Device for testing self-repairing performance of concrete with different crack widths

Abstract

The utility model provides a device for testing the self-repairing performance of concrete with different crack widths, and belongs to the technical field of concrete material inspection. According to the technical scheme, the device comprises a plurality of groups of concrete test pieces with different crack widths, a cavity for sealing the cracks and a pressurized water injection mechanism capable of injecting high-pressure water into the cavity; a groove is formed in the concrete test piece, and the crack is formed in the groove. The device has the beneficial effects that the change rule of the permeability of concrete with different crack widths along with time can be effectively measured, and the repairing effect of concrete structures which are self-repaired through different crack widths can be effectively compared through the device; the self-repairing mechanism of the capillary crystalline material on the concrete crack is favorably researched.

Description

Technical Field

[0001] The utility model relates to the technical field of concrete material inspection, in particular to a device for testing the self-repairing performance of concrete cracks with different widths. Background Art

[0002] The durability of concrete is one of the hot issues in the engineering field. This issue involves a lot of content. The most fundamental reason is related to the difficulty of water or harmful gases entering its interior. The permeability of concrete directly affects its durability. Highly permeable concrete is easily damaged by external environmental factors, including climate erosion, chemical erosion, steel corrosion, freeze-thaw cycles and alkali-aggregate reaction. This may lead to problems such as peeling, cracking, and reduced strength of the concrete surface, affecting its overall performance and life. In order to improve the durability of concrete, measures such as using high-performance concrete, adding waterproofing agents, controlling concrete mix ratios, and surface sealing treatment can be taken to reduce permeability and improve the ability of concrete to resist external damage. These steps help to extend the service life of concrete and maintain its structural integrity. At present, with the continuous improvement of underground engineering construction technology, underwater tunnels with high water pressure and deep burial depth have appeared one after another, and the huge water pressure has put a great test on the permeability of concrete in these projects. Once cracks appear in the concrete of such a project, they must be repaired in time. Penetrating crystallization materials are usually used to repair and heal concrete cracks. At present, no experimental methods and experimental equipment for testing the repair performance and effect of concrete have been found in relevant standards and literature at home and abroad, nor have any evaluation methods for the repair performance of concrete cracks been found.

[0003] It is a very feasible method to evaluate the self-repairing performance of concrete cracks by measuring the permeability of concrete. At present, the concrete water permeability test is based on Darcy's law of fluid mechanics. Concrete is regarded as a porous solid material, and the permeability coefficient is used to evaluate the concrete's impermeability, which is called the permeability coefficient method; the permeability coefficient method refers to a method of studying the permeability of concrete by using the principle that the fluid gradually penetrates from one end to the other through the pores of the object under test under certain pressure conditions. However, the current permeability testing machine needs to seal the side of the specimen and place it in a rigid mold during the test, which is bound to change the crack state of the self-repairing concrete specimen, making it difficult to measure the repair effect of the permeable crystallization material on the concrete cracks, and it is even more impossible to study the repair performance of concrete with different crack widths. For this reason, the utility model proposes a self-repairing performance testing device for concrete with different crack widths. Utility Model Content

[0004] The utility model aims to provide a device for testing the self-repairing performance of concrete with different crack widths, which cannot be tested by existing methods.

[0005] The utility model is achieved through the following measures:

[0006] A self-repairing performance testing device for concrete cracks of different widths, characterized in that it comprises a plurality of concrete specimens with cracks of different widths, a cavity for sealing the cracks, and a pressurized water injection mechanism capable of injecting high-pressure water into the cavity, wherein the cracks are artificially made, and the widths of the cracks on different concrete specimens are different, specifically 0.05-0.1mm, 0.1-0.2mm, 0.2-0.3mm, etc., and an external coating agent is provided at the cracks;

[0007] The concrete specimen is provided with a groove, and the crack is provided in the groove.

[0008] The specific features of the utility model also include:

[0009] The concrete test piece is in the shape of a dumbbell with the groove being an annular groove, including a thin cylinder in the middle and two thick cylinders located at both ends of the thin cylinder, and the thin cylinder is provided with an annular crack, specifically, the diameter of the thick cylinder is 100 mm, and the diameter of the thin cylinder is 70 mm;

[0010] Water injection holes penetrating into the cavity are arranged on both side end faces of the concrete specimen, and high-pressure water is injected into the cavity through the water injection holes. Specifically, the water injection hole on one side is used for water injection, and the water injection hole on the other side is used for exhausting gas during the water injection process. When the water is filled, the water injection hole here needs to be blocked. A pressure measuring hole is arranged at the center of one side end face of the concrete specimen, and the pressure measuring hole penetrates the thick cylinder and extends into the thin cylinder until it exceeds the cross section where the crack is located. A piezometer is installed at the pressure measuring hole, and the piezometer is used to measure water pressure changes;

[0011] The outer surface of the concrete specimen is wrapped with protective silicone rubber, and the protective silicone rubber and the groove form the cavity.

[0012] The pressurized water injection mechanism includes a pressurized pump and several groups of fixing devices;

[0013] The concrete test pieces are installed on a plurality of groups of the fixing devices;

[0014] The inlet of the booster pump is connected to a water source, and the output port of the booster pump is provided with a drainage pipe. The drainage pipe is provided with a plurality of groups of branch pipes corresponding to the concrete specimens, and the outlet ends of the branch pipes are connected to the corresponding concrete specimens. Specifically, the outlet ends of the branch pipes are connected to the water injection holes on the corresponding sides, and water is injected into the cavity through the water injection holes. Different water pressures are injected into the cavity during the experiment, and the water head height of 1m to 5m is adjustable.

[0015] The fixing device comprises a pair of fixing parts, and the fixing parts on both sides are connected into a whole through a plurality of sets of long screws and corresponding nuts;

[0016] The fixing part comprises a pair of symmetrically arranged clamping plates, and arc-shaped grooves matching with the concrete specimen are arranged on opposite sides of the clamping plates at both sides. Specifically, the thick cylinders at both sides of the concrete specimen are respectively arranged between the arc-shaped grooves at the corresponding sides of the fixing parts at both sides;

[0017] A fixing plate is provided on both sides of the clamping plate, and a corresponding threaded hole 1 is provided on the fixing plate, and the clamping plates on both sides are connected and fixed by bolts provided in the threaded hole 1;

[0018] The clamping plate is provided with a plurality of groups of threaded holes 2, and the long screws are arranged in the corresponding threaded holes 2 on the fixing parts at both sides;

[0019] The drainage tube is provided with a valve.

[0020] The beneficial effects of the utility model are as follows: the utility model fixes the cracked concrete specimen from the beginning, and the boundary conditions of the specimen will not change until the end of the test, so as to objectively and truly evaluate the improvement effect of the self-repairing ability of concrete after adding internal admixtures and spraying external coating agents, as well as the width range and repair time of cracks that can be self-repaired;

[0021] The utility model solves the technical problems that the existing methods cannot measure the self-repairing of concrete cracks under high water pressure, cannot test the self-repairing effect of concrete cracks when the crack width changes, and cannot accurately reflect the self-repairing performance of concrete cracks;

[0022] The utility model can effectively measure the change law of the permeability performance of concrete with different crack widths over time. Through this device, the repair effect of concrete structures that have undergone self-repair of cracks with different crack widths can be effectively compared, which is helpful to study the mechanism of self-repair of concrete cracks by permeable crystallization materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the utility model.

[0024] Figure 2 It is a structural schematic diagram of a concrete specimen in an embodiment of the utility model.

[0025] Figure 3 It is a schematic diagram of the structure of the fixing device in the embodiment of the utility model.

[0026] Figure 4 It is a schematic diagram of a concrete specimen installed in a fixing device in an embodiment of the utility model.

[0027] Figure 5 It is a schematic diagram of a concrete specimen wrapped with waterproof silicone rubber in an embodiment of the utility model.

[0028] Among them, the accompanying drawings are marked as: 1. concrete specimen; 2. pressure pump; 3. drainage pipe; 4. water injection hole; 5. fixing device; 6. pressure measuring hole; 7. waterproof silicone rubber; 8. piezometer; 9. valve; 10. splint; 11. long screw. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0030] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0032] In order to clearly illustrate the technical features of this solution, this solution is described below through a specific implementation method.

[0033] See also Figure 1-5, a self-repairing performance testing device for concrete cracks of different widths, comprising a plurality of concrete specimens with cracks of different widths, a cavity for sealing the cracks, and a pressurized water injection mechanism capable of injecting high-pressure water into the cavity, the cracks are artificially made, the crack widths on different concrete specimens are different, specifically 0.05-0.1mm, 0.1-0.2mm, 0.2-0.3mm, etc., and an external coating agent is provided at the cracks;

[0034] A groove is arranged on the concrete specimen 1, and a crack is arranged in the groove.

[0035] Concrete specimen 1 is dumbbell-shaped with an annular groove, including a thin cylinder in the middle and two thick cylinders located at both ends of the thin cylinder. An annular crack is provided on the thin cylinder. Specifically, the diameter of the thick cylinder is 100 mm, and the diameter of the thin cylinder is 70 mm.

[0036] Water injection holes 4 penetrating into the cavity are provided on both side end faces of the concrete specimen 1, and high-pressure water is injected into the cavity through the water injection holes 4. Specifically, the water injection holes 4 on one side are used for water injection, and the water injection holes 4 on the other side are used for exhausting gas during the water injection process. When the water is filled, the water injection holes 4 here need to be blocked. A pressure measuring hole 6 is provided at the center of one side end face of the concrete specimen 1. The pressure measuring hole 6 penetrates the thick cylinder and extends into the thin cylinder until it exceeds the cross section where the crack is located. A piezometer 8 is installed at the pressure measuring hole 6, and the piezometer 8 is used to measure the water pressure change;

[0037] The outer surface of the concrete specimen 1 is wrapped with protective silicone rubber, and the protective silicone rubber and the groove form a cavity.

[0038] The pressurized water injection mechanism includes a pressurized pump 2 and a plurality of fixing devices 5;

[0039] A plurality of sets of fixtures 5 are each mounted with a concrete specimen 1;

[0040] The inlet of the booster pump 2 is connected to a water source, and the output port of the booster pump 2 is provided with a drainage pipe 3. The drainage pipe 3 is provided with several groups of branch pipes corresponding to the concrete specimen 1, and the outlet ends of the branch pipes are connected to the corresponding concrete specimen 1. Specifically, the outlet ends of the branch pipes are connected to the corresponding side water injection holes 4, and water is injected into the cavity through the water injection holes 4. Different water pressures are injected into the cavity during the experiment, and the water head height of 1m to 5m is adjustable.

[0041] The fixing device 5 comprises a pair of fixing parts, and the fixing parts on both sides are connected into a whole through a plurality of sets of long screws 11 and corresponding nuts;

[0042] The fixing part includes a pair of symmetrically arranged clamping plates 10, and arc grooves matching with the concrete specimen 1 are arranged on the opposite sides of the clamping plates 10 on both sides. Specifically, the thick cylinders on both sides of the concrete specimen 1 are respectively arranged between the corresponding arc grooves on both sides of the fixing parts on both sides;

[0043] A fixing plate is provided on both sides of the clamping plate 10, and a corresponding threaded hole 1 is provided on the fixing plate. The clamping plates 10 on both sides are connected and fixed by bolts provided in the threaded hole 1;

[0044] A plurality of groups of threaded holes 2 are provided on the clamping plate 10, and long screws 11 are provided in the corresponding threaded holes 2 on the fixing parts on both sides;

[0045] A valve 9 is provided on the drainage pipe 3 , and the valve 9 is close to the pressure pump, and the water injection is regulated by the valve 9 .

[0046] When using this device for testing, the specific steps are as follows:

[0047] S1, making multiple groups of dumbbell-shaped concrete specimens 1 containing internal admixtures, and reserving water injection holes 4 and pressure measuring holes 6, the specific concrete specimens 1 have a diameter of 100 mm at both ends of the thick cylinder and a diameter of 70 mm in the middle thin cylinder;

[0048] S2. Cracks of different widths are set at the thin cylinders in the middle of multiple groups of concrete specimens 1, and the specific widths of the cracks are 0.05-0.1mm, 0.1-0.2mm, and 0.2-0.3mm;

[0049] S3, spray the external coating agent on the surface and cracks of the concrete specimen 1 and maintain it;

[0050] S4, wrap the groove in the middle of the concrete specimen 1 with protective silicone rubber to form a cavity, use a pressure pump 2 to inject water into the cavity through the water injection hole 4, and measure the water pressure change by installing a piezometer 8 on the pressure measuring hole 6;

[0051] S5. Evaluate the self-repairing performance of concrete after adding internal admixtures and spraying external coating agents based on the test results. Specifically, the concrete specimen with a larger water pressure change indicates that its cracks have stronger permeability, so it can be judged that the self-repairing performance of the concrete specimen is poor, that is, under the crack width state corresponding to the concrete specimen, the internal admixture and external coating agent have a poor repair effect on it.

[0052] Technical features not described in the present invention can be achieved through or by adopting existing technologies, and will not be elaborated here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A device for testing the self-repairing performance of concrete cracks of different widths, characterized in that: It comprises a plurality of groups of concrete test pieces (1) with cracks of different widths, a cavity for sealing the cracks, and a pressurized water injection mechanism capable of injecting high-pressure water into the cavity; The concrete test piece (1) is provided with a groove, and the crack is provided in the groove.

2. The self-repairing performance testing device for concrete cracks of different widths according to claim 1 is characterized in that: The concrete test piece (1) is in the shape of a dumbbell with the groove being an annular groove, comprising a thin cylinder in the middle and two thick cylinders located at both ends of the thin cylinder, and the thin cylinder is provided with an annular crack.

3. The self-repairing performance testing device for concrete cracks of different widths according to claim 2 is characterized in that: Water injection holes (4) penetrating into the cavity are arranged on both side end faces of the concrete specimen (1), a pressure measuring hole (6) is arranged at the center of one side end face of the concrete specimen (1), the pressure measuring hole (6) penetrates the thick cylinder and extends into the thin cylinder until it exceeds the cross section where the crack is located, and a piezometer (8) is installed at the pressure measuring hole (6).

4. The self-repairing performance testing device for concrete cracks of different widths according to claim 3 is characterized in that: The outer surface of the concrete specimen (1) is wrapped with protective silicone rubber, and the protective silicone rubber and the groove form the cavity.

5. The self-repairing performance testing device for concrete cracks of different widths according to claim 1, characterized in that: The pressurized water injection mechanism comprises a pressurized pump (2) and a plurality of sets of fixing devices (5); The concrete test pieces (1) are installed on a plurality of groups of the fixing devices (5); The inlet of the booster pump (2) is connected to a water source, the outlet of the booster pump (2) is provided with a drainage pipe (3), the drainage pipe (3) is provided with a plurality of groups of branch pipes corresponding to the concrete specimens (1), and the outlet ends of the branch pipes are connected to the corresponding concrete specimens (1).

6. The self-repairing performance testing device for concrete cracks of different widths according to claim 5, characterized in that: The fixing device (5) comprises a pair of fixing parts, and the fixing parts on both sides are connected into a whole through a plurality of sets of long screw rods (11) and corresponding nuts; The fixing portion comprises a pair of symmetrically arranged clamping plates (10), and arc-shaped grooves matching the concrete test piece (1) are arranged on opposite sides of the clamping plates (10).

7. The self-repairing performance testing device for concrete cracks of different widths according to claim 6, characterized in that: A fixing plate is provided on both sides of the clamping plate (10), and a corresponding threaded hole 1 is provided on the fixing plate. The clamping plates (10) on both sides are connected and fixed by bolts provided in the threaded hole 1.

8. The device for testing the self-repairing performance of concrete cracks of different widths according to claim 7, characterized in that: The clamping plate (10) is provided with a plurality of groups of threaded holes 2, and the long screw rods (11) are arranged in the corresponding threaded holes 2 on the fixing parts at both sides; The drainage tube (3) is provided with a valve (9).

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