CN113433301A - Concrete shrinkage deformation testing device and method - Google Patents
Concrete shrinkage deformation testing device and method Download PDFInfo
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- G—PHYSICS
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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Abstract
本发明公开了一种混凝土收缩变形测试装置及方法，包括“L”型测试台、激光三维扫描仪和便携式工作站；所述“L”型测试台包括扫描基准平面和扫描标记平面，所述扫描标记平面划分为扫描标记区和测试试件布置区，所述扫描标记区分布有若干数量的扫描标记点，用于激光三维扫描仪的标定校准；所述测试试件布置区用于限定混凝土试件的放置位置；所述激光三维扫描仪用于对测试试件布置区的混凝土试件进行三维扫描，并将数据传输至便携式工作站。本发明能够进行一块或同时进行多块混凝土试件自收缩的测量，其在自收缩方向上的测量精度可达1μm，可实现混凝土试件自收缩的精确测量。The invention discloses a concrete shrinkage deformation testing device and method, comprising an "L"-shaped test table, a laser three-dimensional scanner and a portable workstation; the "L"-shaped test table includes a scanning reference plane and a scanning mark plane. The marking plane is divided into a scanning mark area and a test specimen arrangement area. The scan mark area is distributed with a number of scanning mark points for calibration and calibration of the laser three-dimensional scanner; the test specimen arrangement area is used to define the concrete test specimen. The placement position of the specimen; the laser 3D scanner is used to perform 3D scanning on the concrete specimen in the test specimen arrangement area, and transmit the data to the portable workstation. The invention can measure the self-shrinkage of one or more concrete specimens at the same time, the measurement accuracy in the self-shrinkage direction can reach 1 μm, and the precise measurement of the self-shrinkage of the concrete specimen can be realized.
Description
Technical Field
The invention relates to the technical field of concrete testing, in particular to a concrete shrinkage deformation testing device and method based on three-dimensional scanning.
Background
Along with the construction and development of various large civil engineering at home and abroad, the research on the performance of concrete is gradually deepened in the industry, the self-shrinkage test of the concrete is taken as an important test means of the performance of the concrete, the self-shrinkage index of the concrete can provide a basis for the evaluation of the crack resistance of a concrete structure, and the self-shrinkage index of the concrete is also an important basis for calculating a stress field and a crack risk in the crack risk evaluation of the concrete structure.
Concrete shrinkage measurements are mainly divided into two categories, drying shrinkage measurements and shrinkage tests. The concrete shrinkage test methods are divided into two main categories, namely a volume method and a linear method, and specifically divided into three categories, namely an embedded type shrinkage test method, a non-contact type shrinkage test method and a contact type external measurement method. The embedded type shrinkage test can realize real-time continuous data acquisition by embedding corresponding sensors and strain gauges at two ends of a concrete test piece, wherein the sensors and the strain gauges are mainly differential strain gauges, linear differential displacement sensors and linear vibration meters which are suggested in DL/T5150-2001 hydraulic concrete test rules, but the embedded type strain gauges, the sensors and internal concrete are not bonded sufficiently, and the measured concrete self-shrinkage data is not reliable easily. The non-contact shrinkage test method is suitable for measuring the self-shrinkage deformation of common concrete in an unconstrained state, and a plurality of scholars realize the measurement of the self-shrinkage of the concrete by a capacitance type micrometer method, an eddy current sensor measurement method and the like, but the non-contact shrinkage test method is complex and has higher cost. The contact type external measurement method adopts a dial indicator measurement method, and the measurement method is easily influenced by factors such as instrument stability and the like and can not realize continuous measurement.
In conclusion, the development of a non-contact, continuous and accurate shrinkage measuring device for a concrete test piece is an urgent technical problem to be solved in a concrete shrinkage measuring mode.
Disclosure of Invention
In order to solve the problems of the existing concrete shrinkage measurement technology, the invention aims to provide a concrete shrinkage deformation testing device and method based on three-dimensional scanning, which can measure the self-shrinkage of one or more concrete test pieces simultaneously, the measurement precision of the self-shrinkage direction of the concrete test pieces can reach 1 micrometer, and the concrete test pieces can be accurately measured.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a concrete shrinkage deformation testing device comprises an L-shaped testing platform, a laser three-dimensional scanner and a portable workstation; the L-shaped test bench comprises a scanning reference plane and a scanning mark plane, the scanning mark plane is divided into a scanning mark area and a test specimen arrangement area, and a plurality of scanning mark points are distributed in the scanning mark area and used for calibrating the laser three-dimensional scanner; the test specimen arrangement area is used for limiting the placement position of the concrete specimen; the laser three-dimensional scanner is used for three-dimensionally scanning the concrete test piece in the test piece arrangement area and transmitting data to the portable workstation.
Preferably, the scanning mark area and the test specimen arrangement area are alternately arranged, and a concrete specimen can be placed in the area of each test specimen arrangement area, so that simultaneous testing of multiple concrete specimens is realized.
The invention also provides a concrete shrinkage deformation testing method, which comprises the following steps:
(1) taking the scanning mark points as a standard, and calibrating the laser three-dimensional scanner;
(2) three-dimensionally scanning a concrete test piece placed in a test piece arrangement area by using a laser three-dimensional scanner, collecting three-dimensional model data of the concrete test piece, and reconstructing a three-dimensional model in a portable workstation;
(3) the reconstructed three-dimensional model is led into Geomagic software in the portable workstation, and the reconstructed three-dimensional model is processed, so that the contraction direction of the three-dimensional model corresponds to the coordinate axis direction;
(4) importing a plurality of three-dimensional models of the same concrete test piece which are repeatedly scanned and reconstructed in the same time interval and processed into a plurality of network measurement softwareAligning and fitting the 3D model of the standard CAD test piece, measuring the length of the three-dimensional model in the shrinkage direction, and recording the measurement length of the concrete test piece for the first time as D1The second measurement length of the concrete specimen is d2Until the concrete sample of the nth time is tested, the measurement length is dnAnd obtaining a shrinkage test value calculation formula of the concrete sample as follows:
preferably, in the step (2), the concrete sample is placed on the scanning reference plane and is located in the test sample arrangement area, the scanning reference plane is used as a reference, the top surface of the concrete sample is used as a test plane, and the laser three-dimensional scanner is moved downwards from the test plane to the reference plane until the three-dimensional model data of the whole concrete sample is completely acquired.
Preferably, in step (4), the time interval is at least 1 day.
Preferably, in the step (4), a standard CAD 3D model of the concrete sample is drawn in Auto CAD drawing software, the reconstructed and processed three-dimensional model and the standard CAD 3D model are introduced into the multiplex measurement software, alignment fitting of the three-dimensional model and the standard CAD 3D model is completed, and a distance between the bottom surface and the top surface of the concrete sample (i.e., a length of the three-dimensional model in a shrinkage direction) is measured.
The invention has the beneficial effects that:
(1) the concrete sample reconstruction model based on the three-dimensional scanning technology has the measurement precision of 1 mu m in the self-contraction direction, and can realize the accurate measurement of the self-contraction of the concrete sample.
(2) The invention can measure the self-shrinkage of a plurality of concrete test pieces at one time or at the same time.
(3) The invention processes the reconstructed three-dimensional model in the portable workstation, avoids errors caused by manually selecting a measuring point and a measuring direction, and has high measuring precision.
Drawings
FIG. 1 is a schematic structural diagram of a concrete shrinkage deformation testing device according to the present invention;
FIG. 2 is a front view of the "L" type test station of FIG. 1;
FIG. 3 is a top view of the "L" type test station of FIG. 1;
in FIGS. 1-3: 1- "L" type testboard; 2-laser three-dimensional scanner; 3-Portable workstation
101-scanning a reference plane; 102-scanning the marking plane; 1021-scanning the mark area; 1022-test piece placement area.
FIG. 4 is a process change diagram of a three-dimensional scanning reconstruction model technology of a concrete specimen.
FIG. 5 is a graph of alignment fitting variation of a three-dimensional model and a standard CAD specimen 3D model.
FIG. 6 is a schematic diagram showing the length measurement results of the fitted three-dimensional model in the contraction direction.
Detailed Description
The present invention is described in further detail below with reference to the attached drawings.
As shown in fig. 1-3, which are schematic structural diagrams of a concrete shrinkage deformation testing device according to the present invention, the concrete shrinkage deformation testing device includes an "L" type testing platform 1, a laser three-dimensional scanner 2 and a portable workstation 3; the L-shaped test bench comprises a scanning reference plane 101 (namely a bottom surface) and a scanning mark plane 102 (namely a vertical surface), wherein the scanning mark plane 102 is divided into a scanning mark area 1021 and a test piece arrangement area 1022, and a plurality of scanning mark points are distributed in the scanning mark area 1021 and used for calibration and calibration of the laser three-dimensional scanner 2; the test specimen arrangement area 1022 is used to define the placement position of the concrete specimen;
when a plurality of concrete test pieces need to be tested simultaneously, the scanning mark area 1021 and the test piece arrangement area 1022 are arranged alternately, and the concrete test pieces can be placed in the area of each test piece arrangement area 1022. As in fig. 1, three concrete samples are placed on the scanning reference plane 101, and the position of each concrete sample is defined within the corresponding test sample arrangement region 1022;
the laser three-dimensional scanner 2 is used to three-dimensionally scan the concrete specimen in the test specimen placement area 1022 and transmit the data to a portable workstation 3, such as a conventional data processing terminal.
A concrete shrinkage deformation test method comprises the following steps:
(1) taking randomly distributed scanning mark points on the scanning mark area as a standard, and calibrating the laser three-dimensional scanner;
(2) placing three concrete test pieces on a scanning reference plane, limiting the position of each concrete test piece in a corresponding test piece arrangement area, taking the scanning reference plane as a reference, taking the top surface of each concrete test piece as a test plane, moving a laser three-dimensional scanner downwards from the test plane to the reference plane until the three-dimensional model data of each concrete test piece is completely acquired, and performing three-dimensional model reconstruction in a portable workstation, wherein the three-dimensional model data are shown in (1) of fig. 4;
(3) importing the reconstructed three-dimensional model into Geomagic software in a portable workstation, selecting a ' move ' option under a ' tool ' option card of the image software, selecting four functional options of ' move ' to an object ', ' to an origin ', ' accurately move ' and ' advanced object mover ', selecting ' move ' and then selecting ' to the origin ', clicking a ' dialog box ' confirmation button of the software, and translating the centroid of the reconstructed model to the origin position of the whole coordinate system, as shown in (2) of FIG. 4; selecting the accurate movement option below the movement, clicking the main vector option in a dialog box of the software, clicking a confirmation button, and completing the rotation of the reconstruction model, as shown in (3) of FIG. 4, after translation and rotation processing, the original point of the whole coordinate system is positioned at the centroid of the contraction test surface of the three-dimensional model of the test piece, so that the contraction direction of the three-dimensional model of the test piece is consistent with the Z-axis direction in the whole coordinate system, and errors caused by manually selecting a measurement point and a measurement direction are avoided;
(4) firstly, drawing a standard CAD 3D model of a concrete test piece in Auto CAD drawing software, then importing a plurality of three-dimensional models of the same concrete test piece and the standard CAD 3D model which are repeatedly three-dimensionally scanned and three-dimensionally reconstructed in the same time interval and are processed by translation and rotation into a multiplex measurement software, and aligning and fitting the three-dimensional models and the standard CAD 3D model, wherein the method specifically comprises the following steps: opening a multiplex MS 2018 software, opening a working area, selecting an 'input' tab, selecting three functional options of 'input point cloud file', 'input triangulated model' and 'input CAD model' under the 'input' tab, firstly selecting the 'input CAD model' option, and importing a drawn standard CAD 3D model, as shown in (1) of FIG. 5; selecting an input triangularization model, importing the processed three-dimensional model, finally selecting the best fitting data under an alignment option card to a reference object, clicking a fitting start option of a dialog box, and finishing the alignment fitting of the three-dimensional model and the 3D model of the standard CAD test piece, as shown in (2) of FIG. 5;
(5) measuring the length of the aligned and fitted model, creating two surface characteristics 1 and 2 of the bottom surface and the top surface of the fitted model, clicking a 'measuring' option, measuring the length L of the three-dimensional model in the shrinkage direction (namely the surface distance between the bottom surface and the top surface of the concrete sample), and recording the measuring length of the first concrete sample as d as shown in FIG. 6 (the measuring value shown in the figure is the measuring result of the concrete sample in a certain time)1The second measurement length of the concrete specimen is d2Until the concrete sample is measured for the nth time (n is more than or equal to 2), the measurement length is dnAnd obtaining a shrinkage test value calculation formula of the concrete sample as follows:
example 1
According to the concrete shrinkage deformation test method, the self-shrinkage of the C50 concrete from the beginning of final setting to the age of 28 days is tested, and the concrete shrinkage deformation test method specifically comprises the following steps:
(1) taking scanning mark points randomly distributed on a scanning mark area as a standard, keeping the three-dimensional scanner at a position 20cm away from a scanning mark plane, and calibrating the laser three-dimensional scanner;
(2) placing three C50 concrete test pieces on a scanning reference plane, limiting the position of each concrete test piece in a corresponding test piece arrangement area, taking the scanning reference plane as a reference, taking the top surface of the concrete test piece as a test plane, moving a laser three-dimensional scanner downwards from the test plane to the reference plane until the three-dimensional model data of the concrete test piece is completely collected, and performing three-dimensional model reconstruction in a portable workstation;
(3) the reconstructed three-dimensional model is led into Geomagic software in the portable workstation, and the reconstructed three-dimensional model is processed, so that the contraction direction of the three-dimensional model corresponds to the coordinate axis direction;
(4) introducing a plurality of three-dimensional models of the same concrete test piece (the test time interval is 24h, and the test time is 28 days) which is repeatedly three-dimensionally scanned and reconstructed in the same time interval and processed into the multiplex measurement software to be aligned and fitted with the 3D model of the standard CAD test piece, measuring the length of the three-dimensional model in the shrinkage direction, and recording the measurement length of the first concrete test piece as D1The second measurement length of the concrete specimen is d2Until the concrete sample is tested for the 28 th time, the measurement length is d28And obtaining a shrinkage test value calculation formula of the concrete sample as follows:
The result shows that the shrinkage value of the concrete sample measured in a non-contact way every 24h based on three-dimensional scanning has little difference with the shrinkage value measured by the contact dial indicator, and even the test result is more accurate than the value measured by the dial indicator. In the measuring process, after the concrete test block is moved, the shrinkage values of the concrete test piece measured by the test method are basically consistent before and after the movement, the test result is not influenced by the movement of the concrete test piece, and compared with a contact dial indicator test mode, the influence of an external unstable environment can be greatly avoided.
TABLE 1 comparison of the results of the three-dimensional scan shrinkage test interval of 24h with the results of the dial indicator test
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Cited By (2)
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| CN114295808A (en) * | 2021-12-30 | 2022-04-08 | 长安大学 | A test system and test method for expansion deformation of water-stabilized crushed stone base |
| CN114689820A (en) * | 2022-03-07 | 2022-07-01 | 保山学院 | Expansive soil swelling and shrinking characteristic testing and evaluating method based on three-dimensional scanning |
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