CN104458531A - Device and method for testing water permeability resistance of lateral restriction-free concrete joint - Google Patents

Abstract

The invention discloses a test device and method for the water penetration resistance of concrete joints without lateral restraint force, which is used for testing the water penetration resistance of test blocks at the joints of old and new concrete, and has the function of placing new and old concrete joints to resist water penetration. The double-layer square tube 4 of the seepage test block 5, the bottom of the square tube is sealed, the upper opening of the square tube has an outer flange 14, and the lower part of the square tube is provided with an inner flange 9 with a middle opening 10, and the inner flange separates the square tube It consists of two parts, the test block cabin 6 and the water inlet cabin 13; the inner flange is provided with an elastic sealing gasket 8; the left cover plate 1 and the right cover plate 2 are pressed and fixed on the outer flange of the square cylinder by fastening bolts 3; The water inlet chamber at the lower part of the square tube is connected to the water pressure device 11 and the water inlet, and connected to the water pressure gauge 12; an observation port is provided between the left cover plate and the right cover plate according to the shape and area of the concrete joint to facilitate the observation of water seepage. The invention can realize the anti-water penetration performance test of the new and old concrete joints under the action of no lateral restraint force.

Description

A test device and method for water penetration resistance of concrete joints without lateral restraint

technical field

The invention relates to a test device for the water penetration resistance of the joints of new and old concrete structures caused by construction intervals.

Background technique

In the civil engineering industry, there are parts where there are joints in the concrete structure due to the construction interval, such as the concrete joints and post-casting strips in the basement, the subway station structure with a laminated wall structure, and the joints of the fabricated underground structure Parts, concrete stubble parts of underground passages, post-repair parts of other engineering structures, etc. When these engineering structures are located below the groundwater level, these joints are often the places where the leakage is relatively concentrated during the operation and use stage, which has a great impact on the later use of the structure and the durability of the concrete, and will also cause certain damage. In serious cases, it may even cause the project to be scrapped.

Since the construction quality of the waterproof layer in underground engineering is affected by many factors at present, it is difficult to guarantee a complete waterproof effect. Therefore, some waterproof measures have been proposed to improve the impermeability of these old and new concrete joints, such as patent 1 (publication number CN2801916Y, publication date 2006.08.02), patent 2 (publication number CN201908363U, publication date 2011.07.27), patent 3 (publication number CN202787526U, publication date 2013.03.13), patent 4 (publication number CN201110154743, publication date 2011.11 .23), etc., by increasing the waterproof structure of the joints, improving the bonding performance of new and old concrete, and changing the shape of the joints to enhance its impermeability. However, the current test of concrete impermeability is mainly based on "GB/T50082-2009 Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete" (implementation date: July 1, 2010, Chapter 6 Water Penetration Test) The anti-seepage performance of the circular table-shaped concrete test block (upper small and lower large) was used to test its impermeability performance, which did not involve the anti-seepage performance test method and device of the joints of old and new concrete, and the waterproof measures for such parts cannot be tested effect is tested. Some other published documents, such as Patent 5 (publication number CN102608014A, publication date 2012.07.25), patent 6 (publication number CN101806702B, publication date 2011.04.27), patent 6 (publication number CN201120371533, publication date 2012.05.23), etc. It is also tested for the overall impermeability of the concrete test block, and does not involve the impermeability test of the concrete structure with joints.

The literature published by Xu Hongfa et al. ("Research on Impermeability Test Method for Concrete Joints", "Journal of Sichuan University (Engineering Science Edition)", Volume 42, No. 4, Pages 7-12, July 2010), proposed The invention discloses an improved concrete joint anti-seepage test method using the existing concrete anti-seepage test device. In this method, the conical concrete joint anti-seepage test block is made by two pouring methods, and the joint form of the concrete is considered to be trapezoidal and arc-shaped, and then the conventional concrete anti-seepage tester (such as "GB/ T50082-2009 Ordinary Concrete Long-Term Performance and Durability Test Method Standard)) Water pressure is applied from the bottom of the concrete test block to conduct the impermeability test. The main problem of using this method is: in order to prevent the concrete test block from being pushed out by the water pressure, the steel sleeve on the concrete impermeability instrument is a round table (small at the top and large at the bottom), so when installing the concrete impermeability test block and In the process of adding water pressure from the bottom, a hoop constraint will be formed between the concrete impermeability test block and the steel sleeve, which will increase the extrusion force between the new and old concrete, resulting in different degrees of closure of the joints, which cannot reflect The impermeability of the joints under actual working conditions.

Contents of the invention

The purpose of the present invention is to provide a test device for the water penetration resistance of the joints of concrete structures, which can eliminate the hoop constraint effect of the steel sleeve of the concrete impermeability instrument on the concrete test block, and can be tested under conditions closer to the actual working environment. Next, test the water penetration resistance of the old and new concrete joints, provide a more accurate basis for the design and construction of this type of engineering structure, and reduce the leakage in the later stage of operation.

For realizing the purpose of the invention, the technical scheme that the present invention takes is:

The utility model relates to a test device for the water penetration resistance of concrete joints without lateral restraint, which is used for testing the water penetration resistance of test blocks at joints of old and new concrete. There is a double-layered square tube 4 for placing anti-seepage test blocks 5 of old and new concrete joints, the bottom of the square tube is sealed, the upper opening of the square tube has an outer flange 14, and the lower part of the square tube is provided with an inner flange with a middle opening 10 9. The inner flange divides the square cylinder into two parts: the test block cabin 6 and the water inlet cabin 13; the inner flange 9 is provided with an elastic sealing gasket 8; the left cover plate 1 and the right cover plate 2 are compressed by fastening bolts 3 It is fixed on the outer flange of the square tube; the water inlet chamber 13 at the bottom of the square tube is connected to the hydraulic device 11 and the water inlet, and connected to the water pressure gauge 12; The area is provided with an observation port for easy observation of water seepage.

Another object of the present invention is to provide a method for testing the water penetration resistance of concrete joints without lateral restraint. The anti-seepage test block 5 composed of new concrete and old concrete is installed in part of the double-layer square tube, and water pressure is applied to the joint 7 of the old and new concrete; the inner size of the square tube is adapted to the concrete anti-seepage test block to eliminate the test process. The impact of the lateral restraint force around the middle concrete test block; the concrete impermeability test block is fixed by the top left cover plate 1 and right cover plate 2 through the fastening bolt 3, and through the compression of the left cover plate and the right cover plate The function makes the elastic sealing gasket 8 at the bottom of the concrete anti-seepage test block form a squeeze deformation seal to restrict the pressure water in the water inlet chamber 13 from flowing out from the bottom side of the test block; the pressure water in the water inlet chamber 13 is pressed into the test block chamber through the middle opening 10 The seam part 7 of the medium impermeability test block; the water inlet cabin at the lower part of the square tube is connected to the hydraulic device 11 and the water inlet, and connected to the water pressure gauge; the tester observes the water seepage through the observation port on the cover plate, when the seam part Stop the test when water seepage occurs at the top, and record the maximum water pressure value during the test.

During the specific experiment, the old and new concrete impermeability test blocks (usually 15cm×15cm×15cm in size, but not limited to this) are placed in the upper space of a double-layer square tube that is suitable for its size (slightly larger than the size of the test block). The inner side of the upper layer of the square tube is brushed with lubricant in advance to eliminate the constraints on the test block from the side; the cover plate is divided into two pieces, left and right, and both are tightly connected with the outer edge of the top of the square tube with fastening bolts to fix the test block; the two cover plates are spliced A certain gap and opening are reserved along the concrete joints for observing the results of the penetration test; the lower layer of the square tube is the water inlet cabin, which is connected to the water pressure supply device and the water pressure gauge; a square opening is opened between the upper and lower layers of the square tube, Make the water in the water inlet chamber act on the concrete joint through this part; in order to prevent water from seeping out from the side of the test block, a layer of silicone rubber elastic with a certain thickness is placed on the contact part between the bottom of the concrete impermeability test block and the square tube. The sealing gasket (the size is consistent with the shape of the inner flange between the upper and lower layers inside the square tube), through the fastening effect of the top cover, the concrete test block is tightly compressed to form a closed water ring to ensure that the water seepage is at the concrete joint and not Flow out from the bottom side of the test block.

When multiple concrete anti-seepage test blocks are required to be tested at the same time, multiple identical devices can be connected in parallel, and the same water pressure supply device can be used to supply water to maintain the same water pressure and action time. This scheme is suitable for the water penetration resistance test of the joints of old and new concrete without lateral restraint.

Holes can be opened on both sides or around the side walls of the square tube to reduce or eliminate the lateral binding force of the 4 side walls of the square tube on the concrete anti-seepage test block.

The beneficial effect of the present invention is that, when carrying out the anti-water penetration test on the joints of new and old concrete, the hoop constraint effect of the steel sleeve of the concrete impermeability instrument can be eliminated, and the anti-seepage performance test can be realized when no external force acts on the joints .

Note: This invention is funded by the National Natural Science Foundation of China Youth Fund Project (Project No. 51108385) and the National Natural Science Foundation of China General Project (Project No. 51178401), and thanks for this.

Description of drawings

Fig. 1 is the front view of the test device of the water penetration resistance performance of the concrete joint without lateral restraint of the present invention.

FIG. 2 is a top view of FIG. 1 .

Fig. 3 is an A-A sectional view of Fig. 1 .

In the figure: 1. Left cover plate, 2. Right cover plate, 3. Fastening bolts, 4. Square tube, 5. New and old concrete impermeability test blocks, 6. Test block cabin, 7. New and old concrete joints, 8. Elastic sealing gasket, 9. inner flange, 10. middle opening of inner flange, 11. water inlet and hydraulic device, 12. water pressure gauge, 13. water inlet tank, 14. outer flange.

Detailed ways

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

Example

As shown in Fig. 1-Fig. 3, a kind of specific embodiment of the present invention is, can realize the anti-water penetration performance test under the state of new and old concrete joint without lateral constraint force, and its implementation steps are as follows:

(1) Make half a concrete test block in the concrete cube test form to simulate the old poured concrete, after demoulding, its surface 7 is processed, and then cured for 28 days;

(2) Put the old concrete test block into the concrete cube test form, with the old and new concrete joint interface 7 facing up, pouring concrete on the upper part to simulate the newly poured concrete, forming a complete concrete joint impermeability test block 5, and curing for 28 days after demoulding;

(3) The test device described in the technical solution of the present invention is connected to the hydraulic device 11 and the hydraulic gauge 12, and the elastic sealing gasket 8 is installed, and the bottom water inlet cabin 13 is filled with water;

(4) Put the concrete joint anti-seepage test block into the square tube 4 (paint the inner wall of the square tube 4 with lubricant), cover the left cover plate 1 and the right cover plate 2 and tighten the fastening bolt 3;

(5) Water penetration pressure is applied by the hydraulic device 11 to test the water penetration resistance of the concrete joints. When water seepage occurs at the top of the joints, the test is stopped, and the maximum water pressure value during the test is recorded.

Using the test device and steps of this example, the concrete joint interface 7 has been treated in three ways: wire brushing for laitance, surface chiseling and cleaning, chiseling and brushing with concrete interface agent. The test results of the seepage test block are shown in the table below.

serial number Seam interface processing method Seepage water pressure/MPa

1 Wire brush treatment of laitance 0.20 2 Surface chiseling and cleaning 0.30 3 The surface is chiseled and coated with interface agent 0.50

As can be seen from the test results in the table, the old and new concrete interface 7 is treated differently, and its anti-seepage ability has a certain difference. The technical scheme of the present invention can test the anti-seepage resistance of the new and old concrete joint without lateral binding force under different interface treatment methods. The difference in penetration ability.

Claims (6)

1. the test unit without side direction additional constraining force concrete joint water resistant permeance property, for carrying out the test of water resistant permeance property to the test block of new-old concrete seam areas, it is characterized in that, there is the double-deck square tube (4) for placing the impervious test block of new-old concrete seam (5), the sealed bottom of square tube, the suitable for reading of square tube has outward flange (14), square tube bottom is provided with the inward flange (9) with middle opening (10), and square tube is divided into test block cabin (6) and water inlet cabin (13) two parts by inward flange; Inward flange is provided with resilient seal packing ring (8); Left cover (1) and right cover plate (2) are pressed abd fixed on the outward flange of square tube by fastening bolt (3); The water inlet cabin (13) of square tube bottom connects hydraulic devices (11) and water inlet, and connects water pressure gauge (12); Be provided with the observation panel being convenient to observe infiltration situation according to the shape of concrete joint and region between left cover (1) and right cover plate (2).

2. the test unit without lateral restriction concrete joint water resistant permeance property according to claim 1, it is characterized in that, left cover (1) and right cover plate (2) form a monoblock type cover plate, and it offers viewport according to the shape of concrete joint and region correspondence.

3. the test unit without lateral restriction concrete joint water resistant permeance property according to claim 1, it is characterized in that, square tube both sides or surrounding side-wall hole, reduce or eliminate square tube (4) sidewall to the lateral restriction of concrete impervious test block.

4. the test method without lateral restriction concrete joint water resistant permeance property, it is characterized in that, adopt the test unit of claim 1 or 2 or 3 structure, having in test block cabin (6) and water inlet cabin (13) two-part double-deck square tube the impervious test block (5) formed of installing by novel concrete and old concrete, hydraulic pressure is applied to new-old concrete seam (7); Inside dimensions and the concrete impervious test block of square tube (4) adapt, with square tube sidewall in Elimination test process on the impact of the lateral restriction of concrete test block surrounding; Concrete impervious test block is fixed through fastening bolt (3) by top left cover plate (1) and right cover plate (2), and makes the resilient seal packing ring (8) bottom concrete impervious test block to form in crimp sealing restriction water inlet cabin press water by the pressuring action of left cover and right cover plate to flow out from side bottom test block; The press water in water inlet cabin is pressed into impervious test block seam (7) position in test block cabin by middle opening (10); The water inlet cabin place of square tube bottom connects hydraulic devices and water inlet, and connects water pressure gauge; Experimenter observes infiltration situation by the observation panel on cover plate, stops test when infiltration appears in seam areas at top, the maximum hydraulic pressure value in record process of the test.

5. test method according to claim 4, is characterized in that, adopts mode in parallel to be connected by multiple single test device, provides identical hydraulic pressure, carry out water resistant permeability test simultaneously.

6. test method according to claim 4, is characterized in that, fluid under pressure can be water, also can be the solution of other compositions.