JPH07305511A - Degree of compaction measuring method and compaction control method for fresh concrete or fresh mortar - Google Patents

Abstract

PURPOSE:To judge the degree of compaction in real time and objectively while conducting compacting work of fresh concrete and the like, and provide fresh concrete and the like compacted to a prescribed degree of compaction. CONSTITUTION:The degree of compaction measuring method is a method measuring degree of compaction of fresh concrete and the like, and elastic wave generated by concrete and the like is measured while compacting fresh concrete and the like. The compaction control method is a method controlling compaction of fresh concrete and the like, elastic wave generated by concrete and the like is measured while compacting fresh concrete and the like, and in addition the fresh concrete is repeatedly compacted until the elastic wave measured value reaches a prescribed value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the degree of compaction of fresh concrete or fresh mortar, and a method for managing the degree of compaction.

[0002]

2. Description of the Related Art Fresh concrete or fresh mortar after pouring (hereinafter referred to as "fresh concrete, etc." in the present specification) causes junkers and bean boards when compaction is insufficient. It is being compacted. For example, a rod-shaped vibrator or a form-panel-mounted vibrator is generally used, and a vibrating roller is particularly used in the RCD method for dam construction. As described above, although compaction of fresh concrete etc. is performed by various methods, it is not possible to know in real time how much compaction is performed during compaction work, so the number of rolling pressure of the vibrating roller, the bar vibrator or the mold The vibration time of the vibrator attached to the frame panel or the like may be excessive or insufficient, which may result in inconsistent compaction degree and uneven quality of concrete.

As a method of knowing in real time how much the fresh concrete or the like has been compacted during compaction work, a method of hitting the outside of the form with a mallet and judging by the sound, fresh concrete or the like is used. There is a method of visually observing breathing water, and a method called RI method used for dam RCD method. This RI method embeds the radiation generating terminal in compacted fresh concrete, etc., installs a radiation measuring section on the surface of the fresh concrete, etc., and measures the radiation amount passing through the fresh concrete etc. to determine the degree of compaction. This is the method of judgment.

[0004]

However, in the method of hitting with a mallet and the method of visually observing the breathing water, the compaction degree is judged subjectively by the measurer, so that a certain degree of compaction cannot be obtained. However, there is a problem that the quality of concrete becomes uneven.

Further, the concrete used in the RCD method for dams has been kneaded firmly from the beginning such that the slump is 0 cm, and at the time of compaction, it is further compacted by rolling with a vibrating roller. Therefore, when the RI method is applied to the dam RCD method, a great amount of labor is required to embed the radioactivity generation terminal in the RCD concrete. Therefore, it is difficult to measure the compaction degree in real time while rolling the RCD concrete with the vibrating roller, and there is a problem that the quality of the concrete is likely to be non-uniform because the compaction degree is excessive or insufficient.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to objectively determine the degree of compaction in real time while compacting fresh concrete or the like. It is to provide a degree measuring method.

Another object of the present invention is to provide a method for managing compaction of fresh concrete or the like, which can obtain fresh concrete compacted to a predetermined compaction degree.

[0008]

The present invention has been made in view of the above objects, and its gist is a method for measuring the compaction degree of fresh concrete or fresh mortar, wherein the fresh concrete or fresh A method for measuring the degree of compaction of fresh concrete or fresh mortar, which comprises measuring the elastic wave generated by the concrete or mortar while compacting the mortar.

In the method for measuring the degree of compaction according to the present invention, the fresh concrete to be measured means that concrete constituent materials such as aggregate, cement, water and an admixture are not sufficiently bonded to each other and are not yet solidified. Any concrete can be used, including those that have just been mixed and kneaded in a mixer, to those that are close to hardened concrete in which the hydration reaction of cement has progressed and the concrete constituent materials are integrated. The fresh mortar, like fresh concrete, refers to a state in which the mortar constituent materials are not sufficiently bonded to each other and are not yet solidified.

In the method for measuring the degree of compaction according to the present invention, the elastic wave generated by the concrete or mortar means that when the concrete or mortar is compacted, the constituent materials such as aggregate, cement, water and admixture are mutually present. It refers to sound waves in the ultrasonic region with a frequency of 20 kHz or more, which are generated when the concrete constituent materials are integrally hardened by the hydration reaction of cement, or when the concrete constituent materials harden. As a method of measuring this elastic wave, a sensor called “AE sensor”, which includes a piezoelectric element that converts mechanical vibration into an electric signal, can be used.
By analyzing with an analysis system equipped with a processor, various AE parameters such as AE COUNT, AE envelope detection (event, maximum amplitude, duration, rise time, and energy) can be obtained in real time. , The degree of compaction can be easily determined.

In the method for measuring the degree of compaction according to the present invention, first, the AE sensor is attached to the outer surface of the mold, or the AE sensor is placed on the surface of fresh concrete or the like. When the AE sensor is placed on the surface of fresh concrete, etc., it may be placed directly on the surface of concrete, or a member with good sound wave conductivity, such as a metal plate such as a steel plate, for example The AE sensor may be placed on the surface and placed on the metal plate. Further, in the dam RCD method, the vibration roller and the steel plate may be connected by a cord, and the AE sensor may be arranged on the steel plate.

After the AE sensor is arranged, the elastic wave is measured while compacting the concrete. As the fresh concrete and the like are compacted, the kneading air escapes and the solidity gradually increases. As the density increases, it becomes easier for high-frequency elastic waves to propagate in fresh concrete, and various AE parameters such as AE COUNT and AE envelope detection of the measured elastic waves, that is, AE characteristics also change. Therefore, by preliminarily obtaining the relationship between the predominant frequency of elastic waves, AE COUNT, AE characteristics such as AE envelope detection, and the degree of compaction of fresh concrete, etc. The degree of compaction can be determined in real time.

Another subject matter of the present invention is a compaction management technique for fresh concrete or fresh mortar, wherein the elastic wave generated by the concrete or mortar is measured while compacting the fresh concrete or fresh mortar, A method for controlling compaction of fresh concrete or fresh mortar is characterized in that the fresh concrete or fresh mortar is repeatedly compacted until the elastic wave measurement value reaches a predetermined value.

In the compaction management method of the present invention, the compaction degree of fresh concrete or fresh mortar is measured by the same means and the same procedure as the method for measuring the compaction degree. By repeatedly compacting fresh concrete or the like until a predetermined compaction degree is obtained, it is possible to construct a uniformly compacted high-quality concrete structure.

[0015]

In the method of measuring the degree of compaction of fresh concrete and the method of managing compaction of the present invention, when the fresh concrete or fresh mortar is compacted, its constituent materials, such as aggregate, cement, water and admixture, are mutually The concrete constituent materials are integrally hardened by the hydration reaction of cement, and the generated elastic waves are measured to determine the degree of compaction.

[0016]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the examples described below, the method of measuring the degree of compaction of fresh concrete and the method of controlling the degree of compaction of the present invention is applied to the measurement of the degree of compaction of fresh concrete used in the RCD method of dams. is there.

[0018]

Example 1 RCD having a unit water amount per unit volume of concrete (hereinafter referred to as “W”) of 89 Kg / m ³ .
A sample of concrete for use was prepared, and an elastic wave at that time was measured by an AE sensor (manufactured by Japan Physical Acoustics Co., Ltd.) while the sample was compacted by a VC tester. Here, the VC tester is developed for measuring the consistency of RCD concrete, and is provided with a cylinder for packing the RCD concrete and a vibrating table for vibrating the cylinder. Is. The VC value measured by this VC tester is determined by the time (in seconds) until the RCD concrete is compacted and solidified by placing the cylinder on the vibration table after filling the cylinder with the RCD concrete. Given. The completion of compaction is determined by the mortar breathing on the surface of the RCD concrete.

The measured results are shown in FIGS. 1 and 2. Figure 1
Shows the frequency frequency of 10 seconds after the compaction was started by vibrating the vibrating table of the VC tester, and FIG. 2 shows the frequency frequency of 10 seconds from 50 seconds to 60 seconds after the compaction was started. Is shown.

Start compaction 10 as shown in FIG.
Most of the elastic waves are measured in the range of 1 MHz or less for a second, but as shown in FIG.
In 10 seconds of up to 60 seconds, as compared with FIG. 1, many elastic waves of 1 MHz or more are also measured. From this, it can be seen that as the fresh concrete or the like is compacted, elastic waves having a high frequency are easily transmitted to the concrete surface. Therefore, at the actual construction work site, while performing the compaction work, the elastic wave is measured by the AE sensor, and further, by the analysis system equipped with the arithmetic processing device, as shown in FIG. 1 and FIG. If the frequency distribution is obtained, the compaction degree can be determined in real time.

[0021]

Example 2 Next, RC of W = 84, 89, 91 kg / m ³
A sample of concrete for D was prepared, and while the sample was compacted by a VC tester, the acoustic wave at that time was measured by an AE sensor, and the VC value was also visually measured.

FIGS. 3 (a) to 3 (d) show that acoustic waves from the start of compaction to 100 seconds after being compacted by the AE sensor while compacting a sample of RCD concrete with W = 84 kg / m ³ by a VC tester. FIG. 3 (a) shows measured values of the elastic waves measured at a predetermined threshold value or more, that is, AE COUNT every 2 seconds.
FIG. 3B shows the measurement result of FIG. 3A integrated over the measurement time. Further, FIG. 3 (c) shows AE ENERGY (AE energy) every 2 seconds, and FIG. 3 (d) is an integration of the measurement results of FIG. 3 (c) over the measurement time.
From the graph in Fig. 3, the compaction time when the AE COUNT rapidly increases is 91 seconds and the compaction time when the AE ENERGY rapidly increases is 92.
You can see that the seconds are. The VC value of this sample is 9
It was 0 seconds.

4 (a) to 4 (d) show R of W = 89 Kg / m ³ .
It is the measured value which experimented the sample of the concrete for CD like FIG.3 (a)-(d), of which FIG.4 (a) is AE C.
OUNT is shown every 2 seconds, and FIG. 4 (b) is shown in FIG.
The measurement result of (a) is integrated over the measurement time. Further, FIG. 4 (c) shows AE ENERGY every 2 seconds, and FIG. 4 (d) shows the measurement result of FIG. 4 (c) integrated over the measurement time. From the graph of this Figure 4, AE COUN
It can be seen that the compaction time for T and AE ENERGY increases rapidly is 62 seconds. The VC value of this sample was 60 seconds.

Further, in FIGS. 5A to 5D, W = 91 kg / m
While compressing the RCD concrete sample of ³ with a VC tester, elastic waves from the start of compaction to 62 seconds have been measured by an AE sensor, of which Fig. 5 (a) shows AE COUNT of 2 FIG. 5B shows the measurement result of FIG. 5A integrated by the measurement time. Further, FIG. 5 (c) shows AE ENERGY every 2 seconds, and FIG. 5 (d) shows FIG. 5 (c).
It is the result of integration of the measurement result of 1. This Figure 5
The graph shows that the AE COUNT rapidly increases and the compaction time is 43
It can be seen that the compaction time at which the AE ENERGY increases rapidly is 42 seconds. The VC value of this sample was 40 seconds.

FIG. 6 shows the compaction time and AE obtained from FIGS. 3 to 5 at which the AE COUNT of each sample rapidly increases.
This is a graph showing the relationship between the VC value and the compaction time when ENERGY rapidly increases.

From FIG. 6, it can be seen that, in the same sample, the compaction time in which AE COUNT rapidly increases and the compaction time in which AE ENERGY rapidly increases almost coincide with the VC value.
Therefore, even at the actual construction work site, the elastic wave is measured by the AE sensor while performing the compaction work, and further, by the analysis system including the arithmetic processing device, as shown in FIG.
As shown in FIG. 5, if the compaction time in which AE COUNT rapidly increases and the compaction time in which AE ENERGY rapidly increases, the compaction degree can be determined in real time.

[0027]

EFFECT OF THE INVENTION In the method for measuring the degree of compaction of fresh concrete or the like according to the present invention, the degree of compaction of fresh concrete or the like and the predominant frequency of elastic waves generated from fresh concrete during compaction work, AE COUNT, AE By measuring the relationship with the AE characteristics such as envelope detection, elastic waves such as fresh concrete are measured during compaction work, and the measured values are analyzed by an analysis system equipped with an arithmetic processing unit. If the AE characteristics are obtained by using the AE characteristics, the compaction degree of fresh concrete or the like can be determined in real time at the construction site.

In the compaction management method of the present invention, the compaction degree of fresh concrete or the like is measured by the same means and the same procedure as the method for measuring the compaction degree.
By repeatedly compacting fresh concrete or the like until a predetermined compaction degree is obtained, it is possible to construct a uniformly compacted high-quality concrete structure.

[Brief description of drawings]

FIG. 1 is a graph showing the frequency frequency of elastic waves measured in Example 1 for 10 seconds after the start of compaction.

FIG. 2 is 50 to 60 after the start of compaction measured in Example 1.
It is a graph which showed the frequency frequency of the elastic wave for 10 seconds of a second.

FIG. 3 (a) is W = 84 Kg / m measured in Example 2.
³ shows the AE COUNT of the RCD concrete sample every 3 seconds, (b) is the integration of the measurement results of (a) over the measurement time, and (c) is the AE ENERGY of 2
It is shown for each second, and (d) is obtained by integrating the measurement result of (c) with the measurement time.

FIG. 4 (a) is W = 89 Kg / m measured in Example 2.
³ shows the AE COUNT of the RCD concrete sample every 3 seconds, (b) is the integration of the measurement results of (a) over the measurement time, and (c) is the AE ENERGY of 2
It is shown for each second, and (d) is obtained by integrating the measurement result of (c) with the measurement time.

FIG. 5 (a) is W = 91 Kg / m measured in Example 2.
³ shows the AE COUNT of the RCD concrete sample every 3 seconds, (b) is the integration of the measurement results of (a) over the measurement time, and (c) is the AE ENERGY of 2
It is shown for each second, and (d) is obtained by integrating the measurement result of (c) with the measurement time.

FIG. 6 is a graph showing the relationship between the VC value and the compaction time in which the AE COUNT of each sample sharply increases and the compaction time of AE ENERGY sharply increases in Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoaki Tsutsumi 2-4-1 Nishitsutsujigaoka, Chofu City, Tokyo Inside the TEPCO Research Laboratory (72) Inventor Shigenori Yuyama 2-17-10 East Shibuya-ku, Tokyo Japan Physical Acoustics Co., Ltd.

Claims (2)

[Claims] 1. A method for measuring the degree of compaction of fresh concrete or fresh mortar, characterized in that the elastic wave generated by the concrete or mortar is measured while compacting the fresh concrete or fresh mortar. Method for measuring compaction degree of fresh concrete or fresh mortar. 2. A method for controlling the compaction of fresh concrete or fresh mortar, comprising measuring the elastic wave generated by the concrete or mortar while compacting the fresh concrete or fresh mortar, and further measuring the elastic wave. The method for controlling compaction of fresh concrete or fresh mortar, characterized in that the fresh concrete or fresh mortar is repeatedly compacted until the value reaches a predetermined value.