Detection method for detecting bonding bending strength and flexibility of mortar

Abstract

The invention relates to a detection method for detecting bonding bending strength and flexibility of mortar. The detection method comprises the following steps: preparing reference mortar to form a basic sample block; equally dividing the basic sample block into two parts along the middle line of the long side of the basic sample block to obtain a sample block blank; placing the sample block blank on one side of a cement mortar test mold to prepare adhesive mortar, pouring the adhesive mortar into the other side of the cement mortar test mold, leveling, standing, and demolding to obtain a cement mortar sample; enabling a bonding surface between the basic sample block and the bonding mortar to be positioned under a compression head of a compression testing machine, and starting the compression testing machine to load at a uniform rate until the cement mortar sample is broken; observing whether the fracture surface is on the cutting surface of the sample block blank, and if not, rejecting the fracture surface to test again; and calculating the bonding bending strength and flexibility of the mortar. According to the detection method for detecting the bonding bending strength and the flexibility of the mortar, the bonding bending strength and the flexibility of the mortar can be efficiently and accurately detected.

Description

Technical Field

[0001] The present application relates to the technical field of mortar performance testing, and in particular to a testing method for testing mortar bonding bending strength and flexibility. Background Art

[0002] Mortar is a widely used bulk building material, which is made of inorganic cementitious materials, various polymer materials and fillers through a unique process. With the increase of application scenarios and functional requirements, mortar is divided into masonry mortar, plaster mortar, waterproof mortar, bonding mortar, interface mortar, repair mortar, etc. However, no matter how it changes, bonding performance as an important indicator has corresponding requirements in most products. Among them, GB / T25181-2019 "Premixed Mortar" puts forward clear requirements for tensile bonding strength.

[0003] The compatibility of materials refers to the common properties of the interaction between the bonding mortar and the substrate. It ensures that the bonding material can be exposed to a specific environment and can still resist the applied stress to maintain the integrity and protection of the structure when it exceeds the designed service life. The damage of building materials is closely related to their design, actual materials, construction technology, construction quality, post-completion use, and the external environment in which they are located. It is a process from quantitative change to qualitative change. However, whether it is the environment formed inside the material system or the effect of the external environment, the performance of the material plays a key role in the damage. How to effectively characterize the performance of the material is particularly important for improving the application of the material.

[0004] At present, the main characterization form of mortar bonding performance is the index of positive tensile bond strength. Although the positive tensile bond strength reflects the bonding performance of the material to a certain extent, due to the differences in chemical composition and structure between the bonding material and the inorganic substrate, there is a large compatibility difference between the two. In the actual service process of the product, there are multiple influences of all-directional forces, especially flexibility and vertical bonding bending performance, which can also reflect the comprehensive bonding performance of the mortar from the side, but there is no mature testing method on the market to test the bonding bending strength and flexibility of the mortar. Summary of the invention

[0005] The present application provides a method for detecting the mortar bonding bending strength and flexibility to improve the following technical problems:

[0006] Due to the differences in chemical composition and structure between the bonding material and the inorganic substrate, there is a large compatibility difference between the two. In the actual service process of the product, there are multiple influences of all-directional forces, especially flexibility and vertical bonding bending performance, which can also reflect the comprehensive bonding performance of the mortar from the side. However, there is no mature testing method on the market to test the bonding bending strength and flexibility of the mortar.

[0007] The present application provides a method for detecting the mortar bonding bending strength and flexibility, which adopts the following technical solution:

[0008] A method for detecting mortar bonding bending strength and flexibility comprises the following steps:

[0009] Step 1: Use cement, sand and water as raw materials to prepare a reference mortar, put it into a mortar forming test mold and let it stand to form a basic specimen block, and then put the basic specimen block into a mortar specimen curing test box for curing;

[0010] Step 2: After the basic sample block reaches the specified age, the basic sample block is divided into two parts along the midline of the long side of the basic sample block by a cutting machine to obtain a sample block blank, and the cut surface of the sample block blank is polished and smoothed for standby use;

[0011] Step 3: Soak the sample block in water and then take it out, wipe the outer surface of the sample block with a wet cloth, and then place the sample block on one side of the cement mortar test mold, prepare the bonding mortar according to the ratio provided by the product manufacturer, pour the bonding mortar into the other side of the cement mortar test mold, scrape it flat, let it stand, and then demould it, and cure it to the specified age to obtain a cement mortar sample;

[0012] Step 4: Determine the actual width w and thickness d of the cement mortar sample, place the cement mortar sample on the compression tester, make the bonding surface between the base sample block and the bonding mortar directly below the compression head of the compression tester, wherein the cement mortar sample is horizontally placed on two lower support fixtures, and the distance between the support points of the two lower support fixtures is L, then start the compression tester to load at a uniform rate until the cement mortar sample breaks, and read the maximum fracture force value F and the displacement value M from the beginning of compression to fracture on the compression tester;

[0013] Step 5: Remove the cement mortar sample and observe whether the fracture surface is at the cutting surface of the sample block blank. If not, discard it and retest it until the fracture surface is at the cutting surface of the sample block blank.

[0014] Step 6: Calculate the bonding bending strength S of the mortar according to the following formula: (3×F×L) / (2×w×d2), and calculate the flexibility σ of the mortar according to the following formula: M / L×100%.

[0015] In a feasible technical solution of the present application, in step 1, the mass ratio of cement, sand and water is 1:2-4:0.4-0.6, and the standing time is at least 1 hour.

[0016] In an achievable technical solution of the present application, in step one, the cement is 42.5 grade cement in accordance with the current national standard GB175, the sand is standard sand in accordance with Chinese ISO, and the water is grade 3 water in accordance with the current national standard GB / T 6682.

[0017] In an achievable technical solution of the present application, in step 2, the cut surface is polished using No. 150 sandpaper, No. 180 sandpaper, No. 200 sandpaper or No. 220 sandpaper.

[0018] In a feasible technical solution of the present application, in step three, the sample block blank is immersed in water for 23 to 25 hours, and is left to stand for at least 1 hour after being scraped and leveled.

[0019] In an achievable technical solution of the present application, in step 2 and step 3, the prescribed age is 28 days, 35 days or 42 days.

[0020] In an achievable technical solution of the present application, the size of the basic sample block is 15 mm×60 mm×400 mm, and the size of the sample block blank is 15 mm×60 mm×400 mm.

[0021] In a feasible technical solution of the present application, in step 4, the uniform rate loading of the compression testing machine is 0.8 to 1.2 KN per second.

[0022] In an achievable technical solution of the present application, in step one, before adding the reference mortar into the mortar forming test mold, it is necessary to apply engine oil or a release agent to the inner wall of the mortar forming test mold; in step three, before placing the sample block blank into the cement mortar test mold, it is necessary to apply engine oil or a release agent to the inner wall of the cement mortar test mold.

[0023] In an achievable technical solution of the present application, in step four, the compression head of the compression testing machine is a spherical structure, and the top of the lower supporting fixture is provided with a spherical supporting portion for abutting the lower surface of the cement mortar sample.

[0024] In summary, the present application includes at least one of the following beneficial technical effects:

[0025] The detection method is highly operational, accurate and stable, and can truly reflect the bonding bending strength and flexibility of the mortar during actual service. It can be combined with the common forward tensile bonding strength to further comprehensively reflect the bonding performance of the mortar. Two other characterization methods of the mortar bonding performance are proposed: bonding bending strength and flexibility, which provide an important basis for product design and performance improvement. It can adapt to the sizes of different products to be tested, thereby adapting to the bending bonding performance and flexibility of materials under different environmental conditions. It has good adaptability to different types of substrates. Different application scenarios often appear in actual engineering, and the detection method of the present application is not prone to poor adaptability to different types of construction substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 It is a schematic structural diagram of the folding head and the lower supporting fixture of the compression testing machine in the embodiment of the present application.

[0028] Description of reference numerals:

[0029] 100, cement mortar specimen; 11, cutting surface; 200, folding head; 300, lower supporting fixture. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0031] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0032] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0034] The following is combined with Figure 1 This application is described in further detail.

[0035] The present application embodiment discloses a method for detecting the mortar bonding bending strength and flexibility. Figure 1 A method for detecting the mortar bonding bending strength and flexibility comprises the following steps:

[0036] Step 1: Use cement, sand and water as raw materials to prepare a reference mortar, wherein the mass ratio of cement, sand and water is 1:2-4:0.4-0.6, and the cement is 42.5 grade cement in accordance with the current national standard GB 175, the sand is standard sand in accordance with China ISO, and the water is grade 3 water in accordance with the current national standard GB / T 6682. Apply engine oil or mold release agent on the inner wall of the mortar forming test mold, put the reference mortar into the mortar forming test mold and let it stand to form a basic specimen block, wherein the standing time is 1 hour, and then put the basic specimen block into the mortar specimen curing test box for curing, wherein the size of the basic specimen block is 15 mm×60 mm×400 mm;

[0037] Step 2: After the basic sample block reaches the prescribed age, the prescribed age is 28 days (can be extended to 35 days or 42 days for special products), the basic sample block is divided into two parts along the long side center line of the basic sample block by a cutting machine to obtain a sample block blank, wherein the size of the sample block blank is 15mm×60mm×400mm, and the cut surface 11 of the sample block blank is polished and flat for standby use, and the cut surface 11 is polished with No. 200 sandpaper (No. 150 sandpaper, No. 180 sandpaper or No. 220 sandpaper can also be used);

[0038] Step 3: Soak the sample block blank in water and then take it out, wherein the soaking time is 23 to 25 hours, wipe the outer surface of the sample block blank with a wet cloth, apply engine oil or a release agent on the inner wall of the cement mortar test mold, and then place the sample block blank on one side of the cement mortar test mold, prepare the bonding mortar according to the ratio provided by the product manufacturer, pour the bonding mortar into the other side of the cement mortar test mold, scrape it flat, let it stand, and then demold it, wherein the standing time is 1 hour, and cure it to a specified age, which is 28 days (for special products, it can be extended to 35 days or 42 days), and obtain a cement mortar sample 100;

[0039] Step 4: Determine the actual width w and thickness d of the cement mortar sample 100, place the cement mortar sample 100 on the compression tester, make the bonding surface between the base sample block and the bonding mortar directly below the compression folding head 200 of the compression tester, wherein the cement mortar sample 100 is horizontally placed on two lower support fixtures 300, and the distance between the support points of the two lower support fixtures 300 is L, then start the compression tester to load at a uniform rate until the cement mortar sample 100 breaks, the uniform rate loading of the compression tester is 0.8 to 1.2 KN per second (preferably 1 KN per second), and read the maximum fracture force value F and the displacement value M from the beginning of compression to fracture on the compression tester;

[0040] Step 5: Remove the cement mortar sample 100 and observe whether the fracture surface is at the cutting surface 11 of the sample block blank. If not, discard it and retest until the fracture surface is at the cutting surface 11 of the sample block blank.

[0041] Step 6: Calculate the bonding bending strength S of the mortar according to the following formula: (3×F×L) / (2×w×d2), and calculate the flexibility σ of the mortar according to the following formula: M / L×100%.

[0042] In order to facilitate the accuracy of the measurement data, that is, to ensure that the force points of the cement mortar sample 100 in step four are all point contact, the compression head 200 of the compression testing machine is a spherical structure, and the top of the lower support fixture 300 is provided with a spherical support part for abutting the lower surface of the cement mortar sample 100.

[0043] The beneficial technical effects of a method for detecting mortar bonding bending strength and flexibility according to an embodiment of the present application are as follows:

[0044] The detection method is highly operational, accurate and stable, and can truly reflect the bonding bending strength and flexibility of the mortar during actual service. It can be combined with the common forward tensile bonding strength to further comprehensively reflect the bonding performance of the mortar. Two other characterization methods of the mortar bonding performance are proposed: bonding bending strength and flexibility, which provide an important basis for product design and performance improvement. It can adapt to the sizes of different products to be tested, thereby adapting to the bending bonding performance and flexibility of materials under different environmental conditions. It has good adaptability to different types of substrates. Different application scenarios often appear in actual engineering, and the detection method of the present application is not prone to poor adaptability to different types of construction substrates.

[0045] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the application should be included in the protection scope of the present application.

Claims

1. A method for testing the mortar bonding bending strength and flexibility, It is characterized in that The following steps are involved: Step 1: Use cement, sand and water as raw materials to prepare a reference mortar, put it into a mortar forming test mold and let it stand to form a basic specimen block, and then put the basic specimen block into a mortar specimen curing test box for curing; Step 2: After the basic sample block reaches the specified age, the basic sample block is divided into two parts along the midline of the long side of the basic sample block by a cutting machine to obtain a sample block blank, and the cut surface of the sample block blank is polished and smoothed for standby use; Step 3: Soak the sample block in water and then take it out, wipe the outer surface of the sample block with a wet cloth, and then place the sample block on one side of the cement mortar test mold, prepare the bonding mortar according to the ratio provided by the product manufacturer, pour the bonding mortar into the other side of the cement mortar test mold, scrape it flat, let it stand, and then demould it, and cure it to the specified age to obtain a cement mortar sample; Step 4: Determine the actual width w and thickness d of the cement mortar sample, place the cement mortar sample on the compression tester, make the bonding surface between the base sample block and the bonding mortar directly below the compression head of the compression tester, wherein the cement mortar sample is horizontally placed on two lower support fixtures, and the distance between the support points of the two lower support fixtures is L, then start the compression tester to load at a uniform rate until the cement mortar sample breaks, and read the maximum fracture force value F and the displacement value M from the beginning of compression to fracture on the compression tester; Step 5: Remove the cement mortar sample and observe whether the fracture surface is at the cutting surface of the sample block blank. If not, discard it and retest it until the fracture surface is at the cutting surface of the sample block blank. Step 6: Calculate the bonding bending strength S of the mortar according to the following formula: (3×F×L) / (2×w×d2), and calculate the flexibility σ of the mortar according to the following formula: M / L×100%.

2. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step 1, the mass ratio of cement, sand and water is 1:2-4:0.4-0.6, and the standing time is at least 1 hour.

3. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step 1, the cement is 42.5 grade cement in accordance with the current national standard GB 175, the sand is standard sand in accordance with Chinese ISO, and the water is grade 3 water in accordance with the current national standard GB / T 6682.

4. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step 2, the cut surface is polished using 150 grit sandpaper, 180 grit sandpaper, 200 grit sandpaper or 220 grit sandpaper.

5. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step 3, the sample block blank is immersed in water for 23 to 25 hours, and is left to stand for at least 1 hour after being scraped and leveled.

6. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step 2 and step 3, the prescribed age is 28 days, 35 days or 42 days.

7. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that The size of the basic sample block is 15mm×60mm×400mm, and the size of the sample block blank is 15mm×60mm×400mm.

8. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step 4, the uniform rate loading of the compression testing machine is 0.8 to 1.2 kN per second.

9. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step one, before adding the reference mortar into the mortar forming test mold, it is necessary to apply engine oil or a release agent to the inner wall of the mortar forming test mold; in step three, before placing the sample block blank into the cement mortar test mold, it is necessary to apply engine oil or a release agent to the inner wall of the cement mortar test mold.

10. A method for detecting mortar bonding bending strength and flexibility according to claim 1, It is characterized in that In step 4, the compression head of the compression testing machine is a spherical structure, and the top of the lower support fixture is provided with a spherical support portion for abutting the lower surface of the cement mortar sample.

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