阅读说明：本技术 基于钻孔和钻芯取样的新旧混凝土结合面质量检测方法 (New and old concrete joint surface quality detection method based on drilling and core drilling sampling ) 是由 陈玲珠 王卓琳 张富文 许清风 冷予冰 李勇生 于 2020-07-02 设计创作，主要内容包括：本发明公开了一种基于钻孔和钻芯取样的新旧混凝土结合面质量检测方法：S1、选取典型截面,定位加固混凝土内部钢筋位置；S2、进行预检或抽样选取测点,避开钢筋垂直于混凝土结合面钻孔；S3、将内窥镜探头沿钻孔的孔道伸入混凝土内部；S4、开启内窥镜,通过双物镜镜头观测和拍摄混凝土结合面附近情况,发现缺陷则进行缺陷三维扫描形成空间图像；成像时记录各特征点三维坐标；S5、在未发现缺陷附近,抽样选取测点,避开钢筋钻芯取样；每个试件钻芯取样测点不少于3个,取样部位避开受力最大部位；S6、对芯样进行三次横向劈拉试验得到不同位置处混凝土横劈强度；S7、据缺陷外观和混凝土横劈强度结果判定混凝土结合面质量是否合格。(The invention discloses a new and old concrete joint surface quality detection method based on drilling and core drilling sampling, which comprises the following steps: s1, selecting a typical section, and positioning the position of a steel bar in the reinforced concrete; s2, performing pre-inspection or sampling to select a measuring point, and avoiding drilling a hole on the reinforcing steel bar perpendicular to the concrete joint surface; s3, extending the endoscope probe into the concrete along the pore channel of the drilled hole; s4, starting an endoscope, observing and shooting the condition near the concrete joint surface through a double-objective lens, and carrying out defect three-dimensional scanning to form a space image when a defect is found; recording three-dimensional coordinates of each characteristic point during imaging; s5, sampling and selecting a measuring point near the position where the defect is not found, and avoiding the steel bar core drilling and sampling; the number of the sampling measuring points of each test piece core drill is not less than 3, and the sampling part avoids the part with the maximum stress; s6, carrying out three times of transverse splitting and pulling tests on the core sample to obtain the transverse splitting strength of the concrete at different positions; and S7, judging whether the quality of the concrete joint surface is qualified according to the defect appearance and the concrete transverse splitting strength result.)

1. A new and old concrete joint surface quality detection method based on drilling and core drilling sampling is characterized by comprising the following steps:

s1, selecting a typical section, positioning the position of a reinforcing steel bar in reinforced concrete, and drawing reinforcing steel bar distribution grid lines;

s2, performing pre-inspection or sampling to select a measuring point by adopting a hammering method, directly adopting a drilling device, avoiding a reinforcing steel bar, and drilling along a direction vertical to a concrete joint surface;

s3, slowly extending the probe of the endoscope measuring device into the concrete along the hole channel of the drilled hole obtained in the step S2;

s4, starting an endoscope, observing and shooting the condition near the concrete junction surface through a double-objective lens, and if defects are found, performing defect three-dimensional scanning to form a space image; recording three-dimensional coordinates of each characteristic point during imaging;

s5, sampling and selecting a measuring point near the defect not found in the endoscope, and avoiding the steel bar to carry out core drilling sampling; the number of the sampling measuring points of each test piece core drill is not less than 3, and the sampling part avoids the part with the maximum stress;

s6, carrying out three times of transverse split-pull tests on the core sample obtained in the step S5 to obtain the transverse split strength of the concrete at different positions;

and S7, comprehensively judging whether the quality of the concrete joint surface is qualified or not according to the defect appearance and the concrete transverse splitting strength result.

2. The method for testing the quality of the joint surface of the old and new concrete based on drilling and core-drilling sampling as claimed in claim 1, wherein in step S1, the typical section is a section with large bending moment or shearing force.

3. The method for testing the quality of the joint surfaces of new and old concrete based on drilling and core-drilling sampling as claimed in claim 1, wherein in step S2, the distance between adjacent measuring points of each joint surface of a single typical section along the joint line is not more than 300 mm.

4. The method for testing the quality of the joint surface of the new concrete and the old concrete based on the drilling and the core drilling sampling as claimed in claim 1, wherein in the step S2, the diameter of the drill bit during the drilling is not more than 15 mm; the depth of the drilled hole is more than 10mm deep into the old concrete.

5. The method for detecting the quality of a joint surface between new and old concrete based on drilling and core-drilling sampling as claimed in claim 1, wherein in step S4, the diameter of the endoscopic probe is not larger than the inner diameter of the pore canal, and the endoscopic probe is provided with a dual-objective lens and a three-dimensional phase scanning measuring lens.

6. The method for testing the quality of the joint surface of the new concrete and the old concrete based on the drilling and the core drilling sampling as claimed in claim 1, wherein in the step S5, the length of the core sample is more than 40mm deep into the old concrete; the nominal diameter of the core sample is not less than 70mm and not less than 2 times of the maximum particle size of the aggregate.

7. The method for testing the quality of the joint surfaces of the old and new concrete based on drilling and core-drilling sampling as claimed in claim 1, wherein in step S6, the step of three transverse split tests comprises:

(a) drawing a circle parallel to the cross section of the concrete core sample at the splitting surface position, respectively arranging a splitting surface at the new concrete part and the old concrete part, and arranging a splitting surface at the joint surface; wherein the distance between the splitting surface of the new concrete and the splitting surface of the old concrete and the two end surfaces of the core sample is not less than 20 mm;

(b) placing a test pressing tool at the central position of a lower pressing plate of a compression testing machine, centering the upper pressing plate and the lower pressing plate, placing a test piece between pressing knives of the pressing tool, and adjusting the test piece according to the determined splitting surface position;

(c) continuously and uniformly loading at the speed of 0.04-0.06 MPa/s until the test piece is damaged, and recording the damage load of different cleavage planes and the damage plane of the test piece;

(d) the nominal transverse splitting strength of the different splitting planes was calculated according to the following formula:

in the formula: f. of_t-nominal transverse shear strength of the core sample, MPa; p is the breaking load of the core sample specimen, kN; a-area of cross section of core sample, mm²。

8. The method for detecting the quality of the joint surfaces of the new concrete and the old concrete based on the drilling and the core drilling sampling as claimed in claim 1, wherein in the step S7, if obvious defects are observed at the joint surfaces, the quality of the joint surfaces of the concrete is judged to be unqualified; and if the nominal transverse splitting strength of the joint surface is not lower than 90% of the average nominal transverse splitting strength of the new concrete and the old concrete, judging that the quality of the concrete joint surface is qualified, otherwise, judging that the quality is unqualified.

9. The method for detecting the quality of the joint surface of the new concrete and the old concrete based on the drilling and the core drilling sampling as claimed in claim 1, wherein a steel bar detector is used for positioning the position of the steel bars in the reinforced concrete in step S1.

Technical Field

The invention relates to the technical field of building detection, in particular to a new and old concrete joint surface quality detection method based on drilling and core drilling sampling.

Background

At present, as the construction industry changes from a large-scale new construction period to a situation of a new construction and maintenance reconstruction repeated period, a large number of buildings enter an aging stage and face the problem of reinforcement. Although new reinforcing methods are emerging, the concrete section-enlarging reinforcing method is still one of the main methods for reinforcing structures such as buildings and bridges due to its economical and wide application. In view of the fact that the interface quality of the new and old concrete is the key for the successful application of the section-enlarging reinforcing method, the quality and durability of the engineering are affected due to poor bonding of the new and old concrete in a maintenance and reinforcing engineering, the service function and the safety of the whole structure are damaged again, and the loss of huge maintenance and reinforcing cost is caused.

In the prior art, the method for detecting the bonding strength of the concrete bonding surface in the laboratory comprises the following steps: the method comprises the steps of directly stretching, single-sided direct shearing, double-sided direct shearing, pressing and shearing and the like, but the common detection methods are limited to be carried out in a laboratory, cannot be operated and detected on an engineering site, and have obvious limitations.

In view of this, some researchers have proposed on-site testing methods such as a drill core bonding and drawing method and a drill core bar-planting and drawing method to test the bonding strength of the new and old concrete joint surfaces, but the testing and engineering data are insufficient, the on-site testing is not intuitive enough, the data discreteness is large, and the adhesive layer is easy to be damaged due to manual operation. Therefore, technical measures are necessary to develop a detection method combining the field quality and the laboratory quality of the new and old concrete joint surfaces.

Disclosure of Invention

The invention aims to solve the technical problem of providing a new and old concrete joint surface quality detection method which is simple and feasible, can visually observe the defects of the joint surface, can quantitatively test the bonding quality of the well-observed joint surface, and can improve the detection precision based on drilling and core drilling sampling.

The technical problem to be solved can be implemented by the following technical scheme.

A new and old concrete joint surface quality detection method based on drilling and core drilling sampling is characterized by comprising the following steps:

s1, selecting a typical section, positioning the steel bars in the reinforced concrete, and drawing a steel bar distribution net

Grid lines;

s2, performing pre-inspection or sampling to select a measuring point by adopting a hammering method, directly adopting a drilling device, avoiding a reinforcing steel bar, and drilling along a direction vertical to a concrete joint surface;

s3, slowly extending the probe of the endoscope measuring device into the concrete along the hole channel of the drilled hole obtained in the step S2;

s4, starting an endoscope, observing and shooting the condition near the concrete junction surface through a double-objective lens, and if defects are found, performing defect three-dimensional scanning to form a space image; recording three-dimensional coordinates of each characteristic point during imaging;

s5, sampling and selecting a measuring point near the defect not found in the endoscope, and avoiding the steel bar to carry out core drilling sampling; the number of the sampling measuring points of each test piece core drill is not less than 3, and the sampling part avoids the part with the maximum stress;

s6, carrying out three times of transverse split-pull tests on the core sample obtained in the step S5 to obtain the transverse split strength of the concrete at different positions;

and S7, comprehensively judging whether the quality of the concrete joint surface is qualified or not according to the defect appearance and the concrete transverse splitting strength result.

As a further improvement of the present technical solution, in step S1, the typical section is a section with a large bending moment or shearing force.

In step S2, the distance between adjacent measuring points of each joint surface of a single typical section arranged along the joint line is not more than 300 mm.

As a further improvement of the technical scheme, in step S2, the diameter of the drill bit does not exceed 15mm during drilling; the depth of the drilled hole is more than 10mm deep into the old concrete.

Also as a further improvement of the present technical solution, in step S4, the diameter of the endoscopic probe is not greater than the inner diameter of the duct, and the endoscopic probe is provided with a dual-objective lens and a three-dimensional stereo phase scanning measurement lens.

Also as a further improvement of the technical scheme, in step S5, the length of the core sample is extended into the old concrete to exceed 40 mm; the nominal diameter of the core sample is not less than 70mm and not less than 2 times of the maximum particle size of the aggregate.

Also as a further improvement of the present technical solution, in step S6, the step of three lateral split test includes:

(a) drawing a circle parallel to the cross section of the concrete core sample at the splitting surface position, respectively arranging a splitting surface at the new concrete part and the old concrete part, and arranging a splitting surface at the joint surface; wherein the distance between the splitting surface of the new concrete and the splitting surface of the old concrete and the two end surfaces of the core sample is not less than 20 mm;

(b) placing a test pressing tool at the central position of a lower pressing plate of a compression testing machine, centering the upper pressing plate and the lower pressing plate, placing a test piece between pressing knives of the pressing tool, and adjusting the test piece according to the determined splitting surface position;

(c) continuously and uniformly loading at the speed of 0.04-0.06 MPa/s until the test piece is damaged, and recording the damage load of different cleavage planes and the damage plane of the test piece;

(d) the nominal transverse splitting strength of the different splitting planes was calculated according to the following formula:

in the formula: f. of_t-nominal transverse shear strength of the core sample, MPa; p is the breaking load of the core sample specimen, kN; a-area of cross section of core sample, mm²。

As a further improvement of the technical scheme, in step S7, if an obvious defect is observed at the joint surface, determining that the quality of the concrete joint surface is not qualified; and if the nominal transverse splitting strength of the joint surface is not lower than 90% of the average nominal transverse splitting strength of the new concrete and the old concrete, judging that the quality of the concrete joint surface is qualified, otherwise, judging that the quality is unqualified.

As one of the preferred embodiments of the present invention, a reinforcing bar detector is used to locate the position of the reinforcing bars inside the reinforced concrete in step S1.

The method for detecting the quality of the joint surface of the new concrete and the old concrete based on drilling and core drilling sampling has the advantages that:

1. the method is simple and feasible, can visually observe the defects of the joint surface, and can quantitatively test the quality of the well-observed joint surface;

2. compared with a core drilling and drawing method, the method combining field detection and laboratory detection can reduce the dispersion of data, thereby reducing the number of the core drilling and improving the detection precision.

Drawings

FIG. 1 is a schematic diagram of the method for detecting the quality of the joint surface of new and old concrete based on drilling and core drilling sampling to perform endoscopic measurement.

FIG. 2 is a schematic diagram of core drilling and sampling of the new and old concrete joint surface quality detection method based on drilling and core drilling and sampling.

FIG. 3 is a schematic diagram of a transverse split-draw test pressing tool of the new and old concrete joint surface quality detection method based on drilling and core drilling sampling.

FIG. 4 is a schematic diagram of a transverse split-draw test performed by the new and old concrete joint surface quality detection method based on drilling and core drilling sampling.

In the figure, 1 — old concrete; 2-new concrete for reinforcement; 3-joint surface void defect; 4-reinforcing concrete reinforcing steel bars; 5-a pore channel; 6, an endoscope; 7, a probe; 8-core sample; 9-transverse split-draw test pressing tool; 91-pressing a cutter.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Referring to fig. 1 to 3, old concrete 1 represents a concrete column in an existing building, the original section width is 300mm, the section height is 300mm, the reinforcement is performed by adopting an enlarged section method, new concrete 2 for reinforcement represents a reinforcement part, the section width after reinforcement is changed to 420mm, and the section height after reinforcement is changed to 420 mm.

A joint surface of a corner area of the column has a void defect (namely a joint surface void defect 3 in the figure), and as shown in figure 1, the quality of the new and old concrete joint surfaces is detected. The method comprises the following specific steps:

the first step is as follows: and selecting a typical section, positioning the position of a reinforcing steel bar (namely reinforcing concrete steel bar 4) in the reinforced concrete by using a reinforcing steel bar detector, and drawing reinforcing steel bar distribution grid lines.

During detection, a midspan section with large bending moment and a section at a three-point part with large shearing force are selected, and a steel bar detector is adopted to scan the surface of the component to position the position of the steel bar.

The second step is that: and (3) performing pre-inspection or sampling by adopting a hammering method to select measuring points, directly adopting a drilling device, avoiding the reinforcing steel bars, and drilling in a direction vertical to the concrete joint surface to obtain a drilled hole channel 5.

In each typical section, 3 measuring points are arranged on each joint surface along the direction of the joint line, the distance between every two adjacent measuring points is about 200mm, and a drill bit with the diameter of 14mm is adopted during drilling; the depth of the drilled hole is 15mm deep into the old concrete 1.

The third step: a probe 7 of an endoscope 6 extends into the old concrete 1 along the duct 5;

the probe 7 has a diameter of 4mm, and the probe 7 of the endoscope is provided with a double-objective lens and a three-dimensional phase scanning measurement lens.

The endoscopic measurements further comprise the steps of:

(a) the probe 7 of the endoscope 6 is inserted into the old concrete 1 along the lower edge of the tunnel 5.

(b) And starting the endoscope 6, and observing and shooting the condition near the concrete junction surface through the double-objective lens.

(c) When the junction surface is found to have the junction surface cavity defect 3, three-dimensional scanning imaging is carried out on the defect, and three-dimensional coordinates of each characteristic point are recorded, wherein the three-dimensional coordinates comprise a starting point on a pore channel, each characteristic point on a cavity three-dimensional outline and the like.

The fourth step: and (4) sampling and selecting a measuring point when the endoscope 6 does not find the vicinity of the defect, and avoiding the reinforcing steel bar to perform core drilling and sampling to obtain a core sample 8.

The number of the core drilling sampling measuring points of each test piece is 3, and the sampling position is selected at the middle height position of the midspan section. The core sample 8 extends up to 50mm deep into the old concrete 1. The nominal diameter of core sample 8 was taken to be 70 mm.

The fifth step: carrying out three times of transverse split-pull tests on the core sample 8 to obtain the transverse split strength of the concrete at different positions;

the three transverse split pull tests include the steps of:

(a) drawing a circle parallel to the cross section of the concrete core sample 8 on the split surface position by using a pencil and a caliper, respectively arranging a split surface at the new concrete and the old concrete, arranging a split surface at the joint surface, and enabling the distance between the split surface at the new concrete and the split surface at the old concrete and the two end surfaces of the core sample not to be less than 20 mm;

(b) placing a transverse split-draw test pressing tool 9 at the central position of a lower pressing plate of the compression testing machine, centering the upper pressing plate and the lower pressing plate, placing a test piece between pressing knives 91 of the pressing tool, and adjusting the test piece according to the determined split surface position;

(c) continuously and uniformly loading at the speed of 0.04-0.06 MPa/s until the test piece is damaged, and recording the damage load of different cleavage planes and the damage plane of the test piece;

(d) the nominal transverse splitting strength of the different splitting planes was calculated according to the following formula:

in the formula: f. of_t-nominal transverse shear strength of the core sample, MPa; p is the breaking load of the core sample, kN; a-area of cross section of core sample, mm²。

And a sixth step: and comprehensively judging whether the quality of the concrete joint surface is qualified or not according to the defect appearance and the concrete transverse splitting strength result.

Obvious defects are observed at the joint surface, and the quality of the concrete joint surface can be judged to be unqualified.

The nominal transverse splitting strength of the joint surface is not lower than 90% of the average nominal transverse splitting strength of the new concrete and the old concrete, and the quality of the concrete joint surface can be judged to be qualified.

While the preferred embodiments of the present invention have been described, those skilled in the art will appreciate that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.