Testing method for thickness of structural layer of decorated floor and thickness of protective layer of upper steel bar

Abstract

The present invention discloses a method for detecting the thickness of the structural layer of a decorated floor slab and the thickness of the protective layer of the upper row of steel bars. The floor slab comprises a decorative layer, a leveling layer, a structural layer, a putty layer and a coating layer from top to bottom. First, the measuring point position is determined on the floor slab, and the coating layer and the putty layer are removed to expose the original slurry surface of the structural layer. An array ultrasonic imager is used to detect on the original slurry surface to obtain the thickness a of the structural layer. A floor slab thickness gauge is used to perform double-sided measurement on the original slurry surface and the surface of the decorative layer corresponding to it directly above to obtain the total thickness b. A steel bar scanner is used to detect the embedding depth c of the upper row of steel bars to the upper surface of the floor slab on the surface of the decorative layer corresponding to it directly above the original slurry surface. The protective layer thickness e of the upper row of steel bars in the floor slab is calculated by combining the thickness a, the total thickness b and the embedding depth c. The present invention can detect the thickness of the structural layer of the floor slab and the protective layer thickness of the upper row of steel bars when only the putty layer and the coating layer on the lower surface of the decorated floor slab are removed, and the damage is small and very easy to repair.

Description

Technical Field

[0001] The invention relates to the technical field of building structure detection, and in particular to a method for detecting the thickness of a structural layer of a decorated floor slab and the thickness of a protective layer of an upper row of steel bars. Background Art

[0002] When renovating or evaluating existing concrete buildings, it is necessary to find out the thickness of the structural layer of the concrete floor and the thickness of the protective layer of the upper row of steel bars in the floor, especially the thickness of the protective layer of the negative reinforcement of the upper row of steel bars, in order to calculate the bearing capacity of the components. However, for existing buildings, the decorated floor not only includes the reinforced concrete structural layer, but also has a leveling layer and a decorative layer on the upper part of the structural layer, and a putty layer and a paint layer or a decorative ceiling on the lower surface of the floor, which brings great difficulties to the detection of the thickness of the structural layer of the floor and the thickness of the protective layer of the upper row of steel bars.

[0003] When using a floor thickness gauge and a rebar scanner (or handheld radar) to detect a decorated floor, only the total thickness of the floor (the total thickness includes the decorative layer, leveling layer, structural layer, putty layer and paint layer from top to bottom) and the buried depth of the upper row of steel bars in the floor to the surface of the decorative layer can be obtained. These two parameters are meaningless for calculating the bearing capacity of the floor. If you want to find out the thickness of the structural layer of the concrete floor and the thickness of the protective layer of the upper row of steel bars, you need to use the damage method. Specifically, you need to first dig out a detection area on the upper surface of the floor that can accommodate the floor thickness gauge and rebar scanner equipment, and the decorative layer and leveling layer in the area must be chiseled off to expose the upper surface of the concrete structural layer. If you want to detect the protective layer thickness of multiple upper row steel bars, the digging range needs to be larger, and then the putty layer and paint layer on the lower surface of the floor are shoveled off to expose the lower surface of the concrete structural layer. Finally, use the floor thickness gauge and rebar scanner to detect and obtain the thickness of the structural layer and the thickness of the protective layer of the upper row of steel bars.

[0004] According to the survey, the above damage detection method is rejected by most house owners. Taking an existing building with an age of more than 15 years as an example, for the house owner, the materials used for the decorative layer on the upper surface of the floor slab may be marble, floor tiles or wooden floors. Once these decorative materials are damaged due to the detection work, they can no longer be bought in the current building materials market. There will be color differences even if they are repaired. In addition, if the house is used for daily operations, it will be forced to suspend business during the second renovation period, which will cause a lot of operating losses to the owner. For the putty layer, paint layer or ceiling decoration on the lower surface of the floor slab, its color is usually pure color, and in most cases it is pure white. The damage of scraping off the putty layer and paint layer or partially dismantling the ceiling is very small, and it is also very convenient to repair afterwards. There is no color difference after repair. Therefore, most house owners said that if the decoration on the lower surface of the floor slab is only slightly damaged, it is acceptable.

[0005] From the perspective of the structural composition of the decorated floor, to solve the problem of detecting the thickness of the floor structure layer, it is actually necessary to separate the floor structure layer from other structural layers, especially from the leveling layer. Therefore, we can start from the difference in the materials used in the structural layer and the leveling layer. The material used in the structural layer of the floor is concrete, and the material used in the leveling layer is usually cement mortar. One of the more obvious differences between the two materials is that cement mortar has more pores than concrete. This phenomenon is mainly due to the differences in composition, preparation method and use environment between cement mortar and concrete. Cement mortar is mainly composed of cement, fine aggregate (such as sand) and water, and sometimes lime, active admixtures or additives are added. Since the gaps between cement particles in cement mortar are large, if too much water is added, the gaps between cement particles will be larger, making it difficult for cement stone to reach a very dense level, thus forming more pores. In contrast, concrete is an artificial stone made of cementitious materials, granular aggregates (also called aggregates), water, and admixtures and admixtures added when necessary in a certain proportion. During the preparation of concrete, it is evenly mixed, vibrated and compacted into shape, and hardened after curing. The preparation process of concrete pays more attention to density and uniformity to reduce the formation of pores.

[0006] Judging from the layered structural characteristics of the core samples taken from the existing building slabs, it conforms to the above law. The concrete material of the structural layer is relatively dense, and the cement mortar of the leveling layer is porous and loose. How to make good use of this law and combine it with the existing non-destructive testing technology is the key to solving the problem. Ultrasonic testing is an important method in non-destructive testing technology. Ultrasonic waves can propagate normally in dense materials, but when encountering porous and loose materials, the energy of ultrasonic waves will quickly dissipate, making it difficult or even impossible to propagate. In addition, the development of array ultrasonic imaging technology in recent years has enabled the ultrasonic testing of concrete to leap from traditional double-sided testing to single-sided testing. This technology has been applied to the detection of defects on the joint surfaces of prefabricated building concrete composite components.

[0007] Therefore, combining array ultrasonic imaging technology and the differences in the propagation characteristics of ultrasonic waves in dense and porous materials can provide new ideas for solving the problem of detecting the thickness of the structural layer of decorated floors. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a method for detecting the thickness of the structural layer of a decorated floor and the thickness of the protective layer of the upper row of steel bars. The present invention can detect the thickness of the structural layer of the floor and the thickness of the protective layer of the upper row of steel bars by only scraping off the putty layer and the paint layer on the lower surface of the decorated floor.

[0009] In order to solve the above technical problems, the present invention provides a method for detecting the thickness of the structural layer of a decorated floor and the thickness of the protective layer of the upper row of steel bars. The floor comprises a decorative layer, a leveling layer, a structural layer, a putty layer and a coating layer from top to bottom. The material of the structural layer is concrete, and the structural layer contains a lower row of steel bars and an upper row of steel bars. The material of the leveling layer is cement mortar. The detection method comprises the following steps:

[0010] S1. First determine the measuring point on the floor slab, and scrape away the paint layer and putty layer on the lower surface of the floor slab corresponding to the measuring point to expose the original slurry surface of the structural layer;

[0011] S2. Use an array ultrasonic imager to perform detection on the original pulp surface, and obtain a waveform through the A-scan function of the array ultrasonic imager. The waveform uses the propagation distance of the ultrasonic wave in the measured material as the horizontal coordinate and the amplitude of the ultrasonic wave reflected in the measured material as the vertical coordinate. Use the B-scan function of the array ultrasonic imager to obtain a longitudinal section ultrasonic imaging diagram of the measuring point. The first red area displayed from top to bottom in the longitudinal section ultrasonic imaging diagram represents an echo reflection imaging of the ultrasonic wave at the interface between the structural layer and the leveling layer. Move the cursor line of the horizontal coordinate in the waveform diagram to the first red area, and then fine-tune the cursor line up and down to find the position with the largest amplitude of the ultrasonic wave reflection in the waveform diagram, and read the reading z of the horizontal coordinate at this time. The value of the reading z is the thickness a of the structural layer;

[0012] S3. Use a floor thickness gauge to measure the original slurry surface and the corresponding decorative layer surface directly above it to obtain the total thickness b of the decorative layer, leveling layer and structural layer at the measuring point;

[0013] S4, using a steel bar scanner on the surface of the decorative layer corresponding to the original slurry surface to detect the measuring point position of the upper row of steel bars in the floor to the upper surface of the floor slab buried depth c;

[0014] S5. Calculate the protective layer thickness e of the upper row of steel bars in the floor slab based on the thickness a, total thickness b and embedded depth c, e=c-(ba).

[0015] Furthermore, in S1, the scraped size of the paint layer and putty layer on the lower surface of the floor slab is larger than the plane size of the body of the array ultrasonic imager.

[0016] Furthermore, in S2, the array ultrasonic imager uses dry-coupled transducers, and the number of transducers is not less than 24.

[0017] Furthermore, in S2, the wave velocity of the tested concrete is calibrated before detection, and the two parameters of working frequency and gain are adjusted so that the echo reflection imaging of the ultrasonic wave generated at the interface between the structural layer and the leveling layer is displayed in red.

[0018] Furthermore, in S3, the detection error of the total thickness b is less than or equal to 1 mm.

[0019] Furthermore, in S4, the detection range of the steel bar scanner for the steel bar depth position is greater than or equal to 140 mm, and the detection error of the steel bar depth position is less than or equal to 3 mm.

[0020] Furthermore, when the thickness of the protective layer of a plurality of continuous upper-row steel bars in the floor slab is to be detected, the measuring point positions are determined on the floor slab in the area corresponding to the plurality of upper-row steel bars, and steps S1 to S5 are repeated.

[0021] Beneficial effects of the present invention:

[0022] 1. The material property difference between the concrete structural layer and the cement mortar leveling layer in the floor slab is cleverly utilized. The concrete material is relatively dense, and the cement mortar is a porous and loose structure. The propagation characteristics of ultrasonic waves in different materials in ultrasonic detection technology and the technical advantage of array ultrasonic imaging method that can be implemented when there is only one ultrasonic detection surface are cleverly combined. The array ultrasonic imager is used to transmit ultrasonic waves from the bottom of the concrete structural layer into the concrete material. Due to the material property difference between concrete and cement mortar, when the ultrasonic wave passes through the concrete layer and reaches the interface between the structural layer and the leveling layer, part of the ultrasonic wave enters the porous and loose cement mortar material. The ultrasonic wave entering the cement mortar material will rapidly attenuate due to energy divergence, so that it can no longer be received by the instrument. Part of the ultrasonic wave is reflected back at the interface and received by the array ultrasonic imager, so that the thickness of the concrete layer, that is, the thickness of the floor slab structural layer, is measured by the array ultrasonic imager. The method of the present invention does not damage the decorative layer and the leveling layer above the floor slab structural layer, and only partially shovels the putty layer and the paint layer on the lower surface of the floor slab. It is slightly damaged and very easy to repair, and can almost be characterized as a non-destructive method.

[0023] 2. On the basis of solving the problem of thickness detection of floor structure layer, we further cleverly utilized the two parameters of total floor thickness and embedded depth of upper row of steel bars to the upper surface of floor slab, which can be obtained by non-destructive testing but originally had no practical significance, to obtain the thickness of protective layer of upper row of steel bars through calculation, thus realizing non-destructive testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the layered structure of the decorated floor slab of the present invention;

[0025] Figure 2 The waveform diagram and imaging diagram obtained by the array ultrasonic imager of the present invention;

[0026] Figure 3 It is a schematic diagram of the movement of the cursor of the first red area in the longitudinal section ultrasonic imaging diagram and the position of the maximum amplitude in the waveform diagram of the present invention.

[0027] Explanation of numbers in the figure: 1. Decorative layer; 2. Leveling layer; 3. Structural layer; 4. Putty layer; 5. Paint layer; 6. Upper row of steel bars; 7. Lower row of steel bars; 8. Original slurry surface. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0029] Reference Figure 1 As shown, an embodiment of the method for detecting the thickness of the structural layer of a decorated floor slab and the thickness of the protective layer of the upper row of steel bars of the present invention is performed on a decorated floor slab in an existing building. The floor slab comprises a decorative layer 1, a leveling layer 2, a structural layer 3, a putty layer 4 and a coating layer 5 from top to bottom. The material of the structural layer is concrete, which is relatively dense. The designed thickness of the structural layer is 130 mm. The structural layer includes an upper row of steel bars 6 and a lower row of steel bars 7. The material of the leveling layer is cement mortar, which is a porous and loose material. The designed thickness of the leveling layer is 50 mm, and the designed thickness of the decorative layer is 40 mm. The specific detection method comprises the following steps:

[0030] First, determine the measuring point on the floor slab. The measuring point can be determined according to the position of the steel bars in the floor slab. The spacing between the upper or lower rows of steel bars in the floor slab is usually 150mm or 200mm. When selecting the measuring point, you can first locate the steel bar position in the floor slab through a steel bar scanner, or directly define an area with a length of more than 200mm as the measuring point to ensure that the measuring point contains steel bars. Scrape off the paint layer and putty layer on the lower surface of the floor slab corresponding to the measuring point to expose the original slurry surface 8 of the structural layer. The length of the scraped area is 500mm and the width is 200mm. The scraped size is larger than the plane size of the array ultrasonic imager body 370mm×110mm, so that the array ultrasonic imager can fit in contact with the structural layer.

[0031] An array ultrasonic imager is used to detect the original pulp surface of the structural layer. The array ultrasonic imager used in this embodiment is an array ultrasonic imager of model A1040 MIRA of the ACS-SOLUTIONS GMBH brand produced in Russia. It adopts a dry-coupled transducer and does not require the application of coupling agent, which is more convenient to use. The number of transducers is 48. The more transducers there are, the wider the imaging coverage.

[0032] Before the test, the wave velocity of the concrete at the measuring point is calibrated, and the wave velocity after calibration is 2730m / s. The working frequency and gain parameters of the array ultrasonic imager are adjusted. In this embodiment, the working frequency is set to 45kHz, and the gain of the array ultrasonic imager is set to 18dB, so that the ultrasonic wave at the junction of the structural layer and the leveling layer can be displayed in red when the echo reflection imaging occurs;

[0033] The waveform is obtained by the A-scan function of the array ultrasound imager, such as Figure 2 As shown in the middle part of the waveform, the propagation distance of the ultrasonic wave in the measured material is the horizontal coordinate, and the amplitude of the ultrasonic wave reflected in the measured material is the vertical coordinate. The longitudinal section ultrasonic imaging diagram of the measuring point is obtained through the B-scan function of the array ultrasonic imager. The first red area displayed from top to bottom in the longitudinal section ultrasonic imaging diagram represents an echo reflection imaging of the ultrasonic wave at the junction of the structural layer and the leveling layer, as shown in Figure 2 As shown in the right part of the waveform; move the cursor line of the horizontal axis of the waveform to the first red area, and then fine-tune the cursor line up and down to find the position where the amplitude of the ultrasonic reflection in the waveform is the largest, refer to Figure 3 As shown, the reading z of the horizontal axis is read at this time. The value of the reading z is the thickness a of the structural layer. In this embodiment, the thickness a is equal to 134 mm. The measured result 134 mm is close to the designed value 130 mm of the thickness of the floor structure layer, which shows the reliability of the test result. The difference between the measured result and the designed value is the error in the actual pouring construction of the floor structure layer.

[0034] Then, it is necessary to use a floor thickness gauge to measure the original slurry surface and the surface of the decorative layer directly above it to obtain the total thickness b at the measuring point. In this embodiment, the total thickness b is equal to 221mm. In this embodiment, a floor thickness gauge of model HC-HD91 produced by Beijing Haichuang Hi-Tech is used. The detection error of the total thickness b is less than or equal to 1mm. The total thickness of the floor at the measuring point detected by the floor thickness gauge is the sum of the thicknesses of the decorative layer, the leveling layer and the structural layer. It can be seen from the measured thickness of the structural layer in this embodiment that the sum of the actual thicknesses of the decorative layer and the leveling layer is 221-134=87mm. Compared with the sum of the designed thicknesses of the decorative layer and the leveling layer, it is shown that the thicknesses of the decorative layer and the leveling layer have a negative deviation of 3mm during actual construction.

[0035] The steel bar scanner is used to detect the embedded depth c of the upper row of steel bars in the floor slab to the upper surface of the floor slab on the surface of the corresponding decorative layer just above the original slurry surface. The detection range of the steel bar scanner for the depth position of the steel bar is greater than or equal to 140 mm, and the detection error of the depth position of the steel bar is less than or equal to 3 mm. In this embodiment, the measured thickness of the embedded depth c is 104 mm;

[0036] Regarding the selection of the steel bar scanner, considering the influence of the thickness of the leveling layer and the decorative layer of the floor on the measurement of the depth position of the upper row of steel bars in the floor, the embedding depth of the upper row of steel bars to the upper surface of the floor in the decorated floor is usually greater than 80mm. In this embodiment, the sum of the design thickness of the leveling layer and the decorative layer has exceeded 90mm, so the embedding depth of the upper row of steel bars to the upper surface of the floor exceeds 100mm. The range of the ordinary steel bar scanner for detecting the depth position of the steel bar is usually 80mm, which cannot be used in this embodiment. The steel bar scanner used in this embodiment is a PS300 steel bar scanner of the Hilti brand produced in Germany, which has a detection range of 150mm for the depth position of the steel bar, and the detection error of the depth position of the steel bar is not greater than 3mm.

[0037] Finally, the protective layer thickness e of the upper row of steel bars in the floor slab is calculated by combining the thickness a, the total thickness b and the embedded depth c, e=c-(ba), that is, e=104-(221-134)=17mm, thus obtaining the position of the upper row of steel bars in the structural layer. As for the position of the lower row of steel bars in the structural layer, it can be conveniently detected directly from the original mortar surface using a steel bar scanner. At this point, the thickness of the floor slab structural layer and the position of the upper and lower rows of steel bars in the structural layer are known, and the bearing capacity of the floor slab can be calculated.

[0038] In one embodiment, when the protective layer thickness of multiple consecutive upper-row steel bars in a floor slab needs to be detected, the floor slab area corresponding to the multiple consecutive upper-row steel bars is defined as multiple measuring points, and the paint layer and putty layer are scraped off on the lower surface of the floor slab corresponding to each measuring point to expose the original slurry surface of the concrete, and the detection process is repeated on all original slurry surfaces to obtain the protective layer thickness e1, e2, ...en of the upper-row steel bars in the floor slab at each measuring point.

[0039] In order to further verify the reliability of the detection method of the present invention, the thickness of the protective layer of the six consecutive upper rows of steel bars in the floor slab and the thickness of the floor slab structural layer at the corresponding positions of the six upper rows of steel bars are first detected and calculated using the detection method of the present invention, and then detected using the traditional damage method. When the traditional damage method is used for detection, the decorative layer and the leveling layer above the six consecutive upper rows of steel bars are chiseled off to form a continuous strip groove. In addition, the putty layer and the paint layer below the six consecutive upper rows of steel bars have been scraped off when the detection method of the present invention is used for detection. At this time, only the structural layer of the floor slab remains in the area where the six upper rows of steel bars are located. The thickness of the floor slab structural layer at the corresponding position of each upper row of steel bars can be directly detected using a floor slab thickness gauge, or the thickness of the protective layer of each upper row of steel bars can be directly detected using a steel bar scanner. The comparison of the detection results of the two methods is shown in Table 1.

[0040] Table 1

[0041] Detection Methods Test content Upper row of steel bars Upper row of steel bars b Upper row of steel bars c Upper row of steel bars d Upper row of steel bars Upper row of steel bars Method of the present invention Thickness of structural layer / mm 127 127 126 126 126 125 Damage method Structural layer thickness / mm 126 125 125 124 125 124 Method of the present invention Thickness of protective layer / mm 21 21 25 22 22 23 Damage method Thickness of protective layer / mm 19 20 23 21 20 22

[0042] It can be seen from Table 1 that the detection results of the two methods are very close and the error is controllable. The method of the present invention belongs to the micro-damage method and is very easy to repair, so it is worthy of popularization and application.

[0043] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A method for detecting the thickness of the structural layer of a decorated floor and the thickness of the protective layer of the upper row of steel bars, wherein the floor comprises a decorative layer, a leveling layer, a structural layer, a putty layer and a coating layer from top to bottom, wherein the material of the structural layer is concrete, and the structural layer comprises a lower row of steel bars and an upper row of steel bars, and the material of the leveling layer is cement mortar, characterized in that: The detection method includes the following steps: S1. First determine the measuring point on the floor slab, and scrape away the paint layer and putty layer on the lower surface of the floor slab corresponding to the measuring point to expose the original slurry surface of the structural layer; S2. Use an array ultrasonic imager to perform detection on the original pulp surface, and obtain a waveform through the A-scan function of the array ultrasonic imager. The waveform uses the propagation distance of the ultrasonic wave in the measured material as the horizontal coordinate and the amplitude of the ultrasonic wave reflected in the measured material as the vertical coordinate. Use the B-scan function of the array ultrasonic imager to obtain a longitudinal section ultrasonic imaging diagram of the measuring point. The first red area displayed from top to bottom in the longitudinal section ultrasonic imaging diagram represents an echo reflection imaging of the ultrasonic wave at the interface between the structural layer and the leveling layer. Move the cursor line of the horizontal coordinate in the waveform diagram to the first red area, and then fine-tune the cursor line up and down to find the position with the largest amplitude of the ultrasonic wave reflection in the waveform diagram, and read the reading z of the horizontal coordinate at this time. The value of the reading z is the thickness a of the structural layer; S3. Use a floor thickness gauge to measure the original slurry surface and the corresponding decorative layer surface directly above it to obtain the total thickness b of the decorative layer, leveling layer and structural layer at the measuring point; S4, using a steel bar scanner on the surface of the decorative layer corresponding to the original slurry surface to detect the measuring point position of the upper row of steel bars in the floor to the upper surface of the floor slab buried depth c; S5. Calculate the protective layer thickness e of the upper row of steel bars in the floor slab based on the thickness a, total thickness b and embedded depth c, e=c-(ba).

2. The method for detecting the thickness of the structural layer of the decorated floor and the thickness of the protective layer of the upper row of steel bars as claimed in claim 1, characterized in that: In S1, the scraped size of the paint layer and putty layer on the lower surface of the floor slab is larger than the plane size of the body of the array ultrasonic imager.

3. The method for detecting the thickness of the structural layer of the decorated floor and the thickness of the protective layer of the upper row of steel bars as claimed in claim 1, characterized in that: In S2, the array ultrasound imager uses dry-coupled transducers, and the number of transducers is not less than 24.

4. The method for detecting the thickness of the structural layer of the decorated floor and the thickness of the protective layer of the upper row of steel bars as claimed in claim 1, characterized in that: In S2, the wave velocity of the tested concrete is calibrated before detection, and the working frequency and gain parameters are adjusted so that the echo reflection imaging of the ultrasonic wave at the interface between the structural layer and the leveling layer is displayed in red.

5. The method for detecting the thickness of the structural layer of the decorated floor and the thickness of the protective layer of the upper row of steel bars as claimed in claim 1, characterized in that: In S3, the detection error of the total thickness b is less than or equal to 1 mm.

6. The method for detecting the thickness of the structural layer of the decorated floor and the thickness of the protective layer of the upper row of steel bars as claimed in claim 1, characterized in that: In S4, the detection range of the steel bar scanner for the steel bar depth position is greater than or equal to 140 mm, and the detection error for the steel bar depth position is less than or equal to 3 mm.

7. The method for detecting the thickness of the structural layer of the decorated floor and the thickness of the protective layer of the upper row of steel bars as claimed in claim 1, characterized in that: When the protective layer thickness of a plurality of continuous upper-row steel bars in a floor slab is to be detected, the measuring point locations are determined on the floor slab in the area corresponding to the plurality of upper-row steel bars, and steps S1 to S5 are repeated.

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