CN113654986B - Specimen forming device and method for evaluating the interface bonding properties between resin-based cementitious materials and aggregates - Google Patents

Abstract

The invention provides a test piece forming device and method for evaluating the interface bonding performance between resin binder and aggregate. The test piece forming device is prepared from non-adhesive silicone rubber, and includes a collective end forming die and an integral test piece forming die. The test piece forming device and method provided by the invention are simple to operate and easy to popularize; the irregular-shaped aggregate is embedded in the resin-based cementitious material, and the aggregate with a plane is obtained by cutting, and the drawing strength and shearing strength are adopted. Strength evaluation of interfacial bond strength, effectively solving the problem that it is difficult to quantitatively evaluate the interfacial bond strength between resin binders and aggregates due to the irregular shape of aggregates; the obtained aggregate plane can be textured as required , to study the influence law and mechanism of different types of aggregate surface texture on the interface bond strength between resin binder and aggregate. The present invention is not only applicable to resin cementing materials such as polyurethane and epoxy resin, but also applicable to epoxy asphalt cementing materials.

Description

Specimen forming device and method for evaluating the interface bonding performance between resin-based cement and aggregate

technical field

The invention relates to a test piece forming device and method for evaluating the interface bonding performance between resin-based cementitious materials and aggregates, and belongs to the technical field of road engineering materials.

Background technique

With the continuous improvement of people's living standards, people's requirements for travel quality have also increased accordingly. The road surface is not only satisfied with the use requirements, but also develops towards good road performance and intelligent transportation. On the other hand, the traditional asphalt pavement Insufficient long-term performance, large carbon emissions and non-renewable asphalt, a new type of pavement material with high environmental protection and high durability is urgently needed. In recent years, with the continuous development of pavement engineering technology, new pavement pavement materials continue to emerge. As a highly designable room temperature curing polymer, polyurethane has excellent adhesion, flexibility, weather resistance, corrosion resistance, wear resistance, shock resistance and other properties, and has become a substitute for traditional asphalt binders. The first choice for new polymer binders, such as the widely used polyurethane light-duty pavement (park roads, landscape roads, sidewalks), and urban road polyurethane permeable pavement, polyurethane bridge deck pavement, polyurethane Airport pavement, etc.

However, similar to traditional asphalt pavement materials, it is difficult to quantitatively evaluate the interfacial bond strength between binder and aggregate in the new polyurethane pavement material due to the irregularity of aggregate appearance and shape. In the prior art, the adhesion between asphalt and aggregates is generally evaluated by the boiling method and the water immersion method. However, these two methods are greatly influenced by human subjectiveness, and can only be evaluated qualitatively; on the other hand, the new polyurethane Pavement pavement materials cannot evaluate the bonding properties between cementitious materials and aggregates according to the specifications of asphalt pavement due to the inherent characteristics of polyurethane. Therefore, for new polyurethane pavement materials (even including traditional asphalt pavement materials), it is urgent to propose an effective quantitative evaluation method for the interface bond strength between cementitious materials and aggregates, and to design a corresponding test method. Piece forming device.

SUMMARY OF THE INVENTION

In order to solve the technical problem that the quantitative evaluation of the interface bonding strength between the binder and the aggregate mentioned in the above background technology is difficult, the present invention proposes a test piece molding for evaluating the interface bonding performance between the resin binder and the aggregate. device and method.

The present invention provides a test piece forming device and method for evaluating the interface bonding performance between resin-based cementitious materials and aggregates, including an aggregate end forming die and an integral test piece forming die. lumen, where n ≥ 2,

The inner cavity of the collecting end forming mold includes two resin cavities and one collecting cavity, and resin cavities are installed on both sides of the collecting cavity, and the inner cavity of the integral test piece forming mold includes the collecting end cavity and the Resin end cavity.

Preferably, the aggregate end forming mold and the integral test piece forming mold are prepared from silicone rubber.

Preferably, the resin cavity and the collection cavity are both rectangular parallelepipeds, and the cross-sectional area of the collection cavity is larger than the cross-sectional area of the resin cavity.

Preferably, the bottom surfaces of the resin cavities with different cross-sections and the aggregate cavities are on the same plane, and the centerlines of the bottom surfaces are on the same straight line, the three cavities are closely connected longitudinally, the upper surfaces of the aggregate cavities are open, and the centerlines of the upper surfaces of the two resin cavities Slit.

Preferably, the cross-sectional dimensions of the aggregate end cavity and the resin end cavity are different, the aggregate end cavity is a cuboid, the resin end cavity is a cuboid or a cylinder, and the cross-sectional area of the aggregate end cavity is larger than the resin end cavity cross-sectional area.

Preferably, the cross-sectional centers of the aggregate end cavity and the resin end cavity are on the same straight line, the two cavities are closely connected longitudinally, both the upper surface and the side surface of the aggregate end cavity are open, and the side surface of the resin end cavity is open.

A test piece forming method using the described test piece forming device for evaluating the interface bonding performance between resin binder and aggregate, specifically comprising the following steps:

1. Place the aggregate to be tested in the aggregate cavity of the horizontally placed aggregate forming mold, then pour the prepared resin glue into the aggregate cavity, and the glue will automatically flow into the resin cavities on both sides until the liquid level meets the The upper surface of the aggregate cavity is flush, and the No. 1 specimen is taken out after curing at room temperature;

2. Cut the No. 1 specimen into two evenly in half horizontally from the aggregate to obtain two No. 2 specimens. It is necessary to ensure that the cross-section of the aggregate end is aggregate and does not contain resin binder. Then, the No. 2 specimen is cut. The protruding part of the aggregate end is cut off, so that the cross-sectional size of the entire specimen is consistent with the cross-sectional size of the aggregate cavity, and the No. 3 specimen is obtained;

3. Place the No. 3 test piece in the aggregate end cavity of the overall test piece forming mold and fix it. The aggregate end of the No. 3 test piece is close to the resin end cavity, and then place the mold sideways so that the end face of the resin end cavity is open. Face up, pour the prepared resin glue into the resin end cavity until the liquid level is flush with the end surface of the resin end cavity, and take out the No. 4 test piece after curing at room temperature;

4. Use a wallpaper knife to remove the excess resin binder that may exist at the interface between the aggregate end and the resin end of the No. 4 specimen, to ensure that the interface size is the cross-sectional size of the resin end cavity, and to improve the accuracy of the interface bond strength test. A test specimen for the interface bond strength between the resin binder and the aggregate was obtained.

Preferably, the resin glue is polyurethane, epoxy resin or epoxy asphalt.

Preferably, the aggregate is basalt, granite, limestone or andesite, and its particle size is slightly smaller than the minimum side length of the aggregate cavity 5 .

Preferably, the interface bond strength between the resin-based cementitious material and the aggregate adopts the tensile strength and the shear strength as evaluation indicators.

The beneficial effects of the test piece forming device and method for evaluating the interface bonding performance between resin binder and aggregate according to the present invention are:

1. The present invention embeds the irregular-shaped aggregate into the resin-based cementitious material, and obtains the aggregate with a flat surface by cutting, which solves the difficulty in quantitatively evaluating the resin-based cementitious material due to the irregular shape of the aggregate. The problem of interfacial bond strength with aggregates.

2. In the present invention, the obtained aggregate plane can be textured according to needs, and the influence rule and mechanism of different types of aggregate surface texture on the interface bond strength between resin binder and aggregate can be studied.

3. The test piece forming device for testing the interface bond strength between the resin-based cementitious material and the aggregate according to the present invention is easy to process, and the described test piece forming method is simple to operate and easy to popularize.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

In the attached image:

Figure 1 is a side view of the aggregate end forming die;

Figure 2 is a front view of the aggregate end forming die;

Figure 3 is a top view of the aggregate end forming die;

Figure 4 is a schematic diagram of the internal cavity structure of the aggregate end forming die;

Figure 5 is a front view of the inner cavity of the aggregate end forming die;

Figure 6 is a top view of the inner cavity of the aggregate end forming die;

Fig. 7 is the side view of the integral test piece forming mold (resin end cavity section is square);

Fig. 8 is the front view of the integral test piece forming mold (resin end cavity section is square);

Fig. 9 is the top view of integral test piece forming mold (resin end cavity section is square);

Figure 10 is a schematic diagram of the internal cavity of the integral test piece forming mold (the resin end cavity cross-section is square);

Figure 11 is a schematic diagram of a test specimen for the interface bond strength between the resin-based cementitious material and the aggregate (the cross-section of the resin end cavity is a square);

Figure 12 is a side view of Figure 11;

Figure 13 is a side view of the integral test piece forming mold (the resin end cavity cross-section is circular);

Figure 14 is a front view of the integral test piece forming mold (the cross section of the resin end cavity is circular);

Figure 15 is a top view of an integral test piece forming mold (the cross section of the resin end cavity is circular);

Figure 16 is a schematic diagram of the internal cavity of the integral test piece forming mold (the cross section of the resin end cavity is circular);

17 is a schematic diagram of a test specimen for the interface bond strength between resin-based cementitious materials and aggregates (the cross-section of the resin end cavity is circular);

Figure 18 is a side view of Figure 17;

Figure 19 is a schematic diagram of the test method for the tensile bond strength of the interface between the resin-based cementitious material and the aggregate;

Figure 20 is a schematic diagram of the test method for the shear bond strength of the interface between the resin-based cementitious material and the aggregate;

Among them, 1- No. 1 resin binder, 2- aggregate, 3- No. 2 resin binder, 4- resin cavity, 5- aggregate cavity, 6- aggregate end cavity, 7- resin end cavity.

Detailed ways

The specific embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings:

Embodiment 1: This embodiment is described with reference to FIGS. 1-20 . The test piece forming device and method for evaluating the interface bonding performance between resin binder and aggregate described in this embodiment includes an aggregate end forming die and an integral test piece forming die, each of which contains n equal-sized pieces. The lumen of , where n ≥ 2,

The inner cavity of the collecting end forming mold includes two resin cavities 4 and one collecting cavity 5. The resin cavities 4 are installed on both sides of the collecting cavity 5. The inner cavity of the integral test piece forming mold includes a collecting cavity. Material end cavity 6 and resin end cavity 7.

The aggregate end forming die and the integral test piece forming die are prepared from silicone rubber.

The inner cavity of the aggregate end forming mold is formed by connecting 3 cuboids with different cross-sectional sizes, namely two resin cavities 4 and one aggregate cavity 5, and their dimensions (length, width and height) from left to right are 70mm× 10mm×10mm, 20mm×20mm×13mm, 70mm×10mm×10mm, the bottom surfaces of resin cavity 4 and aggregate cavity 5 with different cross-sections are on the same plane, and the center line of the bottom surface is on the same straight line, and the three cavities are closely connected longitudinally. , the upper surface of the collecting cavity 5 is open, and the upper surface of the two resin cavities 4 is slit.

The inner cavity of the integral specimen forming mold is formed by connecting cuboids and cuboids (or cylinders) with different cross-sectional dimensions, named as the aggregate end cavity 6 and the resin end cavity 7 respectively. From left to right are 80mm×10mm×10mm, 80mm×6mm×6mm (or 80mm×φ6mm), the cross-sectional centers of the aggregate end cavity 6 and the resin end cavity 7 are on the same straight line, and the two cavities are longitudinally close to each other. Then, the upper surface and the side surface of the aggregate end cavity 6 are open, and the side surface of the resin end cavity 7 is open.

The aggregate is basalt, granite, limestone or andesite with a particle size between 10mm and 13mm (the particle shape is as close to a cube as possible).

The forming methods of the aggregate end forming die and the integral test piece forming die are as follows:

1) Put a large enough PTFE film (300mm×400mm) on the test bench, and then put a steel mold with an inner cavity size of 200mm×150mm×20mm, and place several steel standard test pieces in the mold cavity. Its size is consistent with the internal cavity of the aggregate end forming die or the internal cavity of the integral test piece forming die.

2) Weigh about 800g of silicone rubber in a beaker, add an appropriate amount of curing agent (2% to 3% of the mass of the silicone rubber), stir evenly with a glass rod, and pour it into the mold cavity.

3) Cover the mold cavity with polytetrafluoroethylene film, then cover it with a glass plate, press a heavy object to flatten it, and remove the mold after 1 day to obtain an aggregate end forming mold or an integral specimen forming mold.

The present invention is not only suitable for resin cementing materials such as polyurethane and epoxy resin, but also for epoxy asphalt cementing materials.

Adopt the following examples to verify the beneficial effects of the present invention:

Example 1:

A test piece forming device and method for evaluating the interface bonding performance between resin-based cementitious materials and aggregates. The sub-type is Elastocoast C 6551C-B), and the aggregates are ordinary basalt aggregates with a particle size between 10mm and 13mm. :

The test piece forming device is described as follows: The test piece forming device is made of non-adhesive silicone rubber, and includes two molds, which are the aggregate end forming mold and the overall test piece forming mold. The molds contain 4 and 6 molds respectively. same size lumen. As shown in Fig. 3 to Fig. 6, the inner cavity of the aggregate end forming mold is formed by connecting three resin cavities 4, aggregate cavities 5 and resin cavities 4 with different cross-sectional sizes, and the dimensions (length, width and height) from left to On the right are 70mm×10mm×10mm, 20mm×20mm×13mm, 70mm×10mm×10mm, the bottom surfaces of the cavities with different cross-sections are on the same plane, and the centerlines of the bottom surfaces are on the same straight line, and the three cavities are closely connected longitudinally. The upper surface of the material cavity 5 is open, and the upper surface of the two resin cavities 4 is slit on the center line; as shown in Figures 7 to 10, the inner cavity of the integral specimen forming mold consists of an aggregate end cavity 6 and a resin end cavity 7 with different cross-sectional sizes. The dimensions (length, width and height) from left to right are 80mm×10mm×10mm and 80mm×6mm×6mm respectively. The cross-sectional centers of different cavities are on the same line, and the two cavities are closely connected longitudinally. Both the upper surface and the side surface of the material end cavity 6 are open, and the side surface of the resin end cavity 7 is open.

The preparation steps of the test piece forming device are as follows:

Put a large enough PTFE film (300mm × 400mm) on the test bench, and then put a steel mold with an inner cavity size of 200mm × 150mm × 20mm, and place a number of steel standard test pieces in the mold cavity. It is the same size as the internal cavity of the aggregate end forming mold (as shown in Figure 4 to Figure 6) or the internal cavity of the integral specimen forming mold (as shown in Figure 4 to Figure 6); weigh 800g of silicone rubber in a beaker, add 2.5 % by mass of the curing agent, stir evenly with a glass rod and pour it into the mold cavity; cover the mold cavity with a polytetrafluoroethylene film, then cover it with a glass plate, press a heavy object to flatten it, and remove the mold after 1 day The aggregate end forming die or the integral specimen forming die can be obtained.

The molding method of the test specimen for the interface bond strength between the resin binder and the aggregate is as follows:

(1) Place the aggregate of suitable size in the aggregate cavity 5 of the horizontally placed aggregate forming mold, and then add the prepared polyurethane glue (the mass ratio of the polyol component to the isocyanate component is 100:65) Pour into the aggregate chamber 5, and the glue liquid automatically flows into the resin chamber 4 on both sides until the liquid level is flush with the upper surface of the aggregate chamber 5. After curing at room temperature for 2 days, take out the No. 1 specimen;

(2) Cut the No. 1 specimen into two evenly in half horizontally from the aggregate to obtain two No. 2 specimens. It is necessary to ensure that the cross-sections of the aggregate ends are aggregates and do not contain resin binders. Then the No. 2 specimens are cut. The protruding part of the aggregate end of the specimen is cut off, so that the cross-sectional dimension of the entire specimen is consistent with the cross-sectional dimension of the aggregate cavity 5, and the No. 3 specimen is obtained;

(3) Place the No. 3 test piece in the aggregate end cavity 6 of the overall test piece forming mold and fix it with a transparent tape. With the end face of the resin end cavity 7 facing upward, pour the prepared polyurethane glue into the resin end cavity 7 until the liquid level is flush with the end face of the resin end cavity 7, and then take out the No. 4 test piece after curing at a constant temperature of 25 °C for 7 days;

(4) Use a wallpaper knife to remove the excess resin binder that may exist at the interface between the aggregate end and the resin end of the No. 4 specimen to ensure that the interface size is 6mm × 6mm, and finally obtain the interface between the resin binder and the aggregate. Knot Strength Test Specimen.

The interface bond strength test between resin binder and aggregate is as follows: The tensile strength and shear strength were tested with a universal mechanical testing machine (WDW-100E) produced by Jinan Times Assay Testing Machine Co., Ltd. at a loading rate of 2 mm/min. In the test, the tensile strength and shear strength of the polyurethane-aggregate interface are about 8.27MPa±0.76MPa and 10.48MPa±1.68MPa, respectively, and the failure modes are interface failure.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention, and may also be a reasonable combination of the features recorded in the above-mentioned various embodiments, all within the spirit and principle of the present invention, Any modification, equivalent replacement, improvement, etc. made should be included within the protection scope of the present invention.

Claims (9)

1. a test piece forming method for evaluating the interface bonding performance between resin binder and aggregate, is characterized in that, specifically comprises the following steps: 1. Place the aggregate to be tested in the aggregate cavity (5) of the horizontally placed aggregate forming mold, then pour the prepared resin glue into the aggregate cavity (5), and the glue will automatically flow into the resin on both sides cavity (4) until the liquid level is flush with the upper surface of the aggregate cavity (5), and after curing and forming at room temperature, take out the No. 1 specimen; 2. Cut the No. 1 specimen into two evenly in half horizontally from the aggregate to obtain two No. 2 specimens. It is necessary to ensure that the cross-section of the aggregate end is aggregate and does not contain resin binder. Then, the No. 2 specimen is cut. The protruding part of the end of the aggregate is cut off, so that the cross-sectional dimension of the entire specimen is consistent with the cross-sectional dimension of the aggregate cavity (5), and the No. 3 specimen is obtained; 3. Place the No. 3 specimen in the aggregate end cavity (6) of the overall specimen forming mold and fix it. The aggregate end of the No. 3 specimen is close to the resin end cavity (7), and then place the mold sideways. Make the end face of the resin end cavity (7) face up, pour the prepared resin glue into the resin end cavity (7) until the liquid level is flush with the end face of the resin end cavity (7), and take out the No. 4 after curing at room temperature. Specimen; 4. Use a wallpaper knife to remove the excess resin binder that may exist at the interface between the aggregate end and the resin end of the No. 4 specimen, to ensure that the interface size is the cross-sectional dimension of the resin end cavity (7), and to improve the accuracy of the interface bond strength test. Finally, a test specimen for the interface bond strength between the resin binder and the aggregate was obtained; The test piece forming method used in the test piece forming method for evaluating the interface bonding performance between resin binder and aggregate includes an aggregate end forming die and an integral test piece forming die, each of which contains n inner diameters of the same size. cavity, where n ≥ 2, The inner cavity of the collecting end forming mold includes two resin cavities (4) and one collecting cavity (5), and resin cavities (4) are installed on both sides of the collecting cavity (5). The inner cavity of the piece forming mold includes an aggregate end cavity (6) and a resin end cavity (7). 2. The test piece forming method for evaluating the interface bonding performance between resin binder and aggregate according to claim 1, is characterized in that, described aggregate end forming die and integral test piece forming die are made of silicone rubber. prepared. 3. The test piece molding method for evaluating the interface bonding performance between resin binder and aggregate according to claim 1, wherein the resin cavity (4) and the aggregate cavity (5) are both cuboid, and the cross-sectional area of the aggregate cavity (5) is larger than the cross-sectional area of the resin cavity (4). 4. The test piece molding method for evaluating the interface bonding performance between resin binder and aggregate according to claim 1, characterized in that the resin cavity (4) and the aggregate cavity (5) of different cross-sections The bottom surfaces are on the same plane, and the center lines of the bottom surfaces are on the same straight line, the three cavities are closely connected longitudinally, the upper surface of the collecting cavity (5) is open, and the upper surfaces of the two resin cavities (4) have slits on the center lines. 5. The test piece molding method for evaluating the interface bonding performance between resin binder and aggregate according to claim 1, characterized in that the aggregate end cavity (6) and the resin end cavity (7) The cross-sectional dimensions are different, the aggregate end cavity (6) is a cuboid, the resin end cavity (7) is a cuboid or a cylinder, and the cross-sectional area of the aggregate end cavity (6) is larger than that of the resin end cavity (7). Sectional area. 6. The test piece molding method for evaluating the interface bonding performance between resin binder and aggregate according to claim 1, characterized in that the aggregate end cavity (6) and the resin end cavity (7) The center of the cross-section is on the same straight line, the two cavities are closely connected longitudinally, the upper surface and the side of the aggregate end cavity (6) are open, and the side of the resin end cavity (7) is open. 7 . The test piece molding method for evaluating the interface bonding performance between resin-based cementitious materials and aggregates according to claim 1 , wherein the resin glue is polyurethane, epoxy resin or epoxy asphalt. 8 . 8. The test piece forming method for evaluating the interface bonding performance between resin binder and aggregate according to claim 1, wherein the aggregate is basalt, granite, limestone or andesite, and its particle size is basalt, granite, limestone or andesite. The size is slightly smaller than the minimum side length of the aggregate cavity (5). 9. The test piece molding method for evaluating the interface bonding performance between the resin-based cementitious material and the aggregate according to claim 1, wherein the interface bonding strength between the resin-based cementitious material and the aggregate adopts the tensile strength and shear strength as evaluation indicators.

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