CN101482468B - Test method for interface impermeability between sealing material and concrete bonded specimen - Google Patents

Abstract

The invention discloses a method for testing interface impervious strength of the sample bonded by sealant and concrete. The method comprises: reserving a seam cavity of a certain size in the middle of the concrete bonded sample, filling in sealant to bond the concrete and the sealant into an integral body to obtain a truncated cone shaped bonded impervious sample; placing the bonded impervious sample on the permeability instrument; increasing the water pressure of the impervious instrument at regular intervals for 0.1MPa each time from 0.1MPa until water seeps from the sample surface; and determining the previous water pressure as the impervious strength of the interface of concrete and sealant. The invention achieves the advantages of simple operation, unique and convenient using, need not adding other equipments, is convenient for popularization; it can detect the impervious strength of any composite material structure, has good instructiveness to engineering practice, is especially suitable for detecting the impervious strength of concrete construction seam and expansion joint such as simulated reservoir dam surface, channel expansion joint, aqueduct expansion joint and pipeline expansion joint, achieves great practical engineering value.

Description

Test method for interface impermeability between sealing material and concrete bonded specimen

technical field

The invention belongs to the field of performance testing of building materials, in particular to a method for testing the interface impermeability of a sealing material and a concrete bonding sample.

Background technique

At present, the method of testing the impermeability of concrete is very mature. At the same time, the sealant as an anti-seepage sealing material does not need to be tested for its impermeability because of its high impermeability level. However, when the sealant is used as a caulking or joint material in concrete construction joints or expansion joints, the bonding interface is often the weakest part of the impermeability. The bonding surface is composed of inorganic materials and polymer materials. First of all, the porosity, void type, roughness of the concrete surface, and the type, ratio, and viscosity of the polymer sealant all affect the bond strength; in addition, the cleanliness, roughness, dry humidity, and application of the interface primer Whether or not, the type of interface primer, etc. also affect the bond strength; finally, environmental conditions such as temperature, humidity, wind, rain and snow during construction also affect the bond strength. The level of bonding strength directly affects the strength of impermeability. The bonding surface with high bonding strength has strong impermeability, and the bonding surface with low bonding strength has low impermeability. For water conservancy projects, the quality of joint treatment directly affects the quality of the project. Poorly treated joints become channels for water seepage, directly or indirectly destroying the concrete structure or the foundation of the project, causing foundation subsidence, causing the weight of the project to drop or to be wrong, and finally destroying the entire project, resulting in huge economic losses. bad social influence. Therefore, it is necessary to develop a test method for the impermeability performance of the sealant-concrete interface.

Contents of the invention

The object of the present invention is to provide a method for testing the interface impermeability of a sealing material and a concrete bonded sample.

In order to realize above-mentioned task, the present invention takes following technical solution:

A method for testing the interface impermeability of a sealing material and a concrete bonded sample, characterized in that it comprises the following steps:

1) First prepare the bonded impermeable sample, which is in the shape of a circular table, made of concrete and sealing material, the sealing material is located in the middle of the sealing material, and the sealing material is closely bonded to the concrete to form a whole. Apply an anti-seepage layer around the bottom and outside of the concrete part of the anti-seepage sample;

A. Put the concrete mixture into the anti-seepage test mold that can be released freely, and insert a wooden board or steel plate with the same width as the left expansion joint in the middle. After the concrete is finally set, carefully take out the wooden board or steel plate to form an expansion joint. Cavities with the same size, place the concrete sample in an environment with a relative humidity above 95% at 20±2°C for 24 hours, then remove the mold, and then place it at 20±2°C with an environment with a relative humidity above 95% for 27 hours Reach the standard strength of concrete in days;

B. Pour the sealing material into the gap cavity left in the middle of the concrete, so that the concrete and the sealing material become a bonded sample as a whole, and make a conical concrete anti-permeability whose size matches the size of the water pressure chamber on the impermeability meter. For the seepage sample, put it in an environment of 20±2°C and a relative humidity of 65±5% for 28 days, and then evenly apply an anti-seepage layer to the bottom and side walls of the concrete part of the impervious sample;

2) Place the concrete anti-seepage sample in the outer steel mold, and fix it on the water pressure chamber of the anti-seepage meter through the rubber gasket, so that the water between the concrete anti-seepage sample and the water pressure chamber of the anti-seepage meter is impermeable. The pressure chamber communicates with the water inlet at one end of the impermeability meter;

3) Apply water pressure from the water inlet of the impermeability meter. The water pressure starts from 0.1MPa, and increases step by step at intervals of 0.1MPa at regular intervals until water emerges from the surface of the bonded impervious sample. The water pressure of the previous level That is, the impermeability strength of the interface between the concrete impermeability sample and the sealing material.

The concrete in the anti-seepage sample prepared by the invention can simulate concrete of any type and any strength level in actual engineering. This method can test the interface impermeability of bonded samples, is simple to operate, easy to use, does not need to add new equipment, is easy to popularize, can detect the impermeability of any composite material structure, and has strong implications for specific engineering practice Instructive, especially to simulate the impermeability of construction joints and expansion joints of concrete such as reservoir dam surface, channel expansion joints, aqueduct expansion joints, pipeline expansion joints, etc., has great practical engineering significance.

Description of drawings

Figure 1 is a schematic diagram of testing the impermeability of the interface between the sealing material and the concrete bonded sample.

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

Detailed ways

Referring to Fig. 1, according to the technical scheme of the present invention, the test method of the interface impermeability of sealing material and concrete bonding sample comprises the following steps:

1. First, prepare a bonded anti-seepage sample. The concrete anti-seepage sample is in the shape of a truncated cone, with a large bottom and a small top as a whole. It is made of concrete 3 and sealant 1. Sealant 1 is located in the middle of concrete 3, and It is completely covered by the concrete 3 and forms a whole with the concrete 3, and the anti-seepage layer is applied around the bottom and outside of the concrete part of the impermeable sample;

2. Place the bonded anti-seepage sample in the outer steel mold 2, and fix it on the water pressure chamber 7 of the anti-seepage instrument 6 through the rubber washer 4 with fastening bolts 5, so that the bonded anti-seepage sample and the anti-seepage instrument The water pressure chamber 7 of 6 is impervious to water, and the water pressure chamber 7 communicates with the water inlet 8 at one end of the anti-seepage instrument 6;

3. Apply water pressure from the water inlet 8 of the anti-seepage meter 6. The water pressure starts from 0.1MPa, and increases step by step at intervals of 0.1MPa at regular intervals until the surface of the bonded anti-seepage sample exits. The grade water pressure is the impermeability strength of the interface between the concrete and the sealing material.

The above sealing materials can be liquid or paste polyurethane sealant, polysulfide sealant, acrylic building sealant, silicone building sealant, fly ash synthetic channel joint anti-seepage material and other sealants for concrete bonding any of these glues.

The above-mentioned polyurethane sealant (paste), polysulfide sealant (paste), acrylic building sealant and silicone Sealants", JC/T484-2006 "Acrylic Building Sealants", GB/T14683-2003 "Silicon Building Sealants" stipulated in the technical standards.

Fly ash synthetic channel joint anti-seepage material is a material that has obtained a national invention patent. The patent number is ZL 200310118992.X. JC/T881-2001 "Concrete Building Joint Sealant" requires various technical standards.

The bonding interface between the concrete 3 and the sealant can be coated with a primer or not treated, depending on the actual situation of the simulated project and the specific purpose of the test.

The concrete of the bonded sample can simulate any type of concrete with any strength level in the actual project.

Both the concrete bottom and the outside of the concrete impervious specimens need to be coated with an anti-seepage layer. The anti-seepage layer can be liquid paraffin or butter cement mixture, etc., to ensure that the bonding interface between sealant and concrete is the only channel for pressure water.

This method can also be extended to the test of the bonding properties of sealant and mortar, sealant and solidified soil, etc.

The specific preparation method of the concrete impermeability sample is: put the concrete mixture into the impermeability test mold that can be released freely, insert a hard object such as a wooden board or a steel plate with the same width as the expansion joint in the middle, and wait until the concrete is finally set. Finally, carefully take out the wooden board or steel plate to form a cavity with the same size as the expansion joint. Put the concrete sample in an environment with a relative humidity of 95% or more at 20±2°C for 24 hours, then demould it, and then place it at 20±2°C. ℃, the relative humidity of 95% or more will reach the standard strength of concrete after curing for 27 days. Pour the sealant into the gap cavity left in the middle of the concrete, so that the concrete and the sealant become a bonded sample as a whole, and make a conical concrete anti-seepage test whose size matches the size of the water pressure chamber on the impermeability tester. After curing for 28 days in an environment of 20±2°C and relative humidity of 65±5%, apply an anti-seepage layer evenly on the concrete bottom and side walls of the sample. The anti-seepage layer can be liquid paraffin or butter cement mixture, etc. , so that the interface between concrete and sealant becomes the only water outlet path under high water pressure.

Claims (3)

1. the method for testing of encapsulant and concrete bonding sample interface anti-permeability performance is characterized in that, comprises the following steps:

1) the impervious sample of at first preparation bonding, this impervious sample that bonds is round table-like, make by concrete and encapsulant, encapsulant is positioned at concrete centre, encapsulant and concrete tight bond, form an integral body, smear impervious barrier around the bottom of the impervious sample concrete part that bonds and the outside;

The impervious sample of described bonding prepares by the following method:

A, with concrete mix and stir material pack into can the free demoulding impervious die trial in, plank or the steel plate with the expansion joint size equal wide of staying inserted at the middle part, treat carefully plank or steel plate to be taken out after the concrete final set, form and measure-alike seam chamber, expansion joint, concrete sample is placed on 20 ± 2 ℃, maintenance demoulding after 24 hours in the environment of relative humidity more than 95% is placed on 20 ± 2 ℃ again, and maintenance reaches concrete standard intensity in the environment of relative humidity more than 95% after 27 days;

In B, the seam chamber that encapsulant penetration concrete middle part is stayed, make concrete and encapsulant become a bonding sample integral body, make be of a size of with Anti-leakage instrument on the concrete impervious sample of circular platform type that is complementary of water pressure chamber size, be placed on 20 ± 2 ℃, maintenance was evenly smeared impervious barrier with the bottom and the limit wall of impervious sample concrete part after 28 days in the environment of relative humidity 65 ± 5%;

2) the impervious sample that will bond places in the overcoat punching block, is fixed in by rubber washer on the water pressure chamber of Anti-leakage instrument, makes between the water pressure chamber of bonding sample and Anti-leakage instrument waterproofly, and this water pressure chamber is communicated with the water inlet of Anti-leakage instrument one end;

3) water inlet from Anti-leakage instrument applies hydraulic pressure, water pressure is from 0.1MPa, strengthen step by step with the interval of 0.1MPa at regular intervals, till the impervious specimen surface water outlet of bonding, the previous stage water pressure is the anti-permeability strength at concrete impervious sample and encapsulant interface.

2. the method for claim 1, it is characterized in that, described encapsulant be liquid state or paste polyurethane sealant, polysulfide sealant, acrylate construction sealant, silicone building sealant, fly ash synthesized channel joint impervious material wherein any.

3. method as claimed in claim 1 or 2 is characterized in that, described impervious barrier is whiteruss or butter cement mix, to guarantee that encapsulant and concrete binding interface are unique passages of press water.

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