JP2004053546A - Measuring method of deterioration degree of concrete in concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring the deterioration degree of concrete simply and quickly without damaging a concrete structure. <P>SOLUTION: This measuring method of the deterioration degree of the concrete in the concrete structure is characterized as follows: a formwork 4 for a plurality of specimens projecting to the outside is formed on a prescribed spot of a concrete structure formwork 1; the concrete 15 is placed in both formworks 1, 4 to thereby form the specimens 17 integrally with the concrete structure; after the hardening of the concrete 15, only the concrete structure formwork 1 is dismantled; after the elapse of a prescribed period from dismantlement of the concrete structure formwork 1, the specimen formwork 4 is dismantled; and the specimens 17 are split successively every time after the elapse of a prescribed period from the concrete 15 placing, to perform various measurements. After the concrete in the specimen formwork comes to have prescribed compressive strength, the specimen formwork is dismantled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for measuring the degree of deterioration of concrete in a concrete structure.
[0002]
[Prior art]
In a concrete structure, calcium hydroxide in the concrete is changed to calcium carbonate by carbon dioxide in the air, so that the neutralization of the concrete progresses with time. When the concrete is alkaline, the reinforcing steel in the concrete structure does not rust, but the concrete is neutralized, and when water and air are present, it gradually starts to rust, which has a significant effect on the quality of the structure. Therefore, when some troubles such as cracks occur in the concrete structure, the depth of carbonation of the concrete is measured, and based on the data, the soundness of the concrete structure is determined, and repairs and seismic reinforcement are performed. I have. As a method of measuring the neutralization depth of this concrete, a method of directly collecting a core from a concrete structure and measuring it, a method of measuring by measuring the surface of the concrete structure, and a method of drilling a hole in a concrete structure with a concrete drill are used. There is a way to measure by digging.
[0003]
[Problems to be solved by the invention]
However, each of the above-mentioned measuring methods has a problem that the concrete structure is damaged, time and labor for the measurement are required, and repair after the measurement is difficult.
[0004]
The present invention has been made in view of these problems, and an object of the present invention is to provide a method for easily and quickly measuring the degree of deterioration of concrete without damaging the concrete structure.
[0005]
[Means for Solving the Problems]
The gist of the invention of a method for measuring the degree of deterioration of concrete in a concrete structure to solve the above problems is to form a plurality of specimen molds projecting outward at predetermined locations of a concrete structure mold, Concrete is cast in both the formwork to form a concrete structure and a test piece integrally, and after the concrete is hardened, only the concrete structure formwork is dismantled, and the concrete structure formwork is removed. After the elapse of a predetermined period from the disassembly, the test piece form is disassembled, and the test pieces are sequentially divided every predetermined period after the concrete is cast to perform various measurements. In addition, the method includes dismantling the specimen mold after the concrete in the specimen mold has a required compressive strength.
[0006]
After a predetermined period has elapsed since the concrete was poured into the formwork, the specimen integrally formed with the concrete structure can be easily cut off from the surface of the concrete, so that the medium without damaging the concrete structure can be obtained. Degradation depth, penetration depth of incoming salt, strength, reinforcing steel corrosion, radioactive contamination, etc. can be measured to determine and evaluate the degree of deterioration. Also, after the concrete in the test specimen form reaches the required compressive strength, by dismantling the test specimen form, the same initial quality as that of the concrete structure can be ensured, and the deterioration due to subsequent aging changes The degree can be measured accurately.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a method for measuring the degree of deterioration of concrete in a concrete structure according to the present invention will be described below with reference to the drawings. The concrete structure according to the present embodiment is a pillar portion of a reinforced concrete building, and a method for measuring the degree of deterioration of concrete for the pillar portion will be described.
[0008]
First, as shown in FIG. 1, a test specimen form 4 is installed from the outside in the cutout hole 3 of the weir plate 2 in the column form 1.
[0009]
As shown in FIGS. 2 and 3, the test sample forming frame 4 has a box 8 having a U-shaped cross section provided with insertion plates 6 and 7 on the upper and lower sides of the opening 5, and a screw on the side surface of the box 8. A stop plate 10 is provided on the side plate 9, and a slit plate 12 having a screw hole 11 is attached to the upper insert plate 6. The plate 10 is provided with a stopper 13 for preventing the test sample form 4 from entering the inside of the column form 1. Therefore, the test specimen form 4 is easily attached to the column form 1 by inserting the insertion plates 6 and 7 into the notch holes 3 from the outside of the column form 1 and pressing the stopper 13 against the dam plate 2. .
[0010]
Then, concrete 15 is poured into the column form 1 on which the test piece form 4 is installed, and only the column form 1 is disassembled after the concrete 15 is hardened (see FIG. 4). Next, after the concrete 15 is cast, after the concrete of the specimen has obtained the required compressive strength, for example, after 3 days, 7 days or 28 days of the material age, the specimen form 4 is dismantled. The specimen 17 is integrally formed with the column 16 with a weather-resistant slit plate (hereinafter simply referred to as a slit plate) 12 embedded in the upper portion (see FIG. 5). Thereafter, since the concrete structure pillar 16 and the specimen 17 are placed under the same environmental conditions such as weather conditions and location conditions, the concrete changes over time become the same.
[0011]
Next, as shown in FIG. 6, after the concrete 15 is cast into the two molds 1 and 4, the specimens 17 are sequentially divided every predetermined period, for example, 5, 10 and 15 years later. As shown in FIG. 7, as shown in FIG. 7, by pushing up the slit plate 12 with a bolt 19 forcibly screwed into the screw hole 11 and applying a tensile force to the specimen 17, the column 16 and the specimen 17 are separated from each other. Cracks are made between them. Since the specimen 17 is cut in a regular shape (rectangular parallelepiped) by the slit plate 12, the neutralization depth is measured using this, and the neutralization depth of the long-term concrete is determined based on this. Predict.
[0012]
This neutralization depth can be predicted by the neutralization rate equation of C = A√t. That is, since the measurement period (t1) and the neutralization depth (C1) at that time are known from the specimen 17 divided from the pillar, the coefficient (A1) is obtained. Therefore, the neutralization depth C1 in the future elapsed (estimated) years t1 can be estimated by the equation of A1√t1 = C1 since the coefficient A1 is determined. Further, when the life of the structure due to the neutralization is defined as the time when the neutralization depth of the concrete becomes C2, the year (t2) can be predicted by the equation t2 = (C2 / A1) 2.
[0013]
Next, by performing a compressive strength test using the specimen 17, it is possible to estimate a change with time in the compressive strength. In this manner, the degree of deterioration of concrete can be measured from the prediction of the neutralization depth of concrete and the estimation of the temporal change in compressive strength. Therefore, the degree of deterioration of concrete can be determined simply and quickly without damaging the reinforced concrete building.
[0014]
In the present embodiment, a reinforced concrete building is used. However, the present invention is not limited to this. In addition to a steel-frame reinforced concrete building, a plain concrete building, and a civil engineering concrete structure such as a bridge, a pier, and a viaduct. To measure deterioration over time by integrally forming specimens on elevated roads, tunnels, dams, retaining walls, nuclear facilities, etc., and measuring the depth of salt penetration and the depth of radioactive contamination. Can also.
[0015]
【The invention's effect】
After a lapse of a predetermined period from the placement of the concrete into the formwork, the specimen integrally formed with the concrete structure can be easily divided, so that the concrete structure has a neutralization depth without damaging the concrete structure, It can measure the degree of deterioration due to the penetration depth, strength, corrosion of reinforcing steel, and radioactive contamination depth of incoming salt.
[0016]
After the concrete in the form for the specimen has reached the required compressive strength, the same initial quality as the concrete structure can be secured by dismantling the form for the specimen and the degree of deterioration due to the subsequent aging. Can be measured accurately.
[0017]
Specimens can be easily separated from the concrete surface of the concrete structure.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view in which concrete is cast in a column formwork, and FIG. 1B is a sectional view of a test form in which concrete is cast.
FIG. 2A is a perspective view of a mold for a specimen, and FIG. 2B is a cross-sectional view of FIG.
FIG. 3 is an exploded perspective view of a mold for a specimen.
FIG. 4 is a cross-sectional view of a column in which a column form is disassembled, and FIG. 4B is a cross-sectional view of a sample cured by a sample form.
FIG. 5A is a sectional view of a column integrally formed with a test piece, and FIG. 5B is a front view of the same.
FIG. 6A is a cross-sectional view of a column from which a specimen is divided, and FIG. 6B is a rear view of the column divided from the column.
FIG. 7A is a sectional view of a pillar obtained by dividing a specimen from a pillar, and FIG. 7B is a front view of the specimen.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Column formwork 2 Weir plate 3 Notch hole 4 Specimen form 5 Opening 6, 7 Insertion plate 8 Box 9 Side plate 10 This plate 11 Screw hole 12 Slit plate 13 Clamp 15 Concrete 16 Column 17 Specimen 19 Bolt

Claims (2)

Forming a plurality of test specimen molds projecting outward at predetermined locations on the concrete structure mold, casting concrete into both the molds, and integrally forming the concrete structure and the test specimen. After the concrete is hardened, only the concrete structure form is dismantled, and after a lapse of a predetermined period from the dismantling of the concrete structure form, the specimen form is dismantled. A method for measuring the degree of deterioration of concrete in a concrete structure, comprising sequentially dividing test specimens and performing various measurements. The method for measuring the degree of deterioration of concrete in a concrete structure according to claim 1, wherein after the concrete in the form for the specimen has a required compressive strength, the form for the specimen is disassembled.

Images