation water tank, permeate with development process test solution The degree of depth；

The transmission performance of concrete is characterized by solution transfer rate and length of penetration.